NBSIR 83-2693

nuuc /mi

AlllDb Ebl3TS

OSH) PUBLICATION NO. 83-103

opment of Draft Construction

Safety Standards for Excavations

An NBS/NIOSH Publication

Volume II

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Geotechnical Engineering Group

Structures Division

Washington, DC 20234

April 1983

Prepared under Interagency Agreement No. 82-06-M for: Department of Health and Human Services

Public Health Service

Centers for Disease Control

National Institute for Occupational Safety and Health

i of Safety Research, Morgantown, WV 26505

L. St3nevich, Project Officer

Divisior

r

uC

100

. Udo

oi-^b05

Hoi

I .
a
NPSIR 83-2693

DHHS (NIOSH) PUBLICATION NO. 83-103

DEVELOPMENT OF DRAFT CONSTRUCTION

SAFETY STANDARDS FOR EXCAVATIONS

An NBS/N10SH Publication

Volume II

Felix Y. Yokel

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Geotechnical Engineering Group

Structures Division

Washington, DC 20234

and

Ronald L. Stanevich

Division of Safety Research

National Institute for Occupational Safety and Health

Morgantown, WV 26505

NATIONAL BUREAP

OF STANDARDS

LIBRARY JUN 21 VJ83

pyoAr Cv-C. Co,'-

fC£-‘

r

~

(3. c 'OO

4 C-/ Cf*

/9/Z3

April 1 983

Prepared under Interagency Agreement No. 82-06-M for: Department of Health and Human Services

Public Health Service

Centers for Disease Control

National Institute for Occupational Safety and Health

Division of Safety Research, Morgantown, WV 26505

Ronald L. Stanevich, Project Officer

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
til

GT3

m

n

i

ira

“ A

-4 . “ w

~~ li
TABLE OF CONTENTS

Page

1. INTRODUCTION 1

2. WORKSHOP SUMMARIES AND PROCEEDINGS 2

3. RESPONSES BY F. Y. YOKEL TO MISCELLANEOUS WORKSHOP

CORRESPONDENCE 146

4. MILWAUKEE, WI, WORKSHOP - WRITTEN COMMENTS AND

CORRESPONDENCE 155

5. ATLANTA, GA, WORKSHOP - WRITTEN COMMENTS AND

CORRESPONDENCE 166

6. DALLAS, TX, WORKSHOP - WRITTEN COMMENTS AND CORRESPONDENCE .. 171

7. SAN FRANCISCO, CA, WORKSHOP - WRITTEN COMMENTS AND

CORRESPONDENCE 195

8. BOSTON, MA, WORKSHOP - WRITTEN COMMENTS AND CORRESPONDENCE .. 232

9. SOURCE DOCUMENT FROM WHICH TECHNICAL PROVISIONS IN SUBPART P WERE DERIVED 259

10. MISCELLANEOUS INPUT AND INFORMATION 268

1. INTRODUCTION

This volume contains background information and supplements Volume

I of the report. Section 2 contains workshop summaries prepared by the

NBS author and by workshop organizers; Section 3 contains responses by

the NBS author to correspondence associated with the industry workshops;

Sections 4 through 8 contain depositions made in the five workshops;

Section 9 contains source documents for the present version of Subpart

P; and Section 10 contains miscellaneous input and information contributed by workshop participants and others.

1
2. WORKSHOP SUMMARIES AND PROCEEDINGS

*

*

w

-

i

-

The following workshops were held:

Milwaukee, WI

Atlanta, GA

Dallas, TX

San Francisco, CA

Boston, MA

June 9, 1981

June 16, 1981

June 30, 1981

July 9, 1981

July 14, 1981

«

*

This section contains a memorandum by the NBS author on each

of the workshops which summarizes the comments. Depositions

made in the workshops are attached to these memoranda. Additionally, there are reports by the local sponsors on the

Milwaukee, WI , and Dallas, TX, workshops.

The workshop reports contain information on the workshops as well as analyses of some of the conments and depositions.

2
Bldg. 226, Room B162

(301) 921-2648

UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

June 23,. 1981

Mr . Edward Hayden

Mr . Arthur Schmuhl

Mr, James Lapping

Mr. John Ramage

Mr. Paul Bouley

Mr . Ronald Stanevich

Prof. Jack Mickle

Mr . John Pannullo

Gentlemen:

Attached is a copy of my draft memorandum on the Milwaukee Workshop.

Please send me your comments before July 3. I shall revise the memo

after I receive your comments. In particular, I want to make sure

that I have no inaccuracies and that I didn't fail to address

important issues which were raised.

Sincerely

,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

Attachment

cc: Mr. John Chambless

Mr . William Driskill

Mr . Paul Henson

Mr. Clifford Simmons

Mr. Bill Zoino

3
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20234

Bldg. 226, Room B-162

Phone (301) 921-2648

June 23, 1981

DRAFT

MEMORANDUM FOR Records of the NIOSH Excavation Project

From: Felix Y. Yokel

Subject: Workshop in Milwaukee, Wisconsin, June 9, 1981

This memorandum is to record my overall impression and my reaction to important

questions that were raised in the Workshop. A Workshop Report, containing

recommendations is being prepared by the Organizing Committee, using taped

records and written depositions.

(1) General : There were both negative and positive comments. However, it

is in the nature of this type of a Workshop that individuals who have negative

comments and recommendations for change will go on record, while those who

generally agree with the recommendations will see no need to make a statement.

There were some statements particularly from contractors from Illiirois , that a change in the present standard is not desirable. To the extent that these

statements are not accompanied by specifics it is difficult to determine

whether the status quo is considered desirable because Subpart P as written

is satisfactory or because of the fact that the present version of Subpart P

is unenforcable.

(2) Soil Classification : There were substantial comments to the effect that

a 1/2 to 1 slope should be permitted in Type A soil. In a technical sense I see no problem in changing the allowable slopes for Type A soils to 1/2 to

1 for 12 ft. or less and 3/4 to 1 for 12 to 20 ft. We originally did not

recommend 1/2 to 1 slope because there was no substantial evidence that it is

being used and there was some concern that it could become a vertical slope

when the work is sloppy.

(3) local Provisions Which Have a Proven Performance Record : In our summary

recommendation (BSS 127) the following statements were made in Appendix A:

page 59, A. 3, 1st paragraph:

'’Traditional timber shoring practice varies widely from location to

location and frequently depends on such variables as sizes and

characteristics of available timber, soil conditions, and local

work practices. In some locations these practices have been used

for many years and appear to be satisfactory to all the parties

concerned. Three such locations are the State of Wisconsin,

New York City, and the State of California (where mainly softwood

is used)

4
- 2 -

Page 65, 2nd paragraph:

"Since, in spite of the results of this analysis, NBS could find no

evidence that traditional timber practice, if properly executed, is

unsafe, consideration could perhaps be given to temporarily exempting

conventional timber shoring from the lateral load requirements until

lateral load effects can be further studied by actual measurements

in the field. If such an approach is adopted, it may be more

reasonable to endorse proven local shoring practices on a regional

basis, only where such shoring is widely used. It is not recommended

to use a single scheme such as Tables A. 2, and A. 3 nationwide, since

local practice evolved on the basis of local workmanship, material

supplies and soil conditions. "

It can be seen from our summary report that the question which arose in the

Milwaukee Workshop was anticipated. It may arise again in the San Francisco

and the Boston Workshops. The question is this:

If we have a local shoring practice which is satisfactory to all the

parties concerned, should it be changed to comply with the new

provisions?

If is is not changed, by which mechanism can it -be approved without

jeopardizing the consistency of the new provisions?

This is a question which must be taken up by the Advisory Committee in order

to come up with a definite recommendation to OSHA. I would like to state

some of my preliminary thoughts:

(a) If we have a traditional practice which has a good track record

and we force contractors to change it, we may well cause an increase in the accident risk and thus defeat our overall purpose.

On the other hand, one of our goals was to get away from prescriptive provisions and provide more options. Thus it would also be

wrong to enforce this traditional approach to the exclusion of

other approaches.

(b) The evidence on which we can base the permission to use a traditional practice which does not comply with our recommended

provisions is its track record, rather than compliance with

engineering principles. Thus, if it is allowed, no changes in

it should be permitted . Such changes would include substitution

of any of its members by other members of "equivalent" strength.

Thus I think that one way to deal with this problem could be some kind of

"grandfather clause," by which widely used traditional practices could be

allowed on a regional basis. However, care should be exercised to permit only

those parts of these practices which are actually widely used, and discard other

parts which do not have a proven track record.

5
- 3 -

Since we are dealing with a specific case of the Wisconsin Administrative Code , I analyzed their timber tables (see Appendix) . My compliance measure is the

"Safety Index" S/Sa, where S = calculated stress and Sa *= allowable stress.

My "Allowable Stress" is the stress for ’’Mixed Hardwood I", Table 5, page 29,

multiplied by 1.33 for short term: fb = 964 psi, fc = 499 psi.

The safety index for struts was calculated for 2 situations: with the 240 lb.

gravity load at the center of the strut as required, and without the gravity

load to assess general adequacy in resisting lateral loads.

Hereafter is a summary of the assessment:

Table 1: Struts in rows 1-5 are generally adequate to resist the

lateral loads, but are overstressed when the 240 lb.

gravity load is applied. In row 6 the situation is similar

for Type B soil (no water) but very marginal for Type C

soil. The wales in row 6 are heavily overstressed..

Table 2: Situation is similar to Table 1 including that in row 5,

which corresponds to row 6 in Table 1.

Table 3: The table is more stringent than the proposed spacing

provisions.

Table 4: This table is for Type B soils. Struts tend to be

overstressed and wales severely overstressed.

Table 5: This table is for wide trenches in Type A soils. It was analyzed for 6 ft. widths and 12 ft. widths. It

can be seen that, with the 240 lb. load the struts are

adequate to 6 ft. width, but overstressed for the

12 ft. width.

There was some evidence from the answers to my questions in the Workshop

that only Table 1, rows 1-5 and Table 3 are widely used. If this is the case,

some of the more marginal cases should probably be eliminated, while the rest

of the practice could be endorsed on the basis that it is successfully used.

It should be noted that the greatest deficiency occurs in wales where the

spacing is 11-1/2 ft.

(4) Exposure : Section 1926.650 (a), which was formulated in the Washington

AGC Workshop, sets a scope for the provisions. After the Wisconsin Workshop

it appears that this section needs to be made more explicit to state that

the provisions don’t apply where workers are not exposed to the effects of

mass movement of soil or rock . This may have to be further amplified to

state how far away from an unshored or inadequately shored face workers would

have to be when they are not exposed.

I •*

f

LS }

'

' A?

Resolution of this question would solve two problems:

(a) In wide excavations the provisions would not necessarily

apply. Thus the demand to distinguish between trenches

and excavation would be satisfied in this way.

(b) When long pipe sections are laid, cross braces interfere

even when they are widely spaced. Thus it is sometimes

necessary to confine adequate shoring to the areas where

workers are exposed. 6
- 4 -

(5) Scope of Standard Practice : In the Workshop document it was originally

proposed to limit the standard practice to a 20 ft. depth. The AGC Washington

Workshop recommends 24 ft., and this seems to be supported By most contractors.

AFL-CIO proposed 15 ft . ASFE originally proposed 20 ft . This issue should

receive serious discussions in the other Workshops and the parties should

attempt to reach a resolution.

(6) Engineer, Qualified Person, Competent Person : Almost all the parties

seemed to agree that there must be a competent person on the job site.

There is disagreement whether a "qualified person" must be a licensed engineer.

AFL-CIO maintains that this is necessary, while many contractors want a broader definition. There is agreement that the "registered architect" should

be dropped from the definition of "Accepted Engineering Requirements."

There was considerable confusion between the terms "competent person" and

"qualified person," however, it was probably caused by inadequate 'study of

the Workshop document

(7) Dust Control : It was noted that Section 1926.651 (i) conflicts with

present EPA requirements. The section is also advisory rather than mandatory

and may noti belong in the regulation (it could be in the guidelines) .

(8) Stoplogs ; It was noted that the provisions of Section 1926.651 (g) are

not practical for excavation work.

(9) General Recommendations : One of the speakers noted that the environment

changed, and the contractor is now in a position of responsibility rather than

in an adversary position when it comes to work safety. This Workshop convinced

me that, while we have a good basic approach, we will need to resolve many

issues, some of which result from regional differences. The Workshops will

bring these issues to the surface, but there will not be enough time to

resolve any of these issues. This will have to be accomplished after the

Workshops.

I therefore strongly recommend that the parties participating in the Workshop

form a committee which can work with NIOSH-OSHA-NBS when the recommendations

are formulated. I also strongly urge 0SHA-NI0SH to fund an additional effort

in this area, so that a strong justification (technical, statistical and other)

can be developed for all the final recommendations.
NOTES ON ANALYSIS OF TABLES

H = depth of excavation

h = horizontal center to center spacing of struts

v « vertical center to center spacing of struts

B = width of trench

Table 1: Row 2 could be A or B soils

Row 6 could be B or C soils

Table 2: Row 2 could be A or B soils

Row 5 could be B or C soils

Table 4: Analysis was carried to 24 ft. depth, : for greater depths

safety index will decrease .

Table 5: Analysis was made for 6 and 12 ft. widths.
a) rH

<8 3U

3T3 O

«c 0 UrH

•H rH <0 pH P 3 • m CM fH in c J2 • • e • UrH rH CN rH iH C Co

u<r

CrtfN

T3

X 33 u 0

*HpH 3 d rH U-1 SO

r iO c unO • • • • =tu U 1 uO

tTKT

O 0 0 O c

r<J

rH

rHO

C < 03 03

CO

in

mm

CQ CO co CO

CO ro CO >

CO ro co - SO «3* CO

3S

d

O 0

rH rH rH ••®c3

GO

OO 9 O O § Z z z u

-30 0 ^0 5 £d

-3O * c —

“8 23 %iZ * c —

*=22 3 ild II d «• 5*^ 2^ 1 .Ida gd a • S *

<j

u -3 .££ a

CJ . © -73

— 03 *• . 9 ® -2 is M 4 3

CM >*“*

co .S ..? W >«o 1 3jcm 3^C • © c—

«o

J2 CM- >*“ a 3 1 3°.

CM

T *i • O O 1 ‘3

cm• «C

J

T jT jT

J2.J jiic ti li a -c « -S'* O u£5 J-s

c© « <0 s co

a

CM 2* <5 2* CM • 3

=3

m

«•- 2 1 1 O -c 73

73a 2 1 1 2 t

•g « t X x X s

.2 e d > — 0 1 3 a 0

S"2 S 3 a — J 0 a a |33 %

•3«3 = 3 3 S a= Jw 2 0 ,

•12 « M

U 93<i 0 *0 2 "« d > a © 5 I 2 i’S2 W. O

a. £ xl *a 3 * 5 'I s a S d= 2

-3 = 2

j-aS a © c- :T| ; 5 

: w e — *o S w

t©*©

O 3

'-

CM > <73

ad

if8 3 Z * « 3i31 

fi3 3 5 3

co »—

O O

a j

1-3

•g

J 3 C-5XJ • u v aa u «s»'U — a 3 5

^*3 © 3 c-* — 30

lid

-a^3

.ill

c“S

50 -2 5? =3 5- I 3?. r ?d o *- 3 = 2 | ill

jz jg c- t» J| 12

'-Q 3 O. 2. H JS #

co

® “O “O 3 a n

sae >. 3 ci - 3 «

-si?

«-a

SI

•sf = " r8

-a3

13

w 2 3

*8O> c. •3 o ns 3

fWiiur, S«pt*mbar. 1778, No. 270

2xcav«cioa *od TunoH Con*traction

G7
DO)i:>rvn*uo3 jMioni po» oontARij

SiZ ‘6*Z1 *w<?cnrv3*g '*rmWfc

C Z. S < © © £ © i«® © © n. 5 * © cc £ *

£. 05 © —

as

r:8.5-

*- A. fi.

© o cr» ._ © JZ * c -C CO) r

g-s 11 f £ s ^

B"S"T §

t- * ©5

©

CO *- .^

©

~,co cTs

ij.e

•D^ f* to D K » O

to=r

P>T3_ ^ eTOJ © =

c-rr> 5' © c o

•e " y

ir*

_*c ©_ Wytt

»,S

r

r p** * c * Sg.

C7i

p

C *5 •-

© *© b" 51. 3 2.® °> © « © r- "°-S ST csis© $ 5 S

to sr p*c

ST 9 3

P?

r cojd

u ?§i i <T®>

©* = K3

r>sr -O. c © — *3 T * » o

f—1 U3

CD CN 0 3' 1 i

B-S3

e.

i-i MS’ © ~ 1 f

C» Co£ to p-^eT ' © < to

£- * *

*• <T©> r © ©

D-*' ST

ft e_ •og"

gr*C T3 lr r

r *-

®

©

© < *c

is* s H

egg©c

&.8

S-c.8

Tr1 ST ar?E_ *«

•* ft Oi 0.3 ©&?!

g’S.s-

,.,

© pH£5

_ c « ?5* a. £« 5

*rl

© O.®

Sm/5 Orr I * > -»C 3*rr 3 rr

ij sr

a*

IXT I C d sr

£> o

UC " H © e 2 r i k » V

£• J. ° 

» 2

I; 2 £ s _ cs

P> PS % 2 1 2

S'

o.o £K 2 ® » C 5 S

ft.

R HB CC [

t:

i:

r.c

r.ro » u o
, -O V- e

Is

-a

03 CJ - H I * CJ

as i e.J

•hcj

0} C

o

CJ

00 •HCJ 3 l CJ

g 5

S I

i 1

3 *

or g a a S a a 2

z * 5 «

1

3 s t

U “

1

‘

M 9

•*2 1 3 I

--

IT0 g |4 ”--2

« « « M CO 'X O •

XXX*" « » k k CS <M C* C«ly— §

*« 5

2 S

a.

1-11

i-J - > > i

<j 3

2 « h£ 3

Aafwtar, 3^wmlw. 19TB, No. 773 Excawtioe *od T\innH Cooacrvjctiaa
H*f

Ul«r.

B*pUinU(,

1078,

No.

273

Tr«och,

Ku«v*(i<«

*od

TuumI

Coo* I t *

IfS L

E- ? O

CD

O

C

-c

rrtj

si; r-»H- D rrj

15 O'

sji

*r *? * r e ? K ? ? E» r? 1? 1 r r t 5 ?» =£ -) A = P ?E s ? rf pS

If

rf

[f

rf ? sp u *r if If f &F f 1

fF|

5F|

fF|

rr1

fFf i * r f Lr lr Lr i i 1 r r r i | 1 l

<< £•c i 1 ic £*< s f? i “ * ® ! I I r 1 i f 1 ? Jr ifu 7 if

u> 7 ir*. 7 £« if =C ?i« B ^ B f

§' = 1 f E b ?r r * a ir If ir If

r s

hO ro NJ N>

.£> o o O MM M

H»

H*

Ln

U3

Ln

LJ

Ln

4>*

Ln

.c*

Ln

.C"

M

MM

M N> N5 N3 N3 ro

ts CO DO CO CO 6

‘0

0.79 0.63

O

Ln

NJ |

(-* o O

O

O CO O' i

CD Ln Ln 1 o o O O 1 •*3 H* M o i° ON O' sO

rf

ifn

N5

-X/3

3>rr I fl -C

5*rt D rfcr 5 =r u oif

u > « 05 T r- c L.

•» *. 3 I F§ 32

l«

K * B 3

*^0

O’• 2

2-1 £

erp. £, e C Z * o K S | « §

si

L
^ore.

\***w c*

UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

(301) 921-2648

June 23, 1981

Mr. John Chambless

Mr. Arthur Schmuhi

Mr. James Lapping

Mr. John Ramage

Mr. Paul Bouley

Mr. Ronald Stanevich

Prof. Jack Mickle

Mr. John Pannullo

Gentlemen

Attached is a copy of my draft memorandum on the Atlanta Workshop.

Please send me your comments before July 10. I shall revise the memo

after I receive your comments. In particular, I want to make sure

that I have no inaccuracies and that I didn't fail to address

important issues which were raised.

Sincerely,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

Attachment

ccMr . Edward Hayden

Mr. William Driskill

Mr. Paul Henson

Mr. Clifford Simmons

Mr. Bill Zoino

13
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

Phone: (301) 921-2648

DRAFT

June 23, 1981

MEMORANDUM FOR Records of the NIOSH Excavation Project

From: Felix Y. Yokel

Subject: Workshop in Atlanta, Georgia, June 16, 1981

This memorandum is in addition to proceedings which are being prepared by

the Construction Trade Department of the AFL-CIO and is intended to cover

important issues raised by the Workshop as perceived by me.

(1) General : My general impression from this Workshop was that even though many important points in our input document were disputed and

criticized, the document was by and large well received. We did not

encounter the problem which exists in Wisconsin, where existing shoring

regulations and practices, which are locally considered satisfactory do

not meet all the provisions in the proposed standard. We also did not

encounter comments such as those voiced by Indiana contractors who question

the need for any change in the existing regulations. However, several very

important issues were raised and are subsequently discussed.

(2) Soil Classification : The overall approach in Table 1 was well received,

but several important issues were raised:

As in the previous Workshop, the need to permit 1/2 in 1 slope for

Type A soil was perceived. Beyond that, the AGC of Kentucky proposed

that a 5 ft . cut at the bottom of a 1/2 in 1 slope be permitted for

Type A soil and a 3 ft . cut at the bottom of a 3/4 in 1 slope be

permitted for Type B soil. The Kentucky AGC, as well as the ASFE

representative also raised a question about the lack of specifics

in defining "vibrations” in the footnote 1 to Table 1. In addition,

it was suggested that instead of changing abruptly from one slope

to another at the 12 ft. depth, the slope be gradually decreased

as the depth increases from 12 to 20 ft.

I have the following comments on these suggestions:

I would go along with a 1/2 in 1 slope for Type A soil. I also do

not object to a gradual transition in allowable slopes as you go

from 12 ft. to 20 ft. depth, though I think it may cause enforcement

problems (originally we proposed a gradual transition, but we dropped

W j

14
- 2 -

it subsequently because we thought it may be too complicated to

implement). I consider the 5 ft. cut at the bottom of a 1/2 in 1

slope for Type A soil as too risky. I think that the comment on vibrations is valid, and I think we may have to drop our reference

to vibration unless we can come up with specifics (heavy traffic

and pile driving within a specific distance). However, such

specifics without research data may be difficult to justify.

(3) Need for Simplicity : The need for simplicity and elimination of all

duplication was stressed. I believe that there is a need to take a look

at the entire write-up of the revised Subpart P, to eliminate all duplication and to use simpler, more precise language wherever possible. This

is endorsed by all the parties participating in the Workshop.

(4) Layered Soils : Footnote to Table 1 was strongly endorsed. This is

important, since I had some second thoughts about this conservative

provision.

(5) Fractured Rock : The definition of fractured rock was criticized as lacking precision, however, we were unable to provide a better definition.

(6) Definition of Short Term Excavations : Different opinions were

expressed, however, there seemed to be a consensus that 7 days is too long

and considerable sentiment to increase the time to more than 1 day. The

ASFE representative warned against extending the time period too much.

(7) Role of Professional Engineer : The troubling observation was made

that it may be often impossible to find a consulting engineer who wants

to assume responsibility for the safety of trenches even if they are deeper

than 20 ft. This may make the requirement for a professional engineer

academic.

(8) Bank Next to Work Area ; There seemed to be consensus that the bank

next to the work area should be increased to 4 ft.

(9) Excavation Below Bottom of Trench ? There seems to be consensus that

allowable excavation below the bottom of sheeting should be increased to

3 ft.

(10) Competent Person : There seems to be consensus that a compet ent

person should be at the job site.

(11) Section 652 (b) (4) (ii) : It was suggested to move this Section to the

end of Section 652(b). since it does not concern field personnel.

(13) General Comment : Some general comments were made which touch on problems which transcend the scope of Subpart P. There are three reasons

which make it difficult for professional engineers to get involved in job

site safety problems:

15
- 3 -

° Inadequate workmen’s compensation coverage and resulting third

party suits.

° Lawyers which take on cases for a 50% contingency fee, eliminating

all financial risks for those who Initiate legal actions.

° Adversary relationships between the parties involved in the

excavation process.

My suggestion that there should be a consensus industry standard in addition

to Government regulation was strongly endorsed.

*1 -A

J _

-A

16
/ \

'Ntmo*'

UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20234

Bldg. 226, Room B162

(301) 921-2648

July 7, 1981

Mr. William Driskill

Mr . Arthur Schmuhi

Mr. James Lapping

Mr. John Ramage

Mr . Paul Bouley

Mr. Ronald Stanevich

Prof. Jack Mickle

Mr. John Pannullo

Gentlemen

Attached is a copy of my draft memorandum on the Dallas Workshop. Please

send me your comments before August 7. I shall revise the memo after I receive your comments. In particular, I want to make sure there are no inaccuracies and that I didn't fail to address important issues.

Sincerely

—f—

Felix Y. Yok^l, Leader

Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

Attachment

cc

Mr. Edward Hayden

Mr. John Chambless

Mr. Paul Henson

Mr. Clifford Simmons

Mr. Bill Zoino

Mr. George Bradberry

Mr. John Cook

17
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

(301) 921-2648

DRAFT

July 7, 1981

MEMORANDUM FOR Records of the NIOSH Excavation Project

From: Felix Y. Yokel

Subject: Workshop in Dallas, Texas, June 31, 1981

This memorandum is in addition to proceedings which are being prepared by

the Dallas AGO and is intended to cover important issues raised in the

Workshop as perceived by me.

(1) General : Art Schmuhl in his introduction raised the issue of

development of industry recommendation in a Washington, D.C. Workshop after

completion of the Regional Workshops. I am very much in favor of such an

effort and I think it needs to be undertaken promptly. However, I think

that Art's appraisal that this can be accomplished in one Workshop, which

is based on the AGC 2-day Workshop we had, is overly optimistic. This time

there will be several groups with different views on some issues, and we

will have to deal with many important problems that were raised in the

Workshops. I think that perhaps, in preparation for such a Workshop, a very small task committee should prepare a revised draft, revise it once more after corresponding with all the industry committee members, and

then have a Workshop on the latest draft. This way you can get all the

non-cont rover sial issues out of the way before the Workshop, and in the

Workshop concentrate on solving the more controversial issues (depth for

standard practice, qualified person, sloping provisions, recognition of

regional practices, etc.).

My general impression from the Dallas Workshop was that, overall, the

concepts in the draft were well received, but several important issues were

raised which will require some substantial revisions in the draft. As in

the Wisconsin Workshop, a contractor from Illinois expressed the view that

the present OSHA provisions should not be changed. While this view is not

shared by the vast majority of contractors who responded to NUCA and AGC

questionnaires and who were interviewed in the NBS field study, it is based

on several legitimate concerns which in my view will have to be carefully

addressed. The trench box manufacturers also submitted a statement and

expressed disagreement with some of the recommendations, based on technical

considerations. The objections will have to be carefully studied. There

was some concern about my statement that the scope of the NBS work was confined to the soil classification and to shoring and sloping provisions.

18
- 2 -

While this is true, I feel that the participants in these Worshops have

the knowledge and experience to address all the issues involved and will

do so successfully.

(2) Opposition to Change in Existing Provisions : Opposition to a change

in the present version of Subpart P was expressed by an Illinois contractor

who works primarily on highway projects. This time I gained some insight

into the rationale for this position. I noted in my Wisconsin memo that

people who tend to agree with our recommendation are less likely to express

their opinion in the Workshop than those who oppose certain recommendations.

The same thing happened to some extent when we conducted our field study.

Almost all the contractors that responded were dissatisfied with Subpart P.

However, the responding contractors who now have concern about changes in

the existing regulations are more involved in earthwork, wide excavations,

borrow pits, etc., where conflicts with OSHA do not normally arise. They

are concerned with two issues.

a. The present provisions have been interpreted in the courts in

past litigations. These interpretations by court rulings tell

the contractor precisely what he can do. When we now propose

to change the wording of many provisions, there will again be

uncertainty about their interpretation by the courts, and we

will lose the benefit of experience gained in past conflicts.

b. We merged "trenches” and "excavations". There is now concern

that as a result new restrictions will be imposed on excavation

work. Part of this problem can probably be resolved by a clear

definition of "exposure." However we need to carefully review

our new recommendations to make sure that they do not

inadvertently result in unnecessary restrictions on excavation

work. An example of this, which was noted in the Workshop,

would be the application of Section 1926.651(d) to borrow pits.

(3) Use of OSHA Regulations on Federal Projects : It was noted that other

Federal Agencies are not bound by OSHA regulations and use their own procedures. This situation can lead to specifications which are difficult to

implement while using methods which comply with our recommendations. I am

not sure what can be done about that, but the situation could be brought

to the attention of the Administration at an appropriately high level by

the participating organizations of the Workshops.

(4) Trench Boxes : Trench box manufacturers suggested that the lateral-load

requirements for trench boxes should be different from those for shoring.

This is based on the contention that a trench box can deflect considerably

and in general will not restrain lateral soil movement as much as a shoring

system, thus causing the pressure distribution to resemble that acting on a retaining wall. This would make the square pressure diagrams associated

with the Standard Practice too conservative. At this time I cannot evaluate

the technical merits of this claim in detail, but I have several preliminary

thoughts

\9
- 3 -

a. In addition to the allowable stress increase for short-term

excavation, we also allow a 20 percent load reduction for wales

and a 33 percent reduction for sheeting. These reductions,

which account for arching effects would apply to the horizontal

framing members and the skin of a trench box. I wonder if the

industry considers taking advantage of these reductions in their

analysis

b. The trench boxes I saw had about equal stiffness (in terms of

lateral displacement characteristics) near the top and bottom.

Thus, I cannot see how a trench box could act like a retaining

wall, namely rotate inward while the base is fixed.

c. It is obvious that a trench box permits greater lateral inward

displacements of the excavation wall than a shoring system. In

granular soils this will result in a reduction in lateral soil

pressures. In clays, however, the situation is more complex.

Overconsolidated clays such as those is Austin, Texas where we

conducted pressure measurements (NBS GCR 80-202) will develop

tension cracks upon lateral expansion, resulting in increased

lateral soil pressures. It should be noted that Type B soils

include clays.

d. The greatest problem that would arise if stiffness characteristics

of shoring systems are considered is complexity (which our recommendations are designed to avoid). Each case would have to

be considered on its own merit. Considering the inadequacies and

complexities of present models for soil/structure systems and our general lack of data on lateral pressures in shallow braced

excavations, it may be difficult to make a convincing case, and

detailed analysis would not be much better than an educated guess.

e. While the proposed square pressure diagrams may be on the

conservative sides, the 40 lb/ft. ^ equivalent weight effect is

not conservative for medium clays which fall under Type B soils

and are the most common soil type.

It may be helpful if ASFE could review this problem. I am very much afraid

that we may be creating an albatross as soon as we deviate from the principle

of simplicity in the standard practice.

(5) Configuration of Excavations with Compound Slope : Two problems were

discussed in conjunction with Figure 2, page 12:

a. It was suggested to remove the sharp comers in the drawn crosssections, since these cannot be dug in the field with ordinary

equipment. I suggest that we draw broken lines for the idealized

cross-section and back these up with solid lines showing more

rounded corners.

b. The bank adjacent to the work area was discussed. In the previous

two Workshops there seemed to be a consensus that the height of

the bank should be increased to 4 ft. In this Workshop it was suggested to permit a 5 ft . bank for large pipes.. In the latter

case, worker protection would be derived from the large diameter

pipes. I have some problems with the suggestion:

20
- A -

1. If we permit a 5 ft . bank, at the bottom of a slope this

would be inconsistent with our requirement to limit the

height of an unsupported bank in level ground to 5 ft.

This inconsistency would inevitably lead to a court challenge

of the 5 ft . bank on level ground on the grounds that a higher

unsupported bank would provide equivalent stability.

2. I believe that this configuration would be much more

hazardous than a 5 ft . bank in level ground, since a much

greater quantity of soil would slide into the trench in

case of a stability failure.

It should be noted that Section 1926. 652 (c) in the present

provision states that "... the sides of the trench above

the 5 ft. level may be sloped to preclude collapse, but

shall not be steeper than 1 ft. rise in 1/2 ft. horizontal."

This conflicts with present Figure P-1 and is less conservative than anything we permit in our present proposal. In

the Atlanta Workshop, members of the Kentucky AGC suggested

that we permit this configuration for Type A soils.

(6) Exit Provisions : It has been suggested that "climbing upon struts"

should be recognized as a legitimate means of exit from a trench. My comment

on that is that our proposed loading provision for a 240 lb. concentrated

load at the center of the strut would provide adequate strength for an emergency exit of a worker whose weight is within the normal range. However,

stepping on struts should be prohibited for non-emergency cases, unless a higher design load is used. This exit option should not be permitted for

systems, such as the Wisconsin system, if these systems are permitted on the basis of prior use.

(7) Short-Term and Long-Term Excavations : Several participants suggested to

drop the distinction between short- and long-term. It was noted that manholes

frequently remain open for 2-3 weeks. I have some problems with this suggestion

a. It may force us to do away with Type A soil, the way California

did. This would impose economic penalties on some regions.

b. It may force us to drop the 33 percent over stress. This in turn

would cause us to require wooden struts which are heavier than

those commonly used (now we come out about right)

c. The proposed compound slopes (Figure 2) are questionable for

long-term use.

The problem may be that our definition of short-term, which is independent of

site conditions, may be too simplistic. It was for instance pointed out that

in New Mexico, Arizona, and some parts of California and Texas, where there

is no rain for long periods of time and no other erosive effects there is

really no difference between the short-term and long-term condition. I

think that this statement is only partially valid. It is for instance not

valid for overconsolidated clays which are common in semi-arid regions.
(8) Depth to Which Standard Practice Applies : Opinions were split between

AGC (24 ft.) and AFL-CIO (15 ft.) as in the previous Workshops. An additional rationale was advanced for the 24 ft. depth.

24 ft. is a practical limit for the reach of backhoes. Thus work methods

for greater depth will be different.

Some sentiments were expressed for a more restrictive limit for Type C soils.

(9) Engineer vs. Qualified Person : It seems that the AGC group in this

region are particularly strong supporters of the use of the term "qualified

person." This may have something to do with regional work practices. Two

pertinent comments were made:

a. It was noted that neither a Federal regulation nor a standard

can force people to be ethical. If somebody wants to let an unqualified person design his shoring he may do so regardless

of provisions.

b. It was suggested that if we require an engineer in Section

1926 . 652 (a) (2) b, it should also be required that shoring and

underpinning be a bid item and thus part of the plans and

specifications. I think that, while this is a good idea,

OSHA does not have the authority to enforce such a requirement

I believe that at the core of this controversy is that AFL-CIO would like to

have some way by tfiichthey can determine if a person is qualified. Perhaps

this could be accomplished by a better definition.

(10) Maximum Allowable Slope : It was pointed out that there are gypsum

and caliche formations which stand safely at a 1/4 in 1 slope. This raises

again two questions: Can our definition of unfractured rock be improved? -

It was suggested in this Workshop that perhaps the "competent person" should

determine when rock is unfractured. This is probably a good idea as long as there is no dispute. If there is a dispute, we would still have to go back

to a precise definition. The other issue is "maximum allowable slope." I do not really believe, that if we go to a quantitative definition (as we have

now) it is reasonable to permit slopes steeper than 1/2 in 1. This could

conceivably be combined with regional approval of steeper configurations by

a "grandfather clause" (see Wisconsin memorandum) . The other way would be to

allow the "stable slope" concept - this is opposed by the AFL-CIO.

(11) Section 1926.651(e) : It was suggested that this section is redundant

and should be eliminated.

(12) Section 1926.651(j) : The requirements in this section received some discussion

a. It was pointed out that these are the requirements for confined

space and that these perhaps should be referenced.
b. It was noted that there were some meetings with OSHA in which

modifications in this section were discussed. These modifications

did not make their way into our draft . Cl never heard about them.)

(13) Section 1926.651(o) : It was suggested that this section not be

eliminated from Subpart P. It was further noted that the requirements for a harness is in some instances counterproductive since harnesses do not work

very well and other protective measures are frequently used. I hope that

specific recommendations for re-wording will be made.

(14) Section 1926,651(s) ; Trench box manufacturers suggested modifications

in this section.

(15) Section 1926.651(t) ; It was noted that the requirements in this section

do not apply to many shoring systems. It was suggested to eliminate this

section. I would recommend that we try to rewrite the section to simply

require that workers engaged in the removal of shoring be not exposed to mass

movement of soil or rock from banks where shoring was removed

(16) Figure 3 : It was suggested to eliminate the projection of the shoring

above the top of the bank, as this is not always the method used to protect

workers from rolling objects.
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

(.301) 921-2648

July 13, 1981

Mr . Paul Henson

Mr. Arthur Schmuhl

Mr. James Lapping

Mr. John Ramage

Mr. Paul Bouley

Mr. Ronald Stanevich

Prof. Jack Mickle

Mr . John Pannullo

Gentlemen

Attached is a copy of my draft memorandum on the San Francisco, California

Workshop. Please send me your comments before August 14. I shall revise

the memo after I receive your comments. In particular, I want to make sure there are no inaccuracies and that I didn't fail to address important issues.

Sincerely,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

Attachment

cc: Mr. William Driskill

Mr. Bruce Summers

Mr . Edward Hayden

Mr. John Chambless

Mr. Clifford Simmons

Mr. Bill Zoino

Mr . George Bradberry

Mr. John Cook

Mr. James Kleinfelder

24
/ y \

T

\Vi«»

UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

(301) 921-2648

DRAFT

July 13, 1981

MEMORANDUM FOR Records of the NIOSH Excavation Project

From: Felix Y. Yokel ‘ •

Subject: Workshop in San Francisco, California, July 9, 1981

This memorandum conveys my personal notes and comments relating to the California

Workshop. In this instance, it is not clear whether AGC will produce a detailed

Workshop report. However, participants have been requested to submit their

comments in writing. These comments will be compiled in one document.

(1) General: The California Occupational Safety and Health Standard Board

recently prepared a new draft standard for excavation, trenches and earthwork

(see Attachment), which seems to be acceptable to the affected parties. It was the understanding of the Workshop participants that the Standards Board

delayed adoption of this draft standard until Subpart P is revised. There

are similarities between the underlying philosophies of our draft and the

proposed California Standard, however there are considerable differences in

the substance of these documents. Many of the suggestions made were in the

direction of trying to eliminate some of the differences between the proposed

California Standard and our proposed standard - generally suggesting that

our draft, rather than the California draft, be changed.

In general, California contractors seem to favor a much more conservative

practice than contractors in other parts of the country. This trend manifests

itself in comments on depth limits for the Standard Practice, allowable slopes

and compound slopes, allowable stresses and soil classification (as perceived

by the participants). One of the reasons for this approach is the widespread

use in California of a contract bid item covering shoring. Such a bid item

seems to somewhat reduce the incentive for trying to cut the shoring costs

resulting from safety regulations. Most of the participants suggested that

OSHA require inclusion of shoring as a bid item in construction contracts.

I indicated that I would favor such an approach, but that it is my understanding

that OSHA does not have the authority to enforce such a requirement. Before

discussing detailed comments, I want to briefly discuss some of the differences

between our draft and the proposed California Standard.

A. Excavation and Trenching : In the present version of Subpart P,

excavation and trenching are covered in a redundant fashion. In our proposed revision of Subpart P, the distinction between excavations and trenches is eliminated, and instead we distinguish between

short- and long-term excavations. The applicability of some of the

requirements to excavations can also be further limited by better

defining exposure. In the proposed California draft there are

25
- 2 -

requirements which apply to both excavations and trenches, and then

additional requirements for trenches only.

While the California draft eliminates the redundancy resulting from

separate requirements for trenches and excavations, it does not

fully eliminate the problems associated with the definition of a trench.

B. Soil Classification : We introduced a simple soil classification with

three soil types - hard and compact, medium, and saturated soft and

submerged. The proposed California Standard has two soil classes:

''hard compact" and "running." Running soils are defined as: "Earth

material whose angle of repose is approximately zero, as in the case

of soil in a nearly liquid state, or dry, unpacked sand which flows

freely under slight pressure. Running material also includes loose

and disturbed earth that can only be contained with solid sheeting"

(the last sentence was added recently)

The proposed California classification is based on a recent Stanford

University study which I did not see. All earth that is not "running"

is "hard compact." The lateral pressures associated with these soil

classes are not explicitly defined. Rather, there are prescriptive

tables for wood, aluminum pipe and hydraulic systems, and steel pipe

and hydraulic systems. However, on Page 26, Plate C-22, which, is

addressed to engineers, it is stated that "A minimum coefficient of

active earth pressure of 35 pcf (KW=35) shall be used in all calculations unless a soil evaluation indicates otherwise."

Normally the "coefficient of active earth pressure" is dimensionless,

so I assume that 35 pcf represents the product of the coefficient and

the unit weight of the soil. Whether it is suggested to also use a square pressure diagram of 0.8KW as stipulated in the present

California Standard is not clear. There is no specific guidance for

"running" soils.

I did some back calculating from the proposed table, using the allowable

timber stress of 1300 psi - 20 /d which is stipulated on Page 14, and

got minimum distributed pressures of about 40 pcf for the compact soil,

and about 68 pcf for the running soil, with most member sizes much more

conservatively designed. (The equation proposed for allowable timber

stresses is no longer used in timber engineering practice. Allowable

stresses come out much higher than those we propose for hardwood,

though they may be O.K. for stress graded softwood.)

I have some problems with the proposed California classification:

as far as I can see, "running" soil would include muck, dry and

submerged sands and probably other dry and submerged cohesionless

soils including fill, and possibly some very fissured and very soft

clays. "Hard compact" soils would include all but the very soft

intact clays and a great many fissured clays which can be contained

by spaced sheeting, and probably many moist cohesionless materials.

Hydrostatic conditions are not mentioned.

26
- 3 -

This leaves me confused. You could have a soft clay under 'hard and

compact" (as long as it has enough cohesion to stand up temporarily

to the bottom of the excavation) and a dry sand under "running."

Yet the clay will develop high lateral pressures while the sand would

develop very low pressures. Thus, while it is probably true that a man in the field could relatively easily identify "running" soils,

the soils do not seem to be sorted out with respect to anticipated

lateral pressures and stable slopes.

There is no one-to-one correspondence between our "hard and compact"

soils and the "hard compact" soils proposed for the California

classification, even though I sense that some of the Workshop

participants may have had that perception. Considering the wide range

of soils that could fall within this category, the 40 pcf I calculated

for the table may be on the low side (California 'hard compact" soils

could include soft clays) . Our "Type A" soils are not broken out in

this classification, but some of our Type B soils are thrown into

"running" (the dry cohesionless soils) and some of our Type C soils

are thrown into ,fhard compact" (the soft clays). I believe that if we do insist having only two soil classes, a more logical split would

be obtained by putting Type A and B together and leaving Type C soils

as we now define them.

Another significant feature of the proposed California system is that

our Type A soils are not broken out as a category. Their 35 pcf

minimum "KW" is an indication of that. I was aware that the lateral

pressure presently stipulated in the California Standard for "hard

compact" soils were deemed inadequate in the "California Trenching

and Shoring Manual" (Caltrans) . If we were to likewise eliminate

Type A soils on a nationwide basis, many shoring systems presently

successfully used would be deemed inadequate.

Somehow the proposed California classification conveys the impression

that soils which will stand vertically when you dig require less shoring.

If we take for instance a clay that would stand up in a 12 ft . cut,

its cohesion would be about 300 lb/ft. 2. This is a soft clay, which

according to what we know could develop a very high lateral pressure,

certainly much higher than that of a dry sand. Yet the clay would be

classified as "hard compact" in the California scheme if the trench

dug is less than 12 ft. deep. In our classification it would be

Type C.

In closing, I would like to note that the present California Standard

contains a soil classification which is very compatible with the one

we are proposing and which to my knowledge has a successful 20 year

track record.

C. Shoring System Selection : As I already noted, the proposed California

Standard stipulates specific shoring systems. Such an approach may

be attractive for our standard practice, and could be accomplished

in an Appendix. However, it would be probably impossible to do this

for timber shoring on a nationwide basis. We also would have to make

sure that all existing and potential future systems get equal

considerat ion

27
(2) Qualified and Competent Person : Several contributions were made to this

controversy: ASFE suggested that it be required that the qualified person , when designing shoring, should submit calculations. This would put him on the

spot when something happens. But it would only reveal deficiencies before an accident if some kind of peer review is used. Peer review is now successfully

used with ASFE. California AGC proposed to require that the qualified person

be "designated by the contractor." This would make the contractor responsible

for the competence of the person. California AGC also proposed to eliminate

the competent person and use only qualified persons for everything. It seems

that both the ASFE and the AGC suggestions contain concepts which would improve

our definition. Another interesting and important point was made by the

Oregon AFL-CIO: a "qualified person" from Montana was in charge of an excavation in Oregon. The excavation in Oregon collapsed, because the man

was not familiar with local conditions. This perhaps underscores the importance

of assigning responsibilities to the contractor which was stressed by the

California AGC.

(3) Depth Limitation of Standard Practice : California AGC supports 20 ft. -

as in the California Standard. A representative of the American Gas Association

(AGA) noted that backhoes in his area have a depth reach of about 20 ft. and

not 24 ft. as was noted in Texas.

(4) Accidents: A representative from Liberty Mutual noted that he has no

record whatsoever of fatalities in shored excavations. Some of the participants

noted that they are aware of such cases. I pointed out, that even though our evidence tends to indicate that many of the collapsed trenches were not shored,

we looked at two cases of fatalities in improperly shored excavations during

our study.

(5) Allowable Slopes : California AGC suggested that the compound slope case

shown in Figure 2, Case IV should be limited to 12 ft. depth in hard compact

soils (California definition) and shown as in the California Standard. It was also noted that a California study shows that the bank next to the work

area in Case III would be safe at 4 ft. depth. I have no problems with these

suggestions (except that we do not have the California "hard compact" category),

except perhaps that they may be too restrictive. They are based on a study

by R. T. Frankian and Assoc, (see Attachment). The concept used in this study was that of equivalency to an unsupported 5 ft. deep vertical bank. Such a bank would "just stand up" in a very soft clay with cohesive strength of only

150 pcf - a very soft soil indeed, which is only rarely encountered. For such

a soil, if it can be sloped at all, our allowable slope would be only 1-1/2 to

1, a very flat slope. Our proposed compound slopes in Figure 2 are based on

a somewhat different set of assumptions: equivalent stability to a sloped

trench for whatever the depth of the trench happens to be. Of course many of our Type B soils will not stand with an unsupported bank of any depth, since

they would be "running" by the California Standard.

Another point that was made was that our steepest allowable slopes in Table 1 are not necessarily stable for the soil type in all cases. This is correct,

and that is the reason why I have trouble with dropping the "stable slope"

concept. It is not practical to come up with slopes which would be stable for

all cases. What we have now is maximum allowable slopes which should not be

exceeded without an engineering study.

28
- 5 -

(6) Short-Term and Long-Term Excavations : California AGC suggested to drop

the distinction. Similar suggestions were made in other Workshops. The

problem I have with those suggestions is that they would force us to increase

the safety margins. But if we increase those by much we will end up with a scheme which is much more conservative than what we now consider good practice.

One interesting suggestion that was made is that a reassessment of shoring in

a long-term situation could be made whenever people are exposed.

(7) Local Options : It was stressed that any National Standard should be

flexible enough to accomodate local options. As I stated in my previous

memoranda, I strongly recommend that we have a mechanism by which we can

permit local options with proven track records which deviate from the

"Standard Practice."

(8) Excavation Below Bottom of Shoring or Trench Box : The California groups

tend to support the 2 ft. limit we have, which is also in the California

Standard. This again is an indication of the conservatism of the California

AGC. It also may be related to work methods.

(9) Section 1926.651(d) : Add "... water shall not be allowed to accumulate

in an excavation while work is in progress ..."

(10) Section 1926.651(e) : "... the side of the excavation shall be shored ..."

is too restrictive. Other methods may be used. Also Section is considered

redundant altogether.

(11) Section 1926.651(g) : Should be eliminated, or perhaps changed to proposed

California provision.

(12) Sect ion 1926.651 (h) : "remotely located" should be eliminated.

(13) Section 1926.651(k) : There should be a height limitation. In the proposed

California Standard it is 7-1/2 ft. (no reason for height was suggested).

(14) Section 1926.651(k) ; There should be a general requirement for good

access like in the California Standard.

(15) Section 1926.651(i) : Should perhaps be eliminated.

(16) Section 1926.651(e) : It is suggested that the California Standard has

a better formulation. However the problem of defining "vibration" which was

noted in Texas is not solved in the proposed California Standard either.

(17) Section 1926.651(h) : There should be rather a performance requirement

for protecting workers against falling into a trench.

(18) Section 1926.651(g) : It was strongly suggested to eliminate this statement.

(19) Section 1926.652 (b) (4) (ii) : . Should., be in an appendix or in the definitions.

(20) Section 1926 .652 (b) (4) (i) ; Was considered perhaps too complicated

(21) Section 1926 . 652 (b) (5) (i) : Option should, be provided to-l’block off" the

intercepting trench with shoring.

29
- 6 -

(22) Section 1926. 653 (g) : Authorized by whom ?

(23) Section 1926.653(h) : Engineer should be "Civil .

11

Attachments

30
RT. FRANKIAN & ASSOCIATES

Tirtvrftno/ omd Applied Earth Mrchantct (14 COUTH IUCNA VtSTA STREET

• URSANK. CALIFORNIA • 1 BOS

(111) 149 »I7«

January 10, 1977

Associated General Contractors

of California

Safety Committee

c/o Granite Construction Company

P.O. Box 900

Watsonville, California 95076

Attention: Mr. Bruce G. Summers, Chairman

Gentlemen:

Transmitted herewith are ten copies of our "Study to

Determine Compound Slopes Equivalent to CAL-OSHA Allowable

Unshored Slope," dated January 10, 1977.

This study was planned in consultation with Mr. Summers

and Mr. J. M. Lyles.

It is the conclusion of this study that when the total

depth of the excavation does not exceed 8 feet, a 3/4 horizontal to 1 vertical slope with a 3h-foot vertical cut at

the toe, is equal and equivalent in stability to a 5-foot

high vertical slope. The same condition exists for cuts up

to 12 feet in total height when the gradient of the slope

above a l^-foot vertical cut is 1 to 1.

Should you wish to discuss the study further or have

any questions, please do not hesitate to call.

Yours very truly.

KSP/RTF/rk (10)
STUDY TO DETERMINE COMPOUND SLOPES THAT ARE

EQUIVALENT TO CAL-OSHA ALLOWABLE UNSHORED SLOPES

INTRODUCTION

The purpose of this study is to determine which unshored

configurations of compound slopes would possess stabilities

equal and equivalent to the stability of either a 5 foot

high vertical or a 12 foot high. 3/4 to 1 unshored slope, as

allowed in the CAL-OSHA Construction Safety Orders. The 5

foot vertical and the 3/4 to 1 slopes are plain, that is,

consist of a single, unbroken slope face. The compound slopes

reported in this study consist of a vertical cut at the toe

of an inclined plane.

This study is limited to soils which possess strengths

sufficient to stand at those configurations permitted by the

CAL-OSHA standards. Consideration of clean, running sands,

saturated sands, and other soils which would not be stable on

a 5 foot high vertical slope have been eliminated from this

study.

32

R T. FRANK1AN & ASSOCIATES

Tbrmrritrm/ mmti ippltrri Ucrkmme*
If

*.•;**»

2-

#

BASIS OF ANALYSIS

The analysis began with the determination of those

strengths which are required for the stability of the plain

5 foot vertical slope and the 12 foot high 3/4 to 1 plain

slope. The method^ of analysis was that commonly used and

referred to as the slip circle method. The analysis included

consideration of a variety of tension crack locations and

calculations were extended until the most critical combination of slip circle and tension crack was obtained.

It was found that the 5 foot high vertical slope was

more critical than the 12 foot high 3/4 to 1 slope, that is,

the 5 foot high slope would require soil strengths IIkmwu

than the strengths required to maintain the same degree of

stability for the 3/4 to 1 slope. For purposes of this report we will refer to the 5 foot vertical slope as the standard slope, since it is that slope which will set the standard

for stability of the compound slopes.

Starting with the strengths which were required for

stability of the standard slope a variety of compound slopes

were analyzed, each with an entire new series of trial slip

circles for each configuration. Each of the calculations

included consideration of the most critical location for a

tension crack. Thus for each total slope height (depth of

trench) one specific configuration was obtained which would

possess a stability equal and equivalent to the stability of

the standard slope.

33

R T. FRANKIAN & ASSOCIATES

7VwmJW
-3-

Equivalent stability is defined by means of the

ratio of the soil resistance available (Sa) as determined

from the standard slope, to the soil resistance required

(Sr) to provide stability for the compound slope. When

Sr is equal to Sa, that is, when the resistance required

is equal to the resistance available, the compound slope

would have a stability equal and equivalent to the standard

slope.

Other ratios of Sa/Sr may be considered, and where

the same ratio occurs between a compound slope and the standard slope, it can be stated that the stabilities of these

two slopes are equal and equivalent. . RESULTS OF ANALYSIS

Calculations were made for compound slopes with overall

heights (depth of trench) of 8 feet and 12 feet. For both 8

and 12 foot slopes the gradient of the upper portion of the

slope was varied and the height of vertical toe was varied.

The results of the calculations for the final configurations

are presented on the following pages.

Where the height of the vertical portion of the slope

at the toe is 3*5 feet, the stability of the 8 feet high

slope is equal and equivalent to the standard slope when the

upper portion of the slope is inclined at 3/4 to 1.

Where the height of the vertical cut is again 3% feet

and the overall height is 12 feet the stability of this

configuration is at least equal and equivalent to the standard slope when the upper portion of the slope is inclined

at 1 to 1.

r

C

L

L

L

C

c

c

t

34

R T. FRANKIAN & ASSOCIATES

mm! / nk MtnUw»r«
height

of

vertical

cut

in

feet

RATIO So / Sr shearing resistance *

•x

tvailofcle

rtqwnd

R T. FRANK1AN & ASSOCIATES

Tlmmtmmt mtd £•«* Urriann
The effect of water collected in the most critical

tension crack has also been investigated. If it is assumed

that the critical tension crack for the standard slope is

filled by water and calculations are made on the effect of

water filling the' most critical tension crack of any of the compound slopes, the ratio of Sa to Sr for the compound slope

is greater than unity, that is, the compound slope possesses

a stability at least equal to that of the standard slope.

CONCLUSIONS

If the total depth of the cut does not exceed 8 feet,

the stability of a 3/4 to 1 slope with the lower 3*5 feet cut

vertically is equal and equivalent to the stability of a 5

foot high vertical cut excavated in the same soil.

If the total depth of the cut does not exceed 12 feet,

the stability of a 1 to 1 slope with the lower 3*5 feet cut

vertically is at least equal and equivalent to the stability

of a 5 foot high vertical cut excavated in the same soil.

L

L

C

C

r

r

r

-oOo

The following Plates are attached and complete this

report:

Sample Calculations

Respectfully Submitted,

36 mg1

R. T. FRANKIAN & ASSOCIATES

TkmWW Urrimmr.
£M.C.ULATlOtO ... OTTULMIUE VIMLI04 RJLTl

Mi* K uiui«a t» y«Jkr< i Utm *i4Cli ma*tmaO m £lCCU« 1% A P«IU6Ttt)0 m 0 « Tmk ^>4*4 l» )UI

4*MC4 I«M iU P*ow*>>a» / Pa

mis£m #

?&4C

MAuiaU *f» r«*viM r«4 A % twr UM 44*4 IT M>4U«t . f , !!• MmhAI /

si* . A4uciu Cwnw. o# m«t cftmuu

• w^»a Aao^rrA.t’ 4mO «®>i_ uotTMirt | ^ mo C

dhk* 141I4T1UC4 IU PA A lll> PMP 4L. Tw

4

-A

*104

r«a. ft*i»4 At. \>14 ^C %L*PO) TM4t UlC4litf4 CJt TMC **.1 4 IWJ *C- TME M*vr At.lT! C4 L. tki^ 4!^Lf

Miw r>® aa*tmoa& p~a. •»»"[ oimujvmubx p*a«Mnti ttuoUTCO A V tamou c fc«A hiAV-BoCMa &*a-"7

)

, X 4^ » |

* M • TAt ^ / C

Auumk H * 5 r«err ( su*mk u«uaT)

4 5 \0*

Fb«_ ft*cu CmlculPib amo . £*u_oa.t Si*** «C- Tuase

VAuiU £•<«. am— CAi act at- V*ti«tkC *tkMVDu ccmm woiATiaiov.

€ts«_ fine* CALCUuMTiwJ kb*i

utc Twois To Rum ®V Tie

TCM^IONt CRAM. 1 BLee.1 C&. ^fc-TA »*4 WHAM lAIlkl

PtU> OUCA t OulDT 1/AU1( At- iMt RATIO aC 5i *>»•

I— ^TtUMTAV UUvcU rtAbUcS MINIMUM -. ^*- «V OmHS «4t

TM* ^-rC.4LXAAT»B UMA16U RtM«.BI4An STMCLI Sl*u4<4 0 iLOfi . 37

R T. FRANK1AN & ASSOCIATES

7W*tn/W4pM£ar*A UkAmti
*vti

,

^AMPue CAlCUlATIi>0 pKAt 2

OCTMLMistC HIMlNUM VAUlfi **- TM*. ILKtia % MW^Ofc tariTMilK

/WkikAlus a T« «>u&*Aioa KkA(»*r**»(.«i Lcjunua Sr r»r_ *wy £«Hrou>ao cum

R T. FRANKIAN & ASSOCIATES

TimmtnmM' mtd iff

iWL*r» UrrMan
• 4^4

V

STANDARDS PRESENTATION Pg_ OF 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend the definition of Excavation, Trenches, Earthwork in Section

1504 to read:

Excavation, Trenches, Earthwork.

• (A) Bell Hole. An additional excavation made into the sides or

bottom of a trench to provide additional work space.

(B) Belled Excavation. A part of a shaft or footing

excavation, usually near the bottom and bell-shaped, that makes the

cross-sectional area at that point larger than that above.

(C)

shoring

Braces for Excavations. The horizontal members of the

system whose ends bear against the uprights or stringers.

(D)

placing

,

Earthwork

and working

The process of excavating, moving,

any type of earth materials.

storing

,

(E) Excavation. A man-made cavity or depression in the earth's

surface, including its sides, walls, or faces formed by earth

removal and producing unsupported earth conditions by reason of the

excavation. If installed forms or similar structures reduce the

depth to width relationship, an excavation may become a trench.

(F) Hard Compact. All earth material not classified as

running. ©r-unsfeableT

(G) Qualified Person. A person designated by the employer who

by reason of experience or instruction is familiar with the

operation to be performed and the hazards involved.

(H) Running. Earth material whose angle of repose is

approximately zero, as in the case of soil in a nearly liquid state,

or dry, unpacked sand which flows freely under slight pressure.

Running material also includes loose or disturbed earth that can

only be contained with solid sheeting,

(I) Shaft. An excavation under earth*s surface whose depth,

either horizontal or vertical, is much greater than its

cross-sectional dimensions such as those formed to serve as wells,

cesspools, certain foundation footings, and under streets,

railroads, buildings, etc.
STANDARDS PRESENTATION Pg^Z.. of _

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD /

/

(J) Sheet Pile, A pile, or sheeting, that may form one of a continuous interlocking line, or a row of timber, concrete, or steel

f

iles, driven in close contact to provide a tight wall to resist the

ateral pressure of water, adjacent earth, or other materials? ‘

(K) Shore (Strut) . A supporting member that resists a compressive force imposed by a load.

( ) Shoring System. A temporary structure for the support of

earth surfaces formed as a result of excavation work.

(M) Sides, Walls r and Faces. The vertical or inclined earth

surfaces formed as a result of excavation work.

(N) Sloping ©f-Ba*bb. ?he-angle-w4th-fehe-h©«, 4-z©ntai-wh4eh-a

pa*t4ettia*-«a-f th-ma fce*4a4-w444-s tand—inde-£4n4tel y-w4 the ut-mavementT

A method of excavation whereby the faces of an excavation or trench

are la id back to provide protection from moving ground.

(0)

Spoil. The earth material that is removed in the formation

of an excavation.

(P) Stringers. The horizontal members of the shoring system

whose sides bear against the uprights ©g-ea-rfch .

(Q)

Trench. Sha4i-meafl-aft-exeavafc4©ft-4n-wh4eh-the-depbh

exeeeda-fche-ave* age-w4dth-©€-4t s-e* ess-see fe4©fw —Bxeava-fcions-bhafe

are-mofe-fchan-l-S-f eet—W4de-at-fche-bettem7-sha4fe37-tttftne4s7-and-m4ne

exeavafciens-are-nofc-ferefteheaT A narrow excavation made below the

surface of the ground. In general, the depth is greater than the

width at the bottom, but the width of a trench at the bottom is not

greater than 15 feet.

(R) Trench Jack. Screw or hydraulic type jacks used as cross

bracing in a trench shoring system.

(S) Trench Shield. A shoring system generally composed -of"

steel plates and bracing, welded or bolted together, which support

the walls of a trench from tne ground level to the trench bottom of

which can be moved along as work progresses.

4P)- —B«stafe4e7-as-«sed-4n-Art4e4e“6T—Earfeh-mate-?4a4-©ther-feban

€©nft4fig-that7-b©ea«se-©-£-4-fes—na-fc are-©?-the-ind-l tsenee-of -re4 a ted

«©fld4t4©ftS7-eafm«t-be-depeftded-ttp©n-t©-rema4n-4ft-p4aee-w4th©tit-ex-fc-fa

•©pp©^t7-««eh-aa-w©tt4d-be-f«-rft4shed-by-a-syatem-©-€-ahor4ftg-f

(T) Uprights. The vertical members of the shoring system.

(U) Waler. A structural member in a horizontal or nearly

horizontal position used for stiffening or securing other components

of concrete forms, excavation sheeting, or similar temporary

structures.
. STANDARDS PRESENTATION Ps 7 0F jt

'CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Section 1540 to read:

1540. Excavations. ~

Scope. Sections 1540(b) through (n) and 1541 apply to all

sxcavat ions , trenches f shafts or earthwork and establlshessential

requirements and minimum standards of safety in earth excavation

work.

NOTE: (1) Whenever the term "excavation (s) * is used it also

applies to trenches, shafts and other earthwork,'

( 2 ) For additional shaft and Incline excavation details, see

Sections 1542 and 1543.

(3) For additional earthwork excavation details, see Sections

1544 through 1547 which apply to such work locations as borrow pits,

road or dam construction sites and similar work areas,

(4) The Orders in this Article do not apply to work covered by

the Mine Safety Orders or the Tunnel Safety Orders.

(b) Preparations.

(1) Prior to opening an excavation, the employer shall

determine whether underground installations sucn as, sewer, water,

fuel, electric lines, telecommunication lines, etc., will be ^ encountered, and if so, where such underground installations are

located. ~

' '

(2) When the excavation work approaches the approximate

crossing or parallel location of such an underground installation

and danger of accidental contact or disturbance is possible, the

exact location shall be determined by appropriate means before

proceeding. When it is uncovered, adequate protection shall be

provided for the existing installation.

(3) All known owners of underground facilities in Nthe area

involved shall be advised of proposed work at leaiV 43 forking hours

prior to the start of excavation work. ^ '

Exception: Emergency repair work to underground facilities.

(4) Trees, boulders, poles and other surface encumbrances

located so as to create a hazard to employees involved in excavation

work, or in the vicinity thereof at any time during operations,

shall be removed or made safe before excavating is begun.

41

ncjcD_Oi t-t r-tc\
STANDARDS PRESENTATION Pg_s of _3±

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

'

(c) Exposure.

(1) No employer shall cause or permit his employees to work in

or adjacent to any excavation until a reasonable examination of same

has been made by a qualified person to determine that no

xecognizable conditions exist exposing them to injury from possible

WoVjinq ground, ' 1 * 4 (2) Excavations shall be inspected by a qualified person after

•very rainstorm or other hazard-increasing occurrence and the

protection against slides and cave-ins shall be increased, if

necessary, before employees are permitted to enter the excavat ion.

(d) Protection. Employees who must enter excavations 5 feet or

aore m depth shall be protected by a system of shoring, sloping of

the ground, benching, or other effective means as provided by these

Orders. Protection for employees who must work in excavations less

than 5 feet in depth shall also be provided when examination by a qualified person indicates that hazardous ground movement may be

expected

(e) Spoil.

(1) Excavated material shall be prevented from falling back

into the area where employees are working. This shall be done by

locating the spoil at a distance from the edge of the excavation

consistent with the character of the material and the nature of the

operations, but unless otherwise contained, in no case shall be

excavated material be placed closer than 2 feet from the edge of

excavations.

(2) No method that disturbs the soil that is in place (such as

driving stakes) shall be used to contain the spoil material.

(f) Supervision. Excavation work and work in an excavation

shall at all times be under the immediate supervision of someone

with authority and qualifications to modify the shoring, sloping or

other system or work methods as necessary to provide greater

safety. Such modification shall not permit the specific dimension

requirements of other Orders to be less restrictive than shown

except as permitted by Section 1541(a)(6). This person shall

examine the material under excavation and improve the shoring or

other methods beyond the minimum requirements, as necessary, to

Insure protection of workers from moving ground.

42

A r*7 /7CY
STANDARDS PRESENTATION Ps 9 OF 34

• CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(g) Access cL c?°-

7

(1) A convenient and safe means of access shall be provided for

employees to enter and leave an excavated area. This shall consist

of a stairway, ladder or ramp securely fastened in place at suitably

guarded or protected locations where employees are working"?

(2) When employees are required to be in trenches 4 feet or

ore in depth^ a safe means of access shall be provided and located

so as to require no more than 25 feet of lateral travel.

Exception: In utility trenches less than 5 feet in depth, earth

ramps or steps are acceptable provided that they are not more than

75 feet on centers.

(h) Crossings.

(1) Trenches shall be crossed only where safe crossings have

been provided.

(2) When walkways or bridges are provided across excavated

areas, they snail be provided with standard guardrails and toeboards

when the depth of excavation exceeds 7-1/2 feet.

{i) Excavators. An employee working in the vicinity of

operating excavating equipment shall be required to work in a safe

position such that the employee is not in danger of falling into or

otherwise contacting the machine's moving parts.

(j) Undermining.

(1) No excavation work shall take place below the level of the

base oil an adjacent foundation, retaining wall or other structure

until it has been determined by a qualified person that such

excavation will in no way create a hazard to workers or until

adequate safety measures have been taken for the protection of

workers.

(2) Undermined sidewalks and/or pavements shall be supported to

safely carry all anticipated loads.

(3) If the stability of adjoining buildings or walls is

endangered by excavations, either shoring, bracing, underpinning , or

other method affording equivalent protection for workers shall -be

provided as necessary to ensure their safety. All such systems

shall be inspected daily or more often / as conditions warrant, by a qualified person and the protection effectively maintained.
STANDARDS PRESENTATION Pg_ 10 -OF 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(k) Retaining Walls.

(l) No existing wall or other structure shall be Bade by reason

of an excavation or backfill f to function as a retaining wall until

It has been determined that such wall will safely withstand all

xpected loads that otherwise might be a source of hazard to workers, “ . (2) Wherever a permanent retaining wall, in lieu of the

temporary shoring system of this Article, is constructed to~~hold any

f

L ' art of an excavation that might endanger workers, such wall shall

e designed and constructed to effectively resist all existing and

expected loads. Standards of design shall be comparable to those of

the California Administrative Code, Title 24, Building Standards, or

any comparable local building code of equal or greater

rest r ict iveness

— ?

s

(Z) Barriers at Unattended Work Locations.

inadvertently entering excavations.

(2) Adequate physical barrier protection shall be provided to

prevent employees from falling into excavations.

ShL All wells, pits, shafts, caissons, etc., shall be

barricaded or securely covered.

SAL Upon completion of exploration and similar operations

,

temporary wells, pits, shafts, etc., shall be backfilled.

(m) Water Accumulation.

(1) Diversion ditches, dikes, or other effective means shall be

used to prevent surface water from entering an excavation and to

provide adequate drainage of the area adjacent to the excavation.

(2) Accumulations of water in excavations which endanger the

stability of those excavations or pose a hazard to employees shall

be cont rolj^e7l~~be~fi>r

further work progresses.

(nO Vibrations ,Xr Superimposed Loads. Special safety

provisions consis^ng of additional bracing or other effective means

shall be taken at excavations adjacent to streets, railroads, or

sources of external vibrations or superimposed loads. Similar * provisions shall be taken in excavations made in areas that have

been previously filled.

44
STANDARDS PRESEN I A 11 ON Pg of

• CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Section 1541 to read:

1541. Shoring, Sloping and Benching Systems.

() General.

• t

(1) All materials of the shoring system used in complying with

the provisions of this Article shall be tree £rom defects and amaq"e

that aight in any way impair their protection function.

(2) Where a shoring system is used it shall be designed and

inatalled to sustain all existing and expected loads.

^3) Provisions shall be made by the employer to prevent injury

to employees engaged in the installation of shoring for trenches and

other excavations. IrT trench work this may be done by providing and

requiring the use of devices that will allow upper cross braces t,o

be placed from the ground surface before employees work in the

trench at those points. In deep trenches requiring additional

braces, workers shall then progress downward, protected by cross

braces that have already been set firmly in place. The reverse

procedure shall be followed when removing shoring.

(4) No part of the shoring system of any excavation shall be

removed until effective means have been taken to avoid hazards to

employees from moving ground. ~

’ ~ “

(5) If a newly installed masonary or concrete wall is to be

depended upon for protection against moving ground , it shall have

attained adequate strength to sustain resulting pressures before

employees are permitted to enter.

() If the excavation is deeper tham 20 feet /or an alternate

sho ring , sloping or benching system or 'combination thereof: is to~be

used, a civil engineer, currently registered in California, shall

prepare detailed plans showing the materials and methods to be

used. See Appendix Plate C-22.

Exception: Sloping or benching as permitted by this Article.

(A) Where alternate shoring, sloping, or benching systems are

used, the engineer's detailed plans shall be available for

inspection by the Division at the work site.

(B) Employees must be adequately trained in the safety

precautions and hazards associated with the alternate shoring,

sloping, or benching systems used.

(C) The written Code of Safe Practices required by Section 1509

shall be revised as appropriate to incorporate the engineer's

recommendations

.

J£L_ Standard Shoring System - General.

* (1) Shoring shall be Installed in accordance with Tables 1 or 2

of these Orders or as detailed in plans and specifications prepared

by a civil engineer currently registered in California. See

Apprendix Plate 022 for engineering criteria.

OSHSB- 9 A ( 7/7 6

)
STANDARDS PRESENTATION

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(2) Solid wood sheeting or wood sheet-piling shall be not less

than 2-inches in thickness. However, plywood 1 1/8-lnch in * thickness nay 'be subst i tuted

(3) Wood uprights shall be not less than 2 Inches by 8 inches.

(4) Wood braces and diagonal shores (struts) shall not be less

thin 4-inch by 4-inch material and not subjected to compressive

‘itress in excess of values given by the following formula:

(5) Diagonal shores (struts) shall be wedged or cleated at the

bulkhead end, and , if bearing on the ground, shall not impose loads

in excess of test-determined soil-bearing values, or in the absence

of test data, those given in Plate C-22 of the Appendix.

NOTE: Allowance should be made for the horizontal component of

to rce

„

~

(6) Diagonal shores (struts) shall not be placed at an angle

greater than 45 degrees with the horizontal.

(7) When tie rods are used to restrain the top of sheeting or

other retaining systems, the rods shall be securely anchored.

(8) When tight sheeting or sheet-piling is used, full loading

due to ground water table shall be assumed, unless prevented by weep

holes, drains or other means.

(9) Additional stringers, ties, and bracing shall be provided

to allow for any necessary temporary removal of individual supports.

(11) All hydraulic shoring systems shall be installed, tested

and maintained in accordance with the manufacturers* recommendations

or in accordance with good engineering practice.

Maximum Ratio (L/D « 50

S « 1303 - (20L/D)

Where L « length, unsupported^ in inches

and D - least side of the timber in inches

S g allowable stress in pounds per

square inch of cross section.

the following thickness and spacing requirements shall be observed:

If nonstress grade lumber is used for sheeting and lagging,

Minimum rough thickness

of sheeting or lagging

Maximum spacing

~~~ of: shoring"

"""

2 inches

3 inches'

4 feet

7 feet

46
STANDARDS PRESENTATION Pg 15 of

' CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(C) Trench Shoring Systems.

(1) Trench shoring systems shall be installed in compliance

with Section 1541(b) and Tables 1 and 2 of this section.

12) Shoring systems in trenches shall consist of uprights held

rigidly opposite each other aqainst the trench walls by lacks or

horizontal cross members (braces) and, if required, longitudinal

embers (str inqers/walers) as required in Tables 1 and 2.

.13) Uprights shall be installed parallel with each o' t her

.

ilL A shored trench shall not be sloped in excess of 15 degrees

from vert ical

.

ILL Uprights shall not be less than 2 inches in nominal

thickness

.

Exception: Plywood panels at least 3/4-lnch thick may be used

behind the uprights in order to hold loose material not likely to

impose heavy 1 o a d s

.

"

(6) Uprights shall extend to at least the top of the trench and

to as near the bottom as permitted by the material being installed,

but not more than 2 feet from the bottom.

Exception: When running soil is encountered, shoring shall

extend to the bottom.

(7) Cross braces shall consist of metal screw-type trench jacks

with a foot or base on each end of pipe, or timbers placed

horizontally and bearing firmly against uprights or stringers.

Hydraulic metal braces may also be used. See Tables 1 and 2.

(3) Tne minimum number of horizontal braces, either jacks or

timbers, required for each pair of uprights shall be determined by

the number of 4-foot zones into which the depth of the trench may be

divided. One horizontal brace shall be required for each of these

zones, but: in no case shall there be less than 2 braces. Trenches,

the depths of which cannot be divided equally into these standard

zones, shall have an extra horizontal brace supplied for the short

remaining zone, if: such zone is greater than 1/2 the 4-foot unitT

" In no case, however, shall the vertical spacing of horizontal braces

be spaced greater than 4 fleet center to center. Minor temporary

*" shifting of horizontal bracing will be permitted when necessary for

the lowering of materials into place.

(9) The dimensions and spacing of the elements of the shoring

system shall be governed by the depth of the trench, type of: soil

encountered, and other special conditions of the site, but in no

case shall they provide less strength than the members listed in the

following tabl es which are to be considered as a minimum requirement.
zO

u

z o

z

* O' ©

R X X ©

o Eel £ XXX X

h- H- 09 o o o

•o u» X X

*- CD o

09 ^ Q9 CD C' g

X X X X X

O' 03 On 0 O' g * O' *• O' *

x X X X X

ON * O' A. O' ^ ?

* O' ^ © A. X X X X X

O' + © * * £k xxx xxx

k* h- »-* © 9- y» Ki in o y< cr H H M CD H ^

cn © cn cn

t* m © © © ©

w to u> kj w to w io u* to u> KJ j- j- j- j- j- j- j- U W U kl U KJ U U K1 J- J- J- J"

H 0 O O' ff> W H H H O © U< o o o o - t- *» ® ® «r> >- - ® o o o o o

W k» W to U» to U VJ M M KJ U

rf’W <f U N M M M M

•r rf- rf- W to to U"

1— )— H» t— ® ^ W ** ff> to k/i © to V w M O ^ ® wwhOm +* I- ®

tn to

(t

* 5

s *5

S

X X • o o • 9 ! S I

1 r_ x © ©

I XXI

c

o

G

zr

V) X

*o o

X

—K *1 ** ft n 3 —* oX

X— — 3

3 • — D

S?a F

3— O

tn < r- a <t n ft

fi. H- c

9- *T5

- !? ^ n

** w3 —' OX

© <

•c e, !-***« ^ n ft r

1 *-• »-• ^30«A t-A

3O

A

3—' in

r

[

L

L

t

[

C

r

r

r

c

r

««

«*

m

48
--3]]]]

TABLE 2

SHOKING

FOR

RUNNING

SOIL
STANDARDS PRESENTATION Pg is of _

3±

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(d) Protective Shields and Welding Huts*

(1) If protective shields or welding huts are used to protect

workers, they shall be constructed of steel or other material that

Will provide protection at least equivalent to that afforded by the

materials specified in Tables 1 and 2. ‘ (2) Plans and calculations prepared by a civil engineer

currently registered in California shall be made available for field

Inspect ion "at the site where the shield or welding hut is used.

(e) Bell or Pot Holes. * 1 — %

(1) Bell (or pot) holes shall provide adequate clearance for

the work to be done, and shall be supported by shoring and bracing

as required by these Orders for trenches unless protective shields

or welding huts are used, ~ ^

(2) If the operation performed in the bell (or pot) hole

requiFes that an employee use welding equipment from a reclined

position on the bottom, the bell (or pot) hole excavation shall be

of such shape that the employee will have adequate space for the

performance of this operation without removing any of the required

shoring system.

(f) Sloping or Benching Systems. In lieu of a shoring system,

the sides or walls of an excavation or trench may be sloped or

benched, provided equivalent protection is thus afforded. Where

sloping is a substitute for shoring that would otherwise be needed,

It shall be 3/4 horizontal to 1 vertical except where the

instability of material requires a slope greater than 3/4 to 1.

3/4 3/4

flatter than

3/4 to 1

50
J

]

J

STANDARDS PRESENTATION Pg » 19

OF

34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Except (1) ions;

In hard, compact soil where the depth of the excavation or

trench Is 8 feet or less, a vertical cut of 3 1/2 feet with sloping

of 3/4 horizontal to 1 vertical Is permitted.

\

• I

(2)

In hard y compact soil where the depth the excavation or

trench is 12 feet of less, a vertical cat of 3 1/2 feet with sloping

of 1 horizontal to 1 vertical is permitted, ~~

J

(3)

In hard, compact soil, benching is permitted provided that

a slope ratio of 3/4 horizontal to 1 vertical/ or flatter, is used.

]

51
20 34 STANDARDS PRESENTATION Pg_ OF

* CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Section 1542 to read:

1542. Shafts.

(a)

( 1 ) employee

•pilling

I2L_

foot abo

shaft or at least five fe^t into solid rock if possible.

NOTE: See pertinent portions of Section 1540 for additional

requirements relating to wells and shafts.

(b) Small Shafts Bry7-€e»ented Hard -r Compact Ground. Two-inch

(nominal

)

cribbing may be used in square shafts not over 4 feet

square in d-ry7 -eeaented hard compact ground. Each member shall be

cut 1/2 way through the width of the member and dovetailed into

position so each member will act as a shore as well as lagging.

Strips shall be nailed in each corner to prevent the boards from

dropping down.

(c) Shafts in Other Than Bryj-Semented Ha rd -r Compact Ground.

(1) A system of lagging supported by braces and corner posts

shall be used for square or rectangular shafts. Corner posts of

4-inch by 4-inch material are normally acceptable in shafts 4 feet

square, or smaller, if they are braced in each direction with

horizontal 4-inch by 4-inch members at intervals not exceeding 4

feet. Braces and corner posts in larger shafts shall be

correspondingly larger.

(2) Round shafts shall be completely lagged with 2-inch

material which is supported at intervals not greater than 4 feet by

means of adjustable rings of metal or timber that are designed to

resist the collapsing force, or cased in a manner that provides

equivalent protection. Means-shall-be-pr ovided-ta-hold-rings-and

lagging-in-plaeeT

General

or shafts over 5 feet in depth into which

itted enter shall be retained with lagging,

or casing

2

ing, spiling /or casing shall extend at least one

und 'level and .shal l' be prov fde<j "the i ul 1 depth cif the
STANDARDS PRESENTATION Pg 21 ,0F _34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD —Shaf ts-over-iSS-feet-ift-^ep^h-shall-have-a-Banway

pa^t4%ia«e<i-off-with-i-4ft«h-aiate*, ‘iai-att -eqtt4valeftfc-aftd-shail-haye-a

4adde*way-w4feh-*a41ed-p£afcforaa-every-30-feetT

**

(c) Belled Excavation. No workman shall be required or permittj

to eW<r any well or shaft particularly those drilled for foundation

footings/l^the purpose of enlarging the bottom by hand^etisimilar

work, unless th^walls of the shaft are supported as desprrtied in these

Orders or unlessWing affording equivalent protection is in service.

The k>«IIed section or*saQy additional shaft ex^wtition in which men

work shall also have equivalent bracing i^-ttie shaft casing does not

provide protection. -The shaftVa^ine op-$noring is not acceptable for

belled excavation protection whei>3<eheight of the bell exceeds 4 feet or its horizontal dimension ext^pdsu feasor more beyond the shaft wall

line. Additionally, men enuring such shaft$>sl}all wear a body harness

securely fastened to aljp^individually mannea^Hcisrparated from any

line used to remove^materials from the excavation>

Note: Jtefetilo Section 1532 for requirements prio

confined-'Spaces

1. Amendment of subsection (e) filed 5-21-75, effective thirtieth day

ter (Register 75. No. 21).

entering

(d) Bell Excavations. Provisions for the protecti on of workers

that are enqaqed in bellinq or enlarging the bottoms of shafts by

hand sha!11 includ e at least the following elements:

(1) Sufficient physical protection from potential ground

movement or colla pse

.

4

2) Adequate mechanical ventilation • . 43) A line. suitable fo r instant rescue, securely fastened to a shoulder harness and worn by each employee entering the shaft (s)

.

(4) A proper ly equipped hoist and platform for hoi stinq or

lowering workers in shafts o ver 50 feet in depth.

Barriers that preve nt materials from falling i nto the

shaft (s) .

53

OSHSR-9 * n /7M
STANDARDS PRESENTATION Pg ' 23 QF _m

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Subsections (a) , (d) and (a) of Section 1544 to read:

1544. Earthwork and Excavating.

MOTE: See pertinent portions of Section 1540 for additional

requirements relating to earthwork and excavating.

+L (a) Whenever fche-Bivision-eonsiders-bhai the height and

condition of the face constitutes a serious hazard to employees,

shall-require the installation of a bench or other suitable method

of working shall be required .

. (b) "When a bench or multiple-bench method of operation is rej quired, a setback of at least $ the height of the single face or bank for

each section of the face or bank shall be required. I (e) When determining the maximum permitted slope of the face,

j consideration shall be given to

(1) Nature of the material being excavated.

(2) Extent to which the material is cemented or consolidated.

(3) Height of the face. (4) Type and size of equipment used at the face and • amount of protection this equipment affords the operator.

j (5) Safety of employees who arc not protected by such

j equipment I *

(d) Where the face is composed of loose or unstable materials,

the slope of the face shall not exceed 3/4 horizontal to 1 vertical

where the height is greater than that which can be reached by the

dipper-©* bucket of the excavator or loader being used.

(e) Where the face is composed of moderately compacted

materials that are not firmly cemented or consolidated but which

experience indicates will stand well in place, the slope shall not

exceed 1/2 horizontal to 1 vertical where the height is greater than

can be reached by the dipper-o-r bucket of the excavator or loader

being used.

Amend Subsection (a) of Section 1545 to read:

1545. Overburden.

(a) Ho person shall be permitted under a face or bank where

stripping or other similar operations constitute a hazard.
STANDARDS PRESENTATION Pg 24 0F

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Subsections (a) , (d) and (e) of Section 1S46 to read:

1546. Face Inspection and Control.

(a) A daily physical inspection shall be made of faces and

tanks, including the tops, where men employees are exposed to

falling or rolling materials. The inspection shall be made by a aompetent-man qualified person who shall dislodge or make safe any

material dangerous to employees, or shall cause such material to be

dislodged or made safe.

(b) No person shall be permitted to work near a face made unsafe by primary blasting, rains, freezing or thawing weather, or earthquakes until the face has been inspected and made safe. 1 (c) Overhanging banks are forbidden, except: j (1) 'Where material is moved away from the face by

mechanical equipment having controls located at a safe dis- tance so that no employee is required to approach the face in the course of normal operation.

(2) Where the bank is undercut with a stream of water*

and the monitor is located at a safe distance from the bank.]

(d) Where necessary, a-eompetent-tra-ined an employee shall be

employed at the faceT and instructed to give warning when loose rock

or other materials are about to fall.

(1

)

The employee shall be provided with a whistle, siren, or

other devices that will give adequate warning to employees.

(2) The employee shall have no other work to distract his

attention from his duties as defined above.

(e) When working at night, sufficient illumination shall be

provided throughout the working area so that movement of men

employees and equipment can be readily observed.
STANDARDS PRESENTATION Pg 25 of 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Section 1547 to read:

1547, Protection of Workers at the Pace.

(a) No work shall be permitted above or below *«* employees at

tke face if such work endangers their safety.

% (b) Workers at the face shall be protected as follows:

(1) On top of the bank, by fencing with guardrails or ropes; by

using railed platform; or by using safety belts and life lines.

This does not apply where the bank is less than 20 feet high or the

slope below is less than 3/4 horizontal to 1 vertical or where no

work is performed within 10 feet of the edge.

(2) On the face, by removing loose rock from over the working

place and by the use of safety belts and life lines, portable

staging, boatswain's chair or skips especially designed for use at

faces. If a boatswain's chair is used, the employee shall be

attached thereto with a safety belt and life line equipped with an

approved effective descent control device.

When-neeessa-ry-fo-r-safetyT-S Two or more persons shall be employed

in cooperation with each other in drilling, blasting, or removing

loose rock.

Life lines used for scaling or inspection shall be protected from

excessive fraying or damage or and shall have a wire center rope.

(3) At the foot of the bank by removing loose rock from above

the working place, and maintaining a ready way of exit to a place of

safety.

56
STANDARDS PRESENTATION Pa 26 0f _2±

‘ « CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Appendix Plate C-22 to read:

PLATE C-22

BEARING VALUE OF SOIL

Shores and similar members that depend upon earth for support will

probably require foot blocks or sills to distribute the load. In

the absence of test data that establish the sustaining power of the

soils in question, the following information should be helpful in

determining the size of f-ii-i sill needed to assure adequate support

from the soil

Tons allowable

Soil type per square foot

Soft clay 1

Wet clay 2

Sand and clay, mixed in layers 2

Fine dry sand 3

Hard dry clay 4

Coarse compact dry sand 4

DESIGN CONSIDERATIONS

EXCAVATIONS , SLOPES AND BENCHES

The determination of the slope or bench configuration or deisgn of

the shoring system shall be based upon careful evaluation of such

pertinent factors as the following:

11 ) Possible variation in water content of the material while

the excavation is open.

13) Anticipated chanqes in materials from exposure to air, sun.

water or freezinq temperatures.

J4) Loading imposed by structures, equipment, overlaying

material or stored material.

,15) Vibration from e'quTpment, blastinq, traffic, trains or

other sources.

J6) Existinq underground facilities.

_(7) New or old adjacent excavations.

_(8) A minimum coefficient of active earth pressure of 35 pcf

(Kw=3 5

)

shall be used in all calculations unless a soils evaluation

ndicates otherwise.

'irn * urxr i.

57
STANDARDS PRESENTATION Pg -33 of 34 L

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD ' . r

Adopt new Appendix Plate C-24-a to read:

Plate C-24-a

MINIMUM SHORING REQUIREMENT

IN HARD COMPACT SOIL

UPRIGHT

///&

/7A\N Wm

*

I

5i EE

DETAIL58
. . STANDARDS PRESENTATION ' PG 34 0f _h

• CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Appendix Plate C-24-Jb, to^ r$a^

CLOSE SHEETING MET

IN RUNNING SOIL ' CLEATS

%

REFER TO TABLE

tw/rtu*e$)

STRINGERS

4"X 4" MINIMUM

2* MAX:

2' MAX.

SHEET PILINGS

TRENCH DEPTH

BRACES

ALL STRINGERS SHALL—*

BE SUPPORTED TO PREVENT

THEM FROM SLIPPING OR FALLING

OSHSB-9A (7/76)

RUNNING MATER la!

SOLID SHEETING

IS REQUIRED
STANDARDS PRESENTATION Pg 3< ~A of

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Appendix Plate C-24-e; to read:

Plate C-24-c

MINIMUM SHORING REQUIREMENT *

60
STANDARDS PRESENTATION Ps

34 ~ B

of

.

•' CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt jrew Appendix Plate C-24-d to read: .

j

- CLOSE SHEETING METHOD"

"

i. ’IN RUNNING SOIL '

HYDRAULIC

SHORING

RUNNING MATERIAL ! SOLID SHEETING

IS REQUIRED
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

Bldg. 226, Room B162

(301) 921-2648

July 24, 1981

Mr. Clifford Simmons

Mr. Arthur Schmuhl

Mr. James Lapping

Mr. John Ramage

Mr. Paul Bouley

Mr. Ronald Stanevich

Prof. Jack Mickle

Mr. John Pannullo

Gentlemen:

Enclosed is a copy of my draft memorandum on the Boston Workshop. Please

send me your comments before August 14. I shall revise the memo a'fter I receive your comments. In particular, I want to make sure that I have no inaccuracies and that I didn’t fail to address important issues which were

tC ftt

Structures and Materials Division

Center for Building Technology, NEL

Sincerely,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Enclosur e

cc: Mr. John Chambless

Mr. Edward Hayden

Mr. William Driskill

Mr. Paul Henson

Mr. Bill Zoino

Mr. Richard Critchell

Mr. Robert Briant

Mr. Clayton Morin

Mr. C. Joseph Williams

62
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20234

Building 226, Room B162

(301) 921-2648

July 24, 1981

MEMORANDUM FOR Records of the NIOSH Excavation Project

From: Felix Y. Yokel

Subject: Workshop in Boston, Massachusetts, July 14, 1981

This memorandum is to record my overall impression and my reaction to

important questions that were raised in the Workshop. I expect that a Workshop report will be prepared by the Organizing Committee on the basis

of taped records and written depositions.

(1) General : This was the last in a series of five Workshops and many issues

that were raised were discussed in previous Workshops and will therefore not

be discussed herein in much detail. My general impression was that the AGC

group participating in this Workshop did not formulate strong opinions on specific issues like those expressed in some of the previous Workshops

(Wisconsin - local options; Atlanta and Dallas - strong emphasis on the issue

of "qualified person," the 24-ft. depth limit and an increased allowable

slope for Type A soils; San Francisco - adoption of some concepts from the

proposed California Standard). This is perhaps an indication of a greater

diversity in work practice in the New England and Mid-Atlantic regions.

Members of the New Jersey NUCA were generally supportive of the recommendation.

Representatives of trench box manufacturers submitted a position statement

(see Attachment 1) which did not substantially differ from that submitted in

Dallas (which is discussed in the Dallas memorandum) . Other trench box manufacturers, which communicated with me prior to the Boston Workshop do not

agree with this statement and are supportive of our recommendations. A letter

discussing the trench box manufacturers statement in the Dallas Workshop is

attached (Attachment 2). Representatives of the Eastman Kodak Company came

in with prepared recommendations, which are generally supportive of the

proposed revisions of Subpart P but also make numerous specific recommendations.

To some extent, the Kodak submission is a new viewpoint since it reflects the

needs of an owner/contractor organization which is primarily engaged in the

repair of utility damage as distinct from utility construction in which most

of the AGC and NUCA contractors are engaged (Attachment 3). AFL-CIO in

essence reiterated statements made in previous Workshops. In the opening

statement, the AFL-CIO representative stated that Contractors and Unions

should make joint recommendations . The substance of the AFL-CIO position

was summarized in the following statement: Excavation safety could be

accomplished in several ways:

63
1 .

- 2 -

by Hamurabi's Code,

2. by OSHA enforcement,

3. by an Engineer, and/or

4. by a Standard Practice.

AFL-CIO would like to see that the workers in 95% of all excavations be

protected by a standard practice, and in the remaining 5% by an engineer.

The ASFE representative noted that ASFE is working on a summary recommendation

which will reflect their position on various issues. ASFE also noted that

comments should be consolidated by an industry-wide committee in a unified

summary . ASFE stressed that local practices should be recognized and should

supplement the national provisions. This concept goes somewhat beyond my

recommendations for local options which I conveyed in the Wisconsin and

California memos, and perhaps reflects a better long-term approach, however

the implementation of this concept requires additional work.

L

L

L

L

r

L

I particularly welcome the concept of a joint industry recommendation

advanced by AFL-CIO and ASFE. I strongly recommend to go beyond that and

develop consensus industry standards . It is my judgement, on the basis of

the five regional Workshops, that such a standard can be successfully developed

and adopted in a relatively short time. Federal regulations which are backed

by such a standard could probably be less sweeping, more effective, and less

difficult to enforce.

(2) Soil Classification : Two issues were raised in conjunction with the

proposed soil classification:

1. It was suggested that we go back to the matrix classification

(Attachment 4).

2. It was stated that the footnotes are too complex.

In conjunction with #1, I have no doubt that in terms of categorizing soils

for stability and lateral pressure, the matrix classification is the best

solution. It would permit us to distinguish between sands and medium clays

in Type B soils and between submerged sands and soft clays in the Type C

soils. This would result in enhanced safety and economy. The problem with

the matrix is that you cannot memorize the 16 matrix intercepts, except if

you have a photographic memory. Thus you would have to use some visual

aid on the job, such as a printed table, or a table engraved on some metal

plaque. I personally do not believe that you can get foremen to use a chart

routinely. It is bad enough that we will have to do this for surcharge

effects. I would, however, strongly recommend that 1) we use the matrix

as an educational tool, and 2) we perhaps try to use it in the field on an experimental basis.

In conjunction with #2, the footnotes to Table 1 play an important role. I will give an example: there is no way a geotechnical engineer could ever determine for sure whether you have a "compacted sharp sand" as shown in

Table P-1 of the present OSHA regulations. Thus you can never resolve a

[

r

L

64

L
- 3

-

dispute. The footnote in Table A on the other hand will tell you exactly

what soils fall into Class A, B or C. The footnotes also convey other

important information such as the thumb test. I doubt very much they can

be simplified without creating ambiguities.

(3) Excavation Below Bottom of Sheeting : Three points were made:

1) It was suggested to change the wording of 1926. 652 (5) (iii) to read

"Short-term excavation up to ft. below ..." Sometimes an excavation may be long-term, but the sheeting is undercut for a short time to install a pipe.

2) It was suggested to limit the length of permitted undercutting.

3) It was noted that in California undercutting is rounded, so that

the depth below sheeting on the side of a trench is less than in

the middle.

(4) Position of Upper Strut Below Top of Trench : It was stated by a shoring

industry representative that it is common practice to place the upper strut

2 ft. below the top of the trench. New Jersey NUCA stated that in their area the distance tends to be 3 ft. There is no stipulation in our proposal,

but perhaps there should be one tied to sheeting thickness.

(5) Guidelines : Trench box manufacturers noted that the guidelines are referenced in the proposed Subpart P revision and should therefore be subject

to public comment. An OSHA representative noted that no guidelines would be

referenced in the regulations.

(6) Page 5, Section 1926.65Q(i) : It was noted that the statement would force

a truck driver to leave the truck while it is loaded and is thus too restrictive. It should perhaps state "No unprotected person ..." AFL-CIO noted

that it should state "no persons shall be permitted under loads" - regardless

how the loads are handled. It was also proposed to strike the last sentence

in (i )

.

(7) Page 5, Section 1926.650(h) : "Approved respiratory protection" should

not be listed as the only means of protection.

(8) Page 6, Section 1926.650(j) : In spite of the California recommendation.

Workshop participants favored keeping "competent person."

(9) Page 6, Section 1926.651(a) : Some participants felt the statement is not

very clear. The California version (see San Francisco memo) which I read to

the participants was favored.

(10) Page 7, Section 1926.651(e) : A representative from the Operating

Engineers noted that this section should list equipment that is used in

excavation work and no other equipment. It was also noted that equipment

positioned on top of the slope at the end of the excavation should be excluded - only equipment placed next to the sides of finished excavations. It was also

noted that the word "near" is much too vague and that this Section may be

redundant.

(11) Page 7, Section 1926.651(g) : It was again recommended to eliminate this

section. It was noted that the "stoplog" only adds hazards.

65
- 4 -

(12) Page 7, Section 1926.651(k) : The need for this section was questioned

(note comments in San Francisco memo).

(13) Page 7, Section 1926.651(1) and (j) : It was proposed to eliminate these

sections

(14) Page 8, Section 1926.651(m), (r) , (t) : It was proposed to eliminate

these sections. (m) is self evident, (r) and (t) are meaningless.

(15) Page 8, Section 1926.651(o) ; It was noted that protection in a belled

hole is too complicated an issue to be handled as an excavation.

(16) Page 8, Section 1926. 651 (p) : It was suggested that one means of exit is

enough for small excavations.

(17) Page 8, Section 1926.651(s) : It was proposed to eliminate the first

sentence. Trench box representatives propose to use "equivalent protection."

This is tied to their objection to our pressure diagrams.

(18) Competent Person : It was proposed that competent persons should be

trained - superintendents licensed, foremen trained.

(19) Page 9, Figure 1 : It was noted that while the 1 to 1 slope in the

figure reflects accepted engineering practice, a footnote should be added

noting that distance from footing should be increased if water seeps into the

side of the excavation.

(20) Page 9 : It was noted that both the "competent" and the "qualified"

person should be designated by the employer.

(21) Page 10, (a) (3) : St. Louis AGC proposed that the depth limit below

which an engineer must be involved should not be applied to sloped excavations .

(22) Page 10, (b) (1) : It was suggested that in the Northeast, short-term

excavations could be 3 or even 7 days, and perhaps more. Parameters identified

were desiccation for sands, fissuring and creep for clays, sensitive clays,

and effects of water.

Again opinions were expressed to drop the distinction, but it was recognized

that we would have to become more conservative.

(23) Page 10, (b) (4) (i) : Trench box people suggested that this section is

confusing. It was however noted by ASFE the alternative of having to use an engineer may be even less attractive. I believe that the use of the "adjusted

depth" is a necessary evil.

(24) Page 13, (ii), last paragraph : Shoring systems, trench shields and

trench boxes . . . The allowable 33 percent strength increase was questioned.

66
- 5 -

(25) The "Operating Engineers" representative noted that he feels that there

is a tendency for those who should assume responsibility for the safety of

the men to avoid it. I believe that this feeling by AFL-CIO underlies their

position in the dispute surrounding the "qualified person" concept. Perhaps

the dispute can be resolved by looking at this problem.

(26) New Mexico AGC noted that great difficulties arise from the fact that

bid documents prepared by municipalities and government agencies do not

recognize the excavation safety problem (i.e. excavation quanities paid on

the basis of 1/4 to 1 slope, etc.)

Attachments (4)

67
r» i« rn-niM&f* i

STATEMENT OE POSITION AND RECOMMENDATIONS

ON

REVISION TO SUBPART P

OP THE

SAPETY AND HEALTH REGULATIONS FOR CONSTRUCTION

PRESENTED BY

THE MAJOR MANUFACTURERS OF TRENCH BOXES

AND TRENCH SHIELDS OF THE UNITED STATES

John B. Cook

Efficiency Production, Inc.

Wendell Wood

Griswold Machine & Engineering
GENERAL STATEMENT OF POSITION

A review in detail has been made of the proposed revisions

in Subpart P 1926.650 - .651 - .652 - .653.

This review was made by, and on behalf of, the ma^jor trench

box manufacturers of the United States, and represents their

consensus opinion of the changes in the proposed standards.

It is our position that the intent to. clarify and simplify,

as it relates to the revised changes of Subpart P, has failed

and in fact, has made it more confusing and more difficult to

apply in the field. The proposed design criteria as they

relate to trench boxes do not conform to accepted engineering

practices. We have specific recommendations for changes in

the proposed revisions.

It is also our position - that if the Guidelines are going

to be referenced within Subpart P and therefore become effectively a part of the law - they should be discussed publicly

as a part of the workshop and in public hearings.
1926.650 GENERAL PROTECTION REQUIREMENTS - NO COMMENT

1926.651 SPECIFIC EXCAVATION REQUIREMENTS

PAGE

8 - item (s) Should read ••• Portable trench boxes or

sliding trench shields may be used for the

protection of personnel. Where such trench

boxes or trench shields are used they shall

be designed, constructed and maintained in

a manner which will provide equivalent protection to that provided by the shoring

required for the excavation as defined by

accepted engineering practice.

1926.652 SPECIFIC SHORING, SLOPING AND SHIELDING REQUIREMENTS

PAGE

9 - item 2a Should read ... Qualified Engineer

10 - item (b) (1) Should be no arbitrary distinction between

long-term and short-term excavation.

10 - item (4) (i) We recommend that this section be clarified

and simplified for effective field application

15 - item (ii) a Should read ... lateral pressure at the bottom

of excavation equal to the equivalent weight

effect (We) in Table 1 times the depth of cut

with lateral pressure diagram appropriate to

the construction as determined by an engineer.

We object to the footnotes attached to Table 1

as being too technical and overly complicated

for interpretation by field personnel, and

recommend they be simplified.

13 - item (ii) c The last paragraph of this section should read

... shoring systems shall be designed in accordance with accepted engineering practices.

70
PAGE (This statement excludes the 33# increase in

allowable working stresses or an equivalent

strength reduction.)

Should read • . • Shoring systems and trench

shields shall be selected in the field on the

basis of accepted engineering practice.

(a) Trench shields, trench boxes, and pre-fabricated

strutwale assemblies and other pre-f abricated

assemblies shall be rated for the maximum depths

in all types of soils in which they can be selected and used accordingly from charts prepared

by the manufacturer.

16 - item (i)(iii)(c) Should read ... rated by an engineer ... .

16 - item (5)(iii) Should read ... Excavation up to 3 feet below the

bottom of sheeting, trench boxes, or trench shields

is permitted provided that: ... (and we agree with

items a & b.)

1926.653 DEFINITIONS APPLICABLE TO THIS SUBPART

PAGE

18 a Should read ... Accepted engineering practices,

those requirements or practices which are compatible with standards required by a registered

professional engineer.

Question - why are you making reference to the

guidelines when they are not meant to be a part

of the law?

19 m Should be eliminated.

19 o Should read ... Negotiable slope is a slope on

which a person can egress from or ingress to an

excavation with relative ease and speed to assure

reasonable safety.

13 - item (iii)

Paragraph 2

13 - item (iii)

71
Should he eliminated.

Should read ... See Figure 4 (Correction)

GUIDELINES SUPPLEMENTING SUBPAPT P

If the Guidelines are going to he referenced within Suhpart P, do

they not become effectively a part of the law? If so, they should

he discussed publicly as a part of the workshop and in public

hearings.

PAGE

19 t

19 z

72
ANSWERS TO Pit, YOKEL’S QUESTIONS

#1 No comment.

#2 No comment.

#3 No comment on 24 foot limitation.

On question of should qualified person be sub

stituted for engineer ... "No, as it relates

to this specific question."

#4 No distinction should be made between shortor long-term excavation.

#5 No comment.

#6 No comment.

#7 Yes, and should be conveyed as part of the

definitions.

#8 No comment.

#9 Yes.

#10 Yes.

#11 No comment.

#12 No.

#13 No - Statement should not be deleted.

73
ATrft-tiftsvn £ r

While this is true, I feel that the participants in these Worshops have

the knowledge and experience to address all the issues involved and will

do so successfully.

(2) Opposition to Change in Existing Provisions : Opposition to a change

in the present version of Subpart P was expressed by an Illinois contractor

who works primarily on highway projects. This time I gained some insight

into the rationale for this position. I noted in my Wisconsin memo that

people who tend to agree with our recommendation are less likely to express

their opinion in the Workshop than those who oppose certain recommendations.

The same thing happened to some extent when we conducted our field study.

Almost all the contractors that responded were dissatisfied with Subpart P.

However, the responding contractors who now have concern about changes in

the existing regulations are more involved in earthwork, wide excavations,

borrow pits, etc., where conflicts with OSHA do not normally arise. They

are concerned with two issues.

a. The present provisions have been interpreted in the courts in

past litigations. These interpretations by court rulings tell

the contractor precisely what he can do. When we now propose

to change the wording of many provisions, there will again be

uncertainty about their interpretation by the courts, and we

will lose the benefit of experience gained in past conflicts.

b. We merged "trenches" and "excavations". There is now concern

that as a result new restrictions will be imposed on excavation

work. Part of this problem can probably be resolved by a clear

definition of "exposure." However we need to carefully review

our new recommendations to make sure that they do not

inadvertently result in unnecessary restrictions on excavation

work. An example of this, which was noted in the Workshop,

would be the application of Section 1926.651(d) to borrow pits.

(3) Use of OSHA Regulations on Federal Projects : It was noted that other

Federal Agencies are not bound by OSHA regulations and use their own procedures. This situation can lead to specifications which are difficult to

implement while using methods which comply with our recommendations. I am

not sure what can be done about that, but the situation could be brought

to the attention of the Administration at an appropriately high level by

the participating organizations of the Workshops.

(4) Trench Boxes : Trench box manufacturers suggested that the lateral-load

requirements for trench boxes should be different from those for shoring.

This is based on the contention that a trench box can deflect considerably

and in general will not restrain lateral soil movement as much as a shoring

system, thus causing the pressure distribution to resemble that acting on a retaining wall. This would make the square pressure diagrams associated

with the Standard Practice too conservative. At this time I cannot evaluate

the technical merits of this claim in detail, but I have several preliminary

thoughts

l

r

[

r

r

74

/
- 3 -

a. In addition to the allowable stress increase for short-term

excavation, ve also allow a 20 percent load reduction for wales

and a 33 percent reduction for sheeting. These reductions,

which account for arching effects would apply to the horizontal

framing members and the skin of a trench box. I wonder if the

industry considers taking advantage of these reductions in their

analysis.

b. The trench boxes I saw had about equal stiffness (in terms of

lateral displacement characteristics) near the top and bottom.

Thus, I cannot see how a trench box could act like a retaining

wall, namely rotate inward while the base is fixed.

c. It is obvious that a trench box permits greater lateral inward

displacements of the excavation wall than a shoring system. In

granular soils this will result in a reduction in lateral soil

pressures. In clays, however, the situation is more complex.

Overconsolidated clays such as those is Austin, Texas where we

conducted pressure measurements (NBS GCR 80-202) will develop

tension cracks upon lateral expansion, resulting in increased

lateral soil pressures. It should be noted that Type B soils

include clays.

d. The greatest problem that would arise if stiffness characteristics

of shoring systems are considered is complexity (which our recommendations are designed to avoid). Each case would have to

be considered on its own merit . Considering the inadequacies and

complexities of present models for soil/structure systems and our general lack of data on lateral pressures in shallow braced

excavations, it may be difficult to make a convincing case, and

detailed analysis would not be much better than an educated guess.

e. While the proposed square pressure diagrams may be on the

conservative sides, the 40 lb/ft. equivalent weight effect is

not conservative for medium clays which fall under Type B soils

and are the most common soil type.

It may be helpful if ASFE could review this problem. I am very much afraid

that we may be creating an albatross as soon as we deviate from the principle

of simplicity in the standard practice.

(5) Configuration of Excavations with Compound Slope : Two problems were

discussed in conjunction with Figure 2, page 12:

a. It was suggested to remove the sharp corners in the drawn crosssections, since these cannot be dug in the field with ordinary

equipment. I suggest that we draw broken lines for the idealized

cross-section and back these up with solid lines showing more

rounded corners.

b. The bank adjacent to the work area was discussed. In the previous

two Workshops there seemed to be a consensus that the height of

the bank should be increased to 4 ft . In this Workshop it was suggested to permit a 5 ft . bank for large pipes. In the latter

case, worker protection would be derived from the large diameter

pipes. I have some problems with the suggestion:

75
July 13

100-y€ar §tart on torngrrow^

3

r

r

, 1981 [

Comments by Kodak Park Division of Eastman

Kodak Company at Boston, MA , Workshop , Trenching & Excavation Standards, on Working

Draft prepared by National Bureau of Standards

dated February 20, 1981 . The Kodak Park Division of Eastman Kodak Company does a large

portion of the construction and maintenance of its buildings

and underground utility lines. This includes excavations for

buildings and other major structures as well as trenching for _ new water, sewer, and electric services. It also includes

excavation for emergency repair of these underground services. L

We are also~inv6lved with many trenching and excavation contractors

at all of our locations in the U.S. and expect that the execution —

of this work be done safely and efficiently.

The hazards of inadequately shored or braced excavations are _ well recognized by experienced persons active in that type of

construction. Unfortunately, satisfactory source standards —

were not available when OSHA promulgated the existing 1926

standards and their subsequent enforcement efforts, have not ”

been entirely productive in the reduction of serious accidents

or in providing assistance in needed safety precautions.

We believe fchat - the, Na tional JBureau of Standards has done

a commendable job in drafting these suggested revisions. They —

have recognized- that' excavation site conditions are widely variable

and the application of judgment for each location by knowledgeable

people is needed. The proposed standard is written in performance i_

language and the supplemental non-mandatory guidelines that

are included should be very helpful in the solution of specific —

problems. Eastman Kodak supported a similar approach used by

OSHA in the revision of the General Industry Standards for Fire

Protection which were adopted last December, and the Electrical

Workplace Standards which were adopted in April 1981.

Attached are .our comments on the identified issues plus

some addition -items. We will be pleased to elaborate on —

these comments if additional information would be helpful.

EASTMAN KODAK COMPANY • KODAK PARK DIVISION
Some Issues that Should be Considered in the Workshop

1. Page 6 . Section 1926.651(a): This section appears to

fall within the scope of Subpart S. Should

it be dropped?

A. Subpart S, Tunnels and Shafts, Caissons, Cofferdams,

and Compressed Air is not the appropriate place to

call for locations of utilities prior to excavation.

The problem of interrupting utilities and the

resulting employee hazards are most likely to be

found while preparing surface excavations and thus

belongs in Subpart P.

2. Page 8. Section 1926.651(p): Should the exit requirements

for excavations start at 5 ft rather than 4 ft depth ?

Please refer to our general comments on this section.

A. Yes, it is reasonable to expect the type of

individuals who work in excavations to have the strength

and agility to make his own way out of a 5 ft deep

excavation without the aid of something or someone

else. Also, the additional one-foot allowance will

include many trenches, and a pipe is often present

which would serve as a step to aid the exit process.

Also, in trenches, the work is being done in a

constantly changing location and the need to frequently

move the ladder or exit device may be considered a nuisance by the trench workers if they do not believe

it is practical to use.

Should exit requirements be waived for excavations

which are wide enough to permit people ,to escape

toward the center of the excavation ?

' .

‘ 1 ^ Z‘e A. Yes, the major concern for death or injury is in

the relatively narrow excavations such as trenches

where escape during rapid cave-in is very much more

difficult because escape options are far fewer than

in wider excavations. The alternative requirement

should be that the excavated area allow unimpeded

movement away from the excavation walls to a safe

location.

V\ i. c"£ ir desirable

to aoc i fenter.ce to

- .. — — - • — - — r r •

77
2

Should it be recognized that large enough pipes or

other covered structures can shelter people ?

The intent of this question is not clear. A large

pipe being installed can serve as a temporary refuge,

but it does not seem appropriate to include that as

part of a planned protection system in lieu of

shields or shoring. However, a permissible practice

would be to permit the use of the pipe as a shelter

while the trench shield is being relocated which is

a normal procedure in many situations. Alternatively,

existing large pipes or structures adjacent to the

excavated area can serve as a type of shoring to

help support the excavation side. Good judgment

and sometimes engineering analysis may be required,

however, for the use of pipes that appear to give

marginal support.

Should "negotiable slope” be better defined?

A. This definition seems adequate for its purpose,

though there may be some arguments about a person's

ability to climb a slope being used. Perhaps the

only validation required should be a physical

demonstration of an employee using the slope to egress

or ingress before work begins.

3. Page 9. Section 1926.652(a)(2)

al Could the depth limitation in the "Standard

Practice" be extended to 24 ft ?

Whether the excavation is 20 ft or 24 ft before

requiring the services of a registered engineer is

somewhat arbitrary. There should be some limit,

however, and since the 20 ft limit has been used in

several standards, such as the New York State Code

Rule 23, it probably should be kept.

b) Should a "qualified person" be substituted for

an "engineer "?

There are probably relatively few registered engineers

who would be competent in the design of earth shoring

systems or slopes, and there a probably many capable

people who are not registered professional engineers

who have developed suitable expert qualifications in

this area. The definition of "qualified person"

probably is more descriptive than the definition for

"engineer" in determining a person competent in

designing shoring systems and earth slopes.
3

4. Page 10. Section 1926.652(b)(1); Should the short-term

excavation definition extend to 7-days rather

than 1-day? If so, do we need more conservative

requirements ?

We do know that a 7-day definition for short-term

excavation can be applied to most soil conditions

in our area. The more commonly found soils which

may range in grain sizes from clays to gravels would

most likely permit a 7-day short-term definition in

. other parts of the country as well.

There are basically two conditions which normally

change the strength of insitu soil with time after

an excavation has been made, both having to do with

changes in water content:

1. If an excavation is dug below the water table

surface, or if an excavation is partially

filled with water and this water is rapidly

drawn down by pumping, relatively large pore

water pressures between the soil particles

remain. This may cause a temporary stability

problem which will improve with time as excess

pore pressures dissipate. So, when excavating

primarily fine grain or relatively impermeable

soils such as clays and silts, the initial

water condition is important. When the walls

stabilize after the water is pumped out, shortterm excavation criteria can be safely applied,

as long as the excavation is not allowed to

refill with water. Paragraph 1926.651(d) and

note 3 (b) of table 1 of the draft Subpart P

revision recognize this problem.

2. When excavating in granular or permeable soils

such as sands, there will be a temporary apparent

cohesion caused by negative pore pressures in

the partially saturated, draining soils. This

negative pore pressure is caused by capillary

tension. As the soil in the excavation walls

dries, the negative pore pressures will dissipate

making the soil weaker in shear and possible

causing sloughing or slides. This is a condition

which will deteriorate with time and the length

of time will depend on how fast the soil in the

excavation walls will dry to a significant depth.

Probably in normal conditions, instability will

occur considerably later than 7 days after the

excavation work, particularly when the excavation

wall is covered with sheeting, retarding evaporation of water.

79
4

We feel the large majority of the cases will

allow the extension of short-term to 7 days.

Perhaps an extension to 3 days might be a good

compromise which would allow, as a worst case,

excavation before a weekend to backfilling

after a weekend, as long as water is not allowed

to accumulate in the excavation and be pumped

down again.

5. Page 11. Table 1: Should the stipulation of maximum slope

be limited to 3/4:1? Should the suggested performance

requirement (footnote b) ( the "stable slope" concept)

be used? Will this approach work ?

A. The 3/4:1 maximum slope should be reasonable.

Judgments of the description of the soil encountered,

degree of saturation and changing conditions as the

excavation progresses might overlook something,

possibly resulting in a marginal stability problem

from time to time. There should be some means to

correct such shortcomings if there is evidence of

instability, and the provision to flatten the slope

by 1/4:1 should be appropriate. This adjustment

should be made before anyone enters the excavation.

6. Page 12. Figure 2: Should the allowable bank next to the work

area in Cases II, III, and IV be increased to 4 ft ?

Should "Case IV" be limited to excavation by trenching

machines ?

A. The purpose, usually, for having a subtrench at

the bottom of a sloped excavation is to provide a

better lateral restraint for the pipe after the pipe

is bedded and in place. This, in most cases, allows

the pipe to withstand greater overburden and ground

surface loads without failure. For large pipes

(6 ft or more in diameter) , it may be important to

be allowed a deeper subtrench. For employee safety

purposes, whether 3 or 4 ft is used is arbitrary, and

would probably depend on judgment of the increased risk,

if there is any, by going to the 4 ft subtrench. The

potential volume of sliding soil, indicated by the

spaces between the solid and dotted lines in figure

one, does seem to be relatively small even at 4 ft.

The upper portion of the trench would have to be

widened or flattened to accommodate the 4 ft subtrench

in order to meet the table 2 criteria. Finally, at

4 ft, the head and shoulders of most workers would

be outside of the subtrench. It seems reasonable

to us to extend the subtrench depth to 4 ft.

80
5

7. Page 13. Section 1926. 652 (b) (4) (ii) s This section, unlike

most others in Subpart P, is not addressed to the

man in the field but to those who pre-design shoring

systems. Yet the section is necessary to avoid

unreasonable vagueness. Should this section be at

the end of Subpart P? Should part of it be conveyed

as definitions ?

A. These loadings are already in the, "Guidelines

Supplementing Subpart P, Section 2.2.2, 'Operational

Loads'." If these loadings, with the possible exception

of the impact load, are meant to also apply to job

designed shoring, which Subpart P does not say, then

these provisions should remain in the body of this

Subpart where they are.

8. Page 16. Section 1926 . 652 (b) (5) (ii) ; This section makes it

difficult to implement some of the slope configurations

allowed in figure 2. Should the proposed performance

statements be substituted to give more options, or

alternatively, should more options be specified or the

specified options identified as examples of implementing

the performance statement ?

A. The performance statement, (Workers in excavations

must be protected against rolling or sliding objects.)

is really all that is needed here. Suggestions as to

how this may be accomplished may be placed in the

appendix if beneficial.

No mention of the amount of slope required before

provisions are applied should be made. It depends

on the specific situation.

9. Page 16. Section 1926.652(b) (5) (iii)

:

Should the allowable

excavation below the bottom of shoring or shields~~be

increased to 3 ft ? ~

A. It certainly would be useful, in some cases, to

be able to extend short-term excavations to 3 ft

below the shoring. It is useful to aid in the bedding

of pipe. Also, more importantly to us, it better

allows working around underground obstructions with

shoring, particularly when reexcavating to repair a broken watermain, sewer, or similar items in a congested

area. We feel it is reasonable to allow this extension

if adequate attention is paid to possible unstable

conditions below the shoring.

81
6

10. Page 18.

11. Page 18.

We also believe this section should be reworded

to clarify that the short-term excavation requirement

applies to the work below the bottom of the sheeting

or shoring system. An excavation for a building or

large structure would come under the long-term

definition. It is often necessary to make short-term

excavations within this excavation for drain lines,

footings, etc. The present wording could be interpreted

as prohibiting this practice. We suggest that this

section be revised to read:

"A short-term excavation up to 3 ft below the

bottom of sheeting, trench shields, or trench

boxes is permitted provided that:."

Definition of accepted engineering requirements . Should a "registered architect" be omitted since

architects do not deal with excavations ?

A. This is not an area in which architects are

normally involved, however, there is probably no

good reason whey they should be excluded, as long

as they have adequate background and experience,

just as any registered engineer working with

excavations should.

Definition of "Competent Person. " Should the

definition be rewritten to require that the competent

person be working at the excavation site ?

L

L

L

L

L

[

L

[

12 .

A. We would consider this to be good practice.

Should "Mass Movement of Soil or Rock" be defined?

A. The term should be self-explanatory. It should

include any ground movement involving volumes greater

than those associated with spalling of rock, or

sloughing of soil and surface erosion of soil.

Perhaps the latter terms should be defined. The

only place these terms appear in Subpart P is in

the definition of "Fractured Rock."

13. Page 52. Old 1926.651(c): Should this statement be deleted ?

Even though this matter is addressed elsewhere , this statement conveys the intent of Section 1926.652

m simple language .

A. This statement should be deleted. It is clearly

redundant with the new Section 1926.652(a).

c

[

c

32
7

In addition

Workshops,

1. Page 7.

2. Page 7.

3. Page 8.

4. Page 11

5. Page 11

6. Page 18

to "Some Issues that Should be Considered in the

we have some additional comments or questions.

Section 1926.651(e) : We feel that this requirement

should apply to completed portions of excavations.

This would clarify that the intent is not apply the

shoring requirement in the areas where the excavation

equipment is working. Substitute "completed sides"

for "side" in line 4.

Section 1926.651(g) : Excavating equipment may be

considered mobile. Is it necessary to place stop

logs or barricades in front of this equipment during

excavation, particularly tracked equipment or those

using outriggers?

Section 1926. 651 (p) : This section currently appears

to apply only to trenches. We believe exit conditions

should be considered for all types of excavations.

Large excavations should have a minimum of two means

of exit. A second condition could be a smaller

excavation of up to approximately 1500 sq ft where

one exit would be permitted. A third condition

would be similar to what is currently proposed.

Table 1 ; Recognizing that many times the excavation

faces are saturated only part of the way up, could

we consider the soil to be type C to the top of the

saturation zone and types A or B above that with the

appropriate We's applied?

Table 1 : The Matrix Classification System shown in

NBS BSS 127, June 1980, is simple to use and offers

more flexibility. Would it be possible to replace

in Subpart P the simplified Classification System

with the Matrix Classification System, or at least

offer the latter in an appendix or another section

as an alternate.

Section 1926. 653 (j): Excavation

The draft standard does not define trench or give

any criteria to distinguish between a trench or

excavation as is done in the current standards.

We believe this is desirable. However, it may be

helpful to add a sentence to the excavation definition

stating that trenches are excavations or alternatively

adding a Trench definition which could state.

83
8

Trench : "One type of excavation commonly used

for the installation of piping, etc."

This would provide emphasis to employers who primarily

do trench type excavation work that the entire standard

is applicable to their operations.

7. Page 19. Section 1926.653(1): Fractured Rock

Can rock have fractures in it and yet be considered

by definition unfractured? It is rare to find

especially sedimentary rock that is not fractured,

yet we would consider that much of it would not

readily spall or crumble when excavated with vertical

slopes. We believe unstable rock would be a more

suitable term for this definition.

84
HTI HvHW\cn t

Table 5.3 Soil Classes in Matrix Classification System ^ Site —- Condition

Soil - _

Hater in Mo Trench

Yes

Fiss Moures

Tea Fissures

Mo | Yes

Stiff Cohesive*/ Z II III

II III III IV

Granular-^ II III

Soft IV IV

Iotas

:

1. Hater in Trench is assumed whenever water drains into the trench from the soil forming

the bank, or water is retained by tight sheeting, or there is s possibility that the trench aay become fully or partially flooded before workers leave it, or aay be

entered by workers within 6 hours after more than half its depth was flooded and puaped

out.

2. Vibrations ; Soils subject to vibrations by heavy traffic, pile driving or similar effects

shall always be assumed fissured .

3. Stiff Cohesive Soils*/ include stiff clays and cohesive or cemented sands and gravels

(till, bardpan). Stiff clays included have an unconfined eoapressivc strength (pocket

penetrometer reading) qu

“ 1.5 tsffi ' or larger.

4. Medium Cohesive Soils */ have an unconfined coapressive strength (pocket penetrometer

reading) between 0.5 and 1.5 tsf^ •

5. Granular Soils^ are gravels, sands and silts that can stand on a slope steeper than

3 hor.: 1 vert, without spalling or slumping.

6. Fractured Rock shall be treated as granular soil. Intact rock is exempt from shoring

and sloping requirements.

7. Soft Soils are cohesive soils */ with an unconfined coapressive strength (pocket penetro- meter reading) of 0.5 taf^' or less and granular soils that can not stand on a slope of

3 hor.: 1 vert, without slumping (suck).

8. Layered Systems (two or more distinctly different soil or rock types, micaceous seams

in rock) which dip toward the trench wall with a slope of 4 hor.: 1 vert, or steeper

are considered Class IV soils.

9. Distrubed Cohesive Soils (backfill) shall be treated as fissured medium cohesive or soft cohesive soil.

10.

Spaced Shoring Systems (skeleton sheathing or skip shoring) are permitted in stiff and medium cohesive soil with maximum center to center spacing in accordance with Table 5.5.

*/ Cohesive Soils are clays (fine grained) or soils with a high clay content which have

cohesive strength. They do not crumble, can be excavated with vertical sides lopes, are

Pi aatic (can be molded into various shapes and rolled into threads) when moist and are hard to break up whan dry.

^/ Granular Soils have no cohesive strength. They normally can not be excavated with vertical

sideslopes (some moist grsnular soils will exhibit apparent cohesion and temporarily stand on a vertical slope), they can not be molded when moist and curable easily whan dry.

1 tsf - 94 k?a

41
P. O. BOX 866

SCOTTDALE, GA. 30079

292-7721

T & B - Scoftdale Contractors, Inc.

(Contractors

July 7, 1981

United States Department of Commerce

National Bureau of Standards

Building 226, Room B162

Washington, D. C. 20234

Att: Dr. Felix Y. Yokel

Dear Sir:

Mr. John Chambless of the Georgia Branch A.G.C. has forwarded

a copy of your draft memorandum on the Atlanta Workshop for

my comment

Comparing your memo with notes I made during the meeting, I

believe the memo accurately states the responses to the issues

raised.

Thank you for being in Atlanta with us and please accept this

note as the response of the Georgia Branch A.G.C.

Sincerely,

I

I
ASSOCIATED PUBLIC WORKS CONTRACTORS

OF CHEATER MILWAUKEE, INC.

IOHN DRAKE

Executive Director

283S N. MAYFAIR ROAD

MILWAUKEE, WIS. S3222

TELEPHONE: 778-1050

June 30, 1981

Mr. Felix Y. Yokel

United States Dept, of Commerce

National Bureau of Standards

Bldg. 226, Room B-162

Washington, D. C. 20234

Dear Mr. Yokel:

We have received a copy of your "Memorandum for Records of the

NIOSH Excavation Project" of the Workshop held in Milwaukee on

June 9, 1981 and would like to express our sincere appreciation

of your evaluation of many of the points that have concerned

our industry since we have implemented the OSHA Regulations in , our operations. Your interest in this vital matter has exhibited

a very practical consideration of these problems that our important

to us.

Following the meeting our committee appreciated the necessity of

submitting a more detailed analysis of Chapter 6 Wisconsin Code

and we are meeting with representatives of the State of Wisconsin

Department of Industry, Labor and Human Relations on Tuesday,

July 7, after which we will be preparing information that we

will submit to you as soon as possible.

Very truly yours

A, : WORKS CONTRACTORS

Jcmn Drake

Executive Director
r

u

ASSOCIATED

GENERAL

CONTRACTORS

of Greater Milwaukee, Inc.

®2733 West Wisconsin Avenue • Post Office Box 08374

Milwaukee, Wisconsin 53208 . (414) 933-7661

June 30, 1981

Dr. Felix Yokel

United States Dept, of Commerce

National Bureau of Standards

Bldg. 226, Room B162

Washington D.C. . 20234

RE: Draft Memorandum

Milwaukee Workshop

June 9, 1981

Dear Dr. Yokel:

We have reviewed your draft memorandum and feel that it

accurately and concisely reflects the Milwaukee proceedings.

You have covered the major areas of local concern in your

memo

We wish to take this opportunity to thank you for your consideration of our problems. You are to be commended for your

excellent effort in producing data for a workable OSHA

Excavating Standard.

We have forwarded your calculations for subchapter 6 to the

State of Wisconsin so that they could compare them with their

original data. We will keep you updated.

Sincerely,

cc: Art Schmuhi

Gil Czaplewski ' ~~ Dick Snow

[
August 25, 1381

Dr. Felix Yokel

United States Department of Commerce

National Bureau of Standards

Bldg. 226, Room B162

Washington, D.C. 20006

Re: Secretarial Report

Trenching and Shoring Workshop

Milwaukee, Wisconsin

June 9, 1981

Dear Dr. Yokel:

We are enclosing our report of the Trenching and Shoring meeting held in

Milwaukee on June 9,~ 1981. Attached to it are copies of the written

statements received.

We wish to thank you again for coming to Milwaukee to hear our concerns and

ideas and to commend you on your excellent efforts to develop an equitable

standard for trenching and excavating operations.

Please feel free to contact us if we can be of any assistance to you.

Sincerely,

Edward J. Haycren

Safety Director

cc: James Elliot

John Ramage

John Drake

Enclosures

EJH/kg

89
Report of the Local Sponsors Workshop

Workshop to Review and Comment on the National Bureau of Standards Recommended

Technical Provisions for Construction Practice in Shoring and Sloping of

Trenches and Excavations.

June 9,' 1981

Red Carpet Inn

Milwaukee, WI

This document constitutes the report of the local sponsors of -the referenced

workshop. The attendance at the workshop was as follows:

Art Schmuhl

John Ramage

Dr. Felix Yokel

Gary L. Dowty

Jim Lapping

Jack Mickle

Greg Johnson

Paul Bouley

David Schuman

Bruce Weber

Patrick Harrison

Jeffrey Miller

Kevin Foley

Roy Mururo

James Elliott

Janomiso Piocchilin

Russ Adam

Jack Peterson

Tom Crandal

George Bradberry

Ed Hayden

Melvin Lischefski

Fred Becker

Robert Hanna

Harvey Peterson

Gil Czaplewski

Philip Kenny

John Drake

Walter Schmitz

Lawrence Michael

Ray Olson

Philip Santacrose

Kennie Hatfield

Ted Trulson

George Stepanik

AGC National

ASFE

hBS

AGC-Indiana

BTC-AFL-CIO

AFL-CIO

AGC

OSHA-Washington

S.J. Groves

Warzyn Engineering

Milwaukee Testing

Giles Engineering

AFL-CIO

Laborers Local 113

Milwaukee Bldg. Trades

Operating Engineers #139

OSHA-Region 5

OSHA-Wisconsin

OSHA-Wisconsin

Underground & Shoring Service

AGC-Milwaukee

OSHA-Wisconsin

Becker Construction

OSHA-Wisconsin

C.G. Schmidt

Klug & Smith

Kenny Construction

Associated Public Works

Rock Contractors

Associated Public Works

Globe Contractors

Thomasini Contractory

K.M. Dunn Co.

F.P. & T. Company

AGC-Wisconsin
4

Jack Love

Joseph Ramuta

Jack Delaney

Thomas Peterson

Richard Snow

Alan Carlson

Milan Racic

Robert Glukas

Donald Zehm

Jim Bonness Russell Zehetner

D & K Construction

Michaels Pipeline Construction

DILHR

Johnson Brothers

AGC-Milwaukee

AGC-Milwaukee

Allied Industry Workers

Soil Testing Services

OSHA

Koch & Bonness

MSS

We are attaching written copies of statements made at the meeting by:

Associated Public Works Contractors

Rock Contractors Inc.

S.J. Groves Inc.

Building and Construction Trades Council

Associated General Contractors of Greater Milwaukee

In addition we are attaching a comment received from A1 Johnson Construction

Company, who were not able to be represented.

The balance of the comments were oral and not submitted in writing. The

workshop was recorded for reference.

As with all programs of this type, there was a' wide divergence of ideas,

interests and philosophies. There was, however, one point that achieved local

consensus—any OSHA standard covering trenching and excavation must be clear

and concise so that the workers in the field can understand what is required

to provide a safe workplace and it should cover as many situations as possible

with standard practices.

Other points of discussion included:

1.

The use of local codes as approved substitutes without further

engineering requirements Wisconsin has an existing code titled Wisconsin

Administration code. Rules of Industry, Labor and Human Relations, Trench,

Excavation and Tunnel Construction. In common usage this is referred to as

Chapter 6. Arguments advanced for permitting its use for compliance included;

1. Its history and track record.

2. Its familarity to both companies and employees.

3. Its use of the same size timber with various spacings depending on

conditions.

/

4. Its allowance of 1/2 to 1 in certain soil types.

The whole crux of the discussion centers around alternatives allowed as

compliance to any standard. A great many Wisconsin area people feel that

existing and proven local codes should be allowable.
2. One provision of subchapter 6 must be singled out because of its number

of supporters. The regulations allow a slope of 1/2 foot to one for dry or

moist soils. The steepest allowable slope in the proposal is 3/A to 1.

Several speakers stated that they knew of no failure in trenches properly

sloped according to Chapter 6 requirements. In metropolitan areas less slope

means less disruption of existing services and facilities (roads, streets,

sidewalks, utilities and lawns. It also decreases exposure time and area when

working adjacent to heavily traveled roads.

3. The Consulting Engineers expressed concern over the increasing

occurrence of third party liability suits. Requirements for engineers to

design and oversee all trenching and shoring protective mechanisms would

increase the liability of the foundation engineer. The engineers stress the

need for a code that takes a reasonable approach to the involvement of the

consulting engineer and their liability exposure.

A. Closely allied to the concerns of the engineers is the question of

competent versus qualified persons. Part of the problem stems from a lack of

understanding of the difference between the two terms. The national AFL-CIO

position is that a license is required. In Milwaukee, contractors contend

that a competent person i.e. "one who Is capable of identifying existing and

predictable hazards in the surroundings or working conditions which are

unsanitory, hazardous, or dangerous to employees and who has authorization to

take prompt corrective measures to eliminate them" is sufficient for most

situations. Similarly, their definition of a Qualified Person would delete

the words "by possession of a recognized degree, certificate, or professional

standing or." Contractors contend that their on-the-job employees are in the

best position to react to job conditions and take proper safety measures.

Part of the contractor’s fears about strict requirements for engineers stems

from the belief that the requirements will increase the amount of "force

account" work done by municipalities that have engineers on their payrolls and

are not bound by 0S-1A requirements in any event.

5. Several parties expressed concern over standards enforcement. In

particular they feel that it must be positively stated that provisions of the

standard apply only to areas where there is employee exposure. If employees

do not enter portions of the trench or excavation no protection should be

required.

6. It was recommended that all portions of the existing standard be

carefully reviewed before they are included in a new standard. For example

salt calcium chloride and oil are no longer environmentally allowable methods

of dust control (1926.651 i) and stop logs are impossible to use in

backfilling situations (1926.652 g)

/ 7. Dr. Yokel's study has gone a long way In analyzing what most parties

agree has been a weakspot in OSHA regulations. There is however many more

opposing viewpoints to be reconciled. We believe that these area workshops

represent a positive advancement in the development of OSHA Standards since

they give all local groups an opportunity to provide their input into future

standards. This can help provide standards that are workable, viable, and

effective.

92
J]]J

]•JJJ

-srl J

Milwaukee

93
ASSOCIATED PUBLIC WORKS CONTRACTORS

OF CREATE* MILWAUKEE, INC

JOHN DRAKE

Executive Director

2835 N. MAYFAIR ROAD

MILWAUKEE, W1S. 53222

TELEPHONE: 778-1050

COMMENTARY BY: ASSOCIATED PUBLIC WORKS CONTRACTORS of Greater

Milwaukee, Inc

TO: U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU

OF STANDARDS

WORKSHOP JUNE 9, 1981 MILWAUKEE, WIS

WORKING DRAFT OF SUGGESTED REVISION IN SUBPART P OF THE SAFETY AND

HEALTH REGULATIONS FOR CONSTRUCTION BASED ON BUILDING SCIENCE

SERIES REPORT BSS 127 BY: FELIX Y. YOKEL.

My name is John Drake. I am the Executive Director of the Associated Public Works Contractors and have been since 1965. Prior to

that I had been working as an engineer for the City of Milwaukee

from 1927-1940, primarily on sewer and tunnel construction and

from 1940-1965 I was superintendent and officer of 2 large sewer

construction companies.

The Association appreciates the opportunity to participate in this

workshop. We feel that the efforts to revise OSHA Rules and Regulations are very important to the industry not only for the safety,

but for the economics involved.

Since 1935 this Association's members have performed the bulk of

the sewer, water and utility work in the State of Wisconsin.

In 1952 we were pleased to have participated with other elements

of the construction industry to assist in developing the WISCONSIN

ADMINISTRATIVE CODE, Rules of Industry, Labor and Human Relations,

Trench Excavation and Tunnel Construction Code Section 6.01, parts

of which are attached. We are proud to advise you of the fact that

not a single injury or fatality has occurred with the use and

utilization of the WISCONSIN CODE Chapter 6.

We respectfully request and suggest that this Code, with the accompanying tables, be considered at least equal or superior to the present

OSHA requirements and become a part of them.

With respect to the draft recommendations of The National Bureau of

Standards we have the following comments on the issues to be considered for the workshops on page 3:

1. We feel that no change is necessary.

- 1 -

94
- 2 - June 9, 1981

2. Yes, 5' rather than 4'.

Yes, exit requirements should be waived.

Yes, large enough pipes should be recognized as shelter.

Definition, "negotiable slope" is satisfactory.

3 * Yes, we feel the depth limit could be, in standard practice,

extended to 24'.

A qualified person should be substituted for an engineer.

4. Yes, 7 days should be considered rather than 1.

5. We definitely feel the maximum slope should not be limited

to three-quarters to one.

The suggested performance requirement should be used; it is

a workable approach.

6. Yes, we agree the allowable bank should be increased.

Excavation should not be limited to trenching machines.

7. No comment.

8. Yes, we agree with more options on proposed performance

statements

.

9. Yes, we certainly agree that the excavation of the bottom

of shoring shields be increased to 3' or more under proper

conditions.

10. Yes, a registered architect should be omitted.

11. Our operation requires that competent people be employed.

We feel the judgment of the degree of competency should

also be extended to the enforcement officer.

12. Yes, mass movement of soil or rock should be defined.

13. Yes, it should be deleted.

In general we would also like the workshop to emphasize:

1. A reasonable evaluation of sloping. This is probably one of

the biggest items to be considered. The history of this

industry indicates that predetermining a slope is practically

an impossibility. This is where the proper, competent person's judgment should be considered more valuable than

textbook calculated slopes. Certainly the necessity of

bracing shallow trenches, those below 5', in many instances,

is most impractical and a costly item.

95
-3- June 9, 1981

2. The predetermining of the depths, whether 20 or 24', is

again very difficult to predetermine because of the varying

soil conditions and other circumstances.

3. A very important item is the practical evaluation of the

"timbering" and bracing of trenches. The variation of

"timbering" sizes in OSHA although calculated to provide

the right support, is not practical. The more practical

installation would be uniform timber sizes with variation

of spacing.

4. The greater majority of our work is under "short term excavation." Restricting this to 1 day would be most impractical and we feel the extension to 7 days is important.

5. The consideration of the depth below "shields" is a very

important item. An evaluation of the specific job being

constructed and the soil conditions should certainly

determine the allowable distance below the shield.

We realize the concern, not only of our industry, but our entire

country regarding the necessity of safety standards. We also

appreciate your making this attempt to make the standards for our

industry not only to provide a safe place. for our men, but to also

safeguard the industry.

Thank you, very much, for this opportunity to speak, not only for

myself but for our members.

John Drake, Executive Director

Associated Public Works Contractors
10 WISCONSIN ADMINISTRATIVE CODE

TABLE 4—TRENCH TIMBERING REQUIREMENTS

For tranche* over 42 Laches in width up to and

Including 12 feet in width

Depth of Trench Uprighu Cram Braces Stringers

Over 48 ft. to 10 ft, ted.

* C)

4s£ inch timbers spaced horizontally 7 ft fees to face 4x6 inch limbers spaced 4 ft c—<

8x8 Inch timbers spaced boniontelly 11 ft fees to (ace 6x6 inch timbers spaced 4 ft ©—e

<*)

6*6 inch timbers spaced horizontally 7 ft face to face 6x6 inch timbbars spaced 4 ft c —<

SO ft. tecL 8x8 inch limbers spaced horizontally

11 ft face to face 8xK inch timbers spaced 4 ft. c—

c

<•>

6x8 inch timbers spaced horizontally 7 ft. fare to fees 6x6 inch limbers spaced U It. c—

c

SO ft tecL 8x8 inch timbers spaced horizontally

11 ft face to face 8x8 inch timbers spaced II It c —

c

C>

8x6 inch timbers spared horizon(ally 7 ft face to face 8x6 inch Umbers genii 3 ft c- —

c

40 ft. ted. 12x12 inch timbers spaced horizontally lift, face to face 12x12 inch umiwn

Apactd 3 ft- e—

c

<•) Upright* (hall coastal of 2 inch planks and «pacad to cnmply with specifications for trenches lees than 42 inches in width. TABLE 5—TRENCH TIMBERING REQUIREMENTS

For trenches 4 W to 15 feet in depth, 3W to 12 feet in width, and

cut in hard soil*

Depth (ft) Width (ft) Uprighu Cram Braces

4M- 8 a»-i2 2x6 inch planks

spaced 4 ft c—

c

2 —3x8 inch struts spaced 4 ft e—

c

8 -12 3Vi-12 2x6 inch planks

spaced 4 ft. c —

c

3 4x6 inch slmU

•fMcnd 4 ft. c -c

13 -16 av»-i3 iltfh apmcmd 4 fi. c—

c

4 —4x6 inch struts spaced 4 ft c—

c

•In case unstable soil is encountered, bracing shell immediately revert beck to that out Hoed in Table 4.

Hietery. Cr. Register. December. 1982, No. 84. eff. 1-1-83; am <11 (intro.), (6) end (9). Register, September, 1978, No. 273, eff. 10-1-78.

Register, September, 1978. No. 273 Trench, Kicavstino aad Tunnel Caostrurtioo
Wisconsin

Administrative Code

Rules of

INDUSTRY, LABOR AND HUMAN

RELATIONS

TRENCH, EXCAVATION AND

TUNNEL CONSTRUCTION

Cite the rules In this Code as

(for example)

Wis. Adm. Code section Ind 6.01

INDUSTRY, LABOR AND HUMAN RELATIONS

201 East Washington Ave.

Madison, Wisconsin 53702

Part II TRENCHES AND EXCAVATIONS

lad (.0$ Timbering requirements sad procedures for trenches

and other excavations. (1) Brack ok slope. All areas in trenches in which persona are permitted to work shall be adequately and securely

timbered or sloped as follows.

(a) Depth. Exception. Trenches cut in hard solid soil need not be

braced or sloped if less than 4 Vi feet in depth. Trenches cut in loose or sandy soil need not be braced or sloped if less than 3 feet in depth.

(b) Rock. Exception. Trenches need not be timbered if excavated in solid rock and if there have been no previous known excavations within

the minimum lateral distance of the depth of the trench being excavated. The total depth of the trench must be in rock or any over burden

must be sloped or braced.

(c) Sloping. Exception. Trenches need not be timbered if the sides are cut down to the angle of repose. The angle of repose shall not be

considered greater than one to one-half (measuring one foot of rise to each H foot horizontal) for dry or moist soils and not more than one to one for wet or heavy soils.

(2) Partial slops and sknchxs. When the sloping of trench walls to the angle of repose does not extend to the bottom of the trench, level benches 2 feet wide shall be provided between the toe of the slope and

the top edge of the vertical walla. The vertical part of a partially sloped

trench shall be braced according to its vertical depth below the bench. If benches are not provided as in case of the necessary trimming back of loose material at the surface, the trench shall be braced according to its

lUcfciar. SvptMabar, 1*78. No. 173 TrwacS, Kua«*tioa and TuhimI Co—tnas ton

L

98
6 WISCONSIN ADMINISTRATIVE CODE

Rafiam. StpUalm. 1978, No. 273 Tnnch, Eicavtuao and Tunaal CnMniction
I

WISCONSIN ADMINISTRATIVE CODE

ua

Sapfenbr, 1V78, No. 273 Tnach, Kuavtiion and Tuoiwl Comtructkm

•e»

koa

B S

ila

k j2

«

>- d

C^eo^d

v ~ CO .il-SJB

Xw

CO

None tNone None 1x6

inch b

placed

bat

uprights

n

trench 6x6

inch t

equivalent

depths

un

4

for

dept

15

ft

S2d k k Q o • J» b k*lO O V ** fcO ® —i %mO V

552

•o . S«i • l 5 l 5 T

B 3 B 3

JS 3 ^

c^=co

aa^

« 1

§S

Is?

JC CO C *'“*

CB J- _

"S. d^5

J* k

c ? • 5 «

a “’I!

timbers

aced

6

ft.

«3 a *c"°_e

*c c- a> JS k"C

-Sw j=

«J x a

•j 5

t:-5

j= k a «0 U k-f; o o _ « o * o 5 K c. 8k

.£<£ Q.

0> C <aiO “ w * c^*o “ k. s

-C ®. u +-> c~o C c<£ <=<s C c

t£> k. Tsr.

tO

1 ‘5*"*“

3—2x6

qaivale 3

ft.: 4

|

(Oil-

<5

1

— JLJ *«> 0*5

eo cr_; CO jTCO CO c6 cro ^ K O-

• O -h CO 4>

2 iT si js T jT‘ 5“ C U c 0 c o

JC « . « . * . bek &£ ”o.<£ aci aw *M bc a jc co J3<*> x: 04 -.£

c"° .5 «u

J*T3

•= 8

1*2

u

c"0 E 8 £ «

CD <3 CO <0 <x> a co a .£ cu h a * a * a J* O’ “x:

(N to 04 B 04 b 04 a) 04 B

"O >,

_J> c

d ‘oa l 1

JS =3 4> V3 >

e" U W

O T> 33 T2

"a.B

*DC

5

O

B

T3 1

2

C

X

eaT

•+*CA . bg=

o £ *

k

X

S

X

*5O «

CO 4* </J.£ 5 cl£ Kc sC> .£ c «2> .3i 3

o s

m

3

# o

*>

B

3

o>

s

JK J3

__ W

4> V

k

S

*5 0

c

2 c k •» a a

JO O k >»

*. ® •a — c c

23 » «

> J3 Wh k

a *> a > 3£H J 2

w £

o

£ S

o

v 00 _ * C» > C

? BO Jl4* *•’*

^

C. go

> c

£ «

«m> o

£3

*w o

8‘-g

g-5

g 5

£82 Id cutf 0,-5 J=S k M

•—i 0>

I

ii

L

S 3

a -

3 1-0 x-t I

•

<C 6 s • ? S

c £ -5 i 8 :

r i

fhi

r.ii

8 I c £

b - 3 : u *5* A *• TO . e» « jo.£

£ * o •

|

C

if

C

r

c

L

II

100
287 -27th STREET

CALEDONIA, Wl 53108

TELEPHONE (414) 835-2935

COMMENTARY ON SUGGESTED REVISION IN SUBPART P

OF THE SAFETY AND HEALTH REGULATIONS FOR

CONSTRUCTION BASED ON BUILDING SCIENCE SERIES

REPORT BSS 127

U. S DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

WORKSHOP - JUNE 9, 1981

MILWAUKEE, WISCONSIN

GENTLEMEN:

MY NAME IS WALTER P. SCHMITZ, PRESIDENT OF ROCK CONTRACTORS, INC.

287 - 27TH STREET, CALEDONIA, WISCONSIN. I AM A REGISTERED

PROFESSIONAL ENGINEER WITH A MASTER OF SCIENCE DEGREE IN CIVIL

ENGINEERING. I HAVE HAD 33 YEARS OF EXPERIENCE IN THE DESIGN AND

INSTALLATION OF UNDERGROUND IMPROVEMENTS UTILIZING TRENCH EXCAVATION

AND TUNNEL CONSTRUCTION. I PREVIOUSLY WAS ENGINEER - IN - CHARGE

OF CONSTRUCTION FOR THE CITY OF MILWAUKEE, RESPONSIBLE FOR ALL

SEWER, WATERMAIN, AND PAVEMENT CONTRACT CONSTRUCTION IN THE CITY.

I ALSO AM A PAST PRESIDENT OF THE ASSOCIATED PUBLIC WORKS

CONTRACTORS ASSOCIATION OF GREATER MILWAUKEE AND A PAST PRESIDENT

OF THE MUNICIPAL ENGINEERS ASSOCIATION. FOR A NUMBER OF YEARS I

WAS CHAIRMAN OF THE CITIZENS’S ADVISORY COMMITTEE FOR REVISIONS TO

THE TRENCH, TUNNEL AND CAISSON BRACING REQUIREMENTS OF THE STATE

OF WISCONSIN ADMINISTRATIVE CODE.

INCORPORATED 1954
-2

AFTER REVIEWING THE PROPOSED STANDARDS, I AM PARTICULARLY CONCERNED

WITH TWO AREAS. THE FIRST IS TRENCH SLOPING AND THE SECOND IS

TIMBERING REQUIREMENTS FOR TRENCHES, SHAFTS, AND TUNNELS. I AM

CONCERNED FOR TWO REASONS «. FIRST, THE ACTUAL SAFETY OF OUR MEN

WHO WORK IN THE TRENCHES — SECONDLY, THE PRACTICAL APPLICATION OF

THE STANDARDS TO THE TYPES OF SOIL- IN WISCONSIN AND THE MATERIALS

AVAILABLE TO US FOR BRACING AT A REASONABLE COST IN OUR STATE.

CHAPTER 6 OF THE WISCONSIN ADMINISTRATIVE CODE OF THE DEPARTMENT OF

INDUSTRY, LABOR AND HUMAN RELATIONS HAS BEEN USED FOR APPROXIMATELY

THIRTY YEARS FOR TRENCH EXCAVATION AND TUNNEL CONSTRUCTION BRACING

REQUIREMENTS. DURING THIS TIME IT HAS HAD A REMARKABLE RECORD

OF PERFORMANCE. DURING MY 33 YEARS OF DEEP INVOLVEMENT IN THE

INDUSTRY, I AM UNAWARE OF ANY ACCIDENT OR INJURY CAUSED BY THE

FAILURE OF THE SLOPING AND BRACING REQUIREMENTS OF THIS CODE.

ACCIDENTS AND INJURIES DO OCCUR DURING BRACING INSTALLATION AND

I SEE NUMEROUS REQUIREMENTS OF THE NEW STANDARDS WHICH WILL LEAD TO A

POSSIBILITY AND PROBABILITY OF INJURIES. TIME AVAILABLE TO ME WILL

NOT ALLOW DETAILING THESE AT THIS TIME, BUT I WILL BE PLEASED TO

HELP IN ANY CONFERENCE WITH THE BUREAU TO DISCUSS THESE PROBLEMS.

BECAUSE OF THE REMARKABLE SAFETY PERFORMANCE OF CHAPTER 6 OF

WISCONSIN’S ADMINISTRATIVE CODE, I IMPLORE THE BUREAU OF STANDARDS

AND THE DEPARTMENT OF LABOR TO ALLOW THE FOLLOWING SECTIONS OF THE

CODE TO BE ALLOWED TO BE USED AS AN "EQUAL OR SUPERIOR" ALTERNATIVE

FOR USE IN WISCONSIN TO THE PROPOSED OSHA STANDARDS. THESE SECTIONS

ARE:

102
-3

PART II IN ITS ENTIRETY

PART III TABLE 6, TABLE 7

IND 6.12 THROUGH 6.22 INCLUDING

FIGURES 3 THROUGH 12.

A CAREFUL APPRAISAL OF THE RECORDS OF THE WISCONSIN DEPARTMENT OF

INDUSTRY, LABOR, AND HUMAN RELATIONS WILL SUPPORT THE FINE SAFETY

RECORD I HAVE REFERRED TO AND WE HOPE THE DEPARTMENT OF LABOR WILL

SEE FIT THROUGH THE BUREAU OF STANDARDS RECOMMENDATION TO ALLOW

THE SUGGESTED ALTERNATIVE. I AM ABSOLUTELY CERTAIN INJURIES AND

DEATHS WILL BE PREVENTED.

THANK YOU FOR YOUR SERIOUS CONSIDERATION OF THIS RECOMMENDATION.

SINCERELY,

ROCK CONTRACTORS, INC.

Walter P. Schmitz, President

103
SUBJECT

• Mr» Edvard J« Hayden

The AGO of Greater Milwaukee

P.C. Box 08308

2733 West Wisconsin Avenue

Milwaukee t VI 33208

S. J. GROVES & SONS CO.

P. O. Box 2009

Springfield, Illinois 62705

Telephone (217) 787-2494

Comments for the workshop on suggested revision in 29 CFR 1926, Subpart P

POLO MC*C “date10 June 8l

Dear Ed t

*

The attached list of comments^ -presented at the workshop June Q t lQ8l, is far

your record. Inasmuch as this was the first of the workshops on this subject t I

feel there is no real evidence which would support the change to the existing

regulations. Thanks again for the opportuni ty to present our riews on the matter

_[

-L

J—

WGNED A. . David Lo Shuman

i—

lias ««CWT POMMS. HiXMAVR, K_L Mm SPEED-MEMO —
1) THE CURRENT STANDARDS ALLOWS THE PROTECTION REQUIRED FOR THE EMPLOYEES, BY THE

EMPLOYER, IREE OF HAZARDS.

2) THE RECOMMENDED CHANGES WILL INCREASE COSTS TO PERFORM THE WORK, WHICH WILL

. ADVERSLY AFFECT OWNERS (TAXPAYERS)

I 3) THE EXISTING REGULATION ARE SOUND AND IF WE ACCEPT A CHANGE OF THIS TYPE IT

WILL DEVELOPE AN AREA OF LIABILITY WHICH STILL DOES NOT RELEIVE THE EMPLOYES

OF THE RESPONSIBILITY OF PROVIDING A SAFE AND HAZARD TREE WORK ENVIRONMENT.

k) NEW REGULATIONS DO NOT ALLOW ACCEPTED INDUSTRY PRACTICE.

5) HAS INDUSTRY HAD ANY SERIOUS PROBLEMS WITH TABLE P-1, IN EXISTING REGULATION ?

6) THE NEW REGULATIONS WILL PLACE STRINGENT CONDITIONS ON SMALL BUSINESS, UNLESS

THE CONTRACT IS AWARDED UNDER SECTION 8(a) (COST PLUS) OF THE SMALL BUSINESS ACT.

7) THE RECOMMENDATIONS DO NOT SHOW ANY COST EFFECTIVE BENEFIT.

8) WILL OSHA INSPECTORS BE ABLE TO UNDERSTAND THE REGULATIONS AS PROPOSED, AND

PROPERLY INSPECT ?

105
V drah

DISCUSSION OF

WORKING DRAFT OF SUGGESTED REVISION IN SUBPART P OF

THE SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION

BASED ON BUILDING SCIENCE SERIES REPORT BSS 127

by Felix Y. Yokel

by

BUILDING AND CONSTRUCTION TRADES DEPARTMENT AFL-CIO

JACK L. MICKLE

MILWAUKEE, WISCONSIN JUNE 9 » 1981

106
DRAFT

Dr. Yokel is to be commended for his efforts to improve upon

the Occupational Safety and Health Administration , (OSHA), 29

CFR Part 1926. Subpart' P, . Excavation , Trenching and Shoring Regulations document.

The Building and Construction Trades Department, APL-CIO has

been supportive of and assisted Dr. Yokel, where possible, since

he began work on this project with the National Bureau of Standards in June, 1976.

In January, 1977 the B&CTD began the planning ' s tage of a

"Trenching Hazard Identification Task Force" , hereinafter called

the Task Force, to help the NBS obtain employee input aimed at

hazard identification. In March, 1977 the Task Force met for a

four day "retreat" type workshop; the six' labor and management

members brought with them 182 years of experience in trenching

and related work. The charge was "to identify procedures and

conditions that create safety hazards during excavation and

trenching operations". Others present for the deliberations

were Jim E. Lapping, Director of Safety and Health, B&CTD, as

coordinator; Felix Y. Yokel as Technical Observer for the NBS

* and Jack L. Mickle, Chairperson. The final report (1) was filed

with the NBS in April, 1977* The final report appears in appendix G of NBSIR 80-1988 (2).

In September, 1978 Dr. Yokel (3) presented the preliminary

findings and recommendations of the NBS study. Out of that twoday workshop came the agreement for this series of workshops to

bring the results of Dr. Yokel's NBS study to the attention of

labor, management and engineers in the field. Actually the

essence of the working draft we are using for this workshop was

printed in the Concrete Pipe News (4) in April of this year.

Since the 1978 workshop the B&CTD has responded to a number

of requests for criticisms of drafts by Dr. Yokel.

* Numbers in parentheses refer to references given at the end of

this paper.

107
DRAFT

Two premises underlie all remarks and criticisms given in

this critique:

TIat the worker he assured of safe and healthful

•working conditions, and

that the journeyman worker and the compliance

officer as well as the management repressntative

he able to fully understand the precautions that

have been taken and the protective measures that

have been provided to assure worker safety and

health, or that the safety of the worker on the

job be placed in the hands of a licensed professional.

The first premise is spelled out in the preamble of the

Occupational Safety and Health Act of 1970.

The second premise assumes that an average journeyman or

compliance officer, using the official OSHA regulations governing excavation and trenching safety, can determine whether or

not the safety provisions on any jobsite- are in compliance with

the appropriate regulations. If the provisions are not "standard practice" as outlined in the regulations then there must be

a certificate issued by a licensed professional which assures

the worker that the jobsite safety and health measures have been

designed by and certified by the licensed professional.

There are undoubtedly many "competent persons" and qualified persons" who are quite capable of designing a safe worksite,

but how are they to be identified by the worker or compliance

officer? The license is the evidence. All licensing laws have

encountered competent or qualified persons and have eventually

incorporated them into or excluded them from practice. While

there are probably quite capable people who know a great deal

about medicine or law, the .prudent individual seeks the licensed

practicioner when medical or legal opinions or services are

sought.

Actually suggesting that registered engineers need to be

consulted is not new with this suggestion. Thompson and Tanenbaum (5) recommend substantial involvement of registered enginc

il

108
DRAFT

eers in construction activities requiring trenching or excavions •In view of the foregoing, this discussion will be concerned

with only the first 20 pages of Dr. Yokel % working draft which

outlines "standard practice". Even portions of the first 20

pages probably belong in the "guidelines" which have been included to assist professionals. It is also assumed that only

the "standard practice" will eventually be recommended for inclusion in the OSHA regulations Subpart Pj Dr. Yokel has indirectly suggested that by what was included in the article which

he co-authored in the Concrete Pipe News ,(4).

109
DRAFT

COMMENTS ON SEIZCTED ITEMS ON PAGES 1-20 OF THE WORKING DRAFT

Page Location Comment

1

2

2

3&4

5

5

6

6

6

8

8

8

.item 3

item 5

last

line

All

Issues

(g)

(i)

(j) 2nd

para,

line 8

(c)(1)

line 3

(c)(2)

line 3

( 1) line 2

(o)

(P)

7. boxes. It is addressed to contractors, shoring

manufacturers and engineers..." Why address it to

the contractor unless the contractor is also an

engineer?

"...which would aide field personnel and contractors in the selection of shoring." Once again,

these persons are going to be dealing with the

standard practice unless they are licensed professionals in their own right.

Note that a qualified person is not an engineer

(recognizing this as just an example)

The items listed on pages 3 and. 4 will be considerindivi dually as they encountered in the text.

..be provided with and shall be inetrueted (required) to wear .... ...shall be permitted under loads handled by

pewes1 —ehevele-r-deyFieksT-ey-heieteT (equipment) . This item is too specific for not listing all

equipment which is used to handle loads; for

example, backhoes are not listed.

...or the shoring system, and shall ineFease-BFe—

tee^ien-agains%-fllides-and-eave-ine—if-neeeesaryT

(see that all work in the excavation shall cease

until necessary precautions have been taken to

safeguard employees.)

7..

shall be effectively stored and retained at

least 2 (3) feet or more from the edge of the

excavation." The Task Force specifically stated

that 3 feet was necessary for proper protection.

"...may use effective barriers ©F-etheF-effeetive

Fe^aiHiRg-4eviees-iH-lieu-theFeef in order..."

Task Force recommended extending tight sheeting

above ground level as an effective barrier. Twelve

to 18 inch extensions were discussed.

7.. equipment, th^ shall be designed—and constructed by qualified persons..." Design implies work

done by a licensed professional.

This item is silent with respect to straight sided

pier holes; some confusion has arisen because

straight sided holes are covered elsewhere. 800(h)(3)

When employees are required to be in trenches 4

feet deep...." leave at 4 feet.

( 5)

Ho
DRAFT

Page Location

8 (s)

9 (a) (l)a

9 (a)(2)

9 (a) (2)a

line 3

9 (a)(2)b

Figure 1

10 (a)(3)

10 (b)(1)

line 6

Comment

"...boxes or shields are used they shall be designed (and certified as to use by a professional

engineer and shall be maintained in a manner which

will provide protection for the worker.)" Strike

the balance of (s).

Excavations less than 5 ft* deep, except when exesinatien-ef-the-gyeynd-by-a-eeapeteRt-peFseR-inda—

eates-that hazardous ground movement may occur."

"Excavations from 5 ft. to 20 ft. 424-ft-r?-) deep.."

Why consider 24 feet? A better choice might be

15 feet for standard practice. Thompson and Tanebaum data (5) indicate that 87 per cent of the fatalities and injuries occur in excavations less than

20 feet deep and that ?2 per cent occur in those

less than 15 feet deep.

Hinze and Carino (2) state in their summary that

their "..study showed that most trenchwork is between 5 and 15 feet deep with the trench width

usually being about 3 feet."

Cass ' (6), speaking about the stacking of two standard 7 ft. aluminum hydraulic shores, notes that

where the trench is over 14 feet deep (page 68)

9 other- shoring systems should be applied" and on

(page 72) "Maximum trench depth, this method, is

15* (4.58 m) • Over 15* (4.58m), see Fig. 60.2,

multi-type shoring." Multi- type shoring shown on

Fig 60.2 is a different system using aluminum

hydraulic shoring and plywood backing.

A maximum depth of 15 feet for standard practice

seems appropriate.

"..sloping requirements must be determined by an

engineer 4a-q«ali*ie4-peFseR?-)~r " May lead an individual to believe that FOOTING A

is. not a cause for concern,* this could be dangerous. It is worthy of note that the role of the

engineer has not been challenged at this point

where property damage as well as personal injury

is possible.

See comments under* page 9 (a)(2). Fifteen ft.

depth may be a better limit for standard practice

rather than 20 ft.

The distinction between short-term and long-term

is very difficult to reckon with; virtually no

firm data exists. Not only stresses in the mass

vary with time, but environmental factors may be

critical. Twenty-four hours seems more logical

than seven days.

( 6 )-

111
DRAFT

Page

11

12

13

13

13

13

13

16

Comment

There may be some merit to allowing steeper slopes

in some cases. The Task Force indicated that

slopes flatter than lxl were probably not necessary

for worker safety. Sopes of lxl were recommended

for most conditions.

This particular configuration should be made a

part of the "guidelines" proposed by NBS. While

the configuration looks good on paper, it may be

difficult to understand and/or enforce in the

field. If included in standard practice the 3 ft.

max bank should be retained.

(b)(1) (i)b. See the first four lines at the top of page 13*

Table 2 is necessary in standard practice only if

Fig. 3(b) is retained.. Moving the option shown

as Fig. 3(b) to the guidelines removes the need

for Table 2 which is confusing and also removes

the need for special tables and figures outlining

the placement of shoring in the lower part of the

ditch.

(b)(4)(i)c. For standard practice it may be . worthwhile to

include all surcharges, including allowances for

heavy equipment, in the adjusted depth. The Task - Force recommended a minimum of 300 pounds per

square foot for surfarge. Dr. Yokel has greatly

simplified Table 3 but it still can be confusing.

Moving Table 3 to the guidelines and greatly increasing the surcharges to allow for heavy equipment may lead to "overdesigned" shoring and

shields, but standard practice would thereby be

greatly simplified.

(i±)b«. The Task Force, recommended a 500 lb gravity load.

(ii)c. This statement is not clear. Does this mean a

240 ft-lb impact load per square foot? The entire

(ii)c. should become a part of the guidelines and

removed from standard practice.

(ii) This entire section devoted to the required

strength of shoring systems, trench shields and

trench boxes needs to be moved to the guidelines

b. If some of the previous: suggestions are followed,

hydraulic shores and other assemblies can be

brought into standard practice. At a meeting in

October, 1980 with NBS and members of the hydraulic shoring industry it was agreed that reasonably simple simple charts for the selection of

shores can be developed. This seems to be in

keeping with Cass' (o) recommendations for depth

to 14 or 15 ft. There is no question that the

resulting system would be greatly over-designed

Location

bottom

of page

last two

lines

Fig. 2

Case IV

( 7 >

112
Page Location

draft

16 *

16

16

18

19

19

19

19

19

20

Comment

c

.

(5) (ii)

last two

lines

(5) (iii)

(a)

(m)

(o)

(P)

(t)

(aa)

(gg)

at times, but the freedom to use standard practince for most work (2) and thereby not requiring

the services of an engineer seems to outweigh

the disadvantages . of overdesign.

Timber shoring is properly located in the guidelines ; selection must be by an engineer. The

guidelines are for the use of licensed professionals . The statement in parentheses is a vague performance specification which detracts from a well

stated, precise paragraph.

Excavation below the bottom of bottom of the

protective element has merit; exactly how much

to allow is difficult to determine. Certainly

engineers can design specific protection for

unique circumstances , the guidelines will help,

but permitting excavation below the protection

device in standard practice will require very

careful consideration.

". • .with standards required by a-Fegietea?e4-aj?ehir

tee-t-r a registered professional engineer, or other

duly licensed er-FeeegHieed authority. . •

Twenty-four hours for short term seems most reasonable.

Negotiable slope needs to be specified; l£il seems

reasonable.

How is a qualified person to be identified? Unless

there is a specific procedure anyone can claim to

be a qualified person. No objection is the qualified person is permitted to use standard practice

only.

same argumentr use 24 hours for short term.

Stable Slone . A meaningless term unless it is

arrived at by a licensed engineer. This term has

no. place in Standard Practice I Working loads are best relegated to the guidlines

where they can be dealt with by an engineer.

( 8 )~

113
Summary

DRAFT

There must he clear separation between Standard Practice

and cases where an engineer has certified the procedure to he

followed;

It is recommended that Standard Practice he permitted to

a depth of. cut of 15 feet; this includes most excavation and

trenching work. At depths greater 'than 15 feet, or for special

work, the engineer must assume full responsibility for the

design of the protective system. The 15 ft. depth needs verified.

Standard Practice must he written such that the protective

measures resulting from the application of Standard Practice

are observable, measurable, understandable by all parties (with

application of the regulations) and provide ,for the safety and

health of the worker. It is recognized that Standard Practice

may at times result in substantial • overdesign , but this would

not be new to the construction field.

It is anticipated that competent or qualified persons working for idle contractor would select methods, within Standard

Practice to protect workers, but that any deviation from Standard

Practice would need to be designed by an engineer. The engineer

is recognizable by a professional license.

Several items which need consi deration t construction

right of way requirements , toxic materials , safety program as

an item in the bid document, soil conditions and utilities in

the bid document and better safety education for all. The Task

Force final report lists other concerns.
DRAFT

References

1. Building and Construction Trades Department AFL - CIO.

Trenching Hazard Identification Task Force; Final Report.

* Prepared for the National Bureau of Standards ; Building

Safety Section; James 0. Bryson, Chief. April, 1977.

2. Hinze, Jimmie and Nicholas J. Carino. A Study of Work

Practices Employed to Protect Workers in Trenches; NBSIR

80-1988. National Bureau of Standards. March 1980.

3« Salomone, Lawrence A. and Felix Y. Yokel. Proceedings,

- Federal Workshop on Excavation Safety, September 19 and

20, 1978. National Bureau of Standards. July, 1979*

4. Yokel, Felix Y., Riley M. Chung and Ronald L. Stanevich.

New Concepts for Construction Practice Standards for

Excavations. Concrete Pipe News; pages 28-33* vol 33

no 2, April, 1981.

5. Thompson, Louis J. and Ronald J. Tanenbaum. Excavations,

Trenching & Shoring: the responsibility for design and

safety. Sponsored by the Associated General Contractors

of America. A report of 'the Texas A & M Research Foundation. College Station Texas. September, 1975-

6. Cass, W. Martin "Red". Common Sense in the Common Trench.

Equipment Guide-Book Company; 2800 West Bayshore Road,

Palo Alto, California 9^303. 1979*

( 10 )

115
ASSOCIATED |

2733 West Wisconsin Avenue • Post Office Box 08374

Milwaukee, Wisconsin 53208 • (414) 933-7661

Greater Milwaukee

Statement for the Workshop on the National Bureau of Standards

Recommended Technical Provisions for Construction Practice in

Shoring and Sloping of Trenches and Excavations.

June 9, 1981

The Milwaukee Construction Industry Safety Council is a cooperative effort originated and . administered by the AGC of

Greater Milwaukee. As such we slid in the safety programs of

800 area construction firms.

In answer to the specific issues outlined in the working draft

we take the following position.

1. We feel that 1926.651 (a) is --pertinent to a trenchinq and

shoring standard. Most underground services are located

in shallow trenches. Any excavation below 18 inches can

encounter buried utility lines. Many states have

laws requiring utility notification.

2. We believe that exit requirements should begin at five

feet. Observation indicates that working crews seldom

use available ladders unless the excavation is over five

feet deep anyway. Using five feet would cause a well

defined trigger point for action since it correlates

directly with the start of trenching and shoring

requirements

It is indisputable that larger excavations

allow effective escape to the center in case of collapse.

Consideration should be given to the use of this method.

The same is true of large pipes or other covered structures.

We feel that "qualified person" should be substituted for

"engineer". The actual work crews are in the best position

to judge the situation. Qualified on the job supervision

should be sufficient for everyday situations. We feel that

you have developed a workable definition of "qualified

person".

GENERAL

CONTRACTORS

of Greater Milwaukee, Inc.

* Associated General Contractors of

3 .
.]

:]

I

, J 6. —1 7.

8 .

- 10 .

. 11 •

J 12 .

13.

ASSOCIATED

GENERAL

CONTRACTORS

of Greater Milwaukee. Inc.

The concept of short term vs. long term excavation is a

difficult one to deal with. The stability of the sides

of the excavation is more a function of climate and other

factors than the length of time an excavation remains open.

The State of Wisconsin allowed a slope of 1/2 to one for

dry or moist -soils in its old code. .:.The code was in existence

for over 30 years. We know of no incidents of a failure in

a trench sloped according, to Wisconsin's code. We would

request that you investigate the validity of the 1/2 to

1 slope for some situations. Its use in Wisconsin would

indicate that it does offer adequate employee protection.

The advantages are obvious. Less material is excavated

with less disruption to existing roads, driveways, lawns,

sidewalks, buildings and utilities. A performance standard

allowing 1/2 to 1 might be a viable alternative to this

proposal.

We have not taken a formal position on this question.

1926.652 (b) (?;) is not appropriate for use by the person

in the field. We appreciate the necessity of including it

in any standard and concur that it would be better if

placed separately in the standard and/or transferred to

definitions.

Workers must be protected from objects rolling or sliding

from sloped ground. We do not believe that how this protection is

accomplished should be specified. The employer and employees

should be allowed great latitude in methods of providing this

protection.

Most stress appears to be in the middle of a trench. We know

of no safety reason why a shield cannot ride at least 3 feet

up from the bottom in good or average soils.

We support the deletion of architects from the list of "accepted

engineering requirements.

We believe that a competent person should be on the jobsite.

Degining a mass movement of soil or rock does not appear to

be necessary.

Old 1926.651 (c) can be eliminated since it is .adequately

covered elsewhere.

117
ASSOCIATED

GENERAL

CONTRACTORS

of Greater Milwaukee. Inc.

We also wish to address other areas in the proposed standard.

On page seven 1926.651 (g) the use of stop logs is required

This is not practical for backfilling operations or for installing

bedding in long trenches.

1926.651 (i) covers the methods of keeping down dust. The

application of large amounts of salt, calcium, chloride, and

oil is not always an environmental sound dust control option.

On page 17 two tables appear (4a and 4b that serve the same purpose.

We suggest that 4a be eliminated and all spacing be done on a

center to center basis.

We favor a standard that permits the use of accepted engineering

codes and practices for the installation of shoring. This allows

for the use of charts on the site as a guide to installing safe

shoring.

We are concerned about the practical applications of the standard.

No contractor has a complete lumberyard on the site. He can

effectively protect his employees by using the same sizes of timber

in a different depths and soil types. This can be accomplished

by decreasing the spacing and increasing the number of struts.

Forcing contractors to use 'excessively large timbers will result

in more back injuries. Greater than necessary sloping requirements means more exposures to traffic hazards in the metro area

where most trenching is done.

We support a practical standard that effectively protects

employees without being economically burdensome. We believe this

study is making excellent progress in this regard.
Al Johnson

CJH/6rd *J. A/iy de

n

Aac of Ctee/rr Al'/tueuket

P.0. Sox aS30 8 J Ms/coat* beet W;

.

JUN - 8 198'

AGC-MU.'WWUtt

^£: \aJoRkSMcP

t Trenchr*, /Jtfor/-1

V, £dL,

S3VC no Jns jCo <=?/k*d,*i c SJte ~St*»e 9

Session, y/uv* c;/y, A,^ Cc»f,J,„cf Ait/ you.’/!

be -7 yjrliC/p**/^ J' /ajPe -/4,'S Vc/sort.

Sl/s

On /Aree Separa/e dec&s/arts, J^'ve made *

c/a se

reyieui o-f

r vuo/£»*j d. raff af So^^steeL revrs/ons £r

Su^Ayf Py I924>. t OS//P *. Overall, £ c*rtssol*r fAe docm j* ch /

rOuclc s*prrI * v* /c yresen / /orat and proAeA/y as realss/sc

£^**pre Lie as Ae deve/oyeeL

~f/e enclose d. %Sef 0/ Copy oSAre/s ^#kv eer/a/a

of /te ~dr*fi

%

Jet c/u ele ayy afenA'frtyjt /rear, rerreto s ...

//» /A/S IViy > *n«L /Aretjk you,, JO +tsyhf Con/rriuft /a V

^Consensus even /AoUo^k,

ex/S ten t //> Cur Cperal/en s.

/rencjuno-iaof/fc sS a/mesf

‘ Ses/ %e?*rds,

**///• & /)^aruo^asQ^

erne,/

.

P. S. 7%3»Ars yfn /Ae rf**/zr *9*/'/r»ys

of * fo& Sarzry's Sa/ec

119
SOME ISSUES THAT SHOULD BE CONSIDERED IN THE WORKSHOPS:

1

2

Page 6.

Page 8-

Section 1926.651(a): This section appears to fall

within the scope of Subpart S. Should it be dropped? AJ

Section 1926. 651 (p): Should the exit requirements

for excavations start at 5 ft, rather than 4 ft depth?

(This would remove most excavations less than 4 ft

deep from the scope of Subpart P.) Should exit

requirements be waved for excavations which are wide

enough to permit people to escape toward the center

of the excavation? Should it be recognized that

large enough pipes or other covered structures can

shelter people? Should "negotiable slope" be better

defined? 'Jes

• «'rr

y

sS

3. Page 9 _

Section 1926.652(a) (2) Could the depth limitation)

in the "Standard Practice" be extended to 24 ft? S

If so, should there be a more stringent limit for

Class C soils? Should a "qualified person" be substituted for an "engineer", and if so, is the definition of a "qualified person" good enough so that a

determination of who is a "qualified person" is

possible? (This issue also applies to other sections

of the working draft .

)

: 4. Page 10 Section 1926.652(b)(1): Should the short-term excava

-J /Jo

tion definition extend to 7-days rather than 1-day?

If so, do we need more conservative requirements?

5. Page 11. Table 1: Should the stipulation of maximum slope

be limited to 3/4:1? Should the suggested performance^

requirement (footnote b) (the "stable slope

be used? Will this approach work?

concept)

6. Page 12 Figure 2: Should the allowable bank next to the work Lr

area in Cases II, III and IV be increased to 4 ft?

Should "Case IV” be limited to excavation by trenching

machines?

Page 13 Section 1926 . 652 (b) (4) (ii) : This section, unlike most

others in Subpart P, is not addressed to the man in

the field, but to those who pre-design shoring systems

Yet the section is necessary to avoid unreasonable

vagueness. Should this section be at the end of Subpart P? Should part of it be conveyed as definitions?

r

k Al Johns

Division of Al Johnson Construction Co. 1700 NORTHWESTERN FINANCIA^NCI^I CENTER

MINNEAPOLIS, MINNESOTA 5*Jt2\

L

c

m

M. O. DUMAS

SAFETY DIRECTOR

812) 831-8131 120
8. Page 16. Section 1926 . 652 (b) (5) (ii) : This section makes it

difficult to implement some of the slope configurations allowed in Fig. 2. Should the proposed performance statements be substituted to give more

options, or alternately, should more options be

specified or the specified options identified as

examples of implementing the performance statement?

9. Page 16.

10. Page 18.

Section 1926 . 652 (b) (5) (iii) : Should the allowable

excavation below the bottom of shoring or shields

be increased to 3 ft?

Definition of ’’Accepted engineering requirements”

Should ”a registered architect" be omitted since yigS

architects do not deal with excavations? v

11. Page 18 Definition of "Competent Person": Should the definition be re-written to require that the competen

person be working at the excavation site?

12 Should "Mass Movement of Soil or Rock" be defined?

13. Page 52. Old 1926.651(c): Should this statement be deleted?

even though this matter is addressed elsewhere, this

statement conveys the intent of Section 1926.652 in

simple language.
-5-

SUBPART P - EXCAVATIONS AND SHORING

1926, 650-GENERAL PROTECTION REQUIREMENTS

/(a) The regulations contain minimum requirements for the

protection of workers in* and adjacent to, excavations against death and injury.

/(b) Walkways, runways, and sidewalks shall be kept

clear of excavated material or other obstructions

and no sidewalks shall be undermined unless shored

to carry a minimum live load of one hundred and

twenty-five 0-25) pounds per square foot.

/(c) If planks are used for raised walkways, runways,

or sidewalks, they shall be laid parallel to the

length of the walk and fastened together against

displacement.

/ (d) Planks shall be uniform in thickness and all exposed

ends shall be provided with beveled cleats to prevent

tripping.

J (e) Raised walkways, runways, and sidewalks shall be

provided with plank steps on strong stringers.

Ramps, used in lieu of steps, shall be provided

with cleats to insure a safe walking surface.

/ (f) All Employees shall be protected with personal

protective equipment for the protection of the

head, eyes, respiratory organs, hands, feet, and

other parts of the body as set forth in Subpart

E of this part.

J (g) Employees exposed to vehicular traffic shall be

provided with and shall be instructed to wear i/

warning vests marked with or made of ref lectorized

or high visibility material.

^ (h) Employees subjected to hazardous dusts, gases,

fumes, mists, or atmospheres deficient in oxygen, y

shall be protected with approved respiratory

protection as set forth in Subpart D of this part.

| (i) No person shall be permitted under loads handled

by power shovels, derricks, or hoists. Employees f

shall be required to stand away from any vehicle

loaded^ "^y .
- 6

-

^(j) A competent person shall inspect the excavation

ins or slides or structural failures is apparent,

all work in the excavation shall cease until

necessary precautions have been taken to safeguard employees.

inspection of the excavation and the ground

adjacant to the excavation at least twice daily

and shall conduct a special inspection after

every rainstrom, penetration of water into the

excavation, or other disturbance that could

weaken the soil or the shoring system, and

increase^ protection against slides and cave

rrtassrsp. cohere de/rc/e* «Cee^^***^

Dewatering operations and equipment shall be

monitored by a competent person to insure their

proper operation and precautions shall be taken

to safeguard the workers in the excavation if

dewatering equipment malfunctions.

made to determine whether underground installations; i.e., sewer, telephone, water, fuel,

electric line% etc., will be encountered, and

if so, where such underground installations are

located. When the excavation approaches the

estimated location of such an installation, the

exact location shall be determined and when it

is uncovered, proper supports shall be provided

for the existing installation. Utility companies

shall be contacted and advised of proposed work

prior to the start of actual excavation.

(b) Trees, boulders, and other surface encumbrances,

located so as to create a hazard to employees

involved in excavation work or in the vicinity

thereof at any time during operations, shall be

removed or made safe before excavating is begun.

y (c) (1) In excavations which employees may be required

to enter, excavated or other material shall ^be

effectively stored and retained at -least 2 feet

or more from the edge of the excavation.

(2) As an alternative to the clearance prescribed

in subparagraph (1) of this paragraph, the employer

may use effective barriers or other effective retaining

devices in lieu thereof in order to prevent excavated

or other materials from falling into the excavation

for evidence of possible cave-ins or slides, ana

indications of structural failure in members of

the shoring system. If evidence of possible caveThe competent person shall conduct an overa 11 /Joreu^L*

1926. 651-SPECIFIC EXCAVATION REQUIREMENTS

(a) Prior to opening an excavation, efforts shall be

123
-*5~, y-^ -^'^rrvf v *>«->;a. -£c->.»^ l^m-£«r Wft; >* ;; - ^Vf ^TM ‘.-d£--<-M^»-*-.».t^^ - -

- 7-

*/ (d) Diversion ditches, dikes or other suitable means

shall be used to prevent surface water from

entering an excavation and to provide adequate

drainage of the area adjacent to the excavation.

Water shall not be allowed to accumulate in an

* excavation, unless this condition is considered

in the design and in the initial work plan and

adequate provisions are made to protect workers.

(e) If it is necessary to place or operate power

shovels, derricks, trucks, materials, or other

heavy objects on a level above and near an

excavation, the side of the excavation shall D*

be ahor c

- d as necessary to resist the extra

pressure due to such superimposed loads.

jbh, f'Zed.

/ (f) Blasting and the use of explosives shall be

performed in accordance with Subpart U of this

part.

/(g) When mobile equipment is utilized or allowed

adjacent to excavations, substantial stop logs

or barricades shall be installed. . If possible,

the grade should be away from the excavation.

A^(h) Adequate barrier physical protection shall be

provided at all remotely located excavations.

All wells, pits, shafts, etc., shall be

barricaded or covered. Upon completion of exploration and similar operations, temporary

wells, pits, shafts, etc., shall be backfilled.

(i) Tf perf.ifrlo, dust conditions shall be kept to

a minimum by the use of water, s al t!—calcium^

chioiide; odd:, or other -means-. e/Vrc//vr srlfJ* S

*/(j) In locations where oxygen deficiency or gaseous

conditions are possible, air in the excavation

shall be tested. Controls, as set forth ieS in

Subparts D and E of this part, shall be established to assure acceptable atmospheric

conditions. When flammable gases are present,

adequate ventilation shall be provided or

sources of ignition shall be eliminated.

Attended emergency rescue equipment, such as

breathing apparatus, a safety harness and

line, basket stretcher, etc., shall be readily

available where adverse atmospheric conditions

may exist or develop in an excavation.

Where employees or equipment are required or

permitted to cross over excavations, walkways

or bridges with standard guardrails shall be

provided.

124
- 8-

(1) Where structural ramps are used for employees or

equipment, they shall be designed and constructed

by qualified persons in accordance with accepted

engineering requirements.

/ (m) All ladders used on excavation operations shall be

in accordance with the requirements of Subpart L

of this part.

4

*/(n) Materials used for shoring, sheeting, and underpinning of structures adjacent to excavations

shall not be damaged or weakened by corrosion,

deterioration or prior use to an extent that

will cause them to have a minimum strength less

than that required in Section 1926. 652(b) (4) (ii)

.

^

(o) Employees entering bell-bottom pier holes shall be

protected by the installation of a removable-type

casing of sufficient strength to resist shifting of

the surrounding earth. Such temporary protection

shall be provided for the full depth of that part

of each pier hole which is above the bell. A lifeline, suitable for instant rescue and securely fastened

to a shoulder harness, shall be worn by each employee.'

entering the shafts. This lifeline shall be individually

manned and separate from any line used to remove materials

excavated from the bell footing.

S (p) When employees are required to be in trenches

4 (5?) feet deep or more, an adequate means of

exit, such as a ladder, steps or a negotiable

slope shall be provided and located so as to

require no more than 25 feet of lateral travel.

>/(q) Shoring shall follow the excavation

as closely as practical in order to avoid long

sections of unshored excavation.

/(r) Members of the shoring system

shall be installed in their proper position

and secured to prevent failure.

f (s) Portable trench boxes or sliding trench

shields may be used for the protection of

personnel in lieu of a shoring system or

sloping. Where such trench boxes or shields

are used they shall be designed, constructed,

and maintained in a manner which will provide

protection equivalent to that provided by the

shoring required for the excavation.

•"'(t) Backfilling and removal of trench support shall

progress together from the bottom of the trench.

Struts shall be released slowly and, in unstable

soils, ropes shall be used to pull out the

jacks or braces from above after employees have

cleared the trench. 125
JCkfr*. ~. l^i'A A.«| -I -AC.--. -« -

- 9

-

1926. 652-SPECIFIC SHORING, SHIELDING AND SLOPING REQUIREMENTS

(a) Acceptable Practice

(1) The following excavations are exempt from shoring,

shielding and sloping requirements: ^ a. t Excavations less than 5. ft. deep, except when

examination of the ground by a competent person

indicates that hazardous ground movement may occur.

b. Excavations in unfractured rock.

I

t

L

L

(2) Excavations from 5 ft. to 20 ft. 1) deep shall be

shored, shielded or sloped in accordance with the Standard

Practice in Section 1926.652(b) with the following exceptions;

a. If there is a deviation from the provisions of

the Standard Practice, shoring, shielding or

sloping requirements must be determined by an i r.jJ engineer f(a qualified person

/ b. An engineer shall determine the shoring, shielding

or sloping requirements whenever the bottom of

a building foundation adjacent to the excavation

which has not been secured by underpinning

extends into the critical zone delineated in

Figure 1.

^

FOOTING A: Standard practice can be followed

*

FOOTING B: An engineer shall be consulted

Figure 1. Effects of Nearby Foundation Loads That

Must be Determined by an Engineer

c

c

c

r

126
- 10-

/(l) Scope

The Standard Practice provides a method

by which field conditions are related to shoring,

shielding and sloping requirement.

The Standard Practice makes a distinction between

short-term and lona-term -excavat ions (see definition

in 1926.653 - 24 hours Q7 days?} is the division

point ) . ' a/c — 3^-4B J>***‘*&

y'(2) Soil Classification

Soils are divided into three types: A, B, and C. For

each soil type the "equivalent weight effect", we , to be used for the calculation of. lateral soil pressure on shoring systems, and the maximum permissible

sideslope for sloped excavations are stipulated.

Table 1 provides guidance for the selection of the

soil type.

^(3) Sloped Excavations

Sloped excavations shall not have sideslopes steeper

than those stipulated in Table 1. If there is any

indication of general or local instability, slopes

shall be cut back to the stable slope. The slope

configurations shown in Figure 2 can be used.

*^(4) Shored and Shielded Excavations

^(i) Determination of Adjusted Depth

For the purpose of selecting shoring systems, trench

shields, or trench boxes the depth of excavations shall

be assumed greater than the actual depth in order to

allow for spoil piles, construction equipment and

sloping ground. This adjusted depth CH

e

l shall be

determined as follows:

J a. For ground sloping down from the supported or shielded

excavation wall, level ground, or ground sloping up

from the supported or shielded excavation wall with a

slope less than 3 hor. in 1 vert, the Adjusted Depth (H )

is the actual depth of the supported excavation (H) plus

2 ft. (surcharge allowance). (See Figure 3(a).)

A 27
Sb.

Sc.

^a.

S(S)

/(i)

•'(ii)

Hydraulic shores or other pre-fabricated sub-assemblies

or members of shoring systems shall be rated for allowable working loads and selected with the aid of the

charts in the guidelines supplementing Subpart P, or

selected directly from special charts prepared by the

manufacturer.

Timber shoring shall be selected with the aid of charts

in the guidelines supplementing Subpart P or from special

charts prepared by an engineer (qualified person?).

Any other shoring system can be pre-designed and rated

by an engineer (qualified person?) and selected on the

basis of soil type and equivalent depth from charts

prepared for this purpose.

Special Provisions

Intersecting Trenches

When two trenches intersect and one trench is shored,

the intersecting trench shall also be shored from the

intersection of the two trench walls to a distance of

not less than its depth.

Sloping Ground

If the ground behind an excavation wall slopes -up from

the excavation wall and the ground slope exceeds

3 hor. in 1 vert, workers in the excavation must be

protected against objects rolling or sliding from the

sloped ground. This can be accomplished by projecting

the sheeting at least 18 inches above the ground surface or by a specially constructed protective toeboard.

If spaced sheeting is used provisions shall be made to

close the gaps between projecting sheeting members.

(Workers in excavations must be protected against rolling

or sliding objects?)

Excavation Below the Bottom of Sheeting, Trench Shields,

or Trench Boxes

Excavation up to (3 ft. ?) below the bottom of

sheeting, trench shields or trench boxes is permitted

in short-term excavations provided that:

”'a. No soil movement below the bottom of the sheeting,

trench shield or trench box is evident; and

^b. The forces acting on the bracing, trench shield, or

trench box are calculated for the full depth of the

excavation, and the lowest wales and struts are

designed to resist the forces that would result if

the sheeting would be projecting to the bottom of

the excavation. 128
I

9

-18-

1

1

J

'(a)

J

•

]-

'(b)

'(c)

]

'(d)

'(e)

'(f)

J

J

J

- "7

J ®

n

' (g)

(h)

(i)

•'(J)

^(k)

1926.653 DEFINITIONS APPLICABLE TO THIS SUBPART

"Accepted engineering requirements (or practices)

Those requirements or pract ices which are compatib

with standards required by Ca7reni stered architect ' registered professional engineer, or other duly

licensed or recognized authority. Guidance for

accepted engineering practices pertaining to excavation

safety is provided in the guidelines supplementing

Subpart P

.

Acceptable Practice is a practice which meets the

minimum requirements in Section 1926.652(a).

Adjusted Depth is the actual depth from the bottom of

the excavation to the top of the supported excavation

wall plus an additional depth to allow for surcharge,

sloping ground, or heavy equipment as stipulated in

Section 1926.652 (b)(4) (i).

Allowable Working Stresses are allowable stresses

determined in accordance with accepted engineering practices

.

Belled Excavation is a part of a shaft or footing excavation, usually near the bottom and bell-shaped? i.e.,

an enlargement of the cross section above.

Clear Spacing of sheering members is the distance between

the edges of sheeting members over which the soil is

unsupported (see Figure 4).

Competent Person means one who is capable of identifying

existing and predictable hazards in the surroundings or

working conditions which are unsanitary, hazardous, or

dangerous to employees, and who has authorization to

take prompt corrective measures to eliminate them.

Engineer is a professional engineer.

Equivalent Weight Effects (we ) is the weight effect

stipulated in Table 1 which is used to calculate pressures

on shoring systems.

Excavation is any manmade cavity or depression in the

earth's surface except as noted, including its sides,

walls, or faces, formed by earth removal and producing

unsupported earth conditions by reasons of excavation.

Excavations do not include tunnels and shafts, caissons

and cofferdams covered by Subpart S of the Safety and

Health Regulations for Construction.

Excavation Wall is the side of an excavation, rising

from the bottom of the excavation to the ground surface.

J

129
-19-

</ (1) Fractured Rock is rock which could spall or crumble when

excavated with vertical slopes. Fractured rock slopes

secured against mass movement and spalling by rock

bolts, netting, or other means approved by a qualified

person are considered stable (equal to unfractured rock)

/ (m)

/ (n)

(o)

Long-Term Excavations are excavations which are open

for more than 24 hours (7 days?)^ ,3£ -42> ( a/o_T

Mud Sills are wales which are installed at the level

of the bottom of the excavation wall.

Negotiable Slope is a slope on which a person can ftdJ'f

egress from or ingress to an excavation.

^(p) Qualified Person means one who, by possession of a recognized degree, certificate, or professional standing,

or who by extensive knowledge, training, and experience,

has successfully demonstrated his ability to solve or

resolve problems relating to the subject matter, the

work, or the project.

^(q) Safety Margin is any measure of excess strength over that

required to resist the working loads.

s (r) Sheeting is composed of members of the shoring system which are

in direct contact with the soil in the supported bank.

S (s) Shoring Systems are structural systems supporting the

bank of an excavation.

S (t) Short-Term Excavations are excavations which are open

for (24 hours ( 7 days?7) or less. 3C-4& Aovxv's ( AJcT~

(u) Sides, Walls, or Faces are the vertical or inclined

earth surfaces formed as a result of excavation work.

^(v) Slope is an incline expressed as a ratio of horizontal

distance to vertical rise.

/(v) Spaced Sheeting is sheeting in which the members

bearing aga inst the excavation wall are spaced (see

^"Figure 6) 4 Z

(x) Spalling is the continuous flaking and falling of soil

or rock from an unsupported trench wall.

y) Standard Practice is the trenching and shoring practice

in Section 1926.652(b).

•s (z) Struts are the primary support members of a shoring

' system including but not li mited to cross braces, raker

braces, jacks and backties ((see Figure^^) 4 ? *

£ y

oc

to *

4 -t%

v*-'y

X

f /

,

*

.V

\

y^(a.a') Stable Slope is the slope which will remain stable for

the duration of the excavation.

\30
- 20- S(bb) Structural Ramp is a ramp built of material other than

soil or rock.

/(cc) Supported Wall is that part of an excavation wall which

is supported by a shoring system or shielded by trench

boxes or trench shields.

''(dd) Trench Box see trench shield.

*^(ee) Trench Shield is a protective device which shields workers

in a trench from the effect of mass movement of soil or

rock and which can be moved along as work progresses.

'(ff ) Wales (walers) are members of the shoring system which

are directly supported by struts and which in turn provide support to the sheeting (see Figure 4).

*^(gg) Working Loads are loads which should reasonably be anticipated to occur and which must be resisted with appropriate

safety margins, determined in accordance with accepted

engineering practice.

for JrPmh'r** (z) -

a . irzrr

Hydraulic

shore

Center to eontor spicing

/j 0 ; Uu si fir

J?AKLZ, 8 RACES Or fcAcMT/CS

Spaced sheeting

Tight sheeting

Clear

spacing

Figure 4. Components of the Shoring System

131
Minutes of Trenching and Shoring Workshop - Dallas

There were 41 persons in attendance at the AMFAC Hotel at Dallas/Ft. Worth

Airport on June 30, 1981. Arthur L. Schmuhl, Director of Safety and Health

Services for the Associated General Contractors, opened the workshop with an

m explanation of why the workshops were being held. He then turned it over

to Bill Driskill, of the Texas Heavy, Municipal & Utilities Branch of A.G.C.,

who had agreed to serve as secretariat for the meeting. There were selfintroductions and the representatives from the National Sponsors were introduced and asked for comments.

John Cook, representing the National Utility Contractors Association,

made a statement that, ’’at this time NUCA is not taking a position on the

working draft of Subpart P and will wait to see what the final draft is."

The next sponsor was Jack Mickle, representing the Building and Construction Trades Department of the AFL-CIO, Mr, Mickle provided a draft

with the Building Trades recommendations on the revisions of Subpart P.

He stated that the stand the Building Trades have taken is that whatever we

wind up with has to be understandable by all. (Mr, Mickle's full text is

attached to these minutes.) Mr. Mickle stated that his group had spent

most of its' time looking at the first twenty pages of the proposed document,

minus the first five pages. Based on this, be made the following recommendations

(1) Remove the misunderstandings such as the definition of stable

slope. (2) Recommend the removal of Table P-2. (3) Include hydraulic

shoring in standard -practice with manufacturers certifications for use on

the shore and shields be included ,in standard practice with manufacturers

certification on the shield.

See attached document of Mr. Mickle's for all of their recommendations.

-1-

132
Mr. Sal M. Gozioglu, representing A.S.F.E,, stated that his group has

distributed the working draft to their members for comments and the comments

will be forwarded to their A.S.F.E. representative, Mr. John Romage, for

k presentation at the Boaston Workshop.

On conclusion of the statements by the sponsors, Dr. Yokel was called

upon to explain what would be done with the products of the various workshops. He stated that the information from the workshops would be discussed

with OSHA and NIOSH representatives and the regulations would be re-drafted.

Dr. Yokel strongly recommended that the parties at the workshops should form

a committee with the possibility of a meeting, or meetings, in Washington,

D. C. -with the idea of coming up with a consensus standard for submission

to OSHA,

Dr. Yokel then gave a video presentation on the.NBS study that was

funded by OSHA. He stated that some 127 recommendations were made on arriving at the working draft by various groups such as labor, A.G.C., A.S.F.E,?

and other interested parties. Following Dr. Yokel's presentation on the various

recommended changes in his working draft on Subpart P, and some of the comments

on the proposals in previous workshops, the workshop was opened for comments.

John Cook, speaking for trench shield manufacturers, offered that it was

their consensus view after they had reviewed in detail the working draft,

that the attempt to clarify and simplify, as it relates to the revised

changes in Subpart P, has failed and, in fact, has made it more confusing

and more difficult to apply in the field and the proposed design criteria,

as it relates to trench boxes, does not conform to accepted engineering

practices and they have specific recommendations to be made later in the

workshop

.

The following comments were made after Mr. Cook's presentation:

-2 -

133
(1) Del Talley, Executive Director, Austin A.G.C., raised the question

as to why the American Society of Safety Engineers are not involved? It was

Mr. Talley's feeling that A.S.S.E. should be involved in some manner since

that organization represents the safety professionals in the United States.

Mr. Talley also asked about the adjusted depth chart and surcharge chart

and what is the involvement of the ’American Society of Civil Engineers?

Dr. Yokel then explained the charts again and stated the idea of the charts

was to be simple enough so the man in the field could readily understand

the standard. There was considerable discussion of the chart on page 14-

Table 3 and the need to clarify this,

(2) Jerry Rosch, Brown & Root, Inc,, Houston Texas, commented on the

selection of competent people or qualified people and stated that OSHA has

told them that the employer is to select that person .and they (Brown & Root)

go with the man with the most experience, Mr. Rosch requested that definitions

be included that explain clearly what a competent person and qualified person

is. Dr, Yokel stated that the definitions are in the documents but probably

need more work to clarify them,

(3) John -Collins, Kent Nowlin Construction Co,, New Mexico, asked

what happens with a six foot hole that is opened for eight days? Does it have

to be designed by a qualified engineer? What is the definition of long term

and short term?

(4) Walter Ruff, Ruff Construction Co,, Dallas, Texas, commented and

raised the question that long term and short term is predicated on a shoring

system being involved. What if the contractor chose, instead of shoring,

laid back or sloped to a safe angle, how would the long term and short term

definition apply?

-3 -

134
(5) Leroy Balser, Robert E. McKee, Dallas, Texas, stated that page 11 on

Soil Classification for the Standard Practice is too arbitrary since soils

vary from area to area.

Following these comments, Dr. Yokel went over the document step by step

and asked for comments on item 1-7 page 3,

. (1) John Cook, representing the trench box industry, commented on number

3 as to whether a qualified person should be substituted for an engineer,

lie felt the answer should be no^, but that there are other areas in the working draft where a qualified person should apply but declined to say where.

On number 4, he felt that more conservative requirements were not needed and

short-term should be 7 days. On item 5, he stated that they felt the allowable slope in Table 1 is not in accordance with acceptable engineering practices

and the stable slope concept should be used. On Item 7, their answer is yes

it should be conveyed as part of definition.

(2) Phil Becker, Utilities Consolidated, San Antonio, Texas commented in

regard to page 3 item 2, he felt that on exit requirements from a ditch, the

exit requirements other than a ladder should be allowed such as shoring as a

means or a negotiable slope allowed. On item 3 he feels that the 24 foot

depth on the standard practice should be utilized and it is a common practice

in his area for the industry. On Item 4, or short term and long term excavation, he feels that it is confusing building construction with utility

construction and it is standard practice to leave areas such as manholes open

a week or so. On Item 5, he felt stable slope should be the concept used.

Item 6 - leave it at two feet.

Item 9 - This needs to be determined at the time it is used but don’t tie

it down. .

Item 11 - He is against having an engineer on the job, but use a qualified person. If you insist on an engineer, put it in the design and make it a bid

item and everyone would bid on these items.

-4-

135
Mr. Becker stated that common sense must prevail in considering these proposals.

(3) Walter Ruff, Ruff Const Co., Dallas, Texas

Item 2 -

enough

• 5 ’ instead of 4 ' . Pipe should be recognized as a shield if large

Item 3 - It should be extended to 24 feet and it is industry practice to work

this deep. Job foreman should be recognised as a qualified person and an

engineer should not be involved unless he include the shoring system at the

design stage and be a bid item and OSHA write the law that the engineer’s

errors and ommission will stand at the courthouse and let him be responsible

for his design.

Item 4 - Short term definition should be deleted.

Item 6 - Leave it at two feet.

Item 9 - Should be a determination on each individual job.

Item 10 - Omit architect.

(4) Alan Hollingsworth, S, J. Groves & Sons.

Item 1 - This should not be dropped in that it causes problems on Highway

projects

,

Item 2 - Definition should be clear on negotiable slope.

Item 3 - Are we better off to leave this the way it is?

Item 4 - It is very controversial and many factors should be considered in

order to establish a definition of ’’short term" or "long term" excavation.

Item 5 - Use the current regulations,

Item 6 - The current regulation is adequate. (2 feet)

Item 7 - What men in the field are we talking about? We recommend consideration be given to existing industry practice.

Item 8 - Bypass

-5 -

136
Item 9 - No problem with this.

Item 10 - If we are going to have all these different people involved, let's

I name everybody since state laws, like in Illinois, can name every party and

each named can be responsible for some portion.

Item 11 - No real problem, but tell us specifically what you want us to do.

Item 12 - 1926,650 gives us enough rationale to understand.

Item 13 - No significant problem with existing regulations.

The construction industry has not had good participation in this workshop paper and more across the country should be consulted.

(4) Phil Becker then referred those present to page 12 and page 15 and asked

Dr. Yokel to explain open excavation without shoring and sloped excavation.

(5) Joe Kinnikin, AGC of New Mexico - Contractors in Texas and New Mexico

are having a problem with 3/4 to 1 slope. We are dealing with undisturbed

soils and not the molten soils like back east.

Dr. Yokel then asked for comments on page 5A. He stated that the two

previous workshops had commented that these provisions should not apply when

workmen are not exposed to mass movement of soil or rock. John Collins,

of Kent Nowlin Const Co., asked the question about where employee exposure

occurs and how far away from the face of an excavation does a workman have

to be to not be exposed?

Alan Hollingsworth, of S, J, Grove, commented on page 7 that

651E £ D appear to him to apply to borrow pits with water accumulating.

He felt that a compliance officer who is not an engineer might make a judgement call that would cause more litigation. Dr. Yokel said this provision

was carried over from the previous regulations,

Jerry Rosch, of Brown £ Root, commented on section J, Emergency procedures in a confined space should be defined in J on page 7, . Walter Ruff, of Ruff Construction Co., commented on page 7 (e) and felt

that this is impossible to meet. On (9) it should be deleted and item (k)

it is not practiced on small ditch and should be deleted.
George Bradberry felt paragraph 1, page 8 should be dropped completely.

$

John Cook, representing trench boxes, stated item (5) should read "as

defined by accepted engineering practice" at the end of that statement.

Also reverse the words "protection equivalent" to read "equivalent protection".

This refers to pre-designed trench boxes.

, Alan Hollingsworth, of S. J. Grove & Co., felt. that specific trenching

9 requirements should stay such and not be put in general excavation so the

contractor can readily identify what he is supposed to do.

Phil Becker, of Utilities Consolidated, commented on page 8 on ladders .

and the length they must come above the trench and would reply in writing.

On (p), it should be 5 instead of 4 and approximately 24' and not 25* specifically. On (q), he felt the section should be deleted. On (t)

,

Mr. Becker

recommended it be deleted.

Bill White, of the Houston Contractors Association, commented on page 7

(j), it should be deleted per prior meeting held by OSHA on this subject.

Dr. Yokel asked Mr. White to submit specific recommendations after the workshop is over since it was not brought to his attention that the_meetings

were held when he made the study,

Jerry Rosch, of Brown & Root, remarked on page 8 (o) where you approach

the situation on rescue, you are limiting yourself when you indicate shoulder

harness without any, etc, following it because in situations there are times,

and it has been proven, that harnesses, if a man wears shoulder harness or

parachute harness or whatever, it is very difficult to get him out if you

are on a vertical pull. I suggest you reword it this way, "adequate lifesaving equipment suitable for instant rescue, shall be required of each employee

entering the shaft. Employee personal protective equipment should include,

but not limited to, harnesses, wristlets, or other acceptable devices. You

need some leeway on this.

-7- 138
Jack Brown, Ruff Construction Company, commented on page 9 on acceptable

practices on excavations less than 5 * and on all charts still show the angle

of repose from the bottom of a trench. If 652 C is to remain in the standards, you are contradicting it with these. type photographs on the angle of

repose.. I would prefer to keep 652 C as it is rather than the proposed regs.

Phil Becker of Utilities Consolidated then commented on page 9 concerning

I the definition of unfractured rock should be clear in that if rock, if cracked,

it doesn't' mean that it is going to fall down. He continued by commenting

on No. 2, page 9. He asked why limit excavations to be shored to 20 or 24 feet?

He recommended that it read 5 feet and deeper or 5 feet and below shall be

shored.

Mr. Becker recommended that a qualified person handle excavations below

24 feet.. He stated that if Mr. Yokel is going to recommend that it is required, that anyone other than a qualified person on the project to excavate

below 24 feet in depth, that he would like to see that Mr, Yokel require,

in the Federal Register, that engineers design it in the project, in the plans,

and have a bid item for that particular portion of that project. He reemphasized his point by saying that a qualified person can handle excavations below 24 feet and that if Mr. Yokel is going to recommend that it be an engineer's

design, that Mr. Yokel recommend that it also be a sublimited design in the

plans and have a bid item for it. ’ -

Continuing on page 9, no. 2, part B, Mr, Becker commented that should be

in the plans and have a bid item for that area. If not, then that should be

a qualified person that shall determine the shoring.. He takes objection to

the way it is written.

On page 10, Mr. Becker objects to No, 3 in regard to 20-24 feet. Wants

engineer put in parenthesis and qualified person in capital letters. Number one

under scope, page 10, would like to see short term and long term eliminated.

8-
Walter Ruff, Ruff Construction Company - Eliminate the short term and

long term and leave it up to the contractor. He commented that short term

and long term takes away from the way a contractor can effectively operate

his project and costs are going to escalate.

pel Tally, Austin AGC - Commented on page 10, No. 1, and said that it

applies to building contractors also. Almost all building excavations are

I open more than seven days for basements, etc. Delete short term and long term.

John Collins, Kent Nowlin - Commented that we do not have the ground

water in this area of the United States, as they do in the Northern states,

.to saddle us with something that applies to Wisconsin is unfair and vice versa.

Phil Becker, Utilities Consolidated - Page 11, objects to (5) rock and

(c) long term excavation.

Joe Kinnikin, New Mexico AGC - Page 11, Type A, .stated the need to recognize native soils and conditions. Need to define it better and reword it.

Del Tally, Austin AGC - Page 11, Chart - A, 3/4:1 should be returned to

h:l.

Phil Becker, Utilities Consolidated - Page 12, commented on the draw9 ing. It is not always benched like it is shown and could be confusing to

OSHA inspectors.

Del Tally, Austin AGC - Page 12, commented that three foot maximum for

bottom bench needs to be discussed. Why couldn't it be 5 feet?

Walter Ruff, Ruff Construction - Added to the wording of that clause

(page 12) , that if it were required, by the size of the conduit, to be

deeper than four feet, the fact that you would have the safety factor there

that a worker could get into the conduit in case of a collapse that you could

take exception to the rule above four feet if the conduit so required for proper

embediment. The pipe is strong enough to hold all of the dead (load, weight) of

backfill, it will be a safe haven to a laborer in case of collapse, to crawl into

it even if it were up to five feet.

-9- 140
, “'I

Del Tally, Austin AGC - Asked why five feet would not be acceptable

' V

there (page 12)? ' Commented that it is confusing to field people in having

V

different footages. Like requiring a ladder at four feet, shoring at five

feet, why not say at five feet you need to do this? Just have one depth.

Alan Hollingsworth, S. J. Groves & Son^ - Commented on page 12. Industry

is concerned about specifications from a contract owner that says he will

Iplace pipe in a specific type of performance activity. And then you indicate

that we' will shore; slope in accordance to given OSHA standard criteria.

Hollingsworth said it seems to be a "Catch 22" situation for the contractors.

Since OSHA regulations are not applicable to any governmental agencies, that

puts the contractor in a situtation where we have to conform, but the people

writing the plans and specs do not. That makes the contractor put a price

on a job that is not stipulated for him to do so. Contractdrs could do a better

job if government agencies had to conform to the regulations and then there

would not be an absence of this information available to the contractors.

Joe Kinnikin, New Mexico AGC - Page 11 and 12, depth of trench, commented

that this will make the contractor shore in cities because of right-of-way

requirements

.

Del Tally, Austin AGC - Page 15, what is the alternative to drawing (c)

showing heavy equipment? Usually you do not operate under the regime.

George Bradberry, Shoring Service, Page 15 (.in diagrams A & C) recommended

to shave off shoring extending above -the top of the trench because it usually

serves as no purpose.

Phil Becker, Utilities Consolidated. Page 16 (D) - Eliminate engineer.

Commented that there could be several other shoring systems that would not

have to be pre-designed by an engineer. Objects to the words "any other shoring

systems".

-10- 141
Del Tally - Austin AGC - Page 16 (iii) - Take out the words "short term

excavation". Second paragraph of (iii), two feet should be three feet.

Jack Mickel - Building and Construction Trades - Commented on the qualiN

field person/engineer discussion. He stated that these standards are going

to be used by everbody. The contractors at this meeting have qualified people,

but there are other small contractors who do not and they will wind up killing

people. That is why the term engineer is used. He raised the question of how

do you define or determine a qualified person?

Alan Hollingsworth - S.J, Groves & Son - Added to the comments of Mr. Mickel.

We cannot regulate morality. To add additional regulations to make others

• t who do not comply with these rules is not going’ to achieve the goal, Mr,

Hollingsworth also had a comment on Page 16 (iii) . He was concerned about

the wording "no soil movement". ^

Johnny Hall - SACC, Inc, - A piece of paper does not qualify anyone to

do anything. The qualified person is the guy who is going to have to wind

up doing it in the end. Recommend that licensing be left out completely.

i. Alan Hollingsworth, S, J. Groves & Sons, Page 18(A) last sentence.

Asked the question if the last sentence in (A) is still a part of the definition? He does not want supplemental guidelines given to OSHA and not given

to the contractor. Recommended having everything that's meaningful in the

standards and not have any back-door guidelines that is not available to

the industry, so we will know what to conform to and no one else will have a

different viewpoint. He added that we do not want to overlook product liability.

Del Tally, Austin AGC - Page 18(H) - Need to leave out the word registered

because some engineers are not registered engineers. Page Z9CC1 - Fractured

Rock - commented that if it is not falling, it must be all right. Added that

bolts and netting to prevent massive movement of the rock is pretty tough,

-11- 142
and doesn't know how that is going to work. Said that items (M) & (T) should

be removed.

Bobby Hargroder - Du-Mor Enterprises - Believes that (L) on page 19

should read, fractured rock - rock which could spall or crumble when excavated

with vertical slopes. Fractured slopes secured aginst mass movement and

spalling. Recommends that competent person needs to be put in place of

I qualified person.

In reaching page 20 of the Working Draft of suggested revisions, Dr,

Yokel stated that the other workshops did not cover anything other than

the material up to page 20. He then asked for general comments from the

audience.

Jack Brown - Ruff Construction Company - Asked if this is drafted up .

and we use all these technical people, engineers, and formulas, then when

it is put into affect, are we still going to get these four week "wonder"

compliance officers to come out and check all of this technical stuff?

Alan Hollingsworth - S. J. Groves & Son - Mr. Hollingsworth had these

final comments. He started out by saying he was concerned with the reason

why OSHA wanted to review and revamp sub-part P. It is his opinion that it

is not for employee safety, but for looking at shoring and sloping characteristics. Unless there is statistical data that says the present standard

has not worked and it is causing a significant amount of injuries and fatalities, then why are we revising something that we don't know why we are

revising? He brought out the point that he knew of several instances where

governmental agencies were performing these trenching and excavating requirements and there were fatalities and not even an OSHA compliance review was held because they are exempt from these regulations. He asked

if the statistics available reflect the real picture of the people who must

conform to OSHA regulations. Mr. Hollingsworth stressed that he did not

-12 -

1.43
want to let factors become requirements unless they are based on sound findings .

Mr. Hollingsworth continued his comments by saying he fully understands

that a lot of contractors have not conformed to the requirements of the standards and therefore the industry has suffered. But sub-part P of the regulations

has sustained a high degree of success in achieving the goal in the field of

l trenching and shoring. The industry has had 11 years of use of the OSHA

regulations and has thus improved the safety factors to establish an acceptable

set of industry practices. If new proposed standards are accepted, we will

again start the litgation process to establish a new set of legal precedence.

Mr. Hollingsworth commented that in light of the economic impact of the construction industry and the government, we cannot afford another 11 years to

establish new legal precedence only because we want to replace the industry

expertise with more educational certificates.

Another concern of Mr. Hollingsworth is it appears whenever there are

factors outside the proposed standard practices, present work must cease until

a registered engineer can establish the certified criteria and procedures

,, 4k to insure safety factors for all interested parties. Employees will be sent

'

home without pay and can affect additional crews that will also be sent home..

Unless the contractor has a registered engineer on his payroll, which many

do not, he must seek to find one to take the responsibility to establish the

new procedure as established by the regulations. The amount of delay this

will cause is an unknown factor, but it can only cause costs to soar and

have the loss of valuable work time. A registered engineer cannot insure

the safety implied by the proposed regulations.

' Mr. Hollingsworth then had a few critical questions he asked. What

statistics are available to show that the current regulations have done

to escalate the cause of injuries or fatalities? If changes are warranted,

13- 144
has a cost benefit analysis been made to allow for a better understanding t \

of the regulatory impact?

' In summation , Mr. Hollingsworth said that if the short set of regulations has not created significant problems for management and the safety of

their employees, then let's not consider efforts to reinvent the wheel and

redundance

.

After those comments, Dr, Yokel made a short statement and turned the

meeting over to Bill Driskill, There being not further questions or comments,

the meeting was adjourned. v .

14 145
3. RESPONSES BY F. Y. YOKEL TO MISCELLANEOUS WORKSHOP CORRESPONDENCE

The letters in this section were written in response to some of _

the written comments submitted in the workshops. Many more com- ments were made, such as written comments submitted by AFL-CIO;

however, there was no follow-up correspondence. Many of the

comments are discussed in the workshop summaries in Section 2. —c

rw

c

c

c

c

c

c

c

r

146 L
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, O.C. £0234

July 16, 1981

Mr. John B . Cook

Efficiency Production, Inc

P.O. Box 24126

Lansing, Michigan 48909

Mr. Wendell Wood

Grisvold Machine & Engineering

Highway M-60

Onion City, Michigan 49094

Gentlemen:

First I want to express my regret that ve did not communicate sooner. Had

you been involved in the preparation of the Workshop input draft, we would

probably be much closer now to a meeting of the minds.

Before going into details, I would like to make some general comments:

1. The ’'Standard Practice” is proposed because we came to the conclusion

that it is in many cases not practical to have an engineer design the

shoring in a trenching situation. This reflects the real-life

situation, and ASFE is in full agreement with this conclusion. The

"Standard Practice” in no way precludes that decisions on shoring be

made by an engineer. If an engineer does make the decisions, he

does not have to follow the Standard Practice [1926.652(a)(2)].

2. The "adjusted depth" in the Standard Practice is designed to enable

the foreman to allow for surcharge situations. While it is true that

a spoil pile is higher than 2 ft., it is very unlikely to cause

lateral loads greater than those caused by an evenly distributed

surcharge of 2 ft. in the typical trenching situation. If we eliminate

this adjustment, an engineer would have to be consulted in every instance.

We do not believe that this is realistic.

3. The introduction of the concept of the short-term excavations again

reflects a real-life situation. It is a fact that in actual construction practice in the U.S. and other countries, slopes are steeper and

shoring systems are weaker than those that would be recommended in

accordance with accepted engineering practice. However, there is no reason to reduce conventional safety margins for excavations which

stay open for many months.

4 . To come back to "accepted engineering practice": Coulomb and Rankine

did their work a long time ago, at a time when actual measurements

were not available. Appendix A reflects present engineering practice

which is based on measurements which were made in the last 20 years,

some of them as recently as 2 years ago. Now it is true that nobody

made measurements for the trench box situation. I expressed my

preliminary thoughts on this in the memorandum on the Dallas Workshop

147
2

(attached). I think you have a point when you draw a distinction

between trench boxes and typical shoring. However , you made a good case for sands, but not for clays. Sands will develop the typical

"active” pressure diagram when enough displacement is allowed.

. However, clays will creep, and when bearing against a retaining

structure which is restrained about equally top and bottom (as distinct

from a retaining wall which can rotate about its base) will exert some

sort of parabolic pressure diagrams which is closer to the square than

the triangular. Once we deviate from the simple lateral-load requirements of the proposed soil classification, one would have to make a case for the extreme in each category. This would be medium clay at

the lower strength limit for Type B soils and soft clay in an excavation with a soft bottom for Type C soils. I am not really opposed to

somehow permit an engineer to make the case for the full range of soils

falling under Type B and Type C soils, as an alternative to using the

proposed pressure diagrams. However, I suspect that if you do that

your gain in material will be trivial (and perhaps you will lose).

If you believe that an engineering alternative to the standard pressure

diagrams is desirable, I would urge you to propose a specific amendment

to Section 1926.652(4) (ii)

Here are some specific comments on your submission:

1 . I suggest that you date future submissions, since you may change

your mind on some points and we must be sure we always reference

the proper memorandum.

2. Page 8 , item(s) - I do not object to this.

3. Page 9, item 2a - Who will determine which engineer is "qualified?"

4. Page 10, item (b)(1) - My own inclination is to make the dividing line

3 days. This will allow leaving trenches over a weekend without extra

6truts. You may choose not to distinguish between long- and 6hort-term

for trench boxes.

5. Page 10, item (4) (i) - An engineer, if he gets involved, would probably

not use the tables.

3

6 . Page 11 - 30 lb. /ft. for Type B soil would be in my opinion grossly

inadequate for medium clays. Even 40 lb. /ft. is on the low side.

7. Page 13, item (ii)a - If an engineer wants to make a case that a trench box is adequate for a certain depth and soil type he could go

to the state-of-the-art and use the appropriate pressure diagram.

Otherwise your proposed modification could produce inadequate design.

I would welcome any specific suggestions for simplifications in

Table 1. We have been trying to do that for a long time.

8. Page 13 (ii)c — See Dallas memorandum.

9. Page 13 (iii) paragraph 2-1 doubt that a foreman in the field could

use engineering practice to select shoring.

148
10 .

- 3 -

Page 13 (iii)a - Would you make a surcharge allowance in your advanced

rating? Otherwise surcharge is likely to be ignored altogether.

11. Page 16, item 4 (iii)(4) - You are probably right.

•12. Page 16, item 5 (iii) - There seems to be a consensus on your suggestion.

' However it has been suggested that item (a) may be too vague as we

" wrote it.

Definitions:

13. 18 a - I agree with you.

14. 18 c - See previous comments.

15. 19 m - See previous comments.

16. 19 o - Your definition is a step in the right direction, but may

still be too vague.

17. 19 t - See previous comments.

18. 19 z - 1 agree.

19. 22 - 2.1 - If we eliminate B (c) there would be the question what is

accepted engineering practice for, say, the oil pressure in hydraulic

systems? However, certainly I have no problem with following

engineering practices to the extent that they are defined.

20. 22 - 2.1 A and B - This should be further discussed.

21. 22 - 2.23 - See previous comments.

22. 27 - 2.32 - How are we going to reasonably control the quality?

23. 30 - Appendix A is at best a guideline. It does, however, agree with

present practice in excavation bracing (see reference listed).

24. 37 - 5(b) - Should be further discussed.

25. 38 - A. 5. 2 - Few practicing geotechnical engineers would agree - however a special case for the trench box, if thoroughly documented,

could conceivably be appropriate. Perhaps Wayne Clough's (Stanford

University) programs could be used to make a study. Unfortunately

the NBS funding situation would not permit me to undertake such

a study.

1 appreciate very much your effort to contribute to an improvement in our draft standard. I would suggest that we try to have a dialogue with ASFE

on some of your suggestions.

Sincerely,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

cc: Mr. Paul Bouley

Mr. John Maragliano

Mr. John Ramage

Mr. Ronald Stanevich

Mr. Bill Zoino

149
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20234

August 13,1981

Mr. Gordon Helmeid

Director, Bureau of Technical Services

State of Wisconsin/Department of

Industry, Labor and Human Relations

201 E. Washington Avenue

P.0, Box 7969

Madison, Wisconsin 53707

Dear Mr . Helmeid

I was gratified with your supportive comments on our proposed

standard practice for excavations and I would like to discuss

some of your specific comments.

1. You take exception to the suggestion in my Workshop

memorandum that n_o changes shoul d b e permitted when a traditional practice is accepted on the basis of its track

record. I think that my statement was somewhat vague and you

therefore misread the intent. What I suggest to stay away

from is taking some traditional scheme - say timber, and then

substituting some of its members by other members of

"equivalent" strength, say aluminum. There is much danger in

this. A wood member may have a safety factor of 4 relative

to its actual failure strength, while the aluminum member has

only a safety factor of 1.6 or even less. There is also the

problem that lateral loads on bracing members depend on their

stiffness and method of installation. Consequently, I propose that if ; any substitution is made , the new m ember

should comply with the standard practice . I certainly would

be the last person to suggest that safety rules should not be

upgraded. However, what I strongly suggest is that the

standard practice be followed when the upgrading is

implemented. This way we will eventually move toward uniform

practices in the U.S. which will be beneficial for safety as

well as economy of the work.

2. I am not sure what you refer to in the fourth paragraph

of the second page of your letter. I thought you may be

talking about comment 1, page 3 of the "Working Draft." This

comment should read: Section 1 92. 65

( o)

3. I take it that you recommend a 20 ft. depth limit. As

you probably know this has been a point of controversy in the

Workshops. Contrator’s in most parts of the Country (except

California) favor 24 ft.. Unions favor 15 ft. You come down

150
in the middle. I think I could live with 24 ft. if we have

some safeguards for soft soils.

4 . Qua 1 1 f 1 ed Person Please note that we have two

d ef i n i t i on s : a "competent person" is one who is competent to

Implement the standard practice in the field. A "qualified

person" is one who can design shoring using engineering

pr inc i pies . You say note that in our draft we refer to an "engineer"

rather than a "qualified person." However, many contractors,

particularly in the South (Dallas and Atlanta Workshops)

favor the definition of "qualified person."

5. The reason for recommending deletion of Table P-2 is that

we could not prove that the timber sizes are consistent with

good engineering practice, and there was also no evidence

(like in the case of the Wisconsin regulations) that the

table is used in practice. We are not against providing

tables for timber, hydraulic shores and possibly other

systems in an appropriate Appendix. But I see no point in

singling out one material for such a presentation.

6. The timber table in the Appendix of the Workshop paper

was developed using the Standard Practice. Allowable timber

stresses used were for Mixed Hardwood II which includes some

weak wood species (see Page 29). Unfortunately, engineering

calculations do not support the common field practice of

using the same timber sizes for struts and wales. Note that

the table goes to very wide horizontal spacing of struts and

uses a 5 ft. vertical spacing (except for spot bracing).

Generally, strut sizes come out to be consistent with

traditional field practice. Wales sizes in our table are

larger than those commonly used (in spite of the 20 percent

load reduction we permit for wales). There is nothing to

prevent a contractor or a region or State from developing

their own timber tables, using the design loads and stresses

stipulated in the Standard Practice.

7. The wood table was developed in our timber study,

precisely for the reason that hardwood is not graded, and is

based on an extensive field survey. It is quite possible

that the hardwood timber supplied in Wisconsin qualifies for

Mixed Hardwood I, or even Mixed Oak. The Forest Products

Laboratory in Madison could probably make this determination.

Note that we recommended in our timber report ( BSS 12 2) that

the Industry adopt grading for trenching timber. If this

were accomplished, we could probably go to higher design

stresses.
8. Soil Cl as s 1 f i c at ion - Unfortunately there are many aoil

types, and any way you want to group then you have sone

problems. We felt that the most important "common *. denominator" for grouping soil is pressure exerted on shoring

systems. We also came to the conclusion that it is

inpractical to have more than three soil types. Thus under

Type C we have all soils which are likely to develop high

lateral pressures. These include soft clays, which can stand

on relatively steep slopes, but also very weak soils such as

marine silts which cannot be sloped at all. Thus the slopes

we stipulate are the "steepest allowable," but not

necessarily the "steepest possible." I am trying to

Introduce the "stable slope" concept, which would put more

responsibility on the contractor in choosing the slope, but

it is opposed by AFL-CIO. Note that on Page 11, footnote 3,

we say that soft soils Include clays which can be easily

penetrated several inches by the thumb and soils that cannot

stand on a 3:1 slope (muck). This is a, reference to two

entirely different soil types. The soft clay will easily

stand on a 1 — 1 / 2 : 1 slope. The muck probably cannot be sloped

at all. Both, however, exert high lateral pressures on

shoring. By the way, I had no problem correlating our soil

classification with yours, and I believe that our

classification could work well in Wisconsin.

9. Gravity Load on St r ut

- The 2*»0 lb. load on struts was

stipulated so that, in an emergency, the strut could support

a man who is trying to climb on it. We found ample evidence

that workers do step on struts, regardless of what we

stipulate in our regulations. This is also the reason why

AFL-CIO would iwant an even larger gravity-load

resistance. I am quite aware that the 2 in. thick Wisconsin

struts cannot support such a gravity load.

I do not know if this letter answers all your questions. I would very much welcome the opportunity of working with you

in an attempt of reconciling your needs with the proposed

Federal Standard. I am trying to get some further funding

from OSHA or NIOSH so NBS can stay involved in this problem

until everything is resolved and I hope that these agencies

will recognize the importance of a successful "end run."

Sincerely

,

Felix T. Yokel, Ph.D., P.E.

Leader, Geotechnical Engineering Group

Structures and Materials Division

Center for Building Technology, NEL

Enclosures

152
August 12, 1981

Mr. A. Youhanaie

Bridge Engineer

Chicago, Milwaukee, St. Paul

and Pacific Railroad Company

516 West Jackson Boulevard

Chicago, Illinois 60606

Dear Mr. Youhenaie:

This is in response to your July 21, 1981 letter. I shall try to answer

your questions.

(1) Surcharge:

Surcharge effects were derived by elastic theory based on the assumption

that the surcharge load is applied after the bracing is in place. Since

1 ft. of additional depth in Type A soil will produce a lateral thrust of

20 psf, and 1 ft. of Type C soil will produce a thrust of 80 psf, the

depth adjustment for Type A soil has to be greater. (See derivation on

Page 44 of the enclosed report.)

(2) Effect of Adjacent Foundations:

The rule of thumb that is proposed to identify cases where adjacent

foundations significantly affect the lateral forces on bracing is presently

widely used and is generally conservative. However we recognise that there

may be instances where it is not conservative enough.

You should keep in wind that the standard practice proposed in the article

is Intended to insure the safety of workmen. Other Important aspects of

excavation practice, such as settlement control of adjacent structures are

HOC within the scope of OSHA jurisdiction.

Sincerely,

Felix Y. Yokel, Leader

Geotechnical Engineering Group

Structures end Materials Division

Center for Building Technology, MEL

Enclosure
Chicago, Milwaukee, St. Paul

and Pacific Railroad Company

516 West Jackson Boulevard

Chicago, Illinois 60606

Phone 312/648-3000

July 21, 1981

^Geotechnical Engineering Group

Center For Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D.C. 2023^

Gentlemen:

This refers to the article '^lew Concepts For Construction Practice Standards

For Excavations," by Messrs. Felix Y. Yokel and Riley M. Chung of the National

Engineering Laboratory, National Bureau of Standards and Mr. Ronald L. Stanevich

of the National Institute for Occupational Safety and Health, as printed in the

April, 1981 issue of "Concrete Pipe News" of the, American Concrete pipe

Association.

Specifically the reference Is to the table for additional surcharge allowance

for heavy equipment near supported excavations.

For a given trench depth and weight of equipment the additional surcharge

depth Is indicated as greatest for soil Type A and least for soil Type C.

In the soil type table Type A soil exerts the least equivalent weight effect

and Type C soil exerts the greatest effect.

Type A soil is indicated as having greater cohesion while Type C soil possibly

could have a coefficient of active earth pressure equal to or greater than

Type A depending on their friction angles 0.

Can you explain the rationale In which Type A soil exerts greater force from

heavy equipment and consequently requires greater additional surcharge than

Type C soil?

The second question Is in reference to the effects of nearby foundations on supports for excavations. Our interpretation of the data for this topic is

that any foundation beyond the limits of a 1 to 1 slope line from bottom of

excavation will not produce force on the excavation supports. Are we correct in this Interpretation?

Any additional information you can supply would be greatly appreciated.

Yours truly.

154
]

j

4. MILWAUKEE, WISCONSIN, WORKSHOP - WRITTEN COMMENTS AND CORRESPONDENCE

— This section contains all the written comments and correspondence

1 associated with the Milwaukee, WI workshop.

D

D

5

1

155
State of Wisconsin \

Department of Industry, Labor and Human Relations

SAFETY & BUILDINGS DIVISION

201 E. Washington Avenue

P.O. Box 7969

Madison, Wisconsin 53707

1981

Dr. Felix Y. Yokel

United States Dept, of Commerce

National Bureau of Standards

Bldg. 226, Room B-162

Washington, D.C. 20234

Dear Mr. Yokel:

The Trenching Code ad hoc Group of Wisconsin DILHR generally agrees with the

spirit of the revisionary work being undertaken by you and your select committee

on the basis that it inspires and provides for a necessary review of the Wisconsin

trenching safety rules. The Wisconsin Trenching Code has historically provided

the State with a good safety experience in this construction activity.

Comment to the effect that a good ’track record' is recognized and given con- sideration in the revision being contemplated is noted in your memorandum of

June 23, 1981. That the State of Wisconsin, which has had a trenching code since

1/2/56 (revised 1/1/63), is singled out, is viewed as both complimentary and

supportive of the past work done in trenching safety in the State of Wisconsin.

We should like to comment more directly on the items contained in your memo

of June 23 and also provide suggestions and what we feel are constructive comments

relating to the WORKING DRAFT1 ?.

Reference is made to Page 1 of your memo wherein you quote from a summary recommendation made in (BSS 127), Appendix A: Page 59, A. 3, first paragraph:

Traditional timber shoring practice varies widely from location to

location and frequently depends on such variables as sizes and characteristics of available timber, soil conditions, and local work practices. In some locations these practices have been used for many

years and appear to be satisfactory to all the parties concerned.

Three such locations are the State of Wisconsin. . .

In the same document. Page 65, second paragraph:

Since, in spite of the results of this analysis, NCS could find no evidence that conventional timber practice, if properly executed

is unsafe, consideration could perhaps be given to temporarily

exempting conventional timber shoring from the lateral load requirements until lateral load effects can be further studied by actual

measurements in the field.

DILHR-SBD-5524 156
Mr. Felix Y. Yokel

Page 2

July 9, 1981

The foregoing commentary has an affirmative and positive air, and it is hoped

that this attitude toward rules of long standing will not be changed by the

obvious trenching rules. A statement made (Dr. Yokel memorandum, Page 2):

(b) The evidence on which we can base the permission to use a tradi-

' tional practice which does not comply with our recommended provisions

is its track record, rather than compliance with engineering principles. Thus, if it is allowed, no changes in it should be permitted . Such changes would include substitution of any of its members by

other members of "equivalent" strength.

It can be stated here that the rules used in the State of Wisconsin were not

developed in an arbitrary and capricious manner, but were developed consistent

with engineering principles and practices in vogue at conception of the rule.

The exceptional track record came about because of the rule, not in spite of

the rule. Further, the statement no changes in it (rule, practice) should

be permitted , tends to prevent upgrading a rule should it be desirable to do

so in the interests of maintaining the good track record established. It

would seem more reasonable to permit change of rule to upgrade the Code based

on approval by some jurisdictional body. However, the precaution to permit

only practices which are actually widely used and discard other parts which do

not have a proven track record, is certainly acceptable.

In the WORKING DRAFT*/, the proposed Subpart, (p), 1926.650 General Protection

Requirements, which appears on Page 5, is generally acceptable to our ad hoc

Group. However, in 1926.651 Specific Excavation Requirements, the Subpart I referred to you under 1926.651 appears to be omitted.

In the WORKING DRAFT*/ tables and charts are based on a depth of 20 feet maximum depth of excavation. It is understood that the question of depth consistent with "Standard Practice", has not been resolved at this writing. It is

hereby suggested that a depth of 20 feet be established and charts be prepared

to reflect this concept. The IND 6.^/ may be adjusted to reflect the 20 feet

depth concept.

In Part 1926.653, WORKING DRAFT*/, Definitions Applicable to this Subpart, (p),

Page 19, a definition is provided for a Qualified Person . It is hereby suggested that the definition, as presented, covers persons in a supervisory

capacity within the scope of Standard Practice. Where conditions of trenching

are met which are beyond the scope of Standard Practice, i.e., trenches of

depth greater than 20 feet, design of ground support must be provided by a Registered Professional Engineer. This will bring about a dual category of

Qualified Person ; a category for the person where the trench is greater than

20 feet in depth.

The reason given for deletion of Table P-2, Page 57, of the WORKING DRAFT*/ is

that "Timber is not the only material used. Revised timber tables are in the

Guidelines, Appendix B." This statement is confusing. Is deletion due to the

fact that no "equivalence" is tolerated (in new rules)?

157
Dr. Felix Y. Yokel

Page 3

July 9, 1981

Descriptive terminology, it is felt, should be examined for clarity particularly in the use of such terms as "Safety Index," "Factory of Safety,"

"Compliance Measure," etc.

The FORKING DRAFT*/ lists twelve (12) timber sizes to be used to fabricate

required shoring (see Tables Bl, B2, B3 and B4). Few occasions will arise

where the trenching contractor will use all the listed sizes for a particular

trench project, but the various sizes must be available for use by the contractor in order to comply with the formulated rules. IND 6. ' on the other hand,

lists six (6) timber sizes.

On Page 29 of the WORKING DRAFT*/, Table 51, refers to allowable stress in wood

members. It is the feeling of this ad hoc Group that the Table is too refined

when it is considered that in the State of Wisconsin wood shoring members are composed of wood which is not 'graded* with the exception of a critical visual

examination at the time it is placed. The wood can be described as mixed hardwood, rough-sawed, and not formally graded.

In the WORKING DRAFT*/, Page 11, Table 1, Soil Classification System for the

Stand and Practice, an inconsistency presents itself. Soil Type C , Saturated,

Submerged or Softmay, at a trench depth of 12 feet or less, have a "steepest

allowable slope hor.iver. of 1-1/2 :

." Our attention is then directed to a qualifying footnote for Soil Type C which describes this soil as ". . ."

soils that cannot stand on a slope of 3 hor . ; 1 ver

without slumping (mack).

It appears that we have here two definitions for Soil Type C . The ad hoc

Group attempted a correlation between "soft" soil Table 1; and Table A. 3, Page

42, in the WORKING DRAFT^/. It is our feeling that soil classifications as presented in IND 6^/ are more appropriate for use in the State of Wisconsin.

On Page 3, second paragraph of Dr. Yokel June 9, 1981, memorandum, reference is

made to a 240 lb. gravity load placed at the center of trenching structures.

The Wisconsin Trenching Code ad hoc Group is not familiar with the 240 lb.

design requirement and would appreciate an explanation or the rationale. We

have also noted that the AFL-CIO discussion prepared by Jack Mickle recommends

a 500 lb. gravity load.

In summary, the good track record for trenching activity in Wisconsin has been

a source of pride to this department and affirms our contention that the shoring

and proposed requirements of IND 6. ' are adequate for ground conditions found

in Wisconsin. These items, which we feel will enhance our IND 6.2/, have been

set forth in this letter to you.

Since we are supportive of your work, and conscious of our own unique position

in the matter of safety and trenching in Wisconsin, we will recommend all

communications from you and your select committee.

158
Dr. Felix Y. Yokel

Page 4

July 9, 1981

Should the occasion arise for you to do so, please feel free to use or adapt

in any way parts of IND 6. 2 /. Should you have any questions concerning this

document (IND 6.2/), or find that we can be of assistance to you or your

committee, please call us at (608) 266-1818.

Sincerely,

Gordon Helmeid, Director

Bureau of Technical Services

GH : lmb

cc: John Wenning

John Drake

John Ramage

Pete Gronbeck

^WORKING DRAFT OF SUGGESTED REVISION OF SUB-PART, (p), OF THE SAFETY AND

HEALTH REGULATIONS FOR CONSTRUCTION BASED ON BUILDING SCIENCE SERIES REPORTS

BSS 127, by Dr. Felix Y. Yokel.

2 /WISCONSIN ADMINISTRATIVE CODE SECTION IND 6, TRENCH, EXCAVATION AND TUNNEL

CONSTRUCTION .
July 13, 1981

National Bureau of Standards

U.S. Department of Commerce

Washington, D.C.

Ref: OSHA, Sub-Part ”P M

, Suggested Revision

Gentlemen

We have reviewed the working draft of the Sub-Part ”P"

revision as issued on February 20, 1981. As an agency charged

with responsibilities for storm and sanitary sewerage in a metropolitan area with an old-core city, safety of personnel

especially during maintenance is of primary importance. Of

almost equal importance, however, is a continual lack of sufficient funding to do the quality job that we would like to do.

Accordingly, our interest in this regulation is that its provisions be appropriate requirements for safety of personnel and

also, that these requirements be not excessively demanding and

therefore, not justifiably costly.

We feel that the draft, as presented with the basic SubPart "P" being supplemented by rather than including guidelines,

is proper format for the regulation.

We regret that the original topic heading ’’Excavations,

Trenching and Shoring” has been changed to "Excavations and

Shoring” because the great majority of the site conditions in

which we are involved, are trenching situations.

For trenching applications, as compared with excavations

for building and other large area construction, with the difference in time span between starting excavation and backfilling,

the more rapid trenching techniques used by the construction

trades are successful because materials in which excavations

are made, may have different physical properties over a short

span of time of up to several days than when excavations are

held open for months.

While much of our new construction is by contract with the

private sector, with plans and specifications usually prepared

by outside consultants working to our design guidelines, the

2000 HAMPTON AVENUE • 8T. LOUIS, MISSOURI 63139 • 766-0200
our specially trained

National Bureau of Standards

July 13, 1981

Page Two

majority of maintenance work is done by

and equipped crews.

Many of our maintenance operations are in areas where previous construction has resulted in situations with subsurface

conditions markedly different from a virgin site. Because of

this, we feel that experience of alert construction personnel

is at least as important as formal academic training. We

strongly suggest that the abilities of the "competent person"

or "qualified person", as defined in 1926.653, paragraphs (g)

and (p), be used to indicate a more reliable and suitable

responsible person that the definition in (h) of an "engineer"

as a registered professional engineer. The intent of SubPart "P" of OSHA is to establish minimum requirements for

safety of personnel working beneath the ground surface. Our

operations are with experienced foremen working with stable,

experienced crews. Most of these foremen; as well as members

of their crews, have the abilities of "qualified persons" and

the foremen have the authority of a "competent person".

In special situations, our competent foremen are aware of

the effects of the history of other construction in the area

as well as the indication of subsurface profiles or soil types.

We feel that for safety, these people best satisfy the intent

of Sub-Part "P", and more important, they are constantly present. The requirement of any additional qualifications or

specialized persons, such as a "registered engineer" is an

unnecessary and excessive cost which we can’t afford.

We feel the "engineer" is the appropriate requirement

rather than the "competent" or "qualified person", when design

of restraining systems to protect structures which usually are

adversely affected by any movement are needed. For construction activities with protection of personnel who reasonably are

more mobile, the need is different and less severe. We understand that in technical terms the contrast between these two

situations would be described as the difference between the

"at rest" and "active" states of lateral pressures.

Since the great majority of our involvement is in trenching,

the difference of stronger soil characteristics in short-term

excavations must be recognized and we strongly endorse seven

days as the suggested change from "short-term" to "long-term"

situations (1926.653(m) and (t))

We urge that the revision of Sub-Part "P" be as indicated

in the working draft with "qualified person" being used rather

than "engineer" in Section 1926.653, subparagraphs 2, 3, 41, c

and d and that "short-term" excavations as compared with "long161
National Bureau of Standards

July 13, 1981

Page Three

term” be defined as "seven days or less”.

Very truly yours.

Charles B. Kaiser, Jr.

Assistant Executive Director

and General Counsel

CBK/kam
OHIO CDNTRROTORS

June 1, 1981

THE NEIL HOUSE MOTOR HOTEL

COLUMBUS. OHIO 43215 • 228-6831

LONG DISTANCE TELEPHONE 800 282-1388

Mr. Felix Y. Yokel

U.S. DEPARTMENT OF COMMERCE

NBS Building Science Series 127

Washington, D.C. 20234

Dear Mr. Yokel:

A review has been made by our safety committee and others , of proposed

subpart P. 1926.650 - .651 - .652. The Ohio Contractors Association

represents 408 contractors in the state of Ohio. This response to this

proposal should be considered as representative of our complete membership. The following is a summary of the evaluations by the membership

of the proposed standards.

1. The intent of the revised changes of subpart P.

to clarify and simplify the standards has in the

main, failed. The main problem, that of soils classifications, has not accomplished its goal. The new

descriptions are as confusing as the old, if not more

so. Years of experience by ’’competent persons” indicate that the safety of persons in trenches with sides

of "intact hard” soils need no more than a h to one

slope when the depth is 12 ft. or less.

2. Unaminous agreement of the need for section 1926.65a

however we suggest changed wording as follows:

’’Utility companies and municipally owned utilities

shall be contacted and advised of proposed work prior

to the start of actual excavation. Prior to opening

an excavation effort shall be made to determine

whether underground installations i.e. sewer, telephone,

electric, water, fuel lines etc. will be encountered

and if so where such underground installations are

located”.

3. Pg.7 .651(d) the wording is not clear and would

imply that the backhoe digging the trench would

be the cause for added shoring.

(Continued)
- 2

-

Pg.7 paragraph(g) should be deleted. The use of

stop logs is not in common use by the industry and

would create greater hazards, from the constant moving,

than it would eliminate.

Pg.7 item(h) a better definition of conditions are

needed to fully explain the intent of this paragraph.

Pg.7 paragraph(i) conflicts with provisions of the

Clean Waters Act and is meaningless when it starts

"If Possible".

Pg.7 paragraph(j) The procedures do not seem warranted in open cut trenching. What is meant by

"Attended emergency rescue equipment?"

Pg.8 paragraph(p) the "5 ft." depth is consistant

with other standards and is the level where a need

would be greater.

Pg.8 paragraph(r) shoring members "secured to prevent failure" is unclear.

Pg.9 Trenching and Large excavations should be

separately delt-with by two distinct set of standards.

Pg.9 paragraph (a) (1) (b) a clearer definition of

"unfractured rock" is needed.

Pg.9 paragraph (a) (2) we urge the adoption of the

24 ft. depth.

Pg.9 paragraph (a) (2) (a) the use of a "qualified

person" is more practical, allowing immediate

determinations and corrections in the field when

questions arise.

Pg.10 paragraph (a) ( 3) we favor the 24 ft. depth

in this item and the determination of proper protection by a qualified person."

Pg.10 paragraph (b) (1) 7 days would be a more

practical time frame for short term excavations.

Pg.ll table 1 we urge h to 1 slope in soils type

A. and a separate table for short § long term

excavations § trenches.

Pg.ll Notes item 4 the description is ambigious

and needs clarification.

(Continued)

164
Pg.12 the 3' ft. depth is too confining for many

installations and conflicts with good engineering

practice. The illustrations will create interpretation problems by persons unfamiliar with this type

of work. The table in case IV should be revised.

Pg.14 § 15 this section has no practical use for

field personnel and creates more confusion than

it answers questions about safe procedures. Keep

diagrams, tables and examples simple.

Pg.16 paragraph(c) we would prefer to use a "qualified person".

Pg.16 paragraph ( 5) (i) when this condition exists

many times it is impossible because of pipes,

lines or other devices to achieve this requirement.

Pg. 16(5) (iii) the use of 3 ft. will give greater

flexibility in various soil conditions without

increasing hazard exposure.

Pg.17 b refer to Figure 4 pg.20.

Pg.18 Mass movement of Soil or Rock definition

will reduce interpretation of requirement.

Pg. 19(b) A more comprehensive definition of

"fractured rock" will eliminate interpretation

confusion.

]

]

]

1

1

J

Pg.19 paragraph(m) 7 days should be used.

Pg.19 paragraph(t) 7 days should be used.

Pg.19 paragraph(x) include this definition with

the definition of fractured rock.

Pg.20 paragraph (bb) an example would clarify this

definition.

Pg.21 thru 50 should be deleted. In our opinion

this section has no practical application or use

in the field. Many of the formulas and computations

are available to engineers if there was a need.

Pg.57 table P-2 should be reworded to allow for

greater spacing between shoring members to be

able to handle longer lengths of pipe being used

today.

These recommendations and suggestions are offered in the hope

will contribute to increased understanding^^nd application of

to improve safety.

Sirfc^rely

T.F/nas

J&2c4i

Freed

Manager of Safety

that they

regulations

165
5. ATLANTA, GEORGIA, WORKSHOP - WRITTEN COMMENTS AND CORRESPONDENCE

166
Duke Power Company

P. 0. BOX 33189 GENERAL. OFFICES TELEPHONE: AREA 704

373-4011

422 SOUTH CHURCH STREET

Charlotte, N. C. 28242

v July 17, 1981

Fel ix Y. Yokel

U.S. Department of Commerce

National Bureau of Standards

Washington, D.C.

Re: Review of Working Draft of Suggested Revision in Subpart P of the Safety and Health Regulations for Construction Part

1926, Excavations and Trenching based on Building Science Series

Report BSS127

The attached Summary represents Duke Power Company's Construction

Department's views on the suggested revision to subpart P of the

OSHA 1926 Standards.

If further interpretation or comment is needed please do not hesitate

in contacting my office.

J E Grogan, Manager

Construction Resources

R S Dugan, Supervisor

Construction Safety

JFE : sr

cc: David Abernethy
Proposed Review

Reference

1926.650(c)

1926.650(j)

1926.651 (e)

1926.651 (f)

1926.651(g)

1926.651 0)

1926.651 (o)

Response t

It is requested that planking material and their

use be specified in construction of raised walkways, runways, or sidewalks to insure an acceptable level of safety.

It is recommended that a qualified engineer be

responsible for the critical function of inspection,

design, and other related decisions concerning

trenching and excavations. By the criteria

document definition "qualified" carries more recognition and proven ability than does "competent".

It is recommended that the engineer not be required

to work at the location since multiple sites would

present availability problems.

L

L

[

(r

r

There is some concern on the proposed requlation

to shore the sides of excavations as necessary where -

trucks and other vehicles may be parked or moved

adjacent to the edges. It is agreeable that employees

should not be in such a trench while a piece of

equipment is nearby but the wording of the regulation

may cause concern in back-filling operations where __ the truck is backed and dumped from the excavation

or trench edge.

Where blasting is necessary then the soil should

be treated as unstable in regard to shoring

considerations.

The question is raised as to how adequate a barricade

or stop log would be required as a stop for vehicles

adjacent to excavation or trenches. Warning flagging

may be adquate to similarly safeguard all employees.

It must be considered that oi

cannot be used to

minimize dust conditions caused by trenching and

excavating activity where prohibited by some states

(examp 1 e-South Carolina) as a hazardous waste

chemical and other government environmental agencies

and regulations.

L

c

c

[

This section referring to work procedures in bellbottom pier holes should not be dropped from the

scope of subpart P since it deals with a type of

excavation. [

[

[

168
Reference Response

1926.651 (p) The 4 feet depth requirement should be retained

as a basis for requiring adequate means of

exit from a trench. The phrase "negotiable slope"

is vague and needs clarification.

f 1926.651 (q)

%

The proposed regulation should read "shoring

where needed" to clarify the intent of the

standard.

1926.652(a)(2) Excavation standards should not be relaxed to allow

depth requirements to be extended from 20 ft. to 24 ft

before following specific requirements. The majority

of excavations are less than 20 feet where the

majority of injuries have been shown to occur.

1926.652(figure 1) Slope requirements in the drawing should be omitted

since the angle of repose would be a primary

governing factor in determining shoring.

1926.652(figure 2) Case IV should be limited to excavation by trenching

machines.

1926.652(figure 2) The allowable bank next to the work area should

remain at 3 feet and not increased to 4 feet in

the interest of increased safety to workers.

1926.652(table 1) The steepest allowable slope should remain at 1:1

instead of 3/4:1 to allow a greater margin of safety.

1926.652(b)(1) A short term excavation or trench should be redefined

to extend from 1 to as much as 3 days.

1926.652(b) (4) (ii) This information requiring specified strength of

protection systems for trenchs and excavations should

be inserted at the end of subpart P with more

options outl ined.

1926.652 (b) (5) (Hi) Excavation up to 2 feet below the bottom of trench

boxes or sheeting should remain as a requirement

and not extended to 3 feet.

1926.653(a) The reference to a registered architect should be

removed since the expertise of this field may not be

concerned with soils.

Definition: Mass movement of soil should be defined to give

guidance in inspection and design specifications.

Appendix A There is general use of the term "should" which

perhaps to insure worker safety should be changed to

"shall" Items.

Examples: A.3»2 Soil and Water Loads

169
There was concern from the workers responsible for actually installing

shoring systems that more emphasis should be placed on system 'instal lation

safety. The standards address finished shoring systems for other work

: processes but not in particular to how they are actually constructed as to

working in trenches and excavations. This important area needs further

consideration.

170
6 . DALLAS, TEXAS, WORKSHOP - WRITTEN COMMENTS AND CORRESPONDENCE J

]

l

I

]

J

171
DRAFT

DISCUSSION OF

t

i

WORKING DRAFT OF SUGGESTED REVISION IN SUBPART P OF

THE SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION

.BASED ON BUILDING SCIENCE SERIES REPORT BSS 127

by Felix Y. Yokel

BUILDING AND CONSTRUCTION TRADES DEPARTMENT AFL-CIO

JACK L. MICKLE

DALLAS, TEXAS JUNE 30, 1981
DRAFT

Dr. Yokel is to be commended for his efforts to improve upon

the Occupational Safety and Health Administration, (OSHA), 29

~]FR Part 1926. Subpart P, Excavation, Trenching and Shoring Regulations document.

The Building and Construction Trades Department, AFL-CIO has

-been supportive of and assisted Dr. Yokel, where possible, since

-he began work on this project with the National Bureau of Standards in June, 1976. ^ In January, 1977 the B&CTD began the planning stage of a

^.'Trenching Hazard Identification Task Force" , hereinafter called

the Task Force, to help the NBS obtain employee input aimed at

hazard identification. In March, 1977. the Task Force met for a

four day "retreat" type workshop; the six labor and management

members brought with them 182 years of experience in trenching

"and related work. The charge was "to identify procedures and

“conditions that create safety hazards during excavation and

^trenching operations". Others present for the deliberations

—were Jim E. Lapping, Director of Safety and Health, B&CTD,as

—coordinator; Felix Y. Yokel as Technical Observer for the NBS

_and Jack L. Mickle, Chairperson. The final report (1) was filed

Jwith the NBS in April, 1977* The final report appears in appendix G of NBSIR 80-1988 (2).

In September, 1978 Dr. Yokel (3) presented the preliminary

• findings and recommendations of the NBS study. Out of that twoday workshop came the agreement for this series of workshops to

bring the results of Dr. Yokel's NBS study to the attention of

"“labor, management and engineers in the field. Actually the

^essence of the working draft we are using for this workshop was

•"printed in the Concrete Pipe News (4) in April of this year.

- Since the 1978 workshop the B&CTD has responded to a number ^ of requests for criticisms of drafts by Dr. Yokel.

i

Numbers in parentheses refer to references given at the end of

this' paper.

173
Two premises underlie all remarks and criticisms given in

. t this critique: \ T*at the worker be assured of safe and healthful

'

, working conditions, and

that the journeyman worker and the compliance

officer as well as the management representative

be able to fully understand the precautions that

have been taken and the protective measures that

have been provided to assure worker safety and

health, or that the safety of the worker on the

job be placed in the hands of a licensed professional.

The first premise is spelled out in the preamble of the

Occupational Safety and Health Act of 1970.

The second premise assumes that an average journeyman or

compliance officer, using the official OSHA regulations governing excavation and trenching safety, can determine whether or

not the safety provisions on any jobsite are in compliance with

the appropriate regulations. If the provisions are not "standard practice" as outlined in the regulations then there must be

a certificate issued by a licensed professional which assures

the worker that the jobsite safety and health measures have been

designed by and certified by the licensed professional.

There are undoubtedly many "competent persons" and "qualified persons" who are quite capable of designing a safe worksite,

but how are they to be identified by the worker or compliance

officer? The license is the evidence. All licensing laws have

encountered competent or qualified persons and have eventually

incorporated them into or excluded them from practice. While

there are probably quite capable people who know a great deal

about medicine or law, the prudent individual seeks the licensed

practitioner when medical or legal opinions or services are

sought.

Actually suggesting that registered engineers need to be

consulted is not new with this suggestion. Thompson and Tanenbaum (5) recommend substantial involvement of registered engin-

( 3 ) 174
draft

t eers in construction activities requiring trenching or excavions..

tn view of the foregoing, this discussion will be concerned

with only the first 20 pages of Dr. Yokel working draft which

outlines "standard practice". Even portions of the first 20

pages probably belong in the "guidelines" which have been included to assist professionals. It is also assumed that only

the "standard practice" will eventually be recommended for inclusion in the OSHA regulations Subpart Pj Dr.' Yokel has indirectly suggested that by what was included in the article which

he co-authored in the Concrete Pipe News. (4);

/ I. \ 175
COMMENTS ON SELECTED ITEMS ON PAGES 1-20 OF THE WORKING DRAFT

Page Location ' Comment

1

2

2

3&4

5

5

6

-6

6

8

8

8

item 3

item 5

last

line

All

Issues

(g)

(i)

(j) 2nd

para,

line 8

(c)(1)

line 3

(c)(2)

line 3

( 1 )

line 2-

(o)

(P)

?. boxes. It is addressed to contractors, shoring

manufacturers and engineers..." Why address it to

the contractor unless the contractor is also an

engineer?

" . . .which would aid field personnel and contractors in the selection of shoring." Once again,

these persons are going to be dealing with the

standard practice unless they are licensed professionals in their own right.

Note that a qualified person is not an engineer

(recognizing this as just an example)

The items listed on pages 3 and 4 will be considerindividually as they encountered in the text.

..be provided with and shall be inetrueted (required) to wear .... ...shall be permitted under loads handled by

pewep-ehevelei-deppieksT-er-heiBtBT (equipment)

This item is too specific for not listing all

equipment which is used to handle loads; for

example, backhoes are not listed.

...or the shoring system, and shall inepeaee-ppeteetien- against- slides- and-eave-iRe-af-ReeeseapyT

(see that all work in the excavation shall cease

until necessary precautions have been taken to

safeguard employees.)

V.. shall be effectively stored and retained at

least 2 (3) feet or more from the edge of the

excavation." The Task Force specifically stated

that 3, feet was necessary for proper protection,

" ...may use effective barriers ©p-ethep-effeetive

petaiRing-deviees-iR-lieu-thepeef in order..."

Task Force recommended extending tight sheeting

above ground level as an effective barrier. Twelve

to 18 inch extensions were discussed.

V.. equipment, th^ shall be designed-and constructed by qualified persons..." Design implies work

done by a licensed professional.

This item is silent with respect to straight sided

pier holes; some confusion has arisen because

straight sided holes are covered elsewhere. 800(h)(3)

When employees are required to be in trenches 4

45?)- feet deep...." Leave at 4 feet.

( 5 )

176
DRAFT

Page Location Comment *

8 (s) t

.

boxes or shields are used they shall te designed (and certified as to use by a professional

engineer and shall be maintained in a manner which

will provide protection for the worker.)" Strike

the balance of (s).

9 (a)(l)a Excavationo leas than 5 ft. deep, except when enawiRatien-ef-the-gFeuRd-by-a-eeiRpeteRt-peFseR-iRdi

eates-that hazardous ground movement may occur."

9 .(.a).(-2) "Exoavations from < ft. to P-0 ft. /.2k- Pi dorm. . " fthy consider 24 feet? A better choice might be

15 feet for Standard Practice. Thompson and Tanebaum data (5) indicate that 8? per cent of the fatalities and injuries occur in excavations less than

20 feet deep and that 72 ’per cent occur in those

less than 15 feet deep.

Hinze and Carino (2) state in their summary that

their "..study showed that most trenchwork is between 5 and 15 feet deep with the trench width

usually being about 3 feet."

Cass (6), speaking about the stacking of two standard 7 ft. aluminum hydraulic shores, notes that

where the trench is over 14 feet deep (page 68)

"other shoring systems should be applied" and on

(page 72) "Maximum trench depth, this method, is

15' (4.58 m). Over 15' (4.58m), see Fig. 60.2,

multi-type shoring." Multi-type shoring shown on

Fig 60.2 is a different system using aluminum

'hydraulic shoring and plywood backing.

A maximum depth of 15 feet for Standard Practice

seems appropriate.

9 (a)(2)a "..sloping requirements must be determined by an

line 3 engineer 4a-qualified-peFeeR?)«r

9

10

10

(a)(2)b May lead an individual to believe that FOOTING A

Figure 1 is not a cause for concern} this could be dangerous. It is worthy of note that the role of the

engineer has not been challenged at this point

where property damage as well as personal injury

is possible.

(a)(3) See comments under » page 9 (a)(2). Fifteen ft.

depth may be a better limit for Standard Practice

rather than 20 ft.

'(b)(1) The distinction between short-term and long-term

line 6 is very difficult to reckon' with j virtually no

firm data exists. Not only stresses in the mass

vary with time, but environmental factors may be

critical. Twenty-four hours seems more logical

than seven days.
DRAFT

Page Location Comment

11

12

13

13

13

13

13

16

bottom There may be some merit to allowing steeper slopes

of pa^e in some cases.' The Task Force indicated that

last two slopes flatter than 1:1 were probably not necessary

lines for worker safety. Slopes of 1:1 were recommended

for most conditions.

Fig. 2 This particular configuration should be made a

Case IV part of the "guidelines” proposed by NBS. While

the configuration looks good on paper, it may be

difficult to understand and/or enforce in the

field. If included in Standard Practice the 3 ft.

max bank should be retained.

(b)(4)(i)b. See the first four lines at the top of page 13*

Table 2 is necessary in Standard Practice only if

* Fig. 3(b) Is retained. Moving the option shown

as Fig. 3(b) to the Guidelines removes the need

for Table 2 which is confusing and also removes

the need for special tables and figures outlining

the placement of shoring in the lower part of the

ditch.

(b)(4)(i)c. For Standard Practice it may be worthwhile to

include all surcharges, including allowances for

heavy equipment, in the adjusted depth. The Task

Force recommended a minimum of 300 pounds per

square foot for surcharge. Dr. Yokel has greatly

simplified Table 3 but it still can be confusing.

Moving Table 3 "to the Guidelines and greatly increasing the surcharges to allow for heavy equip-

• ment may lead to "overdesigned" shoring and

shields, but Standard Practice would thereby be

greatly simplified.

(ii)b. The Task Force recommended a 500 lb gravity load.

(ii)c. This statement is not clear. Does this mean a

240 ft-lb impact load per square foot? The entire

(ii)c. should become a part of the Guidelines and

removed from Standard Practice.

(ii)

b.

This entire section devoted to the required

strength of shoring systems, trench shields and

trench boxes needs to be moved to the Guidelines.

If some of the previous suggestions are followed,

hydraulic shores and other assemblies can be

brought into Standard Practice. At a meeting in

October, 1980 with NBS and members of the hydraulic shoring industry it was agreed that reasonably simple charts for the selection of

shores can be developed. This seems to be in

keeping with Cass' (6) recommendations for depth

to 14 or 15 ft. There is no question that the

resulting system would be greatly over-designed 178
1— I

»_!

I

I

!

j

draft •

" Page Location Comment

at times, but the freedom to use Standard Practice for most work (2) and thereby not requiring

the services of an engineer seems to outweigh

the disadvantages of overdesign.

w 16 fc. Timber shoring is properly located in the Guidelines! selection must be by an engineer. The

Guidelines are for the use of licensed professionals.

16 (5)(ii) The statement in parentheses is a vague performlast two ance specification which detracts from a well

lines stated, precise paragraph.

16 (5)(iii) Excavation below the bottom of the protective

element has merit! exactly how much to allow

• ’ is difficult to determine. Certainly

engineers can design specific, protection for

unique circumstances, the Guidelines will help,

but permitting excavation below the protection

device in Standard Practice will require very

careful consideration.

18 (a) "...with standards required by a-Fegisteped-apehiteet7 a registered professional engineer, or other

duly licensed ep-peeagnised authority. .."

19 (m) Twenty-four hours for short term seems most reasonable.

19 (oj ‘ Negotiable slope needs to be specified; l|sl seems

reasonable.

19 (p) How is a qualified person to be identified? Unless

. . there is a specific procedure anyone can claim to

be a qualified person. No objection if the qualified person is permitted to use Standard Practice

only.

19 (t) same argument!' use 24. hours for. short term.

19 (aa) Stable Slope. A meaningless term unless it is

arrived at by a licensed engineer. This term has

no place in Standard Practice!

« 20 (gg) Working loads are best relegated to the Guidelines

where they can be dealt with by an engineer.

179
Summary

t DRAFT

f There must be clear separation between Standard Practice

and cases where an engineer has certified the procedure to be

followed.

It is recommended that Standard Practice be permitted to

a depth of cut of 15 feeti this includes most excavation and

trenching work. At depths greater than 15 feet, or for special

work, the engineer must assume full responsibility for the

design of -the protective system. The 15 ft. depth needs verified.

Standard Practice must be written such that the protective

measures resulting from the application of Standard Practice

are observable, measurable,, understandable by all parties (with

application of the regulations) and provide for the safety and

health of the worker. It is recognized that Standard Practice

may at times result in substantial overdesign, but this would

not be new to the construction field.

It is anticipated that competent or qualified persons working for the contractor would select methods within Standard

Practice to protect workers, but that any deviation from Standard

Practice would need to be designed by an engineer. The engineer

is recognizable by a professional license.

Several items which need consideration! construction

right of way requirements , . toxic materials , safety program as

an item in the bid document, soil conditions and utilities in

the bid document and better safety education for all. The Task

Force final report lists other concerns.

( 9 )

180
-• DRAFT

• t

i

_

RECOMMENDATIONS r . % -J

2.

1

j

Use Standard Practice to a depth of 15 feet.

Over 15 feet or where Standard Practice is changed an

engineer must assume full responsibility.

]

3 '

“j

Standard Practice must be observable , measurable and

understandable by all parties and above all must be

effective.

4.

1 Competent and qualified persons working for the contractor would select methods within Standard Practice but an • engineer would be required where deviations occur.

5. Construction right-of-way needs to be considered.

i

6. Toxic materials need to be considered.

7. A safety program needs to be outlined in the bid documents.

8. Soil conditions and utilities need to be considered in the

bid documents.

-

9.' Safety education is a must for all.

(9b)

131
DRAFT

References i

1^. Building and Construction Trades Department AFL - CIO.

Trenching Hazard Identification Task Force; Final Report.

Prepared for the National Bureau of Standards; Building

Safety Section; James 0. Bryson, Chief. April, 1977*

2. Hinze, Jimmie and Nicholas J. Carino. A Study of Work

Practices Employed to Protect Workers in Trenches; NBSIR

80-1988. National Bureau of Standards. March 1980.

3% Salomons, Lawrence A. and Felix Y. Yokel. Proceedings,

Federal Workshop on Excavation Safety, September 19 and

20, 1978% National Bureau of Standards. July, 1979%

4% Yokel, Felix Y., Riley M. Chung and Ronald L. Stanevich.

New Concepts for Construction Practice Standards for

Excavations. Concrete Pipe News; pages 28-33, vol 33

no 2, April, 1981.

5% Thompson, Louis J. and Ronald J. Tanenbaum. Excavations,

Trenching & Shoring: the responsibility for design and

safety. Sponsored by the Associated General Contractors

of America. A report of -the Texas A & M Research Foundation. College Station Texas. September, 1975%

6. Cass, W. Martin "Red'1 . Common Sense in the Common Trench.

Equipment Guide-Book Company; 2800 West Bayshore Road,

Palo Alto, California 94303. 1979%

182
Page 5

— Page 7

_ Page 8

Page 9

— Page 10

i Page 11

RECOMMENDED CHANGES TO

WORKING DRAFT

SUBPART P 2/20/81

1926.650(d) Reword "Planks shall be installed in a manner to reduce the

probability of tripping."

(g) Need to define what is meant by "Exposed To Vehicular Traffic".

(i) To restrictive; does not allow for the driver to stay in vehicle

with cab protection. In most cases driver is exposed to a greater

hazard outside of his/her vehicle. Remove second sentence.

1926.651(g) Remove words "substantial stop logs or barricades shall be

installed." Reword: If possible, the grade should be away from the

excavation, when mobile equipment is utilized or allowed adjacent to

excavations.

(i) Delete (This provision is covered under Air Pollution Standards),

(k) Delete (Should only apply to long term usage).

Delete (Any structural ramp of this type would normally be in the project

plans and specifications).

(p) Support the 5' trench. Also consideration should be given to the

exit through pipes (48" in diameter and larger) in the trench. This

would eliminate the emergency exit on a ladder with mud on the boots.

(q) Start paragraph with words "Proper Shoreing".

(r) Delete: repetitive of (q).

(t) Delete: Does not define unstable soils; to restrictive.

1926.652(a) (2) Support 24 foot.

(2) (a) Support qualified person.

(3) Support 24 ft. and an engineer.

/

Table 1 Soil Type 12* or less T2 * & greater Start Sloping

h- 1 **:1 5

' level

3/ 4:1 1:1 3' level

1:1 | 1:1 O' level

183
Page 12

Page 13

Page 14

Notes: 1) Use of Normal Construction Equipment used in the Trenching operation

should not change the sloping requirements.

2) Type C: Soft Soils should not include cohesive soils defined under

• d/ -

Figure #2 Should be changed to consider depth at which slope would start.

(See recommendations under Table 1).

b. To restrictive.

Table #2 More time for study is needed.

Additional comments:

r

L

c

L

1. Too much emphasis is placed on sheeting and shoring systems for semipermanent excavations, such as building foundations? *-

a) Concentration in regulation changes seems to be on building excavations. _

b) Greatest need is for uniformity of enforcement, clarification of regulatic^

and training of compliance officers is in open trenching projects.

c) Regulations, even with proposed changes are still not simple enough for

average compliance officer to comprehend. Regulations are not definitive^

enough to accurately classify various soil types. Most charts are thrown

out window when decision as to bracing is made. Most superintendents rely_ on experience.

2. All backfill material is not soft or unstable, yet regulations assume so.

3. 1926.651(c) is redundant, is covered in several other regulations.

4.

Short term trench opening should be less restrictive and should re-conside;

the effect weather has on long term trench opening in evaluating soil typ

Presented: June 16, 1981, Atlanta, Georgia _

Comments Made by: Michael D. Maguire on behalf of A.G.C. of Kentucky which

represents Chapters in Louisville, Lexington and Paducah,

Kentucky. _

- 2 - 184
MCCLURG & ASSOCIATES, INC. /CONSULTING ENGINEERS

June 25, 1981

Jloomfield Center Building

!5 West Long Lake Road

3 field Hills, Mich. 48013

ireaV, 645-2205 (Bl. Hills) »de 564-4818 (Detroit)

J

.Robert EL Cooper P.E.

r . M. Mac Millan P.E. —

1 R. H. McClurg P.E. John Mikle P.E. Allen J. Nieber P.F..

Office

irg t MacMillan

.North Euclid 3ay City, Ml 48706

;51 7^584-4060

Efficiency Production, Inc.

P.0. Box 24126

Lansing, Michigan 48909

Attn: Mr. John Cook

He: Comments on "Working Draft of Suggested Revision

in Subpart P of the Safety & Health Regulations

for Construction based on Building Science Series

Report BSS 127" by Felix T. Yokel dated 2/20/81

1 926 .652 - Specific Shoring. Shielding & Sloping Requirements

(a) (1) a. Change to excavations less than 4 ft. (vs. 5 ft.)

(a) (2) Change to excavations greater than 24 ft. (vs. 20 ft.)

a. ... 'must be determined by an engineer'.

(a) (3) Change to 24 ft. (vs. 20 ft.) and use engineer

(vs. qualified person)

(b) Standard Practice

(1) Change to 7 days (vs. 24 hours) -(this needs

documentation or at least more study).

(4) (i) Determination of adjusted depth

(a) eliminate the 2' surcharge here and in Figure 3 (a),

therefore adjusted depth equals actual depth H as

determined by a qualified person

(b) eliminate the 2' surcharge in figure 3 (b), make

adjusted depth equal to actual depth.

Page 14 - eliminate Table 2.

(Discussion - the 2' allowance for spoil piles is not

needed in many cases, e.g. paved streets - traffic

maintained; and is not enough in many other cases erring

on the side-'of danger. The design depth should be

selected by a qualified person based on actual field

185
Efficiency Production, Inc.

Page 2

June 25, 1981

conditions. This obviously includes spoil piles (which

may be 10 ft. instead of 2 ft.) and any other surcharge

loads which must be included in the estimation of

depth of cut. Table 2 is an effort to lay down empirical

rules for adjusting depths but it is not controlling and

merely will confuse field personnel. We assume this

table is based on a Rankine or Coulomb theory for sloping

backfill utilizing a failure wedge of earth loading the

retaining structure. The actual depth would control

until you arrive at an exceedingly deep cut. For example

if H = 20 ft., slope 1:1, adjusted depth equals 3 times

H equals 60 ft., which means within the normal range of

excavation the actual depth of cut must exceed 60 ft.

before Table 2 controls. Hopefully in excavation

decisions of this magnitude an engineer would be

investigating a method of determining lateral earth

pressure based on engineering principles and accepted

soils mechanics data available to him and Table . 2 would

be of no value to him.)

(4) (I)

c. delete the reference to a 2 ft. surcharge allowance.

(Table 3 and Figure 3 (c) would probably be helpful

to field personnel who might be required to evaluate

the effects of heavy equipment in close proximitv

to the trench excavation for depths up to 20 ft.)

c

Page 11 - Table 1 _

Type H medium soil should be we 30 lbs./ft3 in accordance

with generally accepted engineering practice. This covers

sand, gravel, sand-gravel, clayey sand-gravel and silty —

sand with unit weights ranging from 100' to 140 lbs./ft3

and friction angles from 28 to 45 degrees. Soil —

classifications exerting pressures greater than 30 lbs./ft3

such as clay-silt, clays, uniform silts and hydrostatic

conditions are special cases which generally exert w

pressures greater than 40 lbs./ft3 and require more

detailed analysis. —

We also fail to understand why the "steepest allowable

slope” should be any different for depths greater than

12 ft. then it is for depths less than 12 ft. We propose

they should be as follows in accordance with average angle

of repose, regardless of depth:

Type A 3/4 horizontal

B 1£ horizontal

C 3 horizontal

1 vertical

1 vertical

1 vertical

186

I

I
Efficiency Production, Inc.

Page 3

June 25, 1981

(4) (ii) Required Strength of Shoring Systems *

a. Change to - lateral pressure at the bottom of

excavation equal to the equivalent weight effect

(we ) in Table 1 times the depth of cut with lateral

pressure diagram appropriate to the construction as

determined by an engineer. (Discussion - the

present statement is an over simplification more

correct for closely cross braced sheeting, but not

applicable to trench boxes and not correct for all

cases of braced sheeting).

c. Delete the entire last sentence. Allowing a 33%

allowable stress increase would reduce the safety

factor against yield for A36 steel to 1.12. This

approach is not recognized by any known building code

and if reasonable criteria' is used for determining

lateral earth pressure it is unwarranted.

(5) Special Provisions

(iii) Excavation up to 3 ft. below the bottom of ...-. 1926.653 Definitions

(m) Long term excavations - which are open more than

7 days.

(t) Short term excavations - which are open 7 days or

less

.

Guidelines Supplementing Subuart P of the Safety and Health

Regulations for Construction

Page 22 - Section 2 Strength Requirements for Pre-Designed

Shoring Systems, Trench Boxes and Trench Shields

to be used in the Standard Practice.

2.1 Design of Shoring Systems

A. Delete the 33% increase in working stress. The

lateral pressures should be accurately estimated and

no distinction made in working stresses as to short

or long term loading.

B. Delete 1.3 times the working load - use 1.7 for short

and long term excavations.

2.2 Loads Acting on Shoring Systems, Trench Shields and

Trench Boxes'

2.2.3 Lateral Soil Pressures - See comment (4) (ii) a. Trench boxes are designed on the basis of

. _ yielding supports for active' soil pressure rather

than passive pressures as in the case of cross

braced sheeting with nonyielding supports. This

entire section should be re-written to make this

distinction.

187
Efficiency Production, Inc.

Page 4

June 25, 1981

Page 25 - Figure 1 . Lateral earth pressure diagrams are for

braced sheeting, this figure should be revised or

supplemented with diagrams applicable to trench

boxes, i.e. triangular or prismatic not rectangular.

2.3.2 Rating Procedures

The annual renewal of this rating may be a worthy objectiv

but is impractical and not enforceable. Why not a

statement to the effect that it is the contractor's

responsibility to periodically inspect trenching

equipment and insure they are in satisfactory condition.

Page 37 Section 5 (b) Delete last sentence allowing 33%

increase

Section 5 (c) Delete "1.3 times the working load for

short-term excavations.

Page 40 Add lateral earth pressure diagrams for the active

soils case utilizing Rankine and Coulomb earth pressure "• solutions

Respectfully submitted,

McCLURG & ASSOCIATES, INC.

AJN/cj
STATEMENT OF POSITION AND RECOMMENDATIONS ON REVISION

TO SUBPART P OF THE SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION

PRESENTED BY

THE MAJOR MANUFACTURERS OF TRENCH BOXES

AND TRENCH SHIELDS OF THE UNITED STATES

John B. Cook

Efficiency Production, Inc.

Wendell Wood

Griswold Machine & Engineering
I

c

t

GENERAL STATEMENT OF POSITION

A review in detail has been made of the proposed revisions in Subpart P 1926.650 -

.651 - .652 and the attached guidelines and appendix.

This review was made by, and on behalf of, the major trench box manufacturers of

the United States, and represents their consenus opinion of the changes in the

proposed standards.

It is our position that the intent to clarify and simplify, as it relates to the

revised changes of Subpart P, has failed, and in fact, has made it more confusing and

more difficult to apply in the field. The proposed design criteria as they relate

to trench boxes do not conform to accepted engineering practices, and at the proper

time we have specific recommendations for changes in the proposed revisions.

i 190
Page 1

1926.650^ENERAL PROTECTION REQUIREMENTS - NO COMMENT

* t . 1926.651 - SPECIFIC EXCAVATION REQUIREMENTS

• * : *

_

- PAGE

8

- Item (s) Should read ... Portable trench boxes or sliding trench shields

. > r

* . may be used for the protection of personnel . Where such trench

boxes or trench shields are used they shall be designed, constructed*

- * and maintained in a manner which will provide equivalent protection

to that provided by the shoring required for the excavation as

„ J defined by accepted engineering practice.

1926.652 - SPECIFIC SHORING, SLOPING AND SHIELDING REQUIREMENTS

PAGE

9

- item 2a Should read ... Qualified Engineer

10

- item b (2) b (3) Should read ... Engineer

10 -

10 -

item (b) (1)

item (4) (i)

Change to 7 days

Based upon the education, training and experience of our professional

engineers, it is our position that there is no foundation in standard

practice for the application of an adjusted trench depth standard as delineated in section 1926.652 (b) (4) (i).

We 'reconroend that this section and it’s tables 2 and 3 and figure 3

be eliminated in their entirety.

10 - item (4) (i) a We recognize the importance of surcharge loads and it should be

dealt with within the realm of accepted engineering practice. We

reconmend the elimination of section 4 i - a,b, and c and table 2.

. n Regarding table 1 on page 11 - type B medium soil should be (we)

30 lbs. /FT in accordance with generally accepted engineering practice.

Regarding slopes in table 1 page 11 - the steepest allowable slope

table, in our opinion, does not conform to standard engineering practice

.

- 13 - item (ii) a Should read ... lateral pressure at the bottom of excavation equal to

the equivalent weight effect (We) In table 1 times the depth of cut with

lateral pressure diagram appropriate to the construction as determined

by an engineer.

191
13 (11) c

13 (111)

Paragraph 2

"We object to the footnotes attached to table 1 as being too

v technical and overly complicated for Interpretation by field

personnel, and recommend they be simplified. M

I m The last paragraph of this section should read.... shoring systems

shall be designed In accordance with accepted engineering practices.

L W

Should read... Shoring systems and trench shields shall be selected j-T

in the field on the basis of accepted engineering practice. 1-

13 (Hi) (a)

16 - item (4) (ill)

16 - item (5) (Hi)

Trench shields, trench boxes, and pre-fabricated strutwale assemblies

and other pre-fabricated assemblies shall be rated for the maximum

depths in Type A, B, and C soils in which they can be used and

selected accordingly.

(c) Should read.... prepared by an engineer.

Should read ... Excavation up to 3 feet below the bottom of

sheeting, trench boxes, or trench shields, excavation up to 3 feet

below the bottom is allowable in short term excavations, (and we agree with items a & b.)

1926.653 - DEFINITIONS APPLICABLE TO THIS SUBPART

18 a

18 c

Should read ... Accepted engineering practices, those requirements

or practices which are compatible with standards required by a registered professional engineer.

We recommend the elimination of this item.

19 m

19 o

19 t

‘

19 z

Should read... Long term excavations are excavations that are open

more than 7 days.

Should read... Negotiable slope is a slope on which a person can egress from or ingress to an excavation with relative ease and speed

to insure reasonable safety.

Should read... 7 days or less.

Should read... See figure 4. (Correction)

192
GUIDELINES SUPPLEMENTING SUBPART P

V

• Page •

22 - 2.1

mFirst paragraph should read... Shoring systems, trench shields, and

trench boxes shall be designed In accordance withf accepted engineering

practices.

\ 22 - 2.1 A Should read... Are not to exceed 1.0 times the allowable working

stresses....

22 - 2.1 B Change 1.3 to 1.7

22 - 2.23 Should read... Lateral pressure at the bottom of excavation equal to

the equivalent weight effect (we) in Table 1 times the depth of cut,

with lateral pressure diagram appropriate to the construction as determined by an engineer, and figure 1 should be eliminated.

27 - 2.3.2 , We question how the annual renewal of the rating can effectively be

1 accomplished.

30 "Is it the intent that Appendix A become a part of Subpart P?"

If the answer is yes, and Appendix A is to become a part of Subpart P

we would like to take exception to several specific items that, as they were applied to Subpart P, do not conform to accepted engineering

practice."

37 - 5. (b) Should read... Allowable stresses should be determined in accordance

with the applicable standards.

37 - 5. (c) Should read... .Ultimate strength, rather than working stress design

may be used whenever such a procedure is stipulated in the applicable

standard or load capacity is determined by test. Ultimate loads

should be taken as 1.7 times the working load in accordance with

accepted engineering practice.

38 A.5.3. First paragraph is O.K.

Add second paragraph, which should include a diagram covering the

active soil pressure case utilizing either the Rankine or Columb

solutions.

193
> ANSWERS TO HR. YOKEL’S QUESTIONS

[

n

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

#12

#13

No conment

No conment

t No conment on 24 foot limitation.

On ques'tion of should qualified person be substituted for engineer...

“No, as it relates to this specific question. There are other areas

in the working draft where qualified person should apply. M

7 days. We do not need more conservative requirements.

We feel that the allowable slope in table 1 is not in accordance with

acceptable engineering practice and that the stable slope concept

should be used.

No conment

Yes, and should be conveyed as part of the definitions.

No conment

Yes

Yes

No conment

No

No - Statement should not be deleted.

[

194
7. SAN FRANCISCO, CALIFORNIA, WORKSHOP - WRITTEN COMMENTS,

CORRESPONDENCE AND INFORMATION
Director! JAMES H. KLEINFELDER

CYRIL M. McRAE

EARL C. KLEINFELDER MICHAEL E. MAHONEY

RICHARD M. WARY

J. H. KLEINFELDER & ASSOCIATES

GEOTECHNICAL CONSULTANTS • MATERIALS TESTINC

1901 OLYMPIC BOULEVARD, SUITE 300 WALNUT CREEK. CA 94596

(415) 938-5610 TELEX: 171266

ROBERT D. HOWELL

WILLIAM E. ELLIS ROBERT A. WILKINSON

DAVID C. MATHY

July 10, 1981

Mr. Felix Yokel

U.S. Dept, of Commerce

National Bureau of Standards

Bldg. 226, Rm. B162

Washington, D.C. 20234

Subject: San Francisco OSHA Subpart P Workshop

Dear Felix:

Listed below are my comments on the workshop and OSHA Draft.

General

I like your idea of an industry committee representing Contractors,

Engineers and Workmen carrying the final draft to the powers that

be in OSHA. This would have to be a well balanced committee.

I imagine A.G.C. would represent contractors, ASFE the design

profession, but I don't know who would represent the workmen.

Specific Comments

1. I am not sure that those representing labor are informing

their people that following the "standard of practice" or

an "engineered" system will only reduce risk, not eliminate

it.

2. Section 1926.651 (P)

. 5 ft. exit requirement sounds reasonable

. Wide excavations could be exempt

. I am not sure about large pipes

. Negotiable slope may be difficult to define

3. Section 1926.652 (a) (2)

. I don't believe that the standard of practice should

go below 20 ft.

. An exploration program should be required in

excavations deeper than 20 ft. In some cases

it may be wise to have a geologist involved as

well as geotechnical engineer. The geol./engr.

should determine the design parameters. If a

196
H. KLEINFELDER & ASSOCIATES Mr. Felix Yokel

July 10, 1981

Page 2

professional engineer is required to design the

shoring, he should be an engineer qualified in

the area of shoring design. If you are not going

to require a qualified engineer, some checking

mechanism should be set up, requiring the

signatures and dates of the designer and the

checker. (A professional engineer may be

required by law in some states)

.

4. Section 1926.652 (b)(1)

. Short term excavation cannot be dropped without

revising your design loads. I can see the

desirability to drop it in some localities, but

not nationwide. Maybe it could be increased to

3 days. Many changes can occur in 7 days.

5. Page 11, Table 1

. The "stable slope" concept must be kept since

the standard of practice is not conservative

enough to be used blindly.

6. Page 12, Figure 2

Four (4) ft. seems to be working in California.

7. Section 1926.652 (b) (4) (ii)

. I see no problem with the existing format.

8. Section 1926.652 (b) (5) (ii)

. No comment

9. Section 1926.652 (b) (5) (iii)

. The sentiment was for 2 ft.

10. This work is normally out of the Architects field.

11. I like the idea of having a competent person in the field.

Certainly the designer will not be in the field.

12. Maybe it could be replaced with "soil or rock movement

that can cause physical harm to workers."

13. Old Section 1926.651 (c)

. No comment

I appreciate the opportunity of attending your workshop.

Sincerely,

DER & ASSOCIATES

nf elder

President

197

JHK : dc

cc: Bill Zoino
DRAFT

DISCUSSION OF:

WORKING DRAFT OF SUGGESTED REVISION IN SUBPART P OF

THE SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION

BASED ON BUILDING SCIENCE SERIES REPORT BSS 12?

by Felix Y. Yokel

by

BUILDING AND CONSTRUCTION TRADES DEPARTMENT AFL-CIO

JACK L. MICKLE

SAN FRANCISCO, CALIFORNIA JULY 8, 1981
DRAFT

Dr. Yokel is to be commended for his efforts to improve upon

the Occupational Safety and Health Administration, (OSHA), 29

CFR Part 1926. Subpart P, Excavation, Trenching and Shoring Regulations document.

The Building and Construction Trades Department, AFL-CIO has

been supportive of and assisted Dr. Yokel, where possible, since

he began work on .this project with the National Bureau of Standards in June, 1976.

In January, 1977 the B&CTD began the planning stage of a

"Trenching Hazard Identification Task Force" , hereinafter called

the Task Force, to help the NBS obtain employee input aimed at

hazard identification. In March, 1977 the Task Force met for a

four day "retreat" type workshop; the six labor and management

members brought with them 182 years of experience in trenching

and related work. The charge was "to identify procedures and

conditions that create safety hazards during excavation and

trenching operations". Others present for the deliberations

were Jim E. Lapping, Director of Safety and Health, B&CTD as

coordinator; Felix Y. Yokel as Technical Observer for the NBS

* and Jack L. Mickle, Chairperson. The final report (1) was filed

with the NBS in April, 1977* The final report appears in appendix G of NBSIR 80-1988 (2).

In September, 1978 Dr. Yokel (3) presented the preliminary

findings and recommendations of the NBS study. Out of that twoday workshop came the agreement for this series of workshops to

bring the results of Dr. Yokel* s NBS study to the attention of

labor, management and engineers in the field. Actually the

essence of the working draft we are using for this workshop was

printed in the Concrete Pipe News (4) in April of this year.

Since the 1978 workshop the B&CTD has responded to a number

of requests for criticisms of drafts by Dr. Yokel.

¥

Numbers in parentheses refer to references given at the end of

this paper.

( 2 ) 199
Two premises underlie all remarks and criticisms given in

this critique:

Ttet the worker be assured of safe and healthful

working conditions, and

that the journeyman worker and the compliance

officer as well as the management representative

be able to fully understand the precautions that

have been taken and the protective measures that

have been provided to assure worker safety and

health, or that the safety of the worker on the

job be placed in the hands of a licensed professional . The first premise is spelled out in the preamble of the

Occupational Safety and Health Act of 1970.

The second premise assumes that an average journeyman or

compliance officer, using the official OSHA regulations governing excavation and trenching safety, can determine whether or

not the safety provisions on any jobsite are in compliance with

the appropriate regulations. If the provisions are not "standard practice" as outlined in the regulations then there must be

a certificate issued by a licensed professional which assures

the worker that the jobsite safety and health measures have been

designed by and certified by the licensed professional.

There are undoubtedly many "competent persons" and "qualified persons" who are quite capable of designing a safe worksite,

but how are they to be identified by the worker or compliance

officer? The license is the evidence. All licensing laws have

encountered competent or qualified persons and have eventually

incorporated them into or excluded them from practice. While

there are probably quite capable people who know a great deal

about medicine or law, the prudent individual seeks the licensed

practitioner when medical or legal opinions or services are

sought.

Actually suggesting that registered engineers need to be

consulted is not new with this suggestion. Thompson and Tanenbaum (5) recommend substantial involvement of registered engin-

( 3 ) 200
draft

eers in construction activities requiring trenching or excavi ons

.

In view of the foregoing, this discussion will be concerned

with only the first 20 pages of Dr. Yokel % working draft which

outlines "standard practice". Even portions of the first 20

pages probably belong in the "guidelines" which have been included to assist professionals. It is also assumed that only

the "standard practice" will eventually be recommended for inclusion in the OSHA regulations Subpart P; Dr. Yokel has indirectly suggested that by what was included in the article which

he co-authored in the Concrete Pipe News. (4).

W
DRAFT

COMMENTS ON SELECTED ITELS ON PAGES 1-20 OF THE WORKING DRAFT

Page Location Comment

1

%

item 3 V. boxes. It is addressed to contractors, shoring

manufacturers and engineers..." Why address it to

the contractor unless the contractor is also an

engineer?

2 item 5

M .., which would aid field personnel and contractors in the selection of shoring." Once again,

these persons are going to be dealing with the

standard practice unless they are licensed professionals in their own right.

2 last

line

Note that a qualified person is not an engineer

(recognizing this as just an example)

3&4 All

Issues

The items listed on pages 3 and. 4 will be considerindividually as they encountered in the text.

5 (g) ..be provided with and shall be iRstraeted (required) to wear....

5 (i) ...shall be permitted under loads handled by

pewep-ehevele7 - 4erFieksT-©3?-heietBT (equipment) . This item is too specific for not listing all

equipment which is used to handle loads j for

example, backhoes are not listed.

6 (j) 2nd

para,

line 8

...or the shoring system, and shall inereaee-pFeteetieR-agaiRet-eladee-aRd-eave-ine-if-ReeeeeapyT

(see that all work in the excavation shall cease

until necessary precautions have been taken to

safeguard employees.)

6 (c)( 1 ) line 3

V.. shall be effectively stored and retained at

least 2 ( 3 ) feet or more from the edge of the

excavation." The Task Force specifically stated

that 3 feet was necessary for proper protection.

6 (c)( 2 ) line 3

"...may use effective barriers ©F-etheF-effeetive

petaiRiRg-devieee-iR-lieu-theFeef in order..."

Task Force recommended extending tight sheeting

above ground level as an effective barrier. Twelve

to 18 inch extensions were discussed.

8 (1)

line 2

V.. equipment, thq/ shall be designed-aRd constructed by qualified persons..." Design implies work

done by a licensed professional.

8 (o) This item is silent with respect to straight sided

pier holes; some confusion has arisen because < 025 , straight sided holes are covered elsewhere. 800 (h)( 3 ) 8 (p) When employees are required to be in trenches 4

45?} feet deep...." Leave at 4 feet.

( 5 )

202
DRAFT

Page Location

8 (s)

9‘ (a) (l)a

9 (a)(2)

9 (a) (2 )

a

line 3

9 (a) (2 )b

Figure 1

10 (a)(3)

10 (b)(1)

line 6

Comment

"

v .. boxes or shields are used they shall be designed (and certified as to use by a professional

engineer and shall be maintained in a manner which

will provide protection for the worker.)" Strike

the balance of (s).

Excavations less than 5 ft. deep, except when examiHatieH-ef-the-gFeuRd-fey-a-ee»peteHt-peFB ©R-iRdi

eates-that hazardous ground movement may occur."

"Excavations from 5 ft. to 20 ft. 424-ft-r?^ deep.."

Why consider 24 feet? A better choice might be

15 feet for Standard Practice. Thompson and Tanebaum data (5) indicate that 87 per cent of the fatalities and injuries occur in excavations less than

20 feet deep and that 72 per cent occur in those

less than 15 feet deep.

Hinze and Carino (2) state in their summary that

their "..study showed that most trenchwork is between 5 and 15 feet deep with the trench width

usually being about 3 feet."

Cass (6), speaking about the stacking of two standard 7 ft. aluminum hydraulic shores, notes that

where the trench is over 14 feet deep (page 68)

"other shoring systems should be applied" and on

(page 72) "Maximum trench depth, this method, is

15' (^»58 m). Over 15' (4.58m), see Fig. 60.2,

multi-type shoring." Multi-type shoring shown on

Fig 60.2 is a different system using aluminum

hydraulic shoring and plywood backing.

A maximum depth of 15 feet for Standard Practice

seems appropriate.

"..sloping requirements must be determined by an

engineer ^a-qualified-perseR?}-*

May lead an individual to believe that FOOTING A

is not a cause for concern; this could be dangerous. It is worthy of note that the role of the

engineer has not been challenged at this point

where property damage as well as personal injury

is possible.

See comments under: page 9 (a)(2). Fifteen ft.

depth may be a better limit for Standard Practice

rather than 20 ft.

The distinction between short-term and long-term

is very difficult to reckon with; virtually no

firm data exists. Not only stresses in the mass

vary with time, but environmental factors may be

critical. Twenty-four hours seems more logical

than seven days.

(6)
DRAFT

Page

11

12 ‘

13

13

13

13

13

16

Comment

There may be some merit to allowing steeper slopes

in some cases. The Task Force indicated that

slopes flatter than 1:1 were probably not necessary

for worker safety. Slopes of 1:1 were recommended

for most conditions.

This particular configuration should be made a

part of the "guidelines" proposed by NBS . While

the configuration looks good on paper, it may be

difficult to understand and/or enforce in the

field. If included in Standard Practice the 3 ft.

max bank should be retained.

(b)(4)(i)b. See the first four lines at the top of page 13*

Table 2 is necessary in Standard Practice only if

Fig. 3(b) is retained. Moving the option shown

as Fig. 3(b) to the Guidelines removes the need

for Table 2 which is confusing and also removes

the need for special tables and figures outlining

the placement of shoring in the lower part of the

ditch.

Location

bottom

of page

last two

lines

Fig. 2

Case IV

(b)(4)(i)c. For Standard Practice it may be worthwhile to

include all surcharges, including allowances for

heavy equipment, in the adjusted depth. The Task

Force recommended a minimum of J00 pounds per

square foot for surcharge. Dr. Yokel has greatly

simplified Table 3 but it. still can be confusing.

Moving Table 3 to the Guidelines and greatly increasing the surcharges to allow for heavy equipment may lead to "overdesigned" shoring and

shields, but Standard Practice would thereby be

greatly simplified.

(ii)b. The Task Force recommended a 500 lb gravity load.

(ii)c. This statement is not clear. Does this mean a

240 ft-lb impact load per square foot? The entire

(ii)c. should become a part of the Guidelines and

removed from Standard Practice.

(ii) This entire section devoted to the required

strength of shoring systems, trench shields and

trench boxes needs to be moved to the Guidelines.

b. If some of the previous suggestions are followed,

hydraulic shores and other assemblies can be

brought into Standard Practice. At a meeting in

October, 1980 with NBS and members of the hydraulic shoring industry it was agreed that reasonably simple charts for the selection of

shores can be developed. This seems to be in

keeping with Cass' (6) recommendations for depth

to 14 or 15 ft. There is no question that the

resulting system would be greatly over-designed

( 7 ) 204
—S' DRAFT

Page Location

16 c

.

%

16 (5) (ii)

last two

lines

16 (5) (iii)

18 (a)

19 (m)

19 (o)

19 (p)

19 (t)

19 (aa)

20 (gg)

Comment

at times, but the freedom to use Standard Practice for most work (2) and thereby not requiring

the services of an engineer seems to outweigh

the disadvantages of overdesign.

Timber shoring is properly located in the Guidelines; selection must be by an engineer. The

Guidelines are for the use of licensed professionals . The statement in parentheses is a vague performance specification which detracts from a well

stated, precise paragraph.

Excavation below the bottom of the protective

element has merit; exactly how much to allow

is difficult to determine. Certainly,

engineers can design specific protection for

unique circumstances, the Guidelines will help,

tut permitting excavation .below the protection

device in Standard Practice will require very

careful consideration.

"...with standards required by a-FegisteFed-arehia registered professional engineer

, ^or other

duly licensed eF-Feeegnised authority. ..”

Twenty-four hours for short term seems most reasonable . Negotiable slope needs to be specified; ljsl seems

reas onable

.

How is a qualified person to be identified? .Unless

there is a specific procedure anyone can claim to

be a qualified person. No objection if the qualified person is permitted to use Standard Practice

only.

same argument; use 24 hours for short term.

Stable Slope. A meaningless . term unless it is

arrived at by a licensed engineer. This term has

no place in Standard Practice l Working loads are best relegated to the Guidelines

where they can be dealt with by an engineer

.

( 8 ) 205
Summary

DRAFT

There must he clear separation between Standard Practice

and cases where an engineer has certified the procedure to be

followed.

It is recommended that Standard Practice be permitted to

a depth of cut of 15 feet; this includes most excavation and

trenching work. At depths greater than 15 feet, or for special

work, the engineer must assume full responsibility for the

design of the protective system. The 15 ft. depth needs verified.

Standard Practice must be written such that the protective

measures resulting from the application of Standard Practice

are observable, measurable, understandable' by all parties (with

application of the regulations) and provide for the safety and

health of the worker. It is recognized that Standard Practice

may at times result in substantial overdesign, but this would

not be new to the construction field.

It is anticipated that competent or qualified persons working for the contractor would select methods within Standard

Practice to protect workers, but that any deviation from Standard

Practice would need to be designed by an engineer. The engineer

is recognizable by a professional license.

Several items which need consideration; construction

right of way requirements , toxic materials , safety program as

an item in the bid document, soil conditions and utilities in

the bid document and better safety education for all. The Task

Force final report lists other concerns.
RECOMMENDATIONS

DRAFT

li Use Standard Practice to a depth of 15 feet.

2. Over 15 feet or where Standard Practice is changed an

engineer must assume full responsibility.

3. Standard Practice must be observable, measurable and

understandable by all parties and above all must be

effective.

4. Competent and qualified persons working for the contractor would select methods within Standard Practice but an

engineer would be required where deviations occur.

5. Construction right-of-way needs to be considered.

6. Toxic materials need to be considered.

7. A safety program needs to be outlined in the bid documents.

8. Soil conditions and utilities need to be considered in the

bid documents.

9. Safety education is a must for all.

(9b)

207
References

DRAFT

1. Building and Construction Trades Department AFL - CIO.

Trenching Hazard Identification Task Force; Final Report.

* Prepared for the National Bureau of Standards; Building

Safety Section; James 0. Bryson, Chief. April, 1977*

2. Hinze, Jimmie and Nicholas J. Carino. A Study of Work

Practices Employed to Protect Workers in Trenches; NBSIR

80-1988. National Bureau of Standards. March 1980.

3. Salomone, Lawrence A. and Felix Y. Yokel. Proceedings,

Federal Workshop on Excavation Safety, September 19 and

20, 1978. National Bureau of Standards. July, 1979*

4. Yokel, Felix Y., Riley M. Chung and Ronald L. Stanevich.

New Concepts for Construction Practice Standards for

Excavations. Concrete Pipe News; pages 28-33 1 vol 33

no 2, April, 1981.

5 . Thompson, Louis J. and Ronald J. Tanenbaum. Excavations,

Trenching & Shoring: the responsibility for design and

safety. Sponsored by the Associated General Contractors

of America. A report of the Texas A & M Research Foundation. College Station Texas. September, 1975*

6. Cass, W. Martin "Red". Common Sense in the Common Trench.

Equipment Guide-Book Company; 2800 West Bayshore Road,

Palo Alto, California 9^-303* 1979*

( 10 ) 208
STANDARDS PRESENTATION

34

fcss»nd the definition of Excavation, Trenches, Earthwork

15*4 to read:

Excavation, Tranches, Earthwork.

Bell Hole. An additional excavation made into the sides or

bottom of a trench to provide additional work apace.

in) Belled Excavation. A part of a shaft or footing

excavation, usually near the bottom and bell-shaped, that makes the

cross-sectional area at that point larger than that above.

fC> Braces for Excavations. The horizontal members of the

shoring system whose ends bear against the uprights or stringers.

(D) Earthwork. The process of excavating, moving, storing,

placing, and working any type of earth materials.

(E) Excavation. A man-made cavity or depression in the earth’s

surface including its sides, walls, or faces formed by earth

removal 'and producing unsupported earth conditions by reason of the

excavation. If installed forms or similar structures reduce the

depth. to width relationship, an excavation may become a trench.

(F) Hard Compact. All earth material not classified as

running. ee-ensfeabier

lalified Person. A person desig nated by the employer who

by rea son of experience or . operation to be performed and the hazards involved,!.

(H) Running. Earth material whose angle of repose is

approximately zero, as in the case of soil in a nearly liquid state,

or ''dry, unpacked sand which flows freely under

*i

lght

Running material also includes loose or dist urbed earth that c an

only be contained with solid sheeti ng.

(I) Shaft. An excavation under earth's surface whose depth,

either horizontal or vertical, is much greater than its

cross-sectional dimensions such as those formed to serve as wells,

cesspools, certain foundation footings, and under streets,

railroads, buildings, etc.

instruction is familiar with the

209
'?

STANDARDS PRESENTATION Pe of 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD / ~ i — /

(J) Sheet Pile. A pile, or sheeting, that cay form one of a continuous i nt e r lock i ng 1 lne , or a row ot timber, concrete, or steel

f

iles, driven in close contact to provide a tight wall to resist the

ateral pressure of water, adjacent earth, or other materials.

(K) Shore (Strut) . A supporting member that resists a compressive force imposed by a load.

( ) Shoring System. A temporary structure for the support of

earth surfaces formed as a result of excavation work.

(M) Sides, Walls#- and Faces. The vertical or inclined earth

surfaces formed as a result of excavation work.

(N) Sloping ef-Barth. fhe-angie-w^th-the-herieontal-wheeh-a

paf t-ietiiar-eaf th-«a ter -ial -w-iil-a tand—indef tn-itely-w-i thou t-mevewentT

A method of excavation whereby the faces of an excavation or trench

are laid back to provide protection from moving ground.

(0)

Spoil. The earth material that is removed in the formation

of an excavation.

(P) Stringers. The horizontal members of the shoring system

whose sides bear against the uprights er-earth .

(Q)

Trench. Shaii-»ean-aft-exeavafci©ft--£n-wh-ieh-fehe-depfeh

exeeeda-the-averag e-w-id th-ef —its-er e3s-aeefce©n-?--Bxeavatieft9-that

ar e-mere- 1 ha n-l-5-feet-w4-de-at-the-b©ttem7-ahaftS7-tttnnel37-and-»'ine

exeavateena-ar e-net-fcr enehesr A narrow excavation made below the

surface of the ground. In general, the depth is greater than the

width at the bottom, but the width of a trench at the bottom is not

greater than 15 feet.

4*UIsench Jack. Screw or hydraulic type jacks used as cross

bracing in a trench shoring system.

(S) Trench Shield. A shoring system generally composed of' ' steel plates and bracing, welded or bolted together, which support

the walls of a trench from tne ground level to the trench bottom~of

which can be moved along as work progresses. —yfl3tate-le7-a3-ttsed-tft-Af, tiele-6T—Eerfch-mate*±ai-ethe?-fehan

**nft4ftg-fchat7-t*eeatt3e-e-£-4t3-ftatttre-©*-the-4flfitiefiee-©f-eeieeed

•eftd-it-i©ft37-eann©t-be-depended-ttp©rt-t©-*ema-in—£f\-p-laee-w-ith©tit-ext'ra

•mp^©<, t7-S9€h-a3-w©«ld-be-f ti^ft-ished-by-a-sya-tem-of-shof -ing-r

(T) Uprights. The vertical members of the shoring system.

(U) Waler. A structural member in a horizontal or nearly

horizontal position used for stiffening or securing other components

of concrete forms, excavation sheeting, or similar temporary

structures.

210

r~i

i

i

i

i

f

i

i

i
J

STANDARDS PRESENTATION Pg 7 0F j4

‘ CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Section 1540 to read:

jlS40. Excavations.

* (a) Scope. Sections 1540(b) through (n) and 1541 apply to all

areivatlons, trenches, shafts or earthwork and establish essential

requirements and minimum standards of safety in earth excavation

work.

MOTE : (1) Whenever the term "excavat Ion (s) * is used it also

applies to trenches, shafts and other earthwork.

For additional shaft and incline excavation details, see

Sections 1542 and 1543.

(3) For additional earthwork excavation details, see Sections

1544 through 1547 which apply to' such work locations as borrow pits,

road or dam construction sites and similar work areas.

(4) The Orders in this Article do not apply to work covered by

the Mine Safety Orders or the Tunnel Safety Orders.

(b) Preparations.

(1 ) Prior to opening an excavation, the employer shall

determine whether underground installations suen as, sewer, water,

i uel , el ectr i c lines, telecommunication lines, etc., will be

encountered, and if so, where such underground installations are

located.

(2) When the excavation work approaches the approximate

crossing or parallel location of such an underground installation

and danger of accidental contact or disturbance is possible, the

exact location shall be determined by appropriate means before

proceeding. When it is uncovered, adequate protection shall be

provided for the existing installation.

(3) All known owners of underground facilities in Nthe area

involved shall be advised of proposed work at 'least* ~43 working hours

prior to the start of excavation work. ^ Exception: Emergency repair work to underground facilities.

(4)

Trees, boulders, poles and other surface encumbrances

located so as to create a hazard to employees involved in excavation

work, or in the vicinity thereof at any time during operations,

shall ‘be removed or cade safe before excavating Is begun.

.OSHSB-9A T7/76)

211
STANDARDS PRESENTATION Pg_s 6 f _34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

'

(c) Exposure.

(1) Ho employer shall cause or permit his employees to vork in

or td]acent 'to any excavation until a reasonable examination of same

has been made by a qualified person to determine that no

xecoqnizable conditions exist exposing them to injury from possible

moving ground,

” ~ 3 J j __(2) Excavations shall be inspected by a qualified person after

eveYy rainstorm or other hazard-increasing occurrence and the

protection against slides and cave-ins shall be increased, i~f necessary, before employees are permitted to enter the excavation.

(d) Protection. Employees who gust enter excavations 5 feet or

ore in depth shall be protected by a system of shoring, sloping of

the ground, benching, or other effective means as provided by these

Orders. Protection for employees who must work in excavations less

than 5 feet in depth shall also be provided when examination by a qualified person ind i cates 'that hazardous ground movement may be

expected

(e) Spoil.

(1) Excavated material shall be prevented from falling back

into the area where employees are working. This shall be done by

locating the spoil at a distance from the edge of the excavation

consistent witn the character of the material and the nature of the

operations, but unless otherwise contained, in no case shall be

excavated material be placed closer than 2 feet from the edge of

exca va t ions

(2) No method that disturbs the soil that is in place (such as

driving stakes) shall be used to contain the spoil material.

(f) Supervision. Excavation vork and work in an excavation

shall at all tiroes be under the immediate supervision of someone

with authority and qualifications to modify the shoring, sloping or

other system or work methods as necessary to provide greater

safety. Such modification shall not permit the specific dimension

requirements oi other Orders to be less restrictive than shown ~~~ except as permitted by Section 1541(a)(6), This person shall

examine the material under excavation and improve the shoring or

other methods beyond the minimum requirements, as necessary, to

Insure protection of workers from moving ground.

212

nswcp-Q ji n \ _

C

[

C

c

[

[
STANDARDS PRESENTATION Pg 9 OF 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

ial Access

.

(1) A convenient and safe means of access shall be provided for

employees to enter and leave an excavated area. This shall consist

of a stairway, ladder or ramp securely fastened in place at suitably

guarded or protected locations where employees are working,

(2) When employees are required to be in trenches 4 feet or

sore in depth^ a safe means ol access shall be provided and loc'ated

so as to require no more than 25 feet of lateral travel.

Exception; In utility trenches less than 5 feet in depth, earth

ramps or steps are acceptable provided that they are not more than

75 f eet on centers.

(n) Crossings,

(1) Trenches shall be crossed only where safe crossings have

been provided.

(2) When walkways or bridges are provided across excavated

areas, they snail be provided with standard guardrails and toeboards

when the depth of excavation exceeds 7-1/2 feet.

(i) Excavators. An employee working in the vicinity of

operating excavating equipment shall be required to work in a safe

position such that the employee is not in danger of falling into or

otherwise contacting the machine's moving parts,

(j) Undermining.

(1) No excavation work shall take place below the level of the

base"of an adjacent foundation, retaining wall or other structure”

- until it has been determined by a qualified person that such

excavation will in no way create a hazard to workers or until

adequate safety measures have been taken for the protection of

workers.

(2) Undermined sidewalks and/or pavements shall be supported to

safely carry all anticipated loads.

(3) If the stability of adjoining buildings or walls is

endangered by excavations, either shoring, bracing, underpinning , or

other method affording equivalent protection for workers shall *be

provided as necessary to ensure their safety. All such systems

shall be inspected daily or more often, as conditions warrant, by a qualified person and the protection effectively maintained.

213
STANDARDS PRESENTATION Pg .m t>F ju

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(k) Retaining Walls,

{!) Wo existing wall or other structure shall be Bade by reason

of an excavanon or backfill, to function as a retaining vail until"

"* It has been determined that such wall will safely withstand all

•jjyxpected loads that otherwise might be a source of hazard to workers.

« () Wherever a permanent retaining wall, in lieu of the

temporary shoring system of this Article, is constructed to hold any

f

art of an excavation that might endanger workers, such wall shall

e 'designed and constructed to effectively resist all existing and

txpected loads. Standards of design shall be comparable to those of

the California Administrative Code, Title 24, Building Standards, or

any comparable local building code of equal or greater

restrict iveness

^ s

. (Z) Barriers at Unattended Work Locations.

(1)

Weans shall be provided to prevent mobile equipment from

inadvertently entering excavations.

(2) Adequate physical barrier protection shall be provided to

prevent employees from falling into excavations.

{A) All veils, pits, shafts, caissons, etc. r shall be

barricaded or securely covered .

' (5) Upon completion of exploration and similar operations,

temporary wells, pits, shafts, etc., shall be backfilled.

(m) Water Accumulation.

(1) Diversion ditches, dikes, or other effective means shall be

used to prevent surface water from entering an excavation and to

provide adequate drainage of the area adjacent to the excavation.

(2) Accumulat ions of water in excavations which endanger the

stability of those excavations or pose a hazard to employees shall

be controj-^d bef~o~re further work progresses. _—// r

Vibrations yfer Superimposed Loads. Special safety

provisions consisX-f'ng of additional bracing or other effective means

shall be taken at excavations adjacent to streets, railroads, or

sources of external vibrations or superimposed loads. Similar * provisions shall be taken in excavations made in areas that have

been previously filled. -

.1

214

ricuen_ e * ft ft r \
STANDARDS PRESENTATION re --

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

OF

f

Adopt new Section 1541 to road:

1541 . Shoring, Sloping and Benching Systems.

{a) General.

# f

(1) All saterials of the shoring system used In complying with

bf provisions of this Article shall be free Irora defects and amage

hat night in any way impair their protection function. ' (2) Where a shoring system is used it shall be designed and

installed to sustain all existing and expected loads.”””"

(3) Provisions shall be made by the employer to prevent injury

to employees engaged in the Installation of shoring for trenches and

other excavations. In" trench work this may be done by providing and

requiring the use o t devices that will allow upper cross braces to

be placed from the ground surface before employees work in the

trench at those points. In deep trenches requiring additional

braces, workers shall then progress downward, protected by cross

braces that have already been set firmly in place. The reverse

procedure shall be followed when removing shoring.

(4) No part of the shoring system of any excavation shall be

removed until effective means have been taken to avoid hazards to

employees from moving ground.

(5) If a newly installed masonary or concrete vail is to be

depended upon for protection against moving ground, it shall have

attained adequate strength to sustain resulting pressures before

employees are permitted to enter. s

*— -* x ~~ If the excavation is deeper th^n 20 feet /or an alternate

bomb : 412shoring, sloping or benching system or bomb i nation thereof is to be

used, a civil engineer, currently registered in California, shall

prepare detailed plans showing the materials and methods to be

used. See Appendix Plate 022.

Exception: Sloping or benching as permitted by this Article

(A) Where alternate shoring, sloping, or benching systems are

used, the engineers detailed plans shall be available for

inspection by the Division at the work site.

(B) Employees must be adequately trained in the safety

precautions and hazards associated with the alternate shoring,

sloping, or benching systems used.

(C) The written Code of Safe Practices required by Section 1509

shall be revised as appropriate to incorporate the engineer7!

recommendations

.

(b) Standard Shoring System - General.

- (1) Shoring shall be installed in accordance with Tables 1 or 2

of these Orders or as detailed in plans and specifications prepared

SEa civil engineer currently registered in Cal ifornia . See

Apprendix Plate C-22 l:or engineering criteria.

OSHSB- 9 A ( 7/7 6

)

215
STANDARDS PRESENTATION Pg ‘i* nF

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(2) Solid wood sheeting or wood sheet-piling shall be not less

than 2-inches In thickness. However, plywood 1 1/8-Inch in

thickness lay be substituted!

(3) Wood uprights shall be not less than 2 inches by 8 Inches.

Wood braces ancj diagonal shores (struts) shall not be less

tb»n 4-inch by 4-Inch material and not subjected to compressive * gtress in excess of values given by the following formula:

S « 1300 - (20L/D)

Maximum Ratio (L/D c 50

“Where L * length, unsupported^ in inches

and D « least side of the timber in inches

S c allowable stress in pounds per

square inch of cross section.

(5) Diagonal shores (struts) shall be wedged or cleated at the

bulkhead end, and, if bearing on the ground, shall not impose loads

In excess of test-determined soil-bearing values, or in the absence

of test data, those given in Plate 022 of the Appendix.

NOTE: Allowance should be made for the horizontal component of

to rce

~

(6) Diagonal shores ^struts) shall not be placed at an angle

greater than 45 degrees with the horizontal.

(7) When tie rods are used to restrain the top of sheeting or

other retaining systems , the rods shall be securely anchored.

(8) When tight sheeting or sheet-piling is used, full loading

due to ground water table shall be assumed, unless prevented by weep

holes, drains or other means.

( 9 ; Additional s tringers, ties, and bracing shall be provided

to alTow t or any necessary temporary removal or individual supports.

(10) If nonstress grade lumber is used for sheeting and lagging,

the following thickness and spacing requirements shall be observed:

Minimum rough thickness Maximum spacing

of sheeting or lagging of shoring

2 inches

3 incheT

4 feet

7 feet

(11) All hydraulic shoring systems shall be installed, tested

and maintained in accordance with the manufacturers' recommendations

or in accordance with good engineering practice.
STANDARDS PRESENTATION Pg 15 of _±* _

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

(c) Trench Shoring Systems,

(1) Trench shoring systems shall be Installed In compliance

with Sect ion 154 1 (b) and Tables 1 and 2 of this section,

f

{2) Shoring systems in trenches shall consist of uprights held

Iqialy opposite each other against the trench walls by jacks or

ori zontal cross 'members (braces) and, if required, longitudinal

abaters (stringers/walers) as required in 'Tables 1 and 2

.

\(3) Uprights shall be instal ledparallel with each other,

{A) A shored trench shall not be sloped in excess of 15 degrees

from vert icalT

(5)

Uprights shall not be less than 2 Inches i n nominal

thickness

.

Exception: Plywood panels at least 3/4-inch thick may be used

behind the uprights in order to hold loose material not likely to

Impose heavy loads, ~~~

(6)

Uprights shall extend to at least the top of the trench and

to as near the bottom as permitted by the material being installed,

but not more than 2 feet from the bottom.

Exception: When running soil is encountered, shoring shall

extend to the bottom.

(7)

Cross braces shall consist of metal screw-type trench jacks

with a foot or base on each end of pipe,' or timbers placed

horizontally and bearing firmly against uprights or stringers.

Hydraulic metal braces may also be used. See Tables 1 and 2.

(3) Tne minimum number of horizontal braces, either jacks or

timbers, required for each pair of uprights shall be determined by

the number o t 4-foot zones into which the depth of the trench may be

divided. One horizontal brace shall be required for each of these

zones, bur in no case shall there be less than 2 braces. Trenches,

the depths of which cannot be divided equally into these standard

zones, shall have an extra horizontal brace supplied for the short

remaining zone, such zone is greater than 1/2 the 4-foot unitT

** In no case, however, shall the vertical spacing of horizontal braces

be spaced greater than 4 feet center to center. Minor temporary*

shifting of horizontal bracing will be permitted when necessary for

~"~~ the lowering of materials into place. t ( 9) The dimensions and spacing of the elements of the shoring

system shall be governed by the depth of the trench, type of soil

encountered, and other special conditions of the site, but in no

case shall they provide less strength than the members listed in the

following tables which are to be considered as a minimum requirement.

217
g

g

o

g

g

5

£ * X tl t | XXXXXXXXX

o o coo

X X X X X ^ S O' B O' si

O' * O' ^

X X X X

O' * O' * f

* O' * O' x x x x © * o> * o> *

fc X

t- *- »- <- ® w» * *-*>-> to w» w w- ® « O' ** k- O' kur> O it V> IT kT V O l/i W> *-“ t— B S B

U U U U U kl WkVWKJWK) U W Ul W W U WWW rf-w V V rf- V W rf- W J- «f

w B d B O' W w (— k- O' ® l/i w w w d B B w»w»o> o ooo o o o o o S B B

w to w u u> to ww rf" j- W rf" Wl kj W Wl w w w w w w w

•r .r rf’.r rfB W V O W

*- ® O' W» » X* W» W» ® w- O' KJ o IT W W o W VSI

«l

- * s

E S

© o

i E i S

O' » * * • £

• •

5 2

tn x

s s

3 0

<G 3

Lr a k

17 H

-x *

•* ft r* 3 — oX

3 • — O

5 ?

£ i* X H

*

-X ft ** 3

r* O — X

X**• — 3

3— O

X

< r* a rt n

A. *- C

*3

? 5 a k

5o

ir < a

tr 3

*rr a

H

2 g

S’

Ol < © t

. ft n

i n r»£

a

*- sn

r

r

rL

»

t

r

r

r

213
*

219

TABLE 2

SMOKING

fOk

RUNNING

SOIL
STANDARDS PRESENTATION Pg is 0 f _34

' CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD %

(d) Protective Shields and Welding Huts.

(1) If protective shields or welding huts are used to protect

workers, they shall be constructed of steel or other aaterial that

vnr provide protection at least equivalent to that afforded by the

pate rials specified In Tables 1 and 2.

(2) Plans and calculations prepared by a civil engineer

currently registered in California shall be cade available for field

Inspection at the site where the shield or welding hut is used.

(e) Bell or Pot Holes.

(1) Bell (or pot) holes shall provide adequate clearance for

the work to be done, and shall be supported by shoring and bracing

as required by these Orders for trenches unless protective shields

or welding huts are used.

( 2 ) If the operation performed in the bell for pot) hole

requires that an employee use welding equipment troni a reclined

position on the bottom, the bell (or pot) hole excavation shall be

of 'such shape that 'the employee will have adequate space for the

performance of this operation without removing any of the required

shoring system.

(f) Sloping or Benching Systems. In lieu of a shoring system,

the sides or walls of an excavation or trench may be sloped or

benched, provided equivalent protection is thus afforded. Where

sloping is a substitute ^or 'shoring 'that would otherwise be needed,

1 1 shal

1

' be '3/4 horizontal to 1 vertical except 'where the ' "Instability of material reguires 'a slope 'greater than 3/4 to 1.

220
STANDARDS PRESENTATION Pg - 19 of

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Exceptions:

(1

)

In hard, compact soil where the depth of the excavation or

trench is 8'feet or less, a vertical cut of 3 1/2 feet. with sloping

of 3/4 horizontal to 1 vertical is permitted?

(2)

In hard, compact soil where the depth the excavation or

trench is 12 feet of less, a vertical cut of 3 1/2 feet with sloping

of 1 horizontal to 1 vertical is permitted!

(3)

In hard, compact soil r benching is permitted prov ided that

a slope ratio of 3/4 horizontal to 1 vertical, or flatter, is used^

221
STANDARDS PRESENTATION Pr,

20 of

' CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Section 1542 to read:

1542. Shafts.

(a) General. .

(1) All^rells or shafts over 5 feet in depth into which

»gpl oyees /S^re permitted ^-^oter shall be retained with lagging,

Spjliifvq Spiling ,/ or casing. \

(2) The lading, spiling /or casing shall extend at least one

foot above^g-Tound level and ’.sha] 1 be provided the full depth of the

shaft or at least five feet into solid rock if possible.

MOTE: See pertinent portions of Section 1540 for additional

requirements relating to wells and shafts.

(b) Small Shafts B*

y

7 -€emenfced Hard r Compact Ground. Two-inch

(nominalcribbing may be used in square shafts not over 4 feet

square in d-ry 7 -eemeflted hard compact ground. Each member shall be

cut 1/2 way through the wid th of the member and dovetailed into

position so each member will act as a shore as well as lagging.

Strips shall be nailed in each corner to prevent the boards from

dropping down.

(c) Shafts in Other Than Br/7 -Semented Hard? Compact Ground.

(1) A system of lagging supported by braces and corner posts

shall be used for square or rectangular shafts. Corner posts of

4-inch by 4-inch material are normally acceptable in shafts 4 feet

square, or smaller, if they are braced in each direction with

horizontal 4-inch by 4-inch members at intervals not exceeding 4

feet. Braces and corner posts in larger shafts shall be

correspondingly larger.

(2) Round shafts shall be completely lagged with 2-inch

material which is supported at intervals not greater than 4 feet by

means of adjustable rings of metal or timber that are designed to

resist the collapsing force, or cased in a manner that provides

equivalent protection. rteafis-shali-be-prov-ided-te-held-'r-iftgs-aftd

ieggifig-in-plaecT

ti f7c\
STANDARDS PRESENTATION Pg , 21 .OF 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD —Bhaf eet-4f»-depth-«hall-h«ve-d-»enway

f«f t4*4esed-©f f-w-ith-l-4fteh-sater4al-©r-eqti4valeftfe-ftfjd-shfl'll”have-e

4adde*way-w4feh-*a44ed-f4atf ©ess-ayeey-30-feefcT

(0) Bell Excavations. Provisions for the protection of workers

that are engaged m belling or enlarging the bottoms of shafts by

hand shall include at least the following elements:

(1) Sufficient physical protection from potential ground

movement or collapse.

(2) Adequate mechanical ventilation.

(T) A line, suitable for Instant rescue, securely fastened to a shoulder ~"~ harness and worn by each employee entering the shaft(s).

(4) A properly equipped hoist and platform for hoisting or

lowering workers in shafts over 50 feet in depth.

(5) Barriers that prevent materials fromfaTlinq into the

shaft (s)

.

*

\\ i
STANDARDS PRESENTATION Ps 34 ' 23 QF . CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Subsections (a )

,

(d) and (e) of Section 1544 to read:

1544. Earthwork and Excavating.

pertinent portions of Section 1540 for additional

requirements relating to earthwork and excavating,

*

* (a) Whenever fche-Biv4s4on-eofts4der s-that the height and

condition of the face constitutes a serious hazard to employees, 4t

•hali -require the installation of a bench or other suitable method

of working shall be required .

(b) When a bench or multiple-bench method of operation is r«-

| quired, a setback of at least j the height of the single face or bank for j each section of the face or bank shall be required. I (e) When determining the maximum permitted slope of the face,

j consideration shall be given to: t (1) Nature of the material being excavated.

(2) Extent to which the material is cemented or consolidated.

(3) Height of the face. (4) Type' «« of equipment used at the face and • amount of protection this equipment affords the operator. : (5) Safety of employee* who arc not protected by such

j equipment. I •

(d) Where the face is composed of loose or unstable materials,

the slope of the face shall not exceed 3/4 horizontal to 1 vertical

where the height is greater than that which can be reached by the

dtpper-or bucket of the excavator or loader being used.

(e) Where the face is composed of moderately compacted

materials that are not firmly cemented or consolidated but which

experience indicates will stand well in place, the slope shall not

exceed 1/2 horizontal to 1 vertical where the height is greater than

can be reached by the dipper-er bucket of the excavator or loader

being used.

Amend Subsection (a) of Section 1545 to read:

1545. Overburden.

(a) Mo person shall be permitted under a face or bank where

•tripping or other similar operations constitute a hazard.

224
STANDARDS PRESENTATION Pg_JJ_ of JH

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Subsections (a) , (d) and (a) of Section 1546 to read:

1546. face Inspection and Control.

(a) A daily physical inspection shall be Bade of faces and

banks, including the tops, where Ben employees are exposed to

falling or rolling materials. The inspection shall be made by a •Bpetent-Ban qualified person who shall dislodge or make safe any

material dangerous to employees, or shall cause such material to be

dislodged or Bade safe.

(b) No person shall be permitted to work near a face made unsafe by primary blastinp, rains, freetinp or thawing weather, or earthquakes until the face has been inspected and made safe. 1 (e) Overhanping banks are forbidden, exeept

:

(1) “Where material is moved away from the face by

mechanical equipment havinp controls located at a safe dis- tance so that no employee is required to approach the face is

the course of sorraal operation.

(2) Where the bank is undercut with a stream of water

and the monitor is- located at a safe distance from the bask.]

(d) Where necessary, a-competent-tra-ined jan employee shall be

employed at the face-; and instructed to give warning when loose rock

or other materials are about to f all

.

(1

)

The employee shall be provided with a whistle, siren, or

other devices that will give adequate warning to employees.

Ill The employee shall have no other work to distract his

attention from his duties as defined above.

(e) When working at night, sufficient illumination shall be

provided throughout the working area so that movement of men

employees and equipment can be readily observed.

225
STANDARDS PRESENTATION Pc' zs

' of 34

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Amend Section 1547 to road:

1547. Protection of Workers at the Face.

(a) Mo work shall be permitted above or below »eti employees at

tke face if such work endangers their safety.

\ (b) Workers at the face shall be protected as follows:

(1) On top of the bank, by fencing with guardrails or ropes; by

using railed platform* or by using safety belts and life lines.

This does not apply where the bank is less than 20 feet high or the

slope below is less than 3/4 horizontal to 1 vertical or where no

work is performed within 10 feet of the edge.

(2) On the face, by removing loose rock from over the working

place and by the use of safety belts and life lines, portable

staging, boatswain's chair or skips especially designed for use at

faces. If a boatswain's chair is used, the employee shall be

attached thereto with a safety belt and life line equipped with an

approved effective descent control device.

When-neeessary-for-safetyj-S Two or more persons shall be employed

in cooperation with each other in drilling, blasting, or removing

loose rock.

Life lines used for scaling or inspection shall be protected from

excessive fraying or damage or and shall have a wire center rope.

(3) At the foot of the bank by removing loose rock from above

the working place, and maintaining a ready way of exit to a place of

safety.

226
STANDARDS PRESENTATION Pc 26 0f _2±

‘ % CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Ax end Appendix Plate C-22 to read:

PLATE C-22

BEARING VALUE OF SOIL

Shores and similar members that depend upon earth for support will

probably require foot blocks or sills to distribute the load. In

the absence of test data that establish the sustaining power of the

soils in question, the following information should be helpful in

determining the size of sill needed to assure adequate support

from the soil

Tons allowable

Soil type per square foot

Soft clay — — l

Wet clay 2

Sand and clay, mixed in layers — 2

Pine dry sand 3

Hard dry clay 4

Coarse compact dry sand 4

DESIGN CONSIDERATIONS

EXCAVATIONS, SLOPES AND BENCHES

The determination of the slope or bench configuration or deisgn of

the shoring system shall be based upon careful evaluation of such”

pertinent factors as the following: ~ in Depth and width of cut.

lii_ Possible variation in water content of the material while

the excavation is open.

J3) Anticipated chanqes in materials from exposure to air, sun.

water or freezing temperatures

.

1.4) Loadinq imposed by structures, equipment, overlaying

material or stored material.

11) Vibration from equipment, blasting, traffic, trains or

other sources.

4

6) Existing underground facilities.

b) New or old adjacent excavations.

18) A minimum coefficient of active earth pressure of 35 pcf

(Kw=35

)

shall be used in all calculations unless a soils evaluation

nd i ca tes otherwise.

<r
STANDARDS PRESENTATION Pg_22_ of _li_ [

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Appendix Plat* C-24-a to raad:

Plate C-24-a

MINIMUM SHORING REQUIREMENT

, -I IN HARD COMPACT SOIL . V

>i>Opi
STANDARDS PRESENTATION’ Pe .

_1<_ of _a±

•'CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt DOW Appendix Pl.t. C-24-b to r CLOSE SHEETING METHOU

IN RUNNING SOIL ' CLEATS

L, REFER TO TABLE

Cw/ACe"Bs)

STRINGERS

2’ MAX:

2’ MAX.

^SHLiT PILINGS

TRENCH DEPTH

ALL STRINGERS SHALL

BE SUPPORTED TO PREVENT

THEM FROM SLIPPING OR FALLING • • •Nrupft n % /•» e \

RUNNING MATER I. SOLID SHEETING

IS REGUIRED
STANDARDS PRESENTATION Pciil of

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

Adopt new Appendix Plate C-24-c to read:

Plate C-24-c

MINIMUM SHORING REQUIREMENT
STANDARDS PRESENTATION

34 -B 34

Adopt new Appendix Plate c*24-d to d | 'CLOSE SHEETING METHOD

i. *|N RUNNING SOIL '

f

HYDRAULIC

SHORING

RUNNING MATERIAL

SOLID SHEETING

IS REQUIRED

231
c

c

£

8. BOSTON, MASSACHUSETTS, WORKSHOP - WRITTEN COMMENTS AND

CORRESPONDENCE U

c

c

c

c

c

c

c

r

c

r

l:

r

r

232
ASSOCIATION OF SOIL AND FOUNDATION ENGINEERS

REPLY TO: Mr. William S. Zoino

c/o Goldberg-Zoino & Associates, Inc.

Newton Upper Falls, MA 02164

July 17, 1981

Mr. Felix Yokel

U.S. Dept, of Commerce

National Bureau of Standards

Bldg. 266, Rm. B162

Washington, D.C. 20234

Re: Boston OSHA Subpart P

Workshop

Dear Felix,

I thought that the workshop in Boston went quite well, and I am

happy to see that we have now finished in all the cities. I have

three brief comments I wish to pass along to you.

1 . Section 1926.652 (b) (5) (iii)

If excavations up to 2 feet (or 3 feet) are allowed below the

bottom of sheeting in short-term excavations , I think that

the longitudinal length of such excavations should be limited.

Obviously, if the length is limited, the soil can conveniently

arch around the area to provide room for excavation of a

utility line, and so forth. But I do not think that a long

stretch of such excavation below the sheeting should be allowed.

2 . Long-Term versus Short-Term Excavations

As you know, there was considerable discussion on this point as

to what is a reasonable definition of "long-term." My personal

choice is anything in excess of one day, and anything less than

one day should be considered "short-term." However, as a maximum,

I think three days to accomodate a weekend would be a practical

limit to a short-term excavation. In this respect, I think you

should also add sensitive clays or sensitive soils to the list of

those soils where the shear strength may deteriorate with time

due to disturbance and vibrations in the area.

8811 COLESV1LLE ROAD / SUITE 225 / SILVER SPRING. MARYLAND 20910 / (301) 565-2733

233
Mr. Felix Yokel - July 17, 1981 - Page Two

3. As you know, there was much discussion on the possibility of

the registered professional engineer certifying the work. I do not think there is any practical way this can be accomplished.

The reason is simply that the behavior of the excavation is

dependent not only on the design parameters utilized by the

geotechnical engineer, but is also based on the method and

quality of workmanship of the contractor. These two

contributions to movement and deformation are inseparable,

and therefore, it is impossible to put the burden entirely on

the design engineer. While I personally prefer that deep

excavations be designed by a registered professional engineer;

nevertheless, we must recognize that it is the contractor who

is responsible for the work area and for everything that goes

on within the work area. Consequently, the contractor should

be given the latitude to design the excavation himself, using

his own experienced, competent people. Whether or not they are

registered professional engineers is a moot point.

By copy of this letter to John Ramage, I am asking John to review

all the comments and input to this date and, if necessary, to

correspond with you further on this subject.

Sincerely yours

, t

WSZ : lab

Enclosure

cc: John Ramage

Jim Kleinfelder
Bo> /

1880 1980

100-y6ar §tart on torngrro\\/~

July 13/ 1981

Comments by Kodak Park Division of Eastman

Kodak Company at Boston, MA , Workshop , Trenching & Excavation Standards, on Working

Draft prepared by National Bureau of Standards

dated February 20, 1981 . The Kodak Park Division of Eastman Kodak Company does a large

portion of the construction and maintenance of its buildings

and underground utility lines. This includes excavations for

buildings and other major structures as well as trenching for

new water, sewer, and electric services. It also includes

excavation for emergency repair of these underground services.

We are also involved with many trenching and excavation contractors

at all of our locations in the U.S. and expect that the execution

of this work be done safely and efficiently.

The hazards of inadequately shored or braced excavations are

well recognized by experienced persons active in that type of

construction. Unfortunately, satisfactory source standards

were not available when OSHA promulgated the existing 1926

standards and their subsequent enforcement efforts have not

been entirely productive in the reduction of serious accidents

or in providing assistance in needed safety precautions.

We believe that the National Bureau of Standards has done

a commendable job in drafting these suggested revisions. They

have recognized that excavation site conditions are widely variable

and the application of judgment for each location by knowledgeable

people is needed. The proposed standard is written in performance

language and the supplemental non-mandatory guidelines that

are included should be very helpful in the solution of specific

problems. Eastman Kodak supported a similar approach used by

OSHA in the revision of the General Industry Standards for Fire

Protection which were adopted last December, and the Electrical

Workplace Standards which were adopted in April 1981.

Attached are our comments on the identified issues plus

some addition items. We will be pleased to elaborate on

these comments if additional information would be helpful.

EASTMAN KODAK COMPANY • KODAK PARK DIVISION 235
Some Issues that Should be Considered in the Workshop

1. Page 6. Section 1926.651(a): This section appears to

fall within the scope of Subpart S. Should

it be dropped ?

A. Subpart S, Tunnels and Shafts, Caissons, Cofferdams,

and Compressed Air is not the appropriate place to

call for locations of utilities prior to excavation.

The problem of interrupting utilities and the

resulting employee hazards are most likely to be

found while preparing surface excavations and thus

belongs in Subpart P.

2. Page 8. Section 1926. 651 (p): Should the exit requirements

for excavations start at 5 ft rather than 4 ft depth ?

Please refer to our general comments on this section.

A. Yes, it is reasonable to expect the type of

individuals who work in excavations to have the strength

and agility to make his own way out of a 5 ft deep

excavation without the aid of something or someone

else. Also, the additional one-foot allowance will

include many trenches, and a pipe is often present

which would serve as a step to aid the exit process.

Also, in trenches, the work is being done in a

constantly changing location and the need to frequently

move the ladder or exit device may be considered a nuisance by the trench workers if they do not believe

it is practical to use.

Should exit requirements be waived for excavations

which are wide enough to permit people to escape

toward the center of the excavation?

A. Yes, the major concern for death or injury is in

the relatively narrow excavations such as trenches

where escape during rapid cave-in is very much more

difficult because escape options are far fewer than

in wider excavations. The alternative requirement

should be that the excavated area allow unimpeded

movement away from the excavation walls to a safe

location.
2

Should it be recognized that large enough pipes or

other covered structures can shelter people ?

The intent of this question is not clear. A large

pipe being installed can serve as a temporary refuge,

but it does not seem appropriate to include that as

part of a planned protection system in lieu of

shields or shoring. However, a permissible practice

would be to permit the use of the pipe as a shelter

while the trench shield is being relocated which is

a normal procedure in many situations. Alternatively,

existing large pipes or structures adjacent to the

excavated area can serve as a type of shoring to

help support the excavation side. Good judgment

and sometimes engineering analysis may be required,

however, for the use of pipes that appear to give

marginal support.

Should "negotiable slope" be better defined?

A. This definition seems adequate for its purpose,

though there may be some arguments about a person's

ability to climb a slope being used. Perhaps the

only validation required should be a physical

demonstration of an employee using the slope to egress

or ingress before work begins.

Page 9. Section 1926.652(a)(2)

a) Could the depth limitation in the "Standard

Practice" be extended to 24 ft ?

Whether the excavation is 20 ft or 24 ft before

requiring the services of a registered engineer is

somewhat arbitrary. There should be some limit,

however, and since the 20 ft limit has been used in

several standards, such as the New York State Code

Rule 23, it probably should be kept.

b) Should a "qualified person” be substituted for

an "engineer "?

There are probably relatively few registered engineers

who would be competent in the design of earth shoring

systems or slopes, and there a probably many capable

people who are not registered professional engineers

who have developed suitable expert qualifications in

this area. The definition of "qualified person"

probably is more descriptive than the definition for

"engineer" in determining a person competent in

designing shoring systems and earth slopes.

237
3

4. Page 10. Section 1926.652(b)(1): Should the short-term

excavation definition extend to 7-days rather

than 1-day? If so, do we need more conservative

requirements ?

We do know that a 7-day definition for short-term

excavation can be applied to most soil conditions

in our area. The more commonly found soils which

may range in grain sizes from clays to gravels would

most likely permit a 7-day short-term definition in

other parts of the country as well.

There are basically two conditions which normally

change the strength of insitu soil with time after

an excavation has been made, both having to do with

changes in water content:

1. If an excavation is dug below the water table

surface, or if an excavation is partially

filled with water and this water is rapidly

drawn down by pumping,' relatively large pore

water pressures between the soil particles

remain. This may cause a temporary stability

problem which will improve with time as excess

pore pressures dissipate. So, when excavating

primarily fine grain or relatively impermeable

soils such as clays and silts, the initial

water condition is important. When the walls

stabilize after the water is pumped out, shortterm excavation criteria can be safely applied,

as long as the excavation is not allowed to

refill with water. Paragraph 1926.651(d) and

note 3 (b) of table 1 of the draft Subpart P

revision recognize this problem.

2. When excavating in granular or permeable soils

such as sands, there will be a temporary apparent

cohesion caused by negative pore pressures in

the partially saturated, draining soils. This

negative pore pressure is caused by capillary

tension. As the soil in the excavation walls

dries, the negative pore pressures will dissipate

making the soil weaker in shear and possible

causing sloughing or slides. This is a condition

which will deteriorate with time and the length

of time will depend on how fast the soil in the

excavation walls will dry to a significant depth.

Probably in normal conditions, instability will

occur considerably later than 7 days after the

excavation work, particularly when the excavation

wall is covered with sheeting, retarding evaporation of water.

238
4

We feel the large majority of the cases will

allow the extension of short-term to 7 days.

Perhaps an extension to 3 days might be a good

compromise which would allow, as a worst case,

excavation before a weekend to backfilling

after a weekend, as long as water is not allowed

to accumulate in the excavation and be pumped

down again.

5. Page 11. Table 1: Should the stipulation of maximum slope

be limited to 3/4:1? Should the suggested performance

requirement (footnote b) ( the "stable slope" concept)

be used? Will this approach work ?

A. The 3/4:1 maximum slope should be reasonable.

Judgments of the description of the soil encountered,

degree of saturation and changing conditions as the

excavation progresses might overlook something,

possibly resulting in a marginal stability problem

from time to time. There should be some means to

correct such shortcomings if there is evidence of

instability, and the provision to flatten the slope

by 1/4:1 should be appropriate. This adjustment

should be made before anyone enters the excavation.

6. Page 12. Figure 2: Should the allowable bank next to the work

area in Cases II, III, and IV be increased to 4 ft ?

Should "Case IV" be limited to excavation by trenching

machines ?

A. The purpose, usually, for having a subtrench at

the bottom of a sloped excavation is to provide a

better lateral restraint for the pipe after the pipe

is bedded and in place. This, in most cases, allows

the pipe to withstand greater overburden and ground

surface loads without failure. For large pipes

(6 ft or more in diameter) , it may be important to

be allowed a deeper subtrench. For employee safety

purposes, whether 3 or 4 ft is used is arbitrary, and

would probably depend on judgment of the increased risk,

if there is any, by going to the 4 ft subtrench. The

potential volume of sliding soil, indicated by the

spaces between the solid and dotted lines in figure

one, does seem to be relatively small even at 4 ft.

The upper portion of the trench would have to be

widened or flattened to accommodate the 4 ft subtrench

in order to meet the table 2 criteria. Finally, at

4 ft, the head and shoulders of most workers would

be outside of the subtrench. It seems reasonable

to us to extend the subtrench depth to 4 ft.
5

7. Page 13. Section 1 926 . 652 (b) (4 ) (ii ) : This section, unlike

most others in Subpart P, is not addressed to the

man in the field but to those who pre-design shoring

systems. Yet the section is necessary to avoid

unreasonable vagueness. Should this section be at

the end of Subpart P? Should part of it be conveyed

as definitions ?

A. These loadings are already in the, "Guidelines

Supplementing Subpart P, Section 2.2.2, 'Operational

Loads'." If these loadings, with the possible exception . of the impact load, are meant to also apply to job

designed shoring, which Subpart P does not say, then

these provisions should remain in the body of this

Subpart where they are.

8. Page 16. Section 1926. 652 (b) (5) (ii)This section makes it

difficult to implement some of the slope configurations

allowed in figure 2. Should the proposed performance

statements be substituted to give more options, or

alternatively, should more options be specified or the

specified options identified as examples of implementing

the performance statement ?

A. The performance statement, (Workers in excavations

must be protected against rolling or sliding objects.)

is really all that is needed here. Suggestions as to

how this may be accomplished may be placed in the

appendix if beneficial.

No mention of the amount of slope required before

provisions are applied should be made. It depends

on the specific situation.

9. Page 16. Section 1926. 652 (b) (5) (iii) ; Should the allowable

excavation below the bottom of shoring or shields be

increased to 3 ft ?

TM~~~

A. It certainly would be useful, in some cases, to

be able to extend short-term excavations to 3 ft

below the shoring. It is useful to aid in the bedding

of pipe. Also, more importantly to us, it better

allows working around underground obstructions with

shoring, particularly when reexcavating to repair a broken watermain, sewer, or similar items in a congested

area. We feel it is reasonable to allow this extension

if adequate attention is paid to possible unstable

conditions below the shoring.

240
6

We also believe this section should be reworded

to clarify that the short-term excavation requirement

applies to the work below the bottom of the sheeting

or shoring system. An excavation for a building or

large structure would come under the long-term

definition. It is often necessary to make short-term

excavations within this excavation for drain lines,

footings, etc. The present wording could be interpreted

as prohibiting this practice. We suggest that this

section be revised to read:

"A short-term excavation up to 3 ft below the

bottom of sheeting, trench shields, or trench

boxes is permitted provided that:."

10. Page 18. Definition of accepted engineering requirements . Should a "registered architect'1 be omitted since

architects do not deal with excavations ?

A. This is not an area in which architects are

normally involved, however, there is probably no

good reason whey they should be excluded, as long

as they have adequate background and experience,

just as any registered engineer working with

excavations should.

11. Page 18. Definition of "Competent Person. " Should the

definition be rewritten to require that the competent

person be working at the excavation site ?

A. We would consider this to be good practice.

12 . Should "Mass Movement of Soil or Rock" be defined ?

A. The term should be self-explanatory. It should

include any ground movement involving volumes greater

than those associated with spalling of rock, or

sloughing of soil and surface erosion of soil.

Perhaps the latter terms should be defined. The

only place these terms appear in Subpart P is in

the definition of "Fractured Rock."

13. Page 52. Old 1926.651(c): Should this statement be deleted ?

Even though this matter is addressed elsewhere , this statement conveys the intent of Section 1926.652

in simple language .

A. This statement should be deleted. It is clearly

redundant with the new Section 1926.652(a).

241
In addition to "Some Issues that Should be Considered in the

Workshops," we have some additional comments or questions.

1. Page 7.

2. Page 7.

3. Page 8.

Section 1926.651(e) : We feel that this requirement

should apply to completed portions of excavations.

This would clarify that the intent is not apply the

shoring requirement in the areas where the excavation

equipment is working. Substitute "completed sides"

for "side" in line 4.

Section 1926.651(g) : Excavating equipment may be

considered mobile. Is it necessary to place stop

logs or barricades in front of this equipment during

excavation, particularly tracked equipment or those

using outriggers?

Section 1926. 651 (p) : This section currently appears

to apply only to trenches. We believe exit conditions

should be considered for all types of excavations.

Large excavations should have a minimum of two means

of exit. A second condition could be a smaller

excavation of up to approximately 1500 sq ft where

one exit would be permitted. A third condition

would be similar to what is currently proposed.

4.

Page 11. Table 1 ; Recognizing that many times the excavation

faces are saturated only part of the way up, could

we consider the soil to be type C to the top of the

saturation zone and types A or B above that with the

appropriate We ’ s applied?

5.

Page 11. Table 1 : The Matrix Classification System shown in

NBS BSS 127, June 1980, is simple to use and offers

more flexibility. Would it be possible to replace

in Subpart P the simplified Classification System

with the Matrix Classification System, or at least

offer the latter in an appendix or another section

as an alternate.

6.

Page 18. Section 1926. 653 (j): Excavation

The draft standard does not define trench or give

any criteria to distinguish between a trench or

excavation as is done in the current standards.

We believe this is desirable. However, it may be

helpful to add a sentence to the excavation definition

stating that trenches are excavations or alternatively

adding a Trench definition which could state.
' Trench : "One type of excavation commonly used

for the installation of piping, etc."

This would provide emphasis to employers who primarily

do trench type excavation work that the entire standard

is applicable to their operations.

7. Page 19. Section 1928.653(1): Fractured Rock

Can rock have fractures in it and yet be considered

by definition unfractured? It is rare to find

especially sedimentary rock that is not fractured,

yet we would consider that much of it would not

readily spall or crumble when excavated with vertical

slopes. We believe unstable rock would be a more

suitable term for this definition.

'i

243
DNJ INDUSTRIAL STEEL FABRICATORS

45 EDISON AVE

OAKLAND NJ 07436

4-043473S1 91 07/10/81 ICS IPMMTZZ CSP RVDB

2013372233 MGM TDMT OAKLAND NJ 126 07-10 0222P EST

FELIX YOKEL

NATIONAL BUREAU OF STANDARDS

RT 2 70

QUINCE ORCHARD BLVD

GAITHERSBURG MD 20760

AFTER RECEIVING THE WORKING DRAFT OF THE SUGGESTED REVISION IN

SUB-PART P OF THE SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION I WANTED TO EXPRESS OUR SUPPORT FOR THE PROPOSED CHANGES QUITE ASIDE

FROM ANY MINOR SUGGESTIONS WE COULD OFFER WITH REGARD TO DEFINITIONS

THAT SHOULD BE CONSIDERED WE’RE IN COMPLETE AGREEMENT WITH YOUR

ENGINEERING ASSUMPTIONS AS THEY PERTAIN TO TRENCH SHORING BOXES WE

UTILIZE ENGINEERING PRINCIPALS AS PROPOSED BY TERZAGHI AND PECK IT IS

OUR FEELING THAT IT IS THE MOST CONSERVATIVE YET MOST APPLICABLE

THEORY PERTAINING TO TRENCH SHORING WE’RE PLEASED THAT WE SHOULD SOON

HAVE INDUSTRY STANDARDS AND GUIDELINES TO WHICH ALL MANUFACTURERS

WILL COMPLY

SHORING BY DNJ

D QUITADAMO

1426 EST

MGM COMP MGM

244

TO REPLY BY MAIlGRAM. SEE REVERSE SIDE FOR WESTFRN liNinw’R thi i . cncc ounwc wumbcbc
517-349-4620

• ICIENCY Toll Free: 1-800-248-9912

roucTON. inc P. O. Box 24126 • Lansing, Michigan 48909 Within Michigan: 1-800-292-6601

Mr. John Maragliano, Gen. Mgr.

~

r

- D & J INDUSTRIAL STEEL FABRICATORS, INC.

45 Edison Avenue

Oakland, New Jersey 07436

^ " Dear John:

) Both Wendell Wood of GME and myself were very disappointed that you did not attend

• - the meeting of the workshop on the proposed revisions to Subpart P of the OSHA

regulations.

. . It was the hope of both GME and ourselves, as I stated to you on the phone on July

9, 1981, that even if we did have some areas of disagreement we would be able to get

)- * together and iron these out so that we could present a consensus opinion as an industry,

so that it would not appear that there was a division within our industry, and thereby

provide a more effective presentation as an industry to the NIOSH Study.

Dr. Yokel informed us at the meeting that you had telephoned him on Monday, July 13,

. - and that you disagreed with our position totally. It's hard for us to believe that

i you would have total disagreement, and that there would be that much of a difference

* when, obviously, we have a common purpose to provide the construction industry with

adequate, well designed, quality products.

w

~~

I got the impression from our phone conversation that you concurred with many of the

statements that we made. It is my recommendation , and sincere hope, that you will

. - see fit to share and conmunicate with us, so that the final results of our work will

be a unified presentation. I am certain that any differences we have can be ironed

* out to the satisfaction of all concerned.

It is my understanding that Dr. Yokel, in the next 60 days, will generate a summary

k of all the work shops and reconmend a formation of an industry study committee with

representation on that committee by all parties concerned. It is our hope that you

will participate with us in the development of an acceptable standard so that the

trench box industry can play the part that is necessary in that study committee.

245
July 17, 1981

Mr. John Maragliano

Page Two (2)

John, enclosed is a copy of our most recent presentation statement presented at the

Boston meeting. Both Wendell Wood and myself would appreciate it if you would take

the time to review and comment on each item in detail so that we can see where we differ, then we can evaluate our position as it relates te yours and start the process

of generating a consensus position.

Looking forward to hearing from you soon.

Sincerely,

EFFICIENCY PRODUCTION; INC.

John B. Cook

Vice Pres. & Gen. Mgr.

Enc.

cc: Dr. Felix Yokel

Mr. Wendell Wood

JBC/slc

246
' 4^1

I

STATEMENT OF POSITION AND RECOMMENDATIONS

ON

REVISION TO SUBPART P

OF THE

SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION

PRESENTED BY

THE MAJOR MANUFACTURERS OF TRENCH BOXES

AND TRENCH SHIELDS OF THE UNITED STATES

John B. Cook

Efficiency Production, Inc.

Wendell Wood

Griswold Machine & Engineering

247
GENERAL STATEMENT OE POSITION

A review in detail has been made of the proposed revisions

in Subpart P 1926.650 - .651 - .652 - .655*

This review was made by, and on behalf of, the major trench

box manufacturers of the United States, and represents their

consensus opinion of the changes in the proposed standards.

It is our position that the intent to clarify and simplify,

as it relates to the revised changes of Subpart P, has failed,

and. in fact, has made it more confusing and more difficult to

apply in the field. The proposed design criteria as they

relate to trench boxes do not conform to accepted engineering

practices. We have specific recommendations for changes in

the proposed revisions.

It is also our position - that if the Guidelines are going

to be referenced within Subpart P and therefore become effectively a part of the law - they should be discussed publicly

as a part of the workshop and in public hearings.

248
1926.650 GENERAL PROTECTION REQUIREMENTS - NO COMMENT

*

1926.651 SPECIFIC EXCAVATION REQUIREMENTS

PAGE

' r 8 - item (s) Should read ... Portable trench boxes or

- - sliding trench shields may be used for the

.r r protection of personnel. Where such trench

boxes or trench shields are used they shall

be designed, constructed and maintained in

a manner which will provide equivalent protection to that provided by the shoring

required for the excavation as defined by

“ accepted engineering practice.

m •

k.

1926.652 SPECIFIC SHORING, SLOPING AND SHIELDING REQUIREMENTS

PAGE

9 - item 2a Should read ... Qualified Engineer

10 - item (b) (1)

10 - item (4) (i)

13 - item (ii) a

Should be no arbitrary distinction between

long-term and short-term excavation.

We recommend that this section be clarified

and simplified for effective field application.

Should read ... lateral pressure at the bottom

of excavation equal to the equivalent weight

effect (We) in Table 1 times the depth of cut

with lateral pressure diagram appropriate to

the construction as determined by an engineer.

We object to the footnotes attached to Table 1

as being too technical and overly complicated

for interpretation by field personnel, and

recommend they be simplified.

13 - item (ii) c The last paragraph of this section should read

... shoring systems shall be designed in accordance with accepted engineering practices.

249
PAGE (This statement excludes the 33% increase in

allowable working stresses or an equivalent

strength reduction.)

13 - item (iii) Should read ... Shoring systems and trench

Paragraph 2 shields shall be selected in the field on the

basis of accepted engineering practice.

13 - item (iii) (a) Trench shields, trench boxes, and pre-f abricated

strutwale assemblies and other pre-f abricated

assemblies shall be rated for the maximum depths

in all types of soils in which they can be selected and used accordingly from charts prepared

by the manufacturer.

16 - item (4)(iii)(c) Should read ... rated by an engineer ... •

16 - item (5) (iii) Should read ... Excavation up to 3 feet below the

bottom of sheeting, trench boxes, or trench shields

is permitted provided that: ... (and we agree with

items a & b.)

1926.653 DEFINITIONS APPLICABLE TO THIS SUBPART

page

18 a Should read ... Accepted engineering practices,

those requirements or practices which are compatible with standards required by a registered

professional engineer.

Question - why are you making reference to the

guidelines when they are not meant to be a part

of the law?

19 m Should be eliminated.

19 o Should read ... Negotiable slope is a slope on

which a person can egress from or ingress to an

excavation with relative ease and speed to assure

reasonable safety.

250
PAGE

19 t Should be eliminated.

19 z Should read ... See Figure 4 (Correction)

GUIDELINES SUPPLEMENTING SUBPART P

If the Guidelines are going to be referenced within Subpart P, do

they not become effectively a part of the law? If so, they should

be discussed publicly as a part of the workshop and in public

hearings.
#1

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

#12

#13

ANSWERS TO DR. YOKEL’S QUESTIONS

No comment.

No comment.

No comment on 24 foot limitation.

On question of should qualified person be sub

stituted for engineer ... "No, as it relates

to this specific question."

No distinction should be made between shortor long-term excavation.

No comment.

No comment.

Yes, and should be conveyed as part of the

definitions.

No comment.

Yes.

Yes.

No comment.

No.

No - Statement should not be deleted.

252

l
Comments of Richard V. Brescia, President

Brescia Construction, Inc.

Caribou, Maine

For the Boston Region Workshop on the Proposed Revisions to Subpart P of the

Safety and Health Regulations for Construction

July 1U, 1981

Ramada Inn - Airport, Boston

l) Section 1926.632(b) it ) Short term excavation definition

I would suggest that if neither the 2U-hour or seven day definition is found

acceptable that a compromise definition of four days be used.

2) Section 1926.652(a)(2) "Qualified Person" definition

I endorse the substitution of "qualified person" for "engineer" in this

section. I would suggest, however, that OSHA in cooperation with the industry,

develop a one or two day training course for superintendents and foremen

engaged in trenching and shoring to insure their qualification. Superintendents

would be required to pass a simple examination on the material, and could be

certified as "qualified". Foremen would be required to attend the training

course, but would not be required to take the examination. Primary responsibility for on-site operations and safety would rest with the "qualified" superintendent .

253
9. SOURCE DOCUMENTS FROM WHICH PRESENT TECHNICAL PROVISIONS IN

SUBPART P WERE DERIVED

When NBS studied the present provisions in Subpart P of the

Safety and Health Regulations for Construction, an attempt

was made to determine the origin of the technical provisions

in the document. The attached documents contain some of the

information which was used as a basis for preparing some of

the provisions, particularly those for timber shoring (Table

2). Note that the documents were written in the early 1940' s.

254
> ^

N a o

i--^!-T:\n CrnV.-?*TTc«*ur'tl» Minimum

on), thj Di. ’•' ^vr Board htr»by \W» and ’"'T'.r.V- lor Ihr ourscie ®* r.io » P“bll ‘ h ',n Si* n»nd»rdf o! *»««•* f;^o.,t.un« rr.rcn.Di* cmBl0TOfD , n _ fmolo T ^fn '' •* . r j i«'r«uA?di ind in \nrwt rl ^T "',

. , „.k

, n ; mrihod* «o*r-

;f- uf« °'*P o\7crfsf' ° : r^olejmenl. »nd

I »U0 I 1 « * n(! ®7erViifd III t*>f m* ll

.,TbS'.,}5

i K^r»w, s:r’:.lVV„ .ssms

: pUid'lnT '-rf I"**"?.

, Tnur?.o»? »r»'OOD CTiflrmaa,

i «?& Suw*35Sce*. ^yThowat •

bvERNMENT

|jM WAGE

OF THE DISTRICT OF COLUMBIA

AND INDUSTRIAL SAFETY BOARD

AND

EIGHT-HOUR njri DAY. LAW DIVISION

EAST ADMINISTRATION BUILDING

I hoiana Annul. N. W

*r\ iv. *?r r-vr

v ° c"

- ** '^TELK.HONe NATIONAL *ooo

500

WASHINGTON.

*?! r>*

MRS ALBERT W ATWOOD. ChaiAman

XXMKXXA^tXA^

FRED S. WALKER

P.Y.K. Howat

ELIZABETH CHAMFE

Ckcutivc SCCRCTAMV

,

. EDWARD J. BUNKER

•• ,k Di.cctea or Inoustaial Safety

August 25, 1943

To be inserted in legal notices of newspapers on August 26

or August 27, 1943.

MINIMUM WAGE AND INDUSTRIAL SAFETY BOARD - Pursuant to the

provisions of Section 4 of the District of Columbia Industrial

Safety Act (Public Law 271 - 77th Congress - Chapter 438 - 1st Session), the District of .Columbia Minimum Wage and

Industrial Safety Eoard hereby calls a public hearing "for

the purpose of investigating reasonable standards of safety

in employment, places of employment, in the use of devices

and safeguards, and in the use of practices, means, methods,

operations, and processes of employment, and any person

interested in the matter being investigated may appear and

testify." Said meeting will- be held in Municipal Center

Building, 300 Indiana Avenue, N. W., on Thursday, September 2,

1943, at 10 a. m. — ,

Mrs. Albert V/. Atwood, Chairman

Fred S. Walker

P • Y .K • Howat

F^DEFENSE

vwmo

ITATt*

* 4Vt»Cft / »O*0S

4*»sua?»

Kespectfullj ts Vfc®

» o*rtetr.t, with lh» c‘.*t«ra*n* Vrv\t th« »Uhi»

fcU .•rt i T .a r s f - ia

,c C tiui.ico *itt th* prtvica* •Ldor»»iB«A.%; 6b*rf*-

g^l9 fasaer&l rtiuifit, 192

255
* :/ZaU~LU- 3>A-

.‘V**’ r

v .'

GCVEEKilENT OF THE DISTRICT OF COLUMBIA

MINIMUM WAGE AND INDUSTRIAL SAFETY BOARD

X

CODE II

CONSTRUCTION SAFETY CODE

(Proposed)

25

;?a^3sns«E«E
PART 25 ;txcav It.:g

' DLi iQLi ttw, ela =ti::g

SECTION 251 EXCAVATION

2510. DEFI’TTTir?T3. A. Excavation shall mean an uncovered cutting

in the earth.

B. Excavating shall mean the operation of making or digging

an excavation.

ji . C. shoring shall mean props, braces, planks, sheeting, etc.,

plaped and held against the side of an excavation to

prevent slips, slides, cave-ins, or the falling of earth.

2511. GENERAL. A. The sides of excavations 5 feet or more in

depth shall be supported by substantial and adequate sheeting, sheet piling, bracing, shoring, etc., or the sides of the

excavation sloped to the angle of repose of the material being

excavated, where there is apparent danger of slides, slips, or

cave-ins, and where under-cutting of banks or walls of the

excavation is pertinent to the excavation system, ouch protection

shall be consistent with the magnitude ,of the work and the

character of the material in which the excavation is made.

B. Ghoring shall be placed as soon after excavating as the

excavating operations will permit*.

C. .Foundations adjacent to an excavation which is lower than

the foundation shall be supported by shoring or underpinning' as long- as the excavation remains open.

D. Excavated or other material shall not be stored within

2 feet of the edge of an excavation.

E. A guardrail shall be installed, or other effective barricade

provided, at or near the edge of an excavation as soon as

possible, except where such barricade will interfere with

operat ions

.

, F. Red lights, torches, or other illuminated warning signs

shall be placed and maintained from sunset to sunrise on

excavation barricades and along the edges of unbarricaded

excavations which are adjacent' to paths, walkways, sidewalks,

driveways, or thoroughfares.

G. Precautions, in addition to those riven be low , may be

required, by the Director, in excavations subjected to

vibrations from moving equipment or other conditions. *

H. Insofar ns ‘practicable ,* measures shall be taken to prevent

the entrance or accumulation of surface water in excavations,

behind the shoring, or on the tops of banks of excavations, where

it is likely to soften or weaken the soil or subsurface material

and cause slips, slides, or cave -ins.

I. The side of an excavation shall not be undercut in excess

of 5 inches unless the overhang is supported by adequate

shoring or underpinning.

-55-

257
1

J. Sketches .shoeing' approved methods of shoring r.re s h ovf n on p ire s .

I'. Excavations mere than 4 feet in depth shall be

. provided with ladders or equivalent means of egress,

extending from the bottom of the ‘excavation to at least

3 feet above,- the top. The interval between ladders in

trenches s^all not exceed 50 feet.

2512. TRENCH EXCAVATIu.. . A. The following requirements

apply to any trench 5 feet or more in depth and

b feet or core in length which serves as a workplace, except

where the trench is in solid rock', hard shale, or hard slag.

1. Trench shoring, not less than the "Minimum Requirements" given in the table cn the follov.’ing page,

shall be provided.

2. The ccmbinr tion tunnel-trench method may be used in

hard, compact soil, provided that a single trench

section does not exceed 3 feet in length, and that the length

of e~rth left in place over the tunnel between the trench __

sections is not less than half the depth of the trench.

In other than hard ,. '-compact earth, the trench sections shall

be provided with shoring not less than specified in the

"Minimum Requirements."

3. Cross ^braces and jacks shall be so placed, fastened,

and maintained that they will net slip or buckle.

4. Workmen shall not be required or permitted to work in

a tunnel section 'unless the earth above is supported

by adequate underpinning. .

-56 -

258
(V3

o

in

rr

f?H-3

fin

259

Minimum

Requirements

PART 2

Excavation Work

SECTION 0

4 Definitions

*^.1 Equipment. “Equipment” shall mean lad- ~ders, scaffolds, ramos, runways, railings, barri- cades, sheet piling, shoring, bracing, and any such

safeguards, protective construction, and devices

used in affording protection to the men engaged in excavating work.

0.2 Jack. A “jack” shall mean a mechanical or hydraulic device to lift, lower, or move a load by man power applied through leverage.

0.3 Ramp. A “ramp” shall mean any inclined

runway including those constructed entirely of dirt. 0.4 Runway. A “runway” shall mean any planked

over walkway or drive constructed and maintained

as a passageway for workmen or rolling equipment.

(See rule 5.6 in Part 2.)

0.5 Shaft. A “shaft” shall mean a hole sunk into the ground at an angle of forty-five (45) degrees

or less with the vertical. 0.6 Trench. A “trench” shall mean a narrow ex- cavation made below the surface of the ground. In

general the depth will be greater than one of the horizontal dimensions.

0.7 “c to c.” “c to c” shall mean center to center.

SECTION 1 General

1.1 This Part on “Excavation Work” provides for

the protection of the public, employees, and property during all excavation work in connection with

building and trenching operations, including re- lated sub-surface or below grade-level work such as

the underpinning, shoring, and bracing of foundations, retaining walls, and the like. 1.2 Any device or equipment used in connection

with excavation work shall be constructed, installed, inspected, maintained, and operated by the owner or user as specified in applicable parts of this code.

1.3 Where applicable, federal, state, or local codes, rules, regulations, and ordinances governing

any and all phases of excavation work shall be observed at all times.

1.4 Trees, boulders, and other surface encumbrances located so as to create a hazard at any time

during operations shall be removed. before excavating is started. 1.5 If the stability of adjoining buildings or walls

is endangered by excavations, shoring, bracing, or underpinning shall be provided as necessary to en- sure their safety. Such shoring, bracing, or under- pinning shall be frequently inspected by a competent person and the protection effectively maintained. 1.6 Excavations shall be inspected after every rainstorm or other hazard-increasing occurrence, and the protection against slides and cave-ins in- creased if necessary. 1.7 If it is necessary to place or operate power

shovels, derricks^ trucks, material, or other heavy

objects on a level above and near an excavation,

the side of the excavation shall be sheet-piled,

shored, and braced as necessary to resist the extra pressure due to such superimposed loads. 1.8 The sides of every excavation four (4) feet or more in depth, where there is danger of slides or

cave-ins, shall be supported by substantially braced

sheet piling or shoring unless the sides of the ex- cavation are sloped to the angle of repose of the material being excavated.

1.9 Whenever any part of an excavation is pro- tected by a masonry wall, such wall shall be braced

to ensure stability. This shall not include reinforced concrete walls known to be of ample strength.

1.10 Temporary sheet piling which has been in- stalled to permit the construction of a retaining wall shall not be removed until such wall has ac- quired its full strength.

1.11 Except in hard rock, excavations below the

level of the base or footing of any foundation or retaining wall shall not be permitted unless the wall is underpinned and all other precautions taken

to ensure the stability of the adjacent walls for the protection of the men. 1.12 Undercutting of earth banks shall not be per- mitted unless they are adequately shored.

1.13 Excavated material shall not be placed on

the ground surface nearer than eighteen (18)

inches from the edge of the excavation.

1.14 All fixed-in-place ladders and stairways giving access to levels twenty (20) or more feet apart

shall be provided with landing platforms at vertical intervals of twenty (20) feet. Every landing

17
18 AMERICAN STANDARD SAFETY CODE FOR BUILDINC CONSTRUCTION

platform shall be equipped with standard railings

and toe boards.

1.15 Lumber sizes, when used in this Part, refer

to nominal sizes.

SECTION 2

Protection to the Public

2.1 All public walkways, sidewalks, and thoroughfares bordering on or running through any construction site shall be provided with substantial

guardrails or board fences. In addition, temporary

footwalks beyond the curb shall be substantially

constructed and provided with protection on both

sides. 2.2 Sidewalks and walkways shall be kept clear of excavated material or other obstructions and no sidewalks shall be undermined unless shored to carry a live load of one hundred and twenty-five

(125) pounds per square foot. 2.3 If planks are used for sidewalks or raised

walkway protection, they shall be laid parallel to the length of the walk and fastened together against

displacement.

2.4 Planks shall be uniform in thickness and all exposed ends shall be provided with beveled cleats

to prevent tripping.

2.5 Raised walkways shall be provided with plank

steps on strong stringers. Ramps used in lieu of

steps shall be provided with cleats to insure safe walking.

2.6 A flagman or watchman shall be designated

to warn the public of the approach of trucks and to direct the trucks in and out of the property. Danger

or warning signs shall be posted at all truck en- trances and exits. 2.7 During the hours of darkness, all public side- walks and walkways shall be adequately illumi- nated, and warning lights or flares shall be placed

about the property to ensure safety for pedestrian

and vehicular traffic. 2.8 The public shall not be required or permitted

to travel under loads handled by power shovels,

derricks, or hoists, unless ample side barricades

and overhead protection are provided.

SECTION 3

. Sheet Piling, Shoring, and Bracing

3.1 All shoring, bracing, or sheet piling shall be

consistent with the magnitude of the work and the character of the soil or material in which the ex- cavation is made.

3.2 If workmen are engaged near the face of an

excavation, where the ground is cracked or of such

character that caving is likely to occur, sheet piling

with shoring and bracing necessary to prevent cav- ing shall be provided.

3.3 All materials used for shoring, bracing, and

sheet piling shall be sound straight-grained timber

equal to long leaf yellow pine,_Douglas fir, or other

material of equal strength. AD timber shall be free from splits, shakes, large or loose knots, and shall be of the required dimensions throughout.

3.4 Wooden sheet piling shall be not less than two

(2) inches in thickness and the thickness shall be

increased as may be necessary to adequately sup- port the sides of the excavation. (See rule 6.13.)

3.5 Where temporary sheet piling is used during

excavation work, the shoring and bracing to be

provided shall comply with the following require- ments. 3.6 When shores and braces are required they

shall be placed at intervals of not more than eight

(8) feet measured parallel with the sheet piling.

3.7 Shores or braces shall bear at the earth against

a footing of sufficient area to keep within the allow- able soil pressure, “dead men” being buried when

necessary to resist the thrust of the braces. 3.8 Shores or braces at the sheet piling shall not be cut to a bevel but shall be held by wedges and

the wedges shall be nailed. 3.9 The timber shores or braces shall be designed

as columns, the following formula being recom- mended:

P=za{^ 1300 -20-^

where:

P=total permissible load in pounds.

A —cross sectional area of timber in square inches.

L —unbraced length of timber in inches. D=least dimension of cross section of timber in inches. 3.10 The shores or braces shall make an angle not greater than thirty (30) degrees with the hori- zontal. Note: For excavations more than sixteen (16) feet in depth, or when heavy lateral pressures are encountered, the use of interlocking steel sheet piling is recommended.

Choice of piling should be made from recognized standard

tables. Piling must be driven sufficiently below the bottom

of the excavation to resist the overturning moment. Steel or timber bracing can be added where necessary.

SECTION 4

Jacks

A. General

4.1 The rated capacity of every jack shall be legibly marked in a prominent location on the jack

by casting or stamping.
EXCAVATION WORK 19

_»4

4.2 To prevent loading beyond the rated capacity,

the manufacturer shall designate in printed matter,

or otherwise, the intended supporting point of the load and the maximum permissible length of lever and force applied.

4.3 If auxiliary load-supporting points are pro- vided, the manufacturer shall also designate the

ratejl capacity for these points.

4.4j The design of all jacks shall incorporate a positive stop to prevent over-travel or an indicator

where a positive stop is impracticable.

4.5 The design shall be such that parts may be

replaced without requiring special adjustment of

either the replacement part or other parts of the

jack.

4.6' Printed instructions concerning the lubrication and operation of the jacks shall be secured

from the manufacturer.

4.7 Lubrication instructions furnished by the jack

manufacturer shall be closely followed.

4.8 When the object has been lifted to the desired

height, blocking or cribbing shall be immediately

placed under it.

4.9 A capable man shall be appointed and held

responsible for the inspection of all jacks at regular

* intervals. The inspection shall be made in accord- ance with rules governing “Inspection of Jacks,”

below.

SECTION S

Ramps anti Runways

5.1 Ramps or runways used for vehicles shall have

a width of not less than twelve (12) feat. Timber

guards not less than eight (8) inches byjeight (8)

* inches shall be securely fastened on T^>p of the runway along each of the outside edgesr

5.2 Ramps or runways, when used as passageways

for workmen, shall be provided with standard

railings.

5.3 All ramps and runways shall be maintained

in a safe and serviceable condition. When ramps

and runways are formed on hard ground without

the use of planking, ruts and holes greater than two

(2) inches deep shall not be permitted.

5.4 W’hen the pitch of the ramp requires it, a man

shall be alongside a loaded truck with a chock pro- vided with a strong handle for blocking a rear wheel if the truck is stalled or otherwise forced to stop orr the ramp. 1

5.5 Workmen, other than chockers, shall be in- structed to stay off ramps and runways when trucks

are passing over them.

5.6 Where the incline of the ramp is too steep for safe walking, foot cleats, not more than sixteen

(16) inches apart, shall be provided to prevent

slipping.

SECTION 6

B. Inspection of Jacks

4.10 Jacks shall be examined for cracked, dis- torted. or worn parts and to ensure that they are receiving proper lubrication. Time of examination

shall depend upon service conditions as follows:

(a) For constant or intermittent use at one locality, thorough inspection once every week,

( b ) For jacks shipped between shop and job,

thorough inspection when sent out and

when returned,

(c) For jacks upon which abnormal load or shock has occurred, thorough inspection

immediately, by foreman in charge.

4.11 Jacks which are found to have cracked, dis- torted, or badly worn parts shall be tagged “out of order” and not re-used until repairs are made.

4.12 Repair or replacement parts shall be examined for possible defects, and only parts which fit perfectly shall be used.

4.13 Before being returned to service, repaired

jacks shall be subjected to test and shall meet the same requirements as when new.

Trenches

A. General Requirements

6.1 In all trench operations where men are at work or where they must pass to and from their work, sufficient light, either natural or artificial, shall be provided at all times.

6.2 Pick and shovel men working in trenches shall be kept a sufficient distance apart to prevent in- jury to one another.

6.3 All trenches four (4) feet or more in depth

shall at all times be supplied with at least one (1)

ladder for each one hundred (100) feet in length

or fraction thereof. The ladder shall extend from

the bottom of the trench to at least three (3) feet above the surface of the ground.

6.4 Red lanterns or torches shall be placed along

the exposed sides of all trenches at night as re- quired for necessary warning to the public.

6.5 Guardrailings or barricades shall be provided

at or near the sides of trenches as necessary to protect the workmen and the public.

r.V

)

r

>

263
20 AMERICAN STANDARD SAFETY CODE FOR BUILDINC CONSTRUCTION

6.6 The sides of all trenches which are four (4)

feet or more in depth, and where the earth is not sloped to the angle of repose, shall be securely held

by timber bracing. The bracing shall be carried

along with the excavation and must in no case be

omitted unless the trench is cut in solid rock or hard shale.

6.7 Where a mechanical digger is used, the brac- ing shall be placed as close as possible [a maximum

of six (6) feet is recommended] to the lower end

of the boom.

6.8 The bracing shall be held in place by screw

jacks or by cross braces cleated and wedged in place. Where the width of the trench prevents this, the lower end of the cross brace shall bear against

a footing in the earth at the bottom of the trench,

provided adequate means are taken to keep it from

kicking ouL

6.9 When the sloping of trenches to the angle of repose does not extend to the bottom of the trench,

the timbering shall be as required to support the

vertical part of the trench. The sheeting shall ex- tend not less than twelve (12) inches above the bottom of the slope and, if necessary, toe boards

shall be placed behind the timbering to prevent material from sliding into the trench. The surface of the slope shall be cleaned of boulders, stumps, or other hard masses of earth to eliminate the danger

of their sliding into the trench. 6.10 Excavated material and superimposed loads

shall not be placed nearer than eighteen (18

inches from the sides of the trench, unless bracing

has been installed and designed to withstand the

load.

6.11 When trenches are undercut, they shall be

shored to safely support the overhanging material.

6.12 If a trench is cut alongside an existing struc- ture and the footings of the structure are nearer to the trench than the plane of repose for the soil, they shall be underpinned or the side wall of the trench rigidly supported.

6.13 Considering the planks used for sheet piling as beams to support the load imposed by the lateral earth pressure, the maximum allowable distance

between the horizontal stringers or wales shall be

such as will keep the planks within their safe bending stress. (See rule 3.4.)

6.14 Where the cross section of the horizontal

stringer or wale is not square, the greater dimension shall be placed in a horizontal plane to gain

the maximum strength of the member.

6.15 Braces shall be considered as columns or

struts and shall be of adequate dimension for stiff- ness. (See rule 3.9.)

6.16 In hand excavated trenches, cleats shall be

spiked or bolted to join the ends of braces to stringers to prevent the braces from being knocked

out of place. In mechanically excavated trenches,

all cleats shall be bojted.

6.17 When the depth of the trench requires two

(2) lengths of sheet_ piling, one above the other, the lower length shall be set inside the bottom

stringers or wales of the upper length and driven

down and braced as the excavation continues.

B. In Trenches of Varying Widths

and Depths

In trenches of varying widths and depths the use of the following timbers is recommended

and any deviations therefrom shall be on the

aide of safety.

6.18 For trenches from four (4) feet to ten (10)

feet in depth and not more than forty-two (42

inches in width:

() In hard solid soil Uprights: 2*6 in. planks spaced approximately 6 ft apart c to c Stringers: None

Cross Braces: Two 2X6 in. planks for depths less than 7 ft Three 2X6 in. planks for depths 7 ft to 10 ft •

If the nature of the soil or parallel excavations close

to trenches necessitate the spacing of uprights closer than six (6) ft. they may be held in place by two

by six (2X6) in. horizontal stringers or wales

and cross braces spaced not more than six (6) ft apart c to c. () In soil likely to crack

Uprights: 2X6 in. planks spaced approximately 3 ft apart c to c Stringers: 2X6 in. planks placed near bottom

and top of trench

Cross Braces: Two 2X6 in. planks for depths less than 7 ft Three 2 X 6 in. planks for depths 7 ft to 10 ft Cross braces spaced horizontally not more than 6 ft apart c to c

(c) In soft sandy soil or filled ground

Uprights: 2X6 in. close sheeting

Stringers: 4X6 in., two for depths less than 7 fL three for depths 7 ft to 20 ft Cross Braces: 4X6 in., spaced horizontally not more than 6 ft c to c

6.19 For trenches from ten (10) feet to fifteen

264
- EXCAVATION WORK 21

fc.

(15) feet in depth and not more than forty-two

(42) inches in width:

(a) In hard solid soil Uprights: 2*6 in. planks spaced approximately 4 ft apart c to c Stringers: None

Qross Braces: Three 2X6 in. planks for depths less * than 13 ft ? * Four 2X6 in. planks for depths 13 ft ' to 15 ft In lieu of one cross brace to each upright, and

where the nature of the soil or nearby parallel ex-

' cavations makes the spacing of uprights closer than

four (4) ft, they may be held in place by two by

six (2X6) in. stringers or wales, and cross braces

spaced not to exceed six (6) ft c to c. (b) In soil likely to crack

Uprights: 2X6 in. planks spaced 3 ft apart c

to c Stringers: 2X6 in. planks, three in the height

of the trench

Cross Braces: Three 2X6 in., for depths less than

13 ft Four 2X6 in., for depths 13 ft to 15 ft Cross braces spaced horizontally not more than 6 ft apart c to c

(c) In soft sandy soil or filled ground

Uprights: 2X6 in. close sheeting

Stringers: 4X6 in., three for depths less than

13 ft, four for depths 13 ft to 15 ft Cross Braces: 4X6 in., spaced horizontally not more than 6 ft apart

6.20 For trenches more than fifteen (15) feet in depth and not more than forty-two (42) inches in width:

(a) In soil of all kinds

Uprights: 2X6 in. close sheeting

Stringers: 4X12 in., spaced vertically not to exceed 4 ft c to c Cross Braces: 4X12 in., spaced horizontally not

to exceed 6 ft c to c 6.21 For trenches from four (4) to ten (10) feet in depth, and more than forty-two (42) inches in width:

() In hard solid soil Uprights: 2X6 in. planks spaced approximately 6 ft apart c to c Stringers: 4X6 in., spaced vertically 4 ft apart c to c Cross Braces: 4X6 in., spaced horizontally 6 ft •part c to c () In soil likely to crack

Uprights: 2X6 in. planks spaced 3 ft apart c

to c

Stringers: 4X6 in., spaced vertically 4 ft apart

c to c Cross Braces: 4X6 in., spaced horizontally 6 ft apart c to c

(c) In soft sandy soil or filled-ground

Uprights: 2X6 in. close sheeting”*

Stringers: 4X6 in., two for depths less than 7 ft, three for depths 7 ft to 10 ft Cross Braces: 4X6 in., spaced horizontally 6 ft •part c to c

6.22 For trenches from ten (10) to twenty (20)

feet in depth, and more than forty-two (42) inches

in width:

(o) In soil of dll kinds

Uprights: 2X6 in. close sheeting

Stringers: 6X6 in., spaced vertically 4 ft apart

c to c Cross Braces: 6X6 in., spaced horizontally 6 ft

• apart c to c

6.23 For trenches more than twenty (20) feet in depth, and more than forty-two (42) inches in width:

(a) In soil of all kinds

Uprights: 2X6 in. close sheeting

Stringers: 6X8 in., spaced vertically 4 ft apart

c to c Cross Braces: 6X8 in., spaced horizontally 6 ft apart c to c

C. In Trenches with Hydrostatic Pressure

6.24 For trenches not more than eight (8) feet in depth:

Uprights: 2X6 in. tongued and grooved close sheeting

Stringers: 6X8 in., spaced vertically 4 ft apart c to c Cross Braces: 6X8 in., spaced horizontally 6 ft apart c to c

6.25 For trenches more than eight (8) feet in depth:

Uprights: 3X6 in. tongued and grooved close sheeting

Stringers: 8X10 in., spaced vertically 4 ft apart

c to c Cross Braces: 6X8 in. or 6X10 in., spaced hori- zontally 6 ft apart c to c The greater dimension of the stringers shall be

placed at right angles to the sheeting

6.26 Where desired, steel sheet piling and brac- ing may be substituted for wood.

*

265
22 AMERICAN STANDARD SAFETY CODE FOR BUILDINC CONSTRUCTION

.. SECTION 7

Power-Driven Shovels

A. General Requirements

7.1 The operator of every shovel shall be protected by a cab, screen, or other suitable means in case a cable should break or material fall from a dipper when racked in close to the machine at a high level. 7J2 No unauthorized person shall be allowed on

the operating platform when the shovel is in operation, and the machine operator shall not converse

with anyone while operating the machine.

73 A suitable ladder or steps and handholds shall be provided to afford safe and easy access to the operating platform.

7.4 All shovels when not in use shall be left with

the dipper on the ground.

7.5 In case of a breakdown, the shovel should, if practicable, be moved well away from the foot of

the slope before repairs are made.

7.6 All persons shall be warned to keep away

from the range of the shovel’s swing, and to avoid

being struck by the cab as it rotates.

7.7 Workmen shall not be permitted to stand back

of the shovel or in line with the swing of the dipper

when the shovel is in operation or being moved.

73 The trucks of all power shovels shall be in- spected regularly, particular consideration being

given to brakes and steering gear. All defects shall be promptly repaired.

7.9 Shovels shall be inspected each morning before starting work.

7.10 All oiling and greasing of equipment shall be done when the machine is shut down.

7.11 Operators shall not be permitted to leave the cab while the master clutch is engaged.

7.12 Whenever it is necessary to move the shovel

under electric wires, ample clearance shall be provided, together with such precautions as may be

necessary to prevent contact between any part of

the shovel and the wires.

7.13 The wire rope on power-operated shovels

shall be regularly inspected and shall be changed

when ten (10) percent of the wires in any three

(3) foot length are broken. «

B. Electric Shovels

7.14 AD wiring and electrical apparatus shall be

installed, equipped, and maintained according to

the rules of the local code governing such equipment and all applicable rules of the National Electrical Code and the National Electrical Safety

Code.

7.15 Temporary wiring shall be properly grounded to minimize the dangej of shock.

7.16 In the handling ofelectrical equipment, ex- perienced electricians and, operators shall be employed to do the work. *

C. Steam Shovels

7.17 Steam boilers shall be installed, equipped,

and maintained as provided in the boiler code of the American Society of Mechanical Engineers.-

and tested in accordance with the rules of local authorities. 7.18 The boiler and all steam pipes shall be in- sulated, and all other necessary precautions taken

to protect workmen from burns.

7.19 Before starting, the drip cocks in the pipes

leading from the boiler to the engine shall be

opened and the cylinders and pipes drained.

7.20 Drains and blow-offs shall discharge under

the shovel or the discharge pipe shall be shielded to protect persons passing or working near the shovel. 7.21 Every boiler shall be provided with safety

valves, gage cock, and steam pressure gage. D. Compressed-Air and Gasoline Shovels

7.22 The compressor, air receiver, and other pirts of the compressed-air equipment shall be installed,

equipped, and maintained as prescribed by the

local code and regulations governing such equipment, and the receiver shall comply with the ASME

Code On Unfired Pressure Vessels. 7.23 Every compressor shall be provided with ap- proved safety devices, including a safety valve, pressure gage, and fusible plug.

7.24 Only a mineral oil having a high flash point

shall be used for lubricating air compressors, and

the quantity carefully regulated.

7.25 All automatic controls shall be inspected

daily and kept in first class working condition.

7.26 Compressors shall always be supplied with

a plentiful supply of cooling water kept in contin- uous free circulation, unless the compressors are

air cooled. 7.27 Smoking in the vicinity of gasoline shovels

shall be prohibited.

7.28 No lights other than approved vapor-proof

incandescent electric lights shall be used in con- nection with gasoline shovels. 7.29 Gasoline shovels shall be effectively

grounded and otherwise protected against the haz- ards of static electricity.
EXCAVATION WORK 23

7.30 When transporting gasoline from the general supply to the equipment in five (5) gallon

quantities or less, safety cans of the non-spill type

shall be used. 7.31 If tank truck service is not available, gasoline in quantities in excess of five (5) gallons shall be transported in steel drums or barrels. All bungs shall be tight, and the drum chocked to pre- vent' movement.

7.32 No open lights shall be used when transporting gasoline. Electric flash lamps only shall be used. 7.33 When gasoline is pumped from drum to stor- age tank on the equipment, a hose with a metallic nozzle shall be used. The pump must be of a type

which does not create pressure inside the drum.

7.34 When gasoline is being pumped into the storage tank, the engine of the shovel shall be shut

down.

7.35 A fire extinguisher of suitable type shall be

placed on or convenient to every shovel or other

similar piece of operating equipment.

SECTION 8

Trucks

* 8.1 Only experienced and physically fit drivers

shall be allowed to operate automobile trucks. 8.2 Brakes, steering gear, tires, and all operating

parts of trucks shall be inspected daily; such in- spections should, preferably, be made before trucks are taken from the garage or storage area for the day’s work.

8.3 All employees shall be strictly prohibited

from:

(a) Riding on trucks unless specifically au- thorized to do so,

( b ) Riding anywhere on a truck except in the seat beside the driver, unless the truck

body is equipped with fixed-in-place seats, a rear gate, and a safe means of getting on and off, (c) Getting on or off moving vehicles. 8.4 Truck engines shall never be allowed to run

idle in closed garages or other enclosed places.

8.5 All parts and accessories of trucks shall be

kept in good repair and safe condition. Trucks with

broken or cracked parts or defective tires shall be

removed from service until the defects have been

corrected. 8.6 On material which projects beyond the rear end of any truck using a public highwaylhere shall be tied or fastened to the projecting end of the material:

(a) A red flag during the daylight hours

( b ) A red light during the hours of darkness

8.7 No person shall be permitted to remain on a truck when it is being loaded by a power shovel or

to remain within reach of the swing of the dipper.

8.8 Material shall never be loaded on a truck so

as to project horizontally beyond the sides of the body nor so that it can be jarred off due to vibration during transit. 8.9 Trucks while being loaded shall be properly

blocked where there is a possibility of their moving

by gravity, vibration from blasts, or other causes. 8.10 Loads not fully contained within the body

of the truck shall be' secured by means of chains,

cables, ropes, or other effective devices.

8.11 The backing up of trucks shall be controlled

by a signal man who shall have a clear view of the driver and the area behind the truck during

each backing-up operation.

8.12 Completely deflated tires on trucks shall never be inflated until after the load has been re- moved by jacking up the truck. Truck drivers and

mechanics shall be instructed in this procedure.

8.13 Dump bodies of dump trucks shall be

blocked or cribbed before inspecting, servicing, or repairing while hoisted.

SECTION 9

’Wheelbarrows

9.1 Wheelbarrows with split or cracked handles

shall not be used. 9.2 Wheels shall be strong, true running, and well secured to the frame.

9.3 When wheelbarrows are used in narrow pas- sageways, knuckle guards shall be provided.

9.4 Workmen shall not be permitted to run with

empty wheelbarrows with the handles in an upright position.

9.5 Wheelbarrows shall never be left in such a position that they can readily tip over or fall.

267
10. MISCELLANEOUS INPUT AND INFORMATION

The correspondence in this section was sent to NBS at various

times and is not associated with any particular workshop.

268
American Gas

Association

N'O ly t'i* ,!

- c V t M T

1515 Wilson Boulevard Arlington Va 2220;’ Telephone (703) 841-8400

September 11, 1981

Dr. Felix Y. Yokel

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D.C. 20234

Dear Dr. Yokel:

The American Gas Association (A.G.A.) is a national trade association which

represents nearly 300 national gas transmission and distribution companies

serving over 160 million consumers in all 50 states. The gas utility industry

employs about 215,000 people with a payroll in excess of $4 billion.

•r ~~

Representatives from the A.G.A. attended two of the recent workshop sessions on

NBS Building Science Series 127 "Recommended Technical Provisions for Construction Practice in Shoring and Sloping of Trenches and Excavations," written as

a basis for proposed changes to Subpart P of 29 C.F.R. Part 1926. Two of the

potential changes discussed cause particular concern. First, consolidating

excavation and trenching rules into a single regulation and, second, comments

proposing a 3 foot set-back for excavations.

The A.G.A., although not in the construction industry, is currently being regulated under 29 C.F.R. Part 1926, including Subpart P for trenching and excavations. We, therefore, have a vital interest in these standards.

As a primary goal we desire to be exempted from construction industry standards.

Since we have not yet attained that goal we must in the meantime insure that

any changes to the current regulations on trenching and excavations in 29 C.F.R.

Part 1926 consider our special interest in trenching. As implied previously,

we see particular significance in retaining the distinction between trenching

and excavations.

Our distribution companies, which by nature of our business operate in urban

areas, are greatly affected by the OSHA trenching and excavation regulations,

especially the 2 foot set-back rule. Inspection of gas lines by OSHA have

occurred in spite of the fact that trenching cave-ins are not a problem within

our industry as documented by our safety record. Equally as important, trenching operations by gas companies, both distribution and transmission, come under

the safety jurisdiction of the Office of Pipeline Safety within the Department

of Transportation. The DOT rules are promulgated under 49 C.F.R. Parts 191 and

192. This potential for dual jurisdiction over trenching safety regulations

between OSHA and DOT causes confusion. For additional discussion of our safety

record in trenching and the jurisdictional issue—see the attachment.

259
2 -

We, therefore, request -that any revision to excavation and trenching standards

in 29 C.F.R. Part 1926 include the following statement: "Natural Gas companies

directly involved in pipeline activities covered by 49 C.F.R. Parts 191 and

192,. as promulgated by the Department of Transportation are exempt_from Subpart

P of 29 C.F.R. Part 1926 standards relating to excavation and trenching operations.

Fori additional information on this subject, please contact Larry T’. Ingels,

703/841-8454 or Randall Griffin, 703/841-8481 at A.G.A. Headquarters in Arlington,

Virginia.

Sincerely,

Manager, Engineering

Services Programs

LTI : lbp

\ "7 Qk —«" Larry a -v-T—ir TT/'•* Tnftol Ingelsc?

270
OVERLAPPING JURISDICTION BETWEEN OSH A AND DOT

S UMMARY OF ARGUMENT

1.

The natural gas utility industry should not be grouped with the

construction industry. Standards developed for the const-ruction

1 industry should not, therefore, be applied to the natural- gas utility

industry.

A. The natural gas utility industry is fundamentally distinct from ¥ the construction industry. Safety records support this contention.

B. The natural gas utility industry took no part - and had no opportunity to take part - in the development of the Construction

Industry Standards 29 C.F.R. Part 1926.

II. OSHA jurisdiction is preempted under Section 4(b)(1) of the Occupational

Safety and Health Administration Act of 1970 (OSH Act) when other

Federal agencies "exercise statutory authority to prescribe or enforce

standards or regulations affecting occupational safety or health."

A. The Department of Transportation exercised its statutory authority

under the Pipeline Safety Act of 1968 by promulgating regulations

. relating to pipeline operations and maintenance (49 C.F.R. Part 192)

and by enforcement of those regulations. _

B. DOT's regulations preempt OSHA jurisdiction over pipeline and

trenching operations, rendering OSHA regulations in Part 1926

inapplicable to the natural gas utility industry.

III. The American Gas Association (A.G.A.), therefore, requests that OSHA

refrain from citiation of the natural gas utility industry under Part 1926.

271
I NTRODUCTION

The American Gas Association (A.G.A.) is a national trade association which

represents nearly 300 natural gas transmission and distribution companies serving

more than 160 million consumers in all 50 states. These companies account for

nearly 85% of the nation's total annual gas utility sales.

The natural gas utility industry is regulated at each and every stage of

their business. Many of these regulations, including OSHA's "General Industry"

standards in 29 C.F.R. Part 1910, are recognized as validly applying to our industry.

We do not believe, however, that the "Construction Industry" standards of 29 C.F.R.^

Part 1926 should be enforced against the natural gas utility industry > We recommend

that OSHA institute a policy of not citing the natural gas utility industry under

Part 1926 for the following reasons.

I . The natural gas utility industry should not be grouped with the construction industry .

According to the National Safety Council data for 1978, the gas utility

industry had an incident rate of 2.69 per 10,0 full-time workers and a severity rate of 15.98 lost work days per injury. This compares very

favorably with the construction industry statistics of 3.94 injuries per

100 full-time workers with a severity of 20.81 lost work days per injury.

Furthermore, a review of safety statistics relating directly to trenching

and pipeline activities indicates that the natural gas utility industry

has an exceptionally good safety record.

• During the six year period (1975 - 1980) 3,837 immediate injury reports

were received by A.G.A.

• Of the above total only 7 were in the accident category which includes

cave-ins and none have been documented as fatalities.

• These few injuries generally occurred in trenches or excavations belonging to someone else who called the gas company to repair a line damaged

during . excavation

• Scaled to the entire industry, this type of accident - "caught under,

in or between a mineral item" which would include cave-ins - would

represent only one-sixth of one percent of the total injuries.

• From this extremely low rate of incidence, it may be concluded that

cave-ins involving trenches or excavations are not a significant problem

within the natural gas industry.

Additionally, the segment of the gas utility industry most likely to be

engaged in the pipeline and trenching activities labelled "construction"

by OSHA - natural gas transmission companies - have incident rates of less

than half of the overall gas utility rate.

The large difference in the incident rates between transmission companies

engaged in trenching activities and construction companies occurs because

trenching and pipeline activities of gas utility companies are performed

by relatively few employees at any given workplace. Construction industries

on the other hand, may have a large number of employees performing a wide

variety of tasks at the same workplace. Due to disparate rates and levels

of risk, the standards designed for the construction industry are not

appropriate to apply to the natural gas utility industry. 272

c

L

C

i

L

C

l

[

[

c

L

L

l

C

i

l

c

t

£
- 2 -

The construction industry standards of Part 1926 have been applied to

the natural gas utility industry without giving that industry an opportunity

to provide input. These standards were developed under the Contract Work

Hours and Safety Standards Act of 1962, (as amended Pub. L. 91-54 of 1969;

40 U.S.C. §333), to regulate construction crews working under government

contracts. In order to cover these crews comprehensively, the standards

were defined very broadly to cover, "construction, alteration, and/or

- repair including painting and decorating..."

M - • The OSH Act of 1970 gave the Secretary of Labor the authority to promul- , gate as occupational safety and health standards, without the notice and/

comment requirements of the Administrative Procedures Act, any "national

concensus standard and any established Federal standard." §6(a) of the

OSH Act, 29 U.S.C. Section 655(a). The natural gas utility industry had

no need to comment on proposed regulations when those regulations applied

only to Federal contractors. There was no opportunity for the gas utility

industry to comment on the regulations when they were promulgated as occupational safety and health standards.

In this context, the 10th Circuit opinion U-,30, Inc, v. Marshall and

OSAHRC , 7 OSHC 1253 (10th Circuit 1980), should be reviewed. The Court

found that there was "no indication in the record .. .that the oil drilling

industry hhd any part or was consulted in the development .of the construction industry standards." The Court then held that the construction

industry standard relating to cranes and derricks used in constructing

•buildings could not be applied under the "general duty clause" of Section 5(a)

(1) of the OSH Act to the oil drilling industry. -• ;

A.G.A. believes that the safety record of the natural gas utility industry

and the rationale outlined above strongly support the establishment of an OSHA policy of not citing the natural gas industry under Part 1926.

I I . A Policy of Not Citing Under Part 1926 is Legally Justified

OSHA has been granted authority by the Secretary of Labor to make and

enforce regulations for the minimum federal safety standards for all

industries. The Secretary of Labor's authority in this area is derived

from the OSH Act of 1970, 29 U.S.C. Section 651, et seg . In order to avoid

overlapping jurisdiction and the inefficiencies and costs of overlapping

jurisdiction, Congress limited the Secretary's authority. The limitation.

Section 4(b)(1) of the OSH Act (20 U.S.C. Section 653(b) (1) ) , provides that:

"Nothing in this chapter shall apply to working conditions of employees

with respect to which other Federal agencies... exercise statutory

authority or regulations affecting safety or health."

It is A.G.A. ’s position that the Office of Pipeline Safety (OPS) of the

Department of Transportation has exercised its statutory under the

Natural Gas Pipeline Safety Act of 1968 by promulgating regulations entitled

"Transportation of Natural and Other Gas by Pipeline: Minimum Federal

Safety Standards." 49 C.F.R. Parts 191 and 192. These regulations com- prehensively cover operation and maintenance of pipelines, mandate safe

working procedures to be documented in an operating and maintenance plan,

and impose strict reporting ana other requirements in case of emergency,

among other safety related requirements.

273
- 3 -

An important concept to keep in mind when reviewing the OSHA Part 1926

regulations is that the OPS regulations need not be parallel in form

or substance to the OSHA regulations in order to preempt jurisdiction.

"Whether the OPS standards are the same or substantially different

from the OSHA standards their content is of little moment. In

Mushroom Transportation Co., Inc ., No. 1588 (1974) own_ authority

over specific working conditions, OSHA cannot enforce its own regulations covering the same conditions. Section 4(b)(1) does not

require that another agency exercise its authority in the same manner , or an equally stringent manner . " Secretary v. Texas Eastern Trans- » portation Corp . , 20 OSHA 712, 717 (1975) (emphasis ajddc-d 'by Commission)

(Citations omitted.) 9

This concept is important to keep in mind because the OPS regulations

are generally structured in terms of maintaining the integrity of the

pipeline and prevention of hazardous situations. The prevention of

hazardous situations^ is mandated through performance language rather

than the prescriptive language generally employed by OSHA.

An example of preemption of an OSHA standard by an OPS standard which

varied significantly from the form of the OSHA standard can be found

in Columbia Gas of Pennsylvania v. secretary and OSAKRC , No. 80-1459,

(erd Cir., December 23, 1980.) In that case, Columbia Gas was cited for

a serious violation of an OSHA regulation — 29 C.F.R. §1926.652(v) —

requiring atmospheric testing of an excavation where oxygen deficiency

or gaseous conditions are possible, prior to use of equipment that could

cause accidental ignition. It should be noted that Section 1926.652(v)

requires compliance with Subparts C and D of Part 1926 in which a large

number of specific requirements are mandated as to personal protective

equipment and engineering controls. In contrast, the OPS regulation,

49 C.F.R. Section 192.751, provides simply that:

Section 192.751 Prevention of Accidental Ignition

Each operator shall take steps to minimize the danger of accidental

ignition of gas in any structure or area where the presence of gas

constitutes a hazard of fire or explosion, including t.he following:

(a) When a hazardous amount of gas is being vented into open air,

each potential source of ignition must be removed from the

area and a fire extinguisher must be provided.

(b) Gas or electric welding or cutting may not be performed on pipe or on pipe components that contain a combustible mixture

of gas and air in the area of work.

(c) Post warning signs, where appropriate.

The OPS regulation does not specifically refer to the repair of a pipeline using a "hot tap" procedure at issue in the case, (tapping into a pipeline without interrupting the flow of gas in the pipeline), nor does

it mandate detailed requirements in a manner similar to OSHA's. Nevertheless, the Third Circuit held that the OPS regulation covered the

"exact working conditions" purportedly within OSHA’s jurisdiction.

274
. -k

- 4 -

Therefore the Court ruled that "this OPS regulation provides safety

standards for the exact conditions of this case and hence find that

Section 4(b)(1) preempted OSHA's authority over the matter."

The above case strongly supports the argument that the DOT has exer- cised its statutory authority and preempted OSHA's jurisdiction over

the natural gas utility industry in the areas of pipeline -safety and trenching.

- « A.G.A. recommends that OSHA examine closely its regulations, particularly

= the excavation and trenching regulations, under Part 1926 for overlap * with DOT regulations. We recommend that special attention be given to » the safety provisions found in Subparts L and M of Part 192 of the OPS

regulations. We believe that such an examination will demonstrate that

the DOT regulations comprehensively provide for employee safety during

pipeline and trenching activities. A policy of not citing these activities

under Part 1926 will leave no gap in the safety net protecting gas

utility industry employees.

*

275
X

« HYDRAULIC

Y STEMS

Underground Shoring Services

P. O. Box 861 • Columbia. LA 71418

318-248-3113

Meets OSHA Requirements

Domestic • International George Bredberry - President

Consultation • Job Planning • System Designs

May 28, 1981

c

l

l

[

L

L

L

C

2. Ref: Should a qualified person be substituted for an engineer?

In the defination of who is a Qualified person, to whom is the ability

demonstrated?

3. Ref: p.10

I think the short term excavation defination could be extended to

3 days or 72 hours, but no more. Reason being the one day shortterm would unduly penalize contractors as over the week-end he would

have to shore for long term excavations as it is now written. *

4. Reft p.ll f I do not feel the stipulation of maximum slope should be limited to

3/4:1 because there are a number of soil conditions that could reuuire

a Itl slope and even a 1^:1 slope.

Felix Y. Yokel PhD P.E.

Center for Building Technology

National Bureau of Standards

Washington, D. C. 20234

Dear Felix:

Have just received the schedule for the A.G.C. Workshops and I

shall be attending by invitation of the AFL-CIO.

I think the guide lines fall somewhat short because you did not

include isometric drawings to cover good trench shoring and bracing

practices. I have prepared the enclosed drawings and recommend

they be included with the documents.

I also suggest the following changes:

1. Ref: p.9

I see no reason why the depth limitation in the "Standard Practice"

cannot be extended to 24' depth. Also no reason why the limits of

Class C soils should be more stringent than they already are, since

we recommend tight sheeting as it is now, so long as the bracing

(struts, wales and sheeting) are strong enough to withstand the expected loads.

I

276
page 2 Suggested changes.

5. Ref : p . 12

Under certain conditions I feel the hank next to the work area in

cases 2,3, and 4, could he increased to 4

f

. I do not believe that

in case 4 we should try to limit to excavations hy trenching

machines only.

6. Refs p.13

I believe this section should he included in the engineering section

as this could be lost on the man in the field.

7. Ref: p .16

In this case I think the specified options identified as examples of

implementing the performance statement should he persued.

8. Ref: p.l6

Excavations up to 3’ below the bottom of the sheeting or trench boxes,

I feel could be allowed under conditions as stated in iii A. & B.

9. Ref: p.18

In "accepted engineering requirements" I think that a regular architect should be omitted, since architects do not deal with excavations.

10. Ref: p.18

I do not see how we could not require that a competent person be

working at the excavation site.

Sincerely yours,

GB : gtb

Hi
• . TyficsL_ 5pci- toAcm/G- F-p /eft. Pstf c/s/fgHy^Mc/tic. s//0 rfs

c

i:

i

c

i

L

i

t

i

L

27 8

L

L

L

l

C

L

t

L

L
I

w Typ'icflL sp*t Bracing f>k ./art-. P*fp. Taen'cn vs/mg- -

f-ly<Afi,/ltji Ac. 5S/exrs /?*'£> pA/^^P

279
TyficfiL Spit BMCIts Fok

VSEp VSI/V& Nf'c

<, p/o PES
281
c

c

c

L

• L

C

L

l

L

l

L

L

L

L

L

'cAl vsis/c*

'</&*/-}f 0t[

282 L

t:
'Ivpicnl JiGWf sHiefjWs- fcR.

l£lQ£E£J-te//Ctf USWG- jftfbrR

SBtEi'/S/G- /j/yp.jJyt/flAvLic J^/lC?S
r

c

c

c

c

i

i

i

c

c

L

L

L

L

L

L

Spc T- BtbCj/yG--FiK- J4- a4

D££p T%£A?/S jJS!ArG- SCREuJ

-UtfeKs /fa/ T/*? l

I

L

284

ikA fffi.iU

3yplolJ7sa77 ^7££±tJs-- - UO/l/G- ~T//?7 gEg _ 5//EEipt'&j

M/gles -rfjv#^Serg£uJ .. Jgcgs

c

[

c

c

[

c

L

c

l

c

i

L

L

L

L

[

L

L

l

L

286
Tyj>iS us'tvG

petfBJl-.OpRlGtiTs /ffi'j C&ttbKters

287
288
TjLfU-CSi L _ $ciio

U^A- EnJ?j-8 eR-, Effi'l (EH^5 ; U-'fi Lf5 ,/A'O SlLEEl*rs F# R

15 F+ Vtrep M

289

I
CORPORATION

Manufacturers of the Finest in Aluminum Hydraulic Shoring Systems

P. 0. BOX 12591

HOUSTON, TEXAS 77017

PHONE: (713) 943-0750

TWX: 910-881-5015

April 9, 1982

Dr. Felix Yokel

Geotechnical Engineering Group

National Bureau of Standards

United States Department of Commerce

Washington, D.C. 20234

Dear Felix:

Here is the work that has been approved by the State of California

for inclusion in the upcoming reprint of the CAL/0SHA Safety Orders,

Title 8, Trench Shoring Tables. As you see, they have addressed

themselves to three separate Tables concerning materials for the

bracing of trenches - (1) - Timber, (2) - Screw Jacks, and (3) - Hydraulic. All concerned, and including California contractors,

feel this clarifies the Code to where they can follow it with ease. The only thing I really disagree with is their decision to go to

two classifications of soil - either hard or running with respect

to the Tables. I feel they should adopt your system of three

classifications of Tables. You might write Mr. Bobis a letter

concerning that matter.

Yonrs very truly.

i_ _ ik

President

DOP : ers

Attachments

cc: Mr. Jim Lapping

Wt Short the World 290

TH
rrl V

OF CALIFCRNIA iRTMENT OF INDUSTRIAL RELATIONS ^:UPATIONAL SAFETY AND HEALTH STANDARDS BOARD

i FOURTH STREET RAMENTO, CA 95314

322-3640

EDMUND C. MOWN JR., Gortrxor

March 24, 1982

Mr. David O. Plank, President

SPEED SHORE CORPORATION

P.O. Box 12591

Houston, Texas 77217

Dear Mr. Plank:

We have received your telegram dated March 23, 1982 with respect to

the proposed revisions to the Trenches and Shoring Tables 1 through

6, Section 1541 as contained in the Construction Safety Orders,

which will be considered by the Standards Board at their Public

Hearing on March 25, 1982 in San Diego, California.

Your telegram will be made part of the Board's official record of

proceedings in this matter.

We appreciate your interest in this matter and can assure you that

your comments will be given every consideration by the Members of

the Occupational Safety and Health Standards Board.

Sincerely,

Executive Officer

/ tlm

cc: Dr. Alvin Greenberg

John L. Bobis

All Standards Board Members RECEIVED

MAR 261982

.SPEED SHORE CORP,

ADM. Derr.

291
State of California

Department of industrial Relations

Memorandum

EXCAVATIONS, TRENCHES AND EARTHWORK

ADVISORY COMMITTEE MEMBERS

Da1e: March 10, 1982

JOHN L. BOBIS, Principal Safety Engineer

Subject: Trenching Tables, March 25, 1982 Public Hearing

The attached proposed tables will be considered by the Occupational

Safety and Health Standards Board at its public hearing scheduled on

March 25, 1982 in San Diego, California.

The proposed tables were developed by the Standards Board's staff in

response to written comments submitted by persons subsequent to the

Board's September 24, 1981 Public Hearing relative to the new

proposed regulations on the subject of excavations, trenches and

earthwork. Since the suggested revisions to the tables constituted

a substantive revision to the September 24, 1981 proposal, the

tables could not be incorporated into that proposal without further

public hearing. Therefore, this matter will be considered by the

Board at its March 25, 1982 Public Hearing. The attached tables are

proposed to be incorporated into the new Section 1541 previously

heard by the Board and are forwarded to you for your information.

Should you have any questions regarding this matter, please feel

free to contact this office.

/tlm

attachment (March 25, 1982 Public Hearing Packet)

RECEIVED

MAR 151982

SPEED SHORE CORP.

ADM. DEPT.

HMi-HIMItMCAMOSP '3 292
OF CAUFORNU

tTMEUT OF INDUSTRIAL RELATIONS EDMUND C. MOWN JR., Governor m _ - —xmm==—r. m m r e=3=C3a»3aw=a»" — - 1 XUPATIONAl SAFETY AND HEALTH STANDARDS BOARD

FOURTH STREET LMENTO, CA 95814 IT322J440 NOTICE OF PUBLIC MEETING AND HEARING - OF THE OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

AND NOTICE OF PROPOSED CHANGES TO TITLE 8

OF THE CALIFORNIA ADMINISTRATIVE CODE

Notice is hereby given pursuant to the provisions of Sections 142,

142.2, 142.3, and 144.6 of the Labor Code, that the Occupational

Safety and Health Standards Board of the State of California has set

the time and place hereinafter set forth for a Public Hearing,

Public Meeting, and Business Meeting:

Public Meeting : On March 25, 1982 at 10:00 a.m. in the

~~ Auditorium, of the California State

Building, 1350 Front Street, Room B-109

San Diego, California.

At the Public Meeting, the Board will make time available to receive

comments or proposals from interested persons on any item concerning

occupational safety and health.

PUBLIC HEARING : On March 25, 1982, following the Public

Meeting, in the Auditorium of the California

State Building, 1350 Front Street, Room B-109

San Diego, California.

At the Public Hearing, the Board will consider the public testimony

on the proposed changes noticed below to occupational safety and

health regulations in Title 8 of the California Administrative Code.

BUSINESS MEETING : On March 25, 1982, following the Public

Hearing, in the Auditorium of the California

State Building, 1350 Front Street, Room B-109

San Diego, California.

At the Business Meeting, the Board will conduct its monthly business.

In the event it becomes necessary to continue the Public Meeting,

Public Hearing, or Business Meeting, the meetings or hearing will be

continued on April 1, 1982 at 10:00 a.m., in the Auditorium of the

California State Building, 1350 Front Street, Room B-109, San Diego,

California.

These meeting facilities are accessible to the physically

handicapped

.

OCCUPATIONAL SAFETY AND HEALTH

STANDARDS BOARD RECEIVED

MAR ] o 1SS2

SPEED SHORE CORP.

ADM. DEFT.

f

293
notice of public

HEARING /MEETING

- 2 - March 25 , 1982

notice of proposed

0F TME

By THE

health sta

"

B0ABD

Notice is hereby given pursuant^o the^rovisions^of Section 142,

S&E'kSS S-VVSil S^t^rl o^the^California

S3Sr.2»tl[t:

i

SSe!

0

.rina

1i=.t.d -low. at its Public Hearing on

March 25, 1982:

1 . TITLE 8: r>nvTc r

r

, pnrTION SAFETY ORDERS _ .

Tn r ° f ^!S

L !

d

| AC

| rr ; Orde r s ^ n concern i ng trench

regulations in the Cons “

the use Q f hydraulic shoring

shoring systems do not addres

U nriqhts) or horizontally (as

units in both a vertical »ode_ (as^uprights^

of Section

walers) when s'?or

J"|

a „ £ a new subsection and tables were

1541 and the adoption of ac"tifornia Administrative Register 81,

previously noticed 1 public Hearing on September 2 ,

' So. 30-Z and considered at Public n

J tems Q r units. As a to clarify the use of bydrauil h

Se ptember Public Hearing,

result of testimony received at tne p into 3 types of

the Board is now proposing new of an excavated

trench shoring systems-^arlulic^ystems. **>• revised “of” trench—wood, metal and y , . a appropriate spacing of

relating to hydraulic systems include position. There are no

these units in a ^°r ^?"^ti°ns addressing this specific subject

Federal counterpart regulations

matter.

These tables are proposed to be incorporated into the new

Section 1541 previously noticed.

^

. ctrIKEOUT/UNDERLINE format is

A copy of the proposed changes 1 ^ sted pers0ns from the

available upon reques t to »n'y

t

and ards Board's Office, 1006

be available at the Public Hearing.

An INITIAL GENERAL STATEMENT OF “^ontsfan^th^sub^antive

ir?i0rthrs?=df

e

Inquiries^ma^be^directed^o Mr. K. T. Kinaldi,

Board s oxtic , Q. 322 - 3640 . Executive Officer at (916) 322 u ..will apply to all the proposed

The following statement

t

Of

b

COS

onsiaered fcy t_^oard!

regulations to Titi

to State Agen£ies: None

Tmpact on Housing Costs: None

RECEIVED

MAR 151982

SPEED SHORE CORP.

ADM. DEPT.
NOTICE OF PUBLIC

HEARING/MEBTING -3- March 25, 1982

Federal Funding to State ; None

To Local Agencies and School Districts : Pursuant to Section 36,

Chapter 1284, Statutes of 1974, the proposed action- does not

create any obligation for reimbursement by the State to any

- local agency under Section 2231 of the Revenue and Taxation Code

for costs that may be incurred by it in complying with these

orders because these orders merely implement Federal law and

regulations

.

Notice is also given that any interested person may present

statements or arguments orally or in writing at the hearing on the

proposed actions under consideration. Written comments should be

received no later than five (5) working days prior to the date of

the hearing. The Occupational Safety and Health Standards Board,

upon its own motion or at the instance of any interested person, may

thereafter adopt the above proposals substantially as set forth

without further notice.

The Occupational Safety and Health Standards Board's rulemaking

files on the proposed action(s) are open to public inspection Monday

through Friday, from 8:30 a.m. to 4:30 p.m. at the Standards Board's

Office, 1006 Fourth Street, Third Floor, Sacramento, California

95814.

There are no building standards contained in these proposed

revisions as defined by Health and Safety Code Section 18909.

OCCUPATIONAL SAFETY AND HEALTH

STANDARDS BOARD

RECEIVED

MAR 151982

SPEED SHORE CORP.

ADM. DEPT.
'' standards presentation A*.--* . mM??- CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

iT,

-

i*'’ > • * . -> .

TITLE 8 : CONSTRUCTION SAFETY ORDERS

. (Tranches and Shoring Tables 1 ‘through 6)

SECTION SUBJECT

1541/- including Repeal existing regulation on Standard

Tables 1 and 2 Shoring System, including Tables 1 and 2.

Note : The repeal of Section 1541 and the

adoption of a new Section 1541 were

previously noticed (California

Administrative Register 81, No.-30-Z) and

heard by the Standards Board on September

24, 1981. Because substantive changes to

the proposed tables were recommended at

the public hearing, the tables are being

renoticed for hearing. The tables are

proposed to be revised to be consistent

with the testimony received by the

Standards Board at its September 24, 1981,

public hearing*- •

Tables 1 through 6 Adopts new Tables 1 through 6.

There are no building standards contained in this proposal.

Pursuant to Section 36, Chapter 1284, Statutes of 1974, the above

order does not create any obligation for reimbursement by the State

to any local agency under Section 2231 of the Revenue and Taxation

Code for costs that may be incurred by it in complying with this

order because this order merely implements Federal law and

regulations.

RECEIVED

MAR Jo 1982

SPEED SHORE CORP,

ADM. DEPT.
Trenches, (a) General. All trenches 5 feet or more .in dep^ vin all types of earth, shall be effectively guarded agamst^he

hazardSsf movibg ground as hereinafter provided. Trenches less fhannazara o s 6 guarded when examination indicates

ha^zarVm^g^und movem^it Ube expected.See Plate 023JppendU

,b, ProtLon While Installing Shonng^

shall be m^e by the ^is may {,e done b/providing

gaged in S.as long-l&Sled jacks -

• -that will allo*\upper cross brace, to.be ^ (( g

surface before *en u’°jk

. workers shall then progress

/trenches by eross^races that have Aready been set

' &Tpl’a?e RXse procedure shall be follow^ when removing

Sh («W,en emP,oyV-e reared to be »

P?dS IndTocldXsm require no mor^than 25 feet of lateral

the boom ' s ”ovi

?

g zi

<C)

^t'^^prigh^he^d rigidly opp^^'e^ch oilier^ agains^'theVrenc^i

consist of uprights held "®,a ZXbers (braces) and, if required,

Provided. Uprights

Sh

t2) n

uVr(ghrs^in^tr^m;

rhes

S oVer

1 ^^^h^be^aMeast^-Inch'by

$sk ife «»d -

requirements applying to /unning gro X . rench to as near ^Ir'SSStTbe

abmTertTMsU,red,bu,„o, more

a foot or base plate on each P P . Wood braces shall be

and bearing firmly against uprights or stnn.|*”' no smaller than tiose listed in the following Uble.\ ^^

Width of Trench Wood Bruces\ Pipe Braces Feet find) 4

. x 4

- \ jy,* STD

H Z" 4* X 6* \2* STD

S-6 6* x 6- Y STD

/

10-12 - 8X9 \

Wider trenches shall have braces of correspondingly larger x^imenSi °n" : In !ieu of the above shoring systems the use of properly

maintained 'hydraulic metal jack shoring units with equivalent

strength is acceptable.

RECEIVED

MAR 1 :> 1982

•«>»*/*»/•? c\

SPEED SHORE CORP.

ADM. DEPT.
STANDARDS PRESENTATION PG 2. of «? CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

The minimum number of horizontal braces, cither screw,

or timbers, required for each pair of uprights shall be determinedly

the number of 4-foot zones into which the depth of trench may be

divided.XOne horizontal brace shall be required for each o£/tnese

zones, but in no case shall there be less than 2 braces or jacks.

Trenches, th p depths of which cannot be divided equally into these

standard zones, snail have an extra horizontal brace supplied for the

short remaining zone, if such zone is greater than '/2 tna''-4-foot unit,

fn no case.boumver, shall the vertical spacing of horizontal braces be

spaced greater trun 5 feet center to center. Minor temporary shifting

of horizontal bracing will be permitted, when necessary, for the lowering of materials nqto place.

(5) The dimensions and spacing of the elements of the shoring'

system shall be governed by the depth of the' tTench, type of soil encountered, ana otherSspeeial conditions of trie site, but in no case

shall they provide less strength then the members listed in the following table, which are to be\onsidered as a/minimum requirement.

So 1 Tvpe

Depth I'pnfcbu / Braren Smnfen

F**«t Sizeinche* Sfwcmc

Soni»vy*j ft*ry /Six* inches Horizontal rp+c* frrt Size mehen Vcrncal

fret Hard, conduct 5-10 2 x S 8 \/ Ol s Where indicated

Ov»*r 10 3 .» S 6 A 4 X 6 6 Where indicated

5-10 2 > 6 .4 X 4 4 2x8 /2 \ y 4 2 Where indicated Over 10 3 \ 8 /Solid Ax 6 5 4 x6 4

Running *

: n-8 2 \ *i / Solid 4 x\ 6 4x6 4 Over H 2 x ftK Solid 6 x 6\ 6 6x6 4

(6) Protective shields or welding huts may qe substituted for shoring systems to provide local protection for w orkmen in trenches only

when the construction materials used comply in\ll respects with the

dimensions and soarings listed herein. Steel construction may be

substituted for timber in such structures provided the steel members

provide protcctiof equivalent to that afforded by thh lumber above

specified. Plans and calculations prepared by a professional engineer

registered in the Slate of California, shall be available forVicld inspection at the site where the shield is used. \

(~) Trench boll holes shall provide adequate clearance for the

work to be done, and shall be supported by shoring and bracing, as required by these Orders for trenenes. If the operation performed in the bell hole requires that a man use welding equipment from a reclined position on the bottom, the bell hole excavation shall Mt of

such shape that he will have adequate space for the performance^

this operation without removing any of the required shoring and

bracing. '

AUTHORITY CITED: Labor Code Section 142.3

Reference: Labor Code Section 142.3

298
STANDARDS PRESENTATION Pg_3_ of _3_ CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

>SHSB-9A(7/76) 299
CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

TABLE 2

WOOD SHORING FOR RUNNING SOIL

Uprights Braces ( Struts)

at 8’ on centers

Strinner i (Walrr) | DEPTH Horizontal

Spacing

(Feet)

Size

(Inches)

Wood Size (Inches)

i and

Trench Width (Feet)

i Size 1 (Inches)

|

5 to 8

- c Solid 2 6x6 All widths ' 8 x 10 |

i up to 15’

j

. i

Over 6 x 6 up to 10’ width,

}

i

8 to 10 Solid 3 8x8 over 10’ width

i 10 x 10 j up to 15’ • I Over 6 x 6 up to S’ width.

f

1 10 to 12 Solid 3 8x8 over 8’ up to 15’ 10 X 12 i

I Over 8x8 All widths 1

i 12 to 15 Solid 3 up to 15’

i 10 x 12

i

Over 8 x 8 up to 12’ width, «

|

| 15 to 20 i Solid

" 4 10 x 10 over 12 ’ up to

20’

12 x 12

[

i

°28 r See Section 1541(a)(6) Strut - Max. horiz.

spacing @ 8’ o.c.

RECEIVED

MAR-HH98? OSHSB-9A(7/76) SPEED S^SZ HORP.

' At*.*- ' r - 300
STANDARDS PRESENTATION Ps 5 OF

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

>OSHSB-9A(7/76)

L..
CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

OSHSB-9A(7/76) SPEEp CORP.

ADM. DEPT.

302
STANDARDS PRESENTATION Pg 7

CALIFORNIA OCCUPATIONAL SAFETY AND HEALTH STANDARDS BOARD

OF

2

<

W> X

ua

£

<

E-

(Xoa

o

2M

(Xo

2

tou(-1 22

g

a

>-

tn 3J3

k

JJ

to

tn3o

flk

ffi

k

3

(O 2

tok

4)2

C

•Hk

JjCO

(0 JJ£

O' -kk

a

2

—3=u * « c « * . « «

4; jj o o o o k .C 3 <N (N «M IN ^ J ^1 3 a

• X 2 IN 2 2 2 It) 2

M —

10 O' jj JJ C 4) C -k 3

c o a

N rz w o U O U

-k a V O U ti k CO C CD 00 VD

tn

'

k

4) 2

CM

M a 2 Q

>. O s s O = s Os : i a

u o S s s a

u j

r

jr -r w k s •H <N S S fN s s tM s r O -T

s m

3 1 i 1 m

fl 1 k

k a Q Q k O 3 MS S MSS MS S O

>> I S s : Ir 2 •• M fM S S 2 M

•t <N (N M

q : j

U -k 4)

**-* W V uo tn m in m m in in in XT Tf

jj 3 a

k a —

4) CO

*5> a

E-i

•* « O

*

* 2 * • • j IB 3 3 a IX jj a jj a < to X CO 2 S

E 3 3 w

a 3 3 k 3 k 3 k 3 3 k 3 2 N C 3 fl 3 fl 3 0 3 3 0 3 a k 3 •H 3 •H *H o to E 2 c 2 C 2 2 2 2 3 fl fl •H r jj S JJ • • • • < vO CO VO to VO CO VO CO

* K « * H

•M « K

HD HD 3 fl! 3 3 N 0C k k k Iki •w 3 fl 3 fl 3 O 3 O to E 3 3 3 3 3 3 VD 3 •H C —I C -H • C 2 fl 2 fl 2 3 2 3 -H 4J JJ JJ JJ fO E S to s tO t to s CO 3 CO CO m CO fH 2 2 2 2 c «-* C — c — c — •k 3 •k 3 •H © •k 3 c H

JJ JJ JJ JJ jj jj JJ JJ o 3 O 3 O 3 O 3 O •H

fl O' — 3 2 3 2 3 2 3 2 4J

JJ C JJ jC .e JZ jC u C -k 3 10 3 to 3 to 3 CO 3 ©

0 0 3 3 3 3 © CO n <o a o to O CO 0 to O 2 •w a 2 2 2 — Z w © k. CO ©

0 8 6 * 8 6 * 9 * • vO ^ « to

*"

•

,

iJ «N fN l£> VO o o

©

r* r* .k M •H tN <N 3 o k k k

fiu 5

1

» tn

Ove to

Ove to

Ove to 3

>o

k

O

m

jj •C

O' •kk

a

3

*3Ck

J=

4) 2

3

OJ

to3

0) a

>1

TO£

rj3JJ

to' 6

jj3

4)k

•k3

cro

• k

0) u to • *k *k Q

O

JZ 4) M

O >

4) s

tn 4) oo

3

oo

<4-1 O •—

I

?

4) S 2 3

-H C JJ a -h to JJ

4; =

4) i£i J3 r-i k M \ JJo

32

tn

2

c

3

>

JJ : o -r

4) 3

vw

VM X 3

k Ir 3 m

J=

JJ <

O

c

0

3

4)k

•k32

4)k

4)>

4)

4) 3 .H

4; 41 JJ 0) CO 4) to O2

*

HSB-9A(7/76) 303

Hydraulic

Shoring

Association

Manual

for

strength

of

rails.
TABLE

6

HYDRAULIC

SHORING

FOR

RUNNING

SOIL

STANDARDS PRESENTATION HG o Or
October 7, 1980

AMERICAN PLYWOOD ASSOCIATION

jWrrTrrfftW^

Felix Y. Yokel, Ph.D., P.E.

D. S. Department of Conmerce

National Bureau of Standards

Geotechnical Engineering Group

Building 226, Room B162

Washington, D.C. 20234

Dear Mr. Yokel:

We appreciate your desire to include plywood as a material in your revisions

to the regulations for "Excavation, Trenching and Shoring." I hope that we can agree on a criteria that will permit us to supply you with some type of

tabular load information for the use of plywood sheeting in trench shoring.

The four-page leaflet I sent to you earlier entitled, "Plywood Trench Shoring,"

was produced some six or seven years ago and all of the people involved with

it are no longer working at APA. This causes a problem in trying to reconstruct

the thinking and decisions that went into production of the tables in that

publication. After searching our file, I have some answers, but in some cases

I can only speculate on the reasoning.

APA at that time saw plywood used in trench shoring in situations that definitely

could not be justified from a theoretical engineering calculation standpoint.

Thus, in developing the tabular data, generous assumptions were made in any case where they could be substantiated with reasonable engineering judgement.

Not being experts in soil engineering, we sidestepped that issue by quoting

from some handbooks and giving pressures in terms of a number of levels of

equivalent fluid density.

All tolled, there are a number of areas where our computations and judgements

vary from the BSS 127 "standard practice." In the tabular data the depth

of the trench did not have built into it any surcharge allowance. Thus, the

two-foot mandatory surcharge you are implying would reduce the effective depth

of the trench by two feet for the tabular information given in the APA brochure.

PLYWOOD DIAMOND JUBILEE

7011 So. 19th St. / P.O. Box 11700 / Tacoma, Washington 9841 1 / 206 565-6600 TLX 32 7430
Felix Yokel - 2- October 7, 1980

While not stated in our publication, the design example implies that thinner

sheeting could be used for the upper part of the trench and a thicker panel

for the lower part. This requires the assumption that the earth -pressure

varies from a maximum at the trench bottom to zero at the surface of the

ground.

In developing the APA publication, information was borrowed from a California

publication on excavations and trenches to justify using a 6/10 factor times

the depth times the equivalent fluid density to determine effective pressure

on the plywood. This 6/10 factor would apparently correspond to the 67Z

tributary loaded area factor given in BSS 127. Though not stated, I assume

this factor is inserted to account for the nonuniform pressure of the earth

on the retaining structure. As it is pointed out, if the structure can deflect

slightly, it will essentially unload itself in that area.

In designing the retaining structure, APA computed on the basis of wet stresses

whereas most plywood structures utilize dry stress levels. After starting

from a normal duration stress level, (ten years) a 33Z increase on the stress

was applied for the shoring duration. Since a 33Z duration increase is only

appropriate for durations of about one day, I suspect that it is in fact more

appropriately entitled "experience factor" with duration of loading as only

one aspect of this stress increase.

The tabulated information given in the APA brochure covers the equivalent

fluid density range from 20 to 80 pcf, and thus we have covered the range

for soil types A, B and C.

In the computations for the table in the APA literature, we have used span

lengths from center of support to center of support. We have at the same

time reviewed computations by other design engineers where the clear span

distance- was used since the supports may be relatively wide. If one is using

verticle supports for the plywood sheeting, that is a 2 or 3 x 8 flat, the

span length changes substantially and the ability of the plywood panel to

resist load increases greatly. However, since the width of the support is a variable and not necessarily one easily controlled, this becomes an individual

matter. I suppose, one could assume a minimum six-inch width of support in

all cases. This would be about the least that could be expected.

I’m enclosing an APA laboratory report on the effect of support width on plywood

deflection. While trench shoring is not deflection critical, the information

gained from the research regarding deflection certainly indicates that something

other than center-to-center span length is appropriate for strength calculations

as well as for deflection calculations.

In order to fit APA data into the criteria you have suggested in your BSS 127,

I would suggest the following:

1. Normal duration wet stresses increased 33Z for short duration shoring.

2. A 67Z tributary load factor for the plywood sheeting.

3. Trench depth computed with a two foot surcharge.
Felix Yokel -3- October 7, 1980

4. Span length computed as clear span plus 5/8 inch, six-inch support width

assumed.

5. Same thickness plywood from top of trench to bottom.

Sincerely yours,

RAYMOND C. MITZNER, P.E.

'* Project Manager, Industrial Markets

Engineering Technology

RCM/saw

Enclosure: Lab Report 120
AMERICAN PLYWOOD ASSOCIATION 1119 A St.

This leaflet has been prepared as an aid in designing trench

shoring using APA® grade-trademarked plywood. Four

basic framing systems are illustrated, and plywood

recommendations are given.

Plywood may be used most readily for trenches up to 8

feet deep. Greater depths are permissible in some soils. In most shoring systems, it is best to orient the plywood face

grain across the supports in order to have the strongest and

stiffest system. For some conditions, however, plywood

panels may be used more efficiently if oriented vertically; that is, with face grain parallel to supports. Minimum

support framing is also desirable, since horizontal support

jacks restrict work inside the trench.

With these points in mina, four plywood-support

configurations have# been calculated for commonly available plywood grades. Tabular information is also presented to

aid the designer in estimating soil pressures, and in selecting appropriate plywood grades and thicknesses.

Four steps are involved in plywood trench shoring design:

1. Determine equivalent fluid density of soil.

2. Select a suitable plywood- support system.

3. Select the proper plywood grade and thickness for the

support framing.

4. Design the support framing.

Earth Pressures on Shoring

Soil-engineering references generally refer to three types of

soil pressures for shoring design: active, at rest, and

passive. At-rest pressures assume no movement of the wall. Passive pressures result from the wall pushing against the

soil until it fails. For most shoring, these two types of soil pressure are not design factors.

Active soil pressure can be safely assumed for most trench

shoring. Active soil pressure can be used where design

permits slight movement of the shoring away from the soil. For most systems, this movement is provided by the

inherent flexibility of the plywood and framing.

The active soil pressure depends on the angle of internal

friction of the soil; soil cohesion, density, and water

content; and depth of the trench. The interaction of these

variables is explained in detail in various references. 1

Tacoma, WA 98401 206 272-2283

The general properties of some soil classifications are known. Using these properties, the soil can be transformed

into an "equivalent fluid" whose density relates to the

pressure exerted by the soil. Some building codes specify

a 30 pcf equivalent fluid density as a minimum design

requirement for foundations. 2

Table 1 shows equivalent fluid densities for various common

soil classifications. A range of densities has been shown

since these soil classifications are not definitive of every

soil property.

Table 1 Equivalent Fluid Density of Soils*

Soil Classification Equivalent Fluid Density (pcf)

Soft flowing mud 75-85

Wet fine sand 35-70

Dry sand 25-45

Gravel 25-45

Compact loam 15-40

Loose loam 25-55

Clay 15-85

• Based on tabular information given in Building Construction Handbook by Merritt.

After determining which soil classification applies to the

soil at the job site, the designer must use professional

judgment in selecting the appropriate equivalent fluid density for his application. For instance. Table 1 shows an equivalent fluid density of 35 to 70 pcf for wet fine sand. The designer may determine by inspection that the actual

soil is sand that does not contain a high percentage of

fines. After comparing the properties given for dry sand, he

may decide that an equivalent fluid density of 50 or 60

pcf would be more appropriate. In any event, the designer

should regard Table 1 as a general guide for estimating soil pressure. After selecting an equivalent fluid density, the design pressure is six-tenths of the product of the equivalent

fluid density times the depth of the trench. 3

1 Soil Mechanics in Engineering Practice by Terzaghi & Peck.

2 Uniform Building Code, 1973.

3 Excavation and Trenches, Agricultural and Service? Agency,

Department of Industrial Relations, State of California.

308
Framing Systems

The following illustrations show four basic framing systems

for trench shoring.

In Types A, B, and C, each panel is supported by only two

framing members, but they are so spaced that the bending

moments in the panel will be minimized. That is, the moment at the supports is the same as at the midspan of the panel. Spacing of supports for Type D has been selected

in a similar manner.

Vertical

!

I

Type B

12- 1 /2

” M

12- 1 /2

'

r

'

i

i

j

^ 1

i U* 4' - 4' •—

Type C Type D

The moment in all four systems is determined by the

following equation:

M supports = = K wB2 M = Moment (ft lb) K *= 0.0214 (Types A, B, C) - 0.00853 (Type D)

w * soil pressure (psf) B = total panel dimension (ft) B = 4 ft for types A and B

= 8 ft for Types C and D

In some cases, the shear stress may be critical in the

design, so this should also be checked. Shear is maximum

at the supports and is determined by the following

equation:

V = ZwB V

Z

maximum shear (lb) 0.293 (Types A, B and C)

0.185 (Type D)

309
By using the equations for maximum moment and shear,

the engineer can determine the required plywood system.

In order to simplify the plywood design. Table 2 has

been prepared, giving the maximum depth of fill behind

each support system for various equivalent fluid densities.

Table 2 Allowable Depths of Plywood Trench Shoring (Ft)

Required

Plywood

Grade

Support

Type

Equivalent Fluid Density (pcf)

20 30 40 50 60 70 80

C-D 32/16 B 7.5 5.0 3.8

INT APA

w/ext. glue D 4.7 3.1

C-C 32/16 B 9.0 6.0 4.5 3.6

EXT APA D 5.6 3.8

C-D 42/20 B 11.5 7.7 5.8 4.6 3.8

INT APA

w/ext. glue D 7.2 4.8 3.6 1

C-C 42/20 B 13.8 9.2 6.9 5.5 4.6 3.9 EXT APA D 8.6 5.8 4.3 3.5

C-D 48/24 A 7.6 5.1 3.8 INT APA

w/ext. glue B 15.0 10.0 7.5 6.0 5.0 4.3 3.8

D 9.4 6.3 4.7 3.8

C-C 48/24 A 9.0 6.0 4.5 3.6

* EXT APA B 18.0 12.0 9.0 7.2 6.0 5.1 4.5 C 4.4 3.0

D 11.3 7.5 5.7 4.5 3.8

5/8” PLVFORM • A 8.0 5.3 4.0

Class 1 B 11.5 7.6 5.7 4.6 3.8

D 7.2 4.8 3.6

3/4” PLVFORM A 13.3 8.9 6.7 5.3 4.4 3.8

Class 1 B 14.6 9.7 7.3 5.8 4.9 4.2 3.7 D 9.2 6.1 4.6 3.7

2-4-1 w/ A 23.2 15.4 11.6 9.3 7.7 6.6 5.8

ext. glue B 30.2 20.1 15.1 12.1 10.1 8.6 7.6 C 7.5 5.0 3.7 D 19.0 12.7 9.5 7.6 6.3 5.4 4.7

The plywood specified in Table 2 is based on the

minimum structural properties for the indicated grades.

Basic plywood design stresses for wet applications were

taken from Plywood Design Specification (Form Q510)

and then increased 33% for duration of load.

A similar level of design stress was used in development

of a shoring system for the Northwest National Gas

Company in Portland, Oregon. Their tests demonstrated

"safety factors" within the range required by the

Occupational Safety and Health Administration.

310
Design Example

Requirements

Shoring is to be designed for a pipe trench varying

from 4 feet to 8 feet deep. Horizontal supports are to

be kept to a minimum.

Solution

1. Determine soil properties: No soil-test report is available, but inspection at the job site reveals a loose loam in most areas, with a coarse sand and gravel

mixture in others. Road cuts in the area indicate these general soil characteristics to a depth of more

than 10 feet. From Table 1, an equivalent fluid density of 40 pcf

is selected as appropriate for the overall design. (With

fine-grain soils such as clays, the possibility of wet

conditions should also be considered. Rain runoff, or other drainage could produce a hydrostatic head of water under extreme conditions.)

2. Select a suitable plywood-support system:

Since the trench depth will vary. Type B support

system will be used.

3. Select the proper plywood:

Table 2 shows that C-C EXT 32/16 plywood will be

adequate for the Type B system up to a trench depth

of 4.5 feet, and C-C EXT 48/24 will be required for the Type B system for depths up to 9.0 feet.

4.

Design of support framing is beyond the scope of this technical note, but basic engineering beam formulas

for uniform loading can be applied. Vertical-support

design will depend on the number and placement of horizontal supports. Use of horizontal supports across the vertical framing can reduce the required number of support jacks—especially for Type A and Type B

systems. For most applications at least two support

jacks will normally be required for each framing

member in trench depths up to*-8 feet. Vertical framing

should be designed to be stable-under lateral impact

loads due to workmen and equipment in the trench. This factor is of particular importance for trench depths over 4 feet.

Note

The Identification Index given in Table 2 as a set of two

numbers in the plywood grade (e.g. C-D 32/16) refers to spacing of framing members. The left-hand number is maximum recommended spacing in inches o.c. for roof

framing. The right-hand number is the recommendation for

floor framing. The Identification Index on any given

panel is based on panel thickness and species makeup and

indicates relative along-the-grain stiffness of the panel.

The recommendations in this leaflet are based on use of plywood

that bears the grade-trademark of the American Plywood Association. For these engineered applications that involve safety, it is best to use plywood that meets manufacturing standards of U.S. Product Standard PS 1 and Association performance repuirements. The APA grade-trademark is positive identification by the manufacturer

that the plywood has been subject to the rigid inspection and

testing program of the Association.

JLameric AMERICAN PLYWOOD ASSOCIATION

1119 A Street / Tacoma, Washington 98401

Y320

311
,
U.S. DEPT. OF COMM. 1. PUBLICATION OR 2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

SHEET (See instructions)

REPORT NO.

83-2693 April 1983

4. TITLE AND SUBTITLE

Development of Draft Construction Safety Standards for Excavations - Volumes I and II

5. AUTHOR(S)

Felix Y. Yokel and Ronald L. Stanevich

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions) 7. Contract/Grant No. national bureau of standards

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City . State. ZIP)

Department of Health and Human Services

Public Health Service, Center for Disease Control

National Institute for Occupational Safety and Health

Division of Safety Research, Morgantown, WV 26505

10. SUPPLEMENTARY NOTES — _ —

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bi bl iography or literature survey, mention it here)

A record of an interim stage in the development of revisions to existing Occupational

Safety and Health Administration (OSHA) regulations governing excavations, trenching and shoring practices in the construction industry, Subpart P 29 CFR 1926, is

presented. The National Bureau of Standards (NBS) prepared a working draft of ,, recommended changes to the regulations based on previous NBS technical studies.

Five regional industry workshops were held to discuss the proposed revisions.

Included in the report is a copy of the recommended revisions, which were submitted to the workshops, and a record of industry's response in the form of suggestions, commentary and summaries of workshop activities. The key section of

the report presents an analysis of industry response and resulting recommendations.

The document is a record intended to aid OSHA during subsequent stages of the rulemaking process.

1 / Yokel, F. Y., "Recommended Technical Provisions for Construction Practice in

Shoring and Sloping of Trenches and Excavation," NBS Building Science Series

127, June 1980.

12.

KEY WORDS (S/'x to twelve entries; alphabet!' cal order; capitalize only proper names; and separate key words by semicolons)

braced excavations; construction; Federal regulations; retaining structures; safety;

shoring; slope stability; soil classification; soil pressures; standards; trenching

13. AVAILABILITY 14. NO. OF

PRINTED PAGES

| X I Unlimited

1 | For Official Distribution. Do Not Release to NTIS

| Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

314

15. Price

j rXl Order F rom National Technical Information Service (NTIS), Springfield, VA. 22161 $25.00

USCOMM-DC 6043-P80