NBSIR 77-1282

Investigation of the Suitability

of Light Duty Pipe Hangers for

Use in Residential and Care

Type Sprinkler Systems

Warren D. Hayes, Jr. and Richard L. P. Custer

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D C. 20234

October 1 977

Final Report

Prepared for Division of Energy, Building Technology and Standards

Office of Policy Development and Research

U.S. Department of Housing and Urban Development

Washington, D.C. 20410

NBSIR 77-1282

INVESTIGATION OF THE SUITABILITY

OF LIGHT DUTY PIPE HANGERS FOR

USE IN RESIDENTIAL AND CARE

TYPE SPRINKLER SYSTEMS

Warren D. Hayes, Jr. and Richard L. P. Custer

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

October 1977

Final Report

Prepared for Division of Energy, Building Technology and Standards

Office of Policy Development and Research

U.S. Department of Housing and Urban Development

Washington, D.C. 20410

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director
S ; t
CONTENTS

Page

LIST OF FIGURES iv

LIST OF TABLES V

Abstract 1

1. INTRODUCTION 1

2. PURPOSE 2

3. TEST FACILITIES 4 3.1. Tensile Test Setup 4

3.2. Fire Test Facility 4

3.3. Pipe Hangers 4

3.4. Fasteners . . . . 5

4. TEST METHODS ..... 6

4.1. Tensile Tests 6

4.2. Fire Tests 6

5. RESULTS 7

5.1. Load Failure Tests 7

5.1.1. Split Ring Hangers 7

5.1.2. Steel Strap Hangers (2 Hole) .... 7

5.1.3. Copper Plated Steel Strap Hangers

(2 Hole) 7

5.1.4. Copper Strap Hangers (2 Hole). ... 7

5.1.5. Malleable Iron Strap Hangers

(1 Hole) 8

5.1.6. Perforated Copper Banding 8

5.2. Fire Tests 9

6. CONCLUSIONS 10

7. GUIDELINES FOR THE SELECTION OF FASTENERS 11

7.1. Fastener Selection 11

7.1.1. Axially Loaded Wood Screws 11

7.1.2. Laterally Loaded Wood Screws .... 12

7.1.3. Axially Loaded Lag Bolts 12

7.2. Pilot Hole Requirements 13

7.3. Self-Drilling and Tapping Screws 14

8. ACKNOWLEDGMENTS 14

9. REFERENCES 14

iii
LIST OF FIGURES

Figure 1.

Figure 2 . Figure 3.

Figure 4 . Figure 5.

Figure 6

.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

Figure 11.

Page

Plan View of the Burn-Room Configuration . 17

Wood Crib Assembly 18

Display of Types of Hangers Tested .... 19

Strap Hanger Connection to Wood Joist. . . 20

Copper Banding Connections to Wood Joist . 21

Temperature versus Time Graph of Fire Test

Number 1 22

Temperature versus Time Graph of Fire Test

Number 2 23

Temperature versus Time Graph of Fire Test

Number 3 24

Temperature versus Time Graph of Fire Test

Number 4 25

Temperature versus Time Graph of Fire Test

Number 5 26

Temperature versus Time Graph of Fire Test

Number 6 27

IV
LIST OF TABLES

Page

Table 1. Pipe Hanger Summary 2 8

Table 2. Fire Tests 29

Table 3. Load Failure Tests 30

Table 4. Excess Load Factors (Strap Fasteners) .... 36

Table 5. Excess Load Factors (Copper Banding) 37

Table 6. Pilot Hole Sizes (Axial Loading) 38

Table 7. Pilot Hole Sizes (Lateral Loading) 39

v

INVESTIGATION OF THE SUITABILITY OF LIGHT DUTY PIPE HANGERS

FOR USE IN RESIDENTIAL AND CARE TYPE SPRINKLER SYSTEMS

Warren D. Hayes, Jr. and Richard L. P. Custer

Abstract

Several sizes of various types of commonly

available light duty hangers for pipe, cable and

conduit were subjected to load failure tests and

while under load to exposure to 70 and 140 pound

(31.8 and 63.5 kg, respectively) crib fires. In

addition, hangers made from thin strap metal were

tested for effect on performance of undersized

screws and for benefit obtained from the use of

washers. All sizes of the two- hole or twofastener hangers met the NFPA No. 13 Standard

for the Installation of Sprinklers load requirement, while only the nominal 1-1/4 inch size of

the one-hole hangers met the requirement. Washers improve the performance of hangers made of

thin strap metal

.

Key words: Automatic sprinklers; care type

occupancies; fire endurance; load failure;

pipe hangers; residential occupancies.

1. INTRODUCTION

In October 1973, the U.S. Department of Housing and

Urban Development (HUD) issued changes to the Minimum Property Standards (MPS) for Multi-family Housing (FHA 2600) , [ 1

]

1

Housing for the Elderly with Special Consideration for the

Handicapped (HUD PG 46) [2], and Nursing Homes (FHA 4514.1)

[3]

.

The changes pertained to fire protection standards for

the above occupancy types. Subsequently, these documents

were superseded by MPS for Multi-family Housing (4910.1) [4]

and MPS for Care Type Housing (4920.1) [5], Our primary

interest in these documents is the requirement for automatic

sprinkler installation as follows:

Numbers in brackets refer to literature references at the

end of this paper.

1
(1) In multi-family residential buildings four stories

or more in height, an automatic sprinkler protection system

must be provided in all corridors, public spaces, service

areas and utility areas.

(2) In care type constructions 3 and 4, automatic

sprinkler protection must be provided throughout.

(3) In care type constructions 1 and 2, automatic

sprinkler protection must be provided in public spaces, in

corridors serving patient rooms, and in hazardous areas such

as soiled linen rooms, paint shops, storage or workshops

involving combustible supplies and in equipment and trash

collection rooms.

It is required that the automatic sprinkler systems

be installed in accordance with the National Fire Protection

Association Standard 13 (NFPA 13) , Installation of Automatic

Sprinklers [ 6 ]

.

In March 1974, a research project, sponsored by HUD,

was initiated at the National Bureau of Standards (NBS) to

develop improved design criteria in terms of spacing require

ments, water discharge rates, hanger requirements and piping

performance criteria for corridor sprinkler systems as

required by the MPS ' s cited above. Water distribution from

automatic sprinkler heads was addressed in a previous report

[7]

.

This report contains the results of load failure and

fire tests conducted on light duty pipe hangers for use in

residential and care type occupancies.

2. PURPOSE

Present requirements for pipe hangers for sprinkler

systems as outlined in NFPA Standard No. 13 specify that

pipe hangers be listed by a nationally recognized testing

laboratory such as Underwriters' Laboratories, Inc. (UL)

(Standard for Pipe Hanger Equipment for Fire Protection

Service, UL 203) [8], or Factory Mutual (FM) (Factory Mutual

Approval Standard for Automatic Sprinkler Systems, Class Nos

1951, 1952, 1953) [9] or certified by a registered professional engineer for the following:

1. Designed to support five times the weight of the

water filled pipe plus 250 pounds at each point

of piping support.

2. Ferrous materials are used for hanger components.

2
Both UL and FM require pipe hangers to withstand a short time

test load equal to the weight of a 12 to 15-foot (3.7 to

4.6-m) length of Standard Weight Schedule 40 pipe filled with

water, (379 pounds (172 kg) for 12 feet of nominal 1 inch

pipe), multiplied by a factor of five (5) plus an added load

of 250 lb (1112 newtons (N))2. The factor of 5 is apparently

intended to provide a margin of strength to compensate for

inaccuracies in design, imperfections in materials, deficiencies in craftsmanship, and deterioration of the system.

The 250 lb (1112 N) additional load is apparently intended

to compensate for human abuse during and after installation.

The form of human abuse envisioned in the development of the

sprinkler hanger standards according to people familiar with

the history [10,11] is that of a person supporting his

weight on an installed pipe. In addition to the previous

loads, UL also imposes a minimum test load of 750 lb (3337 N)

on all hangers. The basis for this load which is three times

the abuse load is undetermined.

The purposes of this investigation were as follows:

1. to determine the ultimate failure load of installed

light-duty pipe hangers typically available through

plumbing supply outlet,

2. to determine whether exposure to fire would cause

the pipe hangers suspended from combustible structural elements (wood joists) to fail prematurely,

causing the sprinkler system to become inoperative

prior to expected sprinkler actuation, and

3. to determine realistic excess load factors to be

used for the selection of hanger spacing.

Hangers suspended from steel beams or concrete slabs

were not considered here since the holding ability in a properly anchored system is considered to be a function of the

strength of the hanger alone rather than the complete hanger

system including the attachment to the structural element.

2 A 1-lb load is regarded as a 1-lb force = 4.45 newton
3. TEST FACILITIES

3.1.

Tensile Test Setup

A screw type tensile-compression machine with a load

range selection of 0-10 000 lb (44 480 N) was used to conduct

the tensile tests. In each instance a short section of pipe

or a substitute of the same diameter was used to transmit

the load to the sample hanger uniformly in order to avoid

stresses not likely in sprinkler system installations. 3.2.

Fire Test Facility

A 7 ft 3 in x 7 ft 3 in x 7 ft 6 in (2.2 m x 2.2 m x 2.3m) high test room lined with asbestos mill board^ was

used to conduct fire testing of the pipe hangers. A nominal

"2 x 4" (actual finish size: 1-1/2 in x 3-1/2 in (3.8 cm x

8.9 cm)) piece of lumber^ simulating a ceiling joist was

supported against the ceiling, narrow edge down, by nominal

2 in x 4 in (actual size: 1-1/2 in x 3-1/2 in (3.8 cm x 8.9

cm)) steel studs at opposite walls of the test enclosure. A

thermocouple was installed 1 ft (30 cm) out the diagonals

from each of the ceiling corners (see figure 1) . The thermocouples were connected in parallel to a recorder to obtain an

average ceiling temperature.

The fire source used consisted of wood cribs constructed

of 22 in (55.9 cm) long nominal 2 in x 4 in lumber as shown

in figure 2. The moisture content of the cribs immediately

before the tests ranged from 7-1/2 to 10 percent. The average

for each crib was determined to be 8 to 9 percent by weight.

The weight of each crib before testing was adjusted to 70 + 1/2 lb (3.18+0.2 kg) by the addition or removal of an appropriate length of stick.

3.3.

Pipe Hangers

A selection of light duty pipe hangers, as shown in

figure 3, common to most plumbing supply houses was chosen

to give a representative cross-section of commonly available

pipe hangers, and included perforated copper banding, one

and two hole copper, steel, and galvanized malleable iron

straps, and split rings with and without swivel features.

Canadian Government Spec. No. 34-GP-18

Select Structural No. 1

4
An effort was made to select designs with implied possible

structural weaknesses such as lightness of hanger, dependency

on only one retaining screw, or a small hinge as an integral

part of the hanger.

Only the nominal 1-1/4 inch one-hole malleable iron

strap hanger met Federal specification for pipe hangers and

supports WW-H-171D [12] . The steel two-hole strap hangers

ranged in thickness from 0.018 inch (0.046 cm) to 0.086 inch

(0.218 cm). The copper two-hole strap hangers ranged in

thickness from 0.028 inch (0.071 cm) to 0.045 inch (0.114 cm).

None of the two-hole strap hangers met Federal specification

for metal retaining strap for conduit, pipe and cable

FF-S-760a [13].

3.4. Fasteners

Since the connections of primary interest in this

investigation were those between pipe hangers and wood joists,

wood screws were selected as the fasteners and these were

sized to support a minimum load of 250 pounds (1112 N) . This

was the load initially thought to be adequate for residential

and care type occupancy applications. In most instances, the

diameter of the screw used was as large as the hanger would

accommodate up to a maximum of 3/8 inch (0.95 cm) which is a limit for insertion into the short edge of a nominal 2 in x

4 in (actual size 1-1/2 in x 3-1/2 in (3.8 cm x 8.9 cm)) lumber.

Guidance in the selection and use of wood screws was obtained

from the National Design Specification for Stress-Grade Lumber

and Its Fastenings [14] , the Wood Handbook [15] , and Holding

Power of Wood Screws [16]

.

Several of the strap hangers made of light gage steel

or copper were fastened with screws one size smaller than

the maximum size they could accommodate for the purpose of

exploring the effect on performance of hanger system strength

of screw size. Additionally, several hangers tested were

fastened with the maximum size screw plus appropriately sized

washers for the purpose of exploring the possible benefit of

washers. In instances where the screws designed for a 250

pound (1112 N) load pulled out of the wood during testing,

additional samples were tested using machine bolts that extended all the way through the nominal 2 in x 4 in wood and

included washers and nuts on the top side.

The perforated copper banding was initially fastened

to the nominal 2 in x 4 in joist with screws shorter than

required by design. The test specimens incorporating washers - and thereby transmitting the greatest load to the wood- screw

interface - did not fail at the connections, so additional

tests with the correct size screws were not conducted.

5
All tests incorporated the use of washers (see table 3)

except for the following: lightweight strap hanger tests

mentioned above, tests incorporating flat head screws mating

to countersunk hanger holes, and tests of the 5/8 in (1.6 cm)

strap hangers where additional samples of the hangers initiallytested were not available.

4. TEST METHODS

4.1. Tensile Tests

Each of the strap hangers was fastened to the short edge

of a nominal 2 in x 4 in joist (actual size 1-1/2 in x 3-1/2 in

(3.8 cm x 8.9 cm)). Appropriately sized pilot holes were

drilled for each screw and the screw was lubricated with

floating white soap to ease insertion. A substitute for a

pipe was inserted in each hanger loop as shown in figure 4

and the fastening screws were tightened. The copper banding

was attached as shown in figure 5. Each assembly was then

positioned in the testing machine and pulled at an elongation

rate of 0.05 inch per minute (0.13 cm/min) until continued

pulling caused no increase in load.

4.2. Fire Tests

For the first test, one wood crib was placed in the burn

room. Several hangers were installed on the joist and weights

suspended from the hangers as shown in table 2. A test load

varying from 75 lb (334 N) to 250 lb (1112 N) was applied to

sample hangers through short sections of steel pipe to simulate a sprinkler system suspended from wood joists in a ceiling. The crib was ignited using 100 ml of heptane in a container centered under the crib. The time from ignition of

the liquid fuel to failure of the hangers as well as the ceiling temperature at each failure occurrence was recorded. It

was noted during the first test that the combustion of one

crib did not produce the desired ceiling temperatures of the

range of 900-1200 °F (482 to 649 °C) , and the decision was

made to utilize 2 cribs in all additional fire tests. Both

cribs were ignited simultaneously, using 100 ml of heptane

each. The time and ceiling temperature for each hanger failure was recorded and is shown in table 2. In the initial test,

the crib was allowed to burn out. In subsequent tests, the

crib fires were extinguished as soon as failure of the hangers

occurred

.

6
5. RESULTS 5.1.

Load Failure Tests

5.1.1.

Split Ring Hangers

The load failure values (see table 3) obtained for

the split-ring hangers for both the nominal 1-inch and the

1-1/4 inch pipe far exceeded the NFPA 13 load requirement.

It should be noted that the comparison of hangers in table 4

is based on the highest hanger mode failure and excludes

consideration of those data related to fastener failure.

Failures were usually by cracking of the beam attachment

plate around the threaded hole for the hanger rod. Variation

in screw size from No. 12 to No. 14 had no effect on the

performance of the hanger. 5.1.2.

Steel Strap Hangers (2 Hole)

The performance of the nominal 1-1/4 inch and 2 inch

two-hole steel strap hangers also far exceeded the NFPA 13

load requirement. These hangers are 11/32 inch wide by

0.024 inch thick (0.87 x 0.06 cm) and 1-1/4 inch wide by

0.086 inch thick (3.18 x 0.22 cm), respectively. One of the

nominal 1-1/4 inch hangers broke at the sharp bend near the

part that attaches to the building element, and another failed

by pulling the screws. The bolt heads broke off in all of the

tests of the nominal 2-inch hangers incorporating throughbolts. Through-bolts were used because hangers with lag bolts

had failed by the bolts pulling out of the wood.

5.1.3.

Copper Plated Steel Strap Hangers (2 Hole)

The more lightly constructed nominal 3/4 inch and 1-1/2

inch two-hole copper plated steel strap hangers also met the

NFPA 13 load requirement. These hangers are 7/16 inch wide

by 0.018 inch thick (1.11 x 0.05 cm) and 3/4 inch wide by

0.034 inch thick (1.91 x 0.09 cm), respectively. The typical

failure mode was shear of the hanger around the screw head

or washer. The use of washers always resulted in some increase in the average failure load, and the use of undersized

screws always resulted in some decrease in the average failure

load

.

5.1.4.

Copper Strap Hangers (2 Hole)

The nominal 5/8 inch, 1 inch and 1-1/4 inch two-hole

copper strap hangers also met the NFPA 13 load requirement.

7
These hangers are 3/8 inch wide by 0.032 inch thick (0.95 x 0.08 cm), 1/2 inch wide by 0.028 inch thick and 9/16 inch

wide by 0.045 inch thick (1.43 x 0.11 cm), respectively. The

performance characteristics of these were the same as the

copper plated steel strap hangers.

5.1.5. Malleable Iron Strap Hangers (1 Hole)

The nominal 3/4 inch, 1 inch, 1-1/2 inch, and 2 inch

one-hole malleable iron strap hangers failed to meet the

NFPA 13 load requirement. The design variations are numerous,

difficult to describe or draw and are therefore here characterized only by width and thickness both of which are measured

in the plane of the top surface through which the fastener

passes. The thickness is not uniform being much greater at

the edges with a relatively thin webbing in between. These

hangers are 13/16 inch wide by 9/32 inch thick (2.06 x 0.71 cm),

27/32 inch wide by 9/32 inch thick (2.14 x 0.71 cm), 1-5/32

inch wide by 11/32 inch thick (2.94 x 0.87 cm), and 1-1/8 inch

wide by 5/8 inch thick (2.86 x 1.59 cm), respectively. The

load failure values for the nominal 3/4 inch hangers ranged

from 80 to 145 lb (346-645 N)

.

The values for the nominal

1-inch hangers ranged from 205 to 225 lb (912-1001 N) . The

values for the nominal 1-1/2 inch hangers ranged from 300 to

325 lb (1335-1446 N) . The values for the nominal 2-inch

hangers ranged from 575 to 600 lb (2559-2670 N)

.

The failure

mode for each was by uncurling of the strap.

Only the nominal 1-1/4 inch one-hole strap hanger met

the NFPA 13 load requirement. This hanger is 25/32 inch wide

by 13/32 inch thick (1.98 x 1.03 cm).

5.1.6. Perforated Copper Banding

The load failure values for the perforated copper banding

when attached without washers to the bottom on the nominal

2 inch x 4 inch (3.8 cm x 8.9 cm) piece of wood ranged from

130 to 210 lb (578-934 N) which is less than the NFPA 13 load

requirement. The banding is 3/4 inch (1.91 cm) wide by 0.027

inch (0.07 cm) thick with 11/32 inch (0.87 cm) holes spaced

3/4 inch (1.91 cm) on centers. The failure mode was deformation of the banding at the attachment perforation. When the

banding was attached without washers to the side of the nominal

2 inch x 4 inch (3.8 cm x 8.9 cm) joist, higher values ranging

from 460 to 510 lb (2047-2270 N) were obtained. The failures

were characterized by enlargement of the attachment hole and

the subsequent pull-through of the screw.

8
The addition of steel flat washers to additional samples

in both side and bottom attachment configurations resulted in

an increased failure load. A substantial strength improvement

ranging from 480 to 550 lb (2136-2448 N) was noted in those

with the banding attached to the bottom of the nominal 2 inch

x 4 inch (3.8 x 8.9 cm) joist. Failure was, in two instances,

by shear of the banding at the edge of the washer and, in one

instance, by elongation of the banding at a hole located several holes from a connection. A marginal strength improvement

ranging from 540 to 580 lb (2403-2581 N) was noted in those

tests with the banding attached on the side of the joist.

Failure was by elongation of the banding at a hole located

several holes from a connection.

As might be expected, hangers incorporating two fasteners

performed better than hangers with one fastener. None of the

two fastener hangers failed structurally under the NFPA 13

required load but all except the nominal 1-1/4 inch size of

the one fastener hangers did.

5.2. Fire Tests

Fire test No. 1 showed first, that the ceiling temperatures obtained from the combustion of one 70 lb (31.8 kg)

crib did not reach the temperatures that would result from a typical building fire; and second, that the perforated copper

banding fails under a load of 75 lb (334 N) due to enlargement

of the fastener holes at relatively low temperatures 482 °F

(250 °C) (see figure 6)

.

In fire tests 2 through 4 (figures 7 through 9) failure

occurred at times ranging between 9 and 17 minutes when the

screws and lag bolts pulled out of the joist after thermal

degradation had reduced the amount of wood at the point of

attachment of the hanger to the joist. There was no apparent

relationship between the amount of load and the failure time

and temperature. In each instance, the joist was well involved

in flames, and temperatures at the ceiling exceeded 932 °F

(500 °C)

.

In fire test No. 5 (figure 10) a nominal 1-inch diameter

section of pipe was suspended from 2 split swivel rings. The

500 lb (227.3 kg) load was evenly distributed along the pipe

length. Failure occurred when the hanger rod pulled out of

the base plate of one hanger causing the weights to be

released. The second hanger was sheared off at the hinges.

9
Test No. 6 (figure 11) consisted of a similar setup,

the difference being that each hanger supported a 250 lb

(1112 N) load separately. During the development of the

fire it was noted that both weights swayed slightly due to

the air currents caused by the fire. Both hangers then

sheared at the hinges, at temperatures lower than those

expected from the previous tests. Both hanger base plates

remained intact, i.e., no separation of rod from base plate

or extraction of bolts from the beam occurred. These results

can be interpreted as indicating that although this type of

hanger is adequate to sustain the minimum required load, it

is not adequate to sustain a moment acting through the

hinges

.

6. CONCLUSIONS

The following conclusions are based upon 6 fire endurance

tests of 5 types of hangers under load and 96 load failure

tests of 6 types of hangers:

1. Fire tests indicate that wood joists supporting

the prescribed load of a sprinkler pipe hanger

must be exposed to substantial fire for at least

nine minutes before thermal degradation of the

wood causes release of the fasteners.

2. There was no clear evidence that time to failure

under fire exposure was related to load over the

range of loads examined (100 to 200 lb)

.

3. The fact that ceiling temperatures during the

fire tests exceeded 932 °F (500 °C) and that the

supporting joists were well involved in the

combustion process at the time of failure indicates

that in situations with exposed hangers, the

automatic sprinkler heads would actuate the

extinguishing system to control the fire before

collapse of the piping support.

4. Commonly available lightly constructed two-hole

or two-fastener hangers for pipe, cable, and

conduit are suitable for residential and care type

sprinkler applications provided that they are

properly fastened to the structure.

5. One-hole malleable iron strap hangers generally

are not suitable for residential and care type

automatic sprinkler applications since four of the

five sizes tested failed at less than the NFPA 13

load requirement.

10
6. Copper is not suitable for use as a structural

element of hangers for automatic sprinkler systems

that might be exposed to an average ambient air

temperature, exceeding 200 °C (the recrystallization

or annealing temperature of pure copper metal)

.

7 . The load can be assumed to be distributed evenly

between two fasteners on a hanger, and therefore

each fastener should be designed to support onehalf of the load.

8. Washers are of benefit in every connection of

thin strap metal to wood and essential for connection

of copper banding to the bottom of joists.

9. Undersized screws reduce the strength of hanger

assemblies made of thin strap metal.

10.

Except for the nominal 2-inch, one-hole strap

hanger and the copper banding used to support a nominal 2-inch pipe, none of the hangers benefit,

from the standpoint of meeting the NFPA 13 load

requirement, by reduction of hanger spacing below

15 feet.

7. GUIDELINES FOR THE SELECTION OF FASTENERS

7.1. Fastener Selection

Since the strength of screw connections increases with

screw diameter as well as length, the process of selection

should begin with a determination of the largest size screw

that will pass through the fastener hole in the hanger snugly

but without force. Thereafter, the determination of appropriate screw sizes may be made from tables 13, 14, 18, and

19 in the National Design Specification for Stress Grade

Lumber [14] . Data in those tables is based on the formulas

that follow.

7.1.1. Axially Loaded Wood Screws

Lengths of wood screws loaded axially are determined

as follows:

1

L

nFKG 2 D

11
where 1 = total length of the screw (inches)

L = load support requirement of the hanger (pounds)

n = number of screws in the hanger connection

G = specific gravity of the wood

K = 2840

D = body diameter of the screw (inches)

F = fraction of threaded part to total length

of the screw. (0.667 for wood screws)

This simplifies to the following:

1894 nG D

7.1.2. Laterally Loaded Wood Screws

The size of wood screws loaded laterally is determined

with the following formula:

where K = 4800 (wood specific gravities from 0.62 to 0.75)

= 3960 (wood specific gravities from 0.51 to 0.54)

= 3240 (wood specific gravities from 0.42 to 0.48)

= 2520 (wood specific gravities from 0.31 to 0.41)

L = load support requirement of the hanger (pounds)

D = body diameter of the screw (inches)

Laterally loaded screws must be embedded in the wood a

distance of 7 times the body diameter of the screw to provide

the lateral strength given in the formula.

7.1.3. Axially Loaded Lag Bolts

Lengths of lag bolts loaded axially are determined with

the following formula:

12
1

L

nFKG 1 * 5 d° * 75

where K = 1800

F = 0.667

This simplifies to the following:

L

1 =

1 5 0 7 5 1200 nG * D

*

7.2. Pilot Hole Requirements

All connections to wood made with non- self -drilling types

of wood screws require appropriately sized pilot holes in

order to develop maximum strength. The withdrawal resistance

and the lateral support capability of a wood screw is dependent

upon the relationship between the diameter of the pilot hole

and the root (minor) diameter of the screw. Lateral support

capability also is dependent upon the relationship between

the diameter of the pilot hole and the body, shank or major

diameter of the screw. Unfortunately, standards for wood

screws do not specify the dimension of the root (minor) diameter. The wood screw manufacturing industry has established

the practice of making the root diameter 67 percent of the

body diameter. From this estimate of the root diameter, the

pilot hole sizes can be determined based on the following

rules provided by the National Design Specification and given

here in tables 6 and 7 for woods commonly used in building

construction (specific gravities of 0.64 and less).

For axial loading:

1. For wood specific gravities greater than 0.65,

the lead hole should approximate 90 percent of

the root diameter.

2. For wood specific gravities less than 0.64, the

lead hole should approximate 70 percent of the

root diameter.

For lateral loading:

1. For wood specific gravities greater than 0.65,

the lead hole receiving the shank should approximate the diameter of the shank, and that receiving

the threaded portion, should approximate the root

diameter

.

13
2. For wood specific gravities less than 0.64, the

part of the hole receiving the shank should

approximate 7/8 of the diameter of the shank and

that for the threaded portion should approximate

7/8 of the root diameter.

7.3. Self-Drilling and Tapping Screws

Recent innovations by certain screw manufacturers are

the self-drilling and tapping screws. The existence of these

types of wood fasteners was not discovered until after the

experimental work was completed and therefore none were

used in these tests. Research by others on the holding power

of these fasteners shows promise for their use for hanger

attachment [17,18]. If these fasteners can be used without

the requirement for pilot holes as reported, a great saving

in installation time can be realized and the dependence on

good craftsmanship can be considerably reduced.

8 . ACKNOWLEDGMENTS

The authors are grateful to Mr. Klaus Wahle who did the

groundwork to initiate this investigation and under whose

direction the fire tests were conducted. Mr. John Grimes

and Mr. Richard Zile also are to be acknowledged for attention

to detail during the fabrication and testing of the numerous

load test samples. The efforts of Josephine Ledford, Phyllis

Martin, and Clare Metzel all of whom lent a hand at typing

the several revisions are appreciated.

9 . REFERENCES

[1] Minimum Property Standards for Multi-family Housing,

FHA 2600, General Revision No. M-23, Department of

Housing and Urban Development, Federal Housing

Administration, Washington, D.C. (Oct. 1973).

[2] Minimum Property Standards, Housing for the Elderly

with Special Consideration for the Handicapped, HUD

PG 46, General Revision No. E-3, Department of Housing

and Urban Development, Federal Housing Administration,

Washington, D.C. (Oct. 1973).

[3] Minimum Property Standards for Nursing Homes, FHA

4514, Change No. 5, Department of Housing and Urban

Development, Federal Housing Administration,

Washington, D.C. (Oct. 1973).

14
[4] Minimum Property Standards for Multi-family Housing,

Volume 2, 4910.1, Department of Housing and Urban

Development, Federal Housing Administration,

Washington, D.C. (1973).

[5] Minimum Property Standards for Care-Type Housing,

Volume 3, 4920.1, Department of Housing and Urban

Development, Federal Housing Administration,

Washington, D.C. (1973).

[6] Installation of Automatic Sprinkler Systems, NFPA

No. 13, National Fire Protection Association,

Boston, MA (1976 Revision)

.

[7] Custer, R.L.P. and Wahle , K. , Distribution of Water

Through a Vertical Plane from Automatic Sprinkler

Heads, Nat. Bur. Stand. (U.S.), NBSIR 75-920

(December 1975). NTIS Order No. PB 248913; $4.00.

[8] Standard for Pipe Hanger Equipment for Fire

Protection Service, UL 203, Underwriters'

Laboratories, Inc. , Northbrook, IL.

[9] Factory Mutual Approval Standard, Pipe Hanger Components

for Automatic Sprinkler Systems, Class Nos. 1951, 1952,

1953 (January 1975), Factory Mutual Research, Norwood,

MA.

[10] Personal Communication with Miles R. Suchomel, Underwriters' Laboratories, Inc.

[11] Personal Communication with William Testa, Grinnell

Fire Protection Systems, Inc., Chairman of NFPA 13,

Chapter 3 Subcommittee.

[12] Federal Specification for Pipe Hangers and Supports,

WW-H-17 ID (October 19, 1970).

[13] Federal Specification for Strap, Retaining (Metal for

Conduit, Pipe, and Cable) FF-S-760a, April 30, 1964,

and Amendment 2, August 26, 1966.

[14] National Design Specification for Stress-Grade Lumber

and Its Fastenings, National Forest Products Association,

Technical Services Division, Washington, D.C. (1973).

[15] Wood Handbook: Wood as an Engineering Material, U.S.

Department of Agriculture Handbook 72 (Revision 1974)

.

GPO/$7 . 85

.

15
[16] Holding Power of Wood Screws, I. J. Fairchild, Technological Paper No. 319, National Bureau of Standards.

[17] Stern, E. G., Wood Screws for Building Construction

and Wood Products Assembly, Wood Research Laboratory,

Virginia Polytechnic Institute, Bulletin No. 39

(May 1959)

.

[18] Wilkinson, T. L. and Laatch, T. R. , Lateral and Withdrawal Resistance of Tapping Screws in Three Densities

of Wood, Forest Products Journal, Vol. 20, No. 7

(July 1970)

.

16
CEILING

THERMOCOUPLES

(4)

if) a:

Idoz<X

h

Of. o

CL

a.

Z>

if)

17

Figure

1.

Plan

View

of

the

Burn-Room

Configuration
Figure 2. Wood Crib Assembly

Note: The numerals above the English dimensions are metric

equivalents in centimeters.

18
Figure 3. Display of Types of Hangers Tested

19

r
20

Figure

4.

Strap

Hanger

Connection

to

Wood

Joist

Note:

During

tests

the

linkage

was

normal

to

the

joist

and

the

assembly

was

inverted

from

that

shown

in

picture.
o

21

Figure

5.

Copper

Banding

Connections

to

Wood

Joist
<n3

C

LxJ

(Do) 3dn±VH3dlN31 9NHI30 WOOd Nd08

c • •rH rQ

1—

1

p 54 CD 54

5-1 > P

0) H O

A tn U

g O

P CDg 0) •H 54 -P 4-3 P

03 —

1

CD CD •H

Eh .C fd

4-> 44

03

54 03 54 •H 0) a 54 tn

fd P

04 g fd 0

.P X

x 0,^0

a fd a)

fd u u

54 Cn 0> U X

P g

CD O P

g . C

•H ^

Eh o

5-i 03 54 3 fd

03

5-1 fp

Q) 0) > 5-1 0)

CD rQ

5-1 e

P P

4J S

fd

>40) •• a a) g -u

a) o

Eh s

<x>

0)

5-1 P

CP •Ha

22

table

2

at

which

the
§

UJ2

I-

(Oo) 3dn±Vd3dtN31 9NHI30 IflOOd NdflS

23

Figure

7.

Temperature

versus

Time

Graph

of

Fire

Test

Number

2

Mote:

Numbered

arrow

on

graph

marks

the

time

given

in

table

2

at

which

the

numbered

hanger

failure

occurred.
O.) 3dfUVd3dW3± 9N 11130 WOOd NdD8

24

Figure

8.

Temperature

versus

Time

Graph

of

Fire

Test

Number

3

Note:

Numbered

arrow

on

graph

marks

the

time

given

in

table

2

at

which

the

numbered

hanger

failure

occurred.
25

Figure

9.

Temperature

versus

Time

Graph

of

Fire

Test

Number

4

Note:

Numbered

arrow

on

graph

marks

the

time

given

in

table

2

at

which

the

numbered

hanger

failure

occurred
26

Figure

10.

Temperature

versus

Time

Graph

of

Fire

Test

Number

5

Note:

Numbered

arrow

on

graph

marks

the

time

given

in

table

2

at

which

the

numbered

hanger

failure

occurred.
LOAD

LOAD

HANGER

(Pounds)

(Newtons)

Oo) 3dniva3diN3i 9NHI30 wooa nana

c • •H tJ

0) vo £ Li

QJ Ll £ > £

OJ -H o b CP O

e o

£ 1) z e a) •H S-l 4-) 44 £

W rH

d) 0) -rH Eh -£ fd

4-> 4-1 QJL M L

•H ^ (D fa Li Cp

fd C

4-i g fd O -d £

,c fazs

a, fd qj

fd Li Li

Li CP QJ U Z|

C £

O £

d

£

E-i O

Li w Li £ (d w

Li TJ

QJ QJ > Li

QJ QJ £3

Li £

£ £

4-> Z

fdLi

QJ •• fa QJ £ -P

QJ O

E-i Z

I I

QJ

Li£

CP •H

fa

27

table

2

at

which

the
Table

1.

Pipe

Hanger

Summary

VO vo VO

rH rH rH rH 00 00 00 00 in UO 00 00 00 00 UO uo i—

UO 00 00 rH CM o 00

00 00 00 in o O o o ro ro o o O o ro ro ro o o CN as o

ro ro ro CM rH inm in in vo vo in uo U0 in vo vo i—

vo uo in ,-h CN i—

uo

X

X

XXXXXXXX

XX

XXX

X

XXXX

X

X

XXX

X

X

R in OS in Os in ro

O roO rH roO ro

O uo UO ro ro ro as as as o i—

rH ro as as 00 in 00 uo 00 UO 00 UO 00 UO ro ro as as in uo in

-P '

VO in VO in VO r- ro ro vo vo r- as as as uo uo in

tnC0 O o O o o o o o o o o o o o O o o o O o o o o o o o o 1—

X o o o o o in o in o o o o o o o o o o O o o o o o in o o o ["- uo o

01 in in r- in i—

o o o o in uo o O o o uo in

CN o o o 00 [•" o

CL) i—

•—

rH rH rH

XX CN CM CN CN CN CM CM CM CM CN CM CMXX OJ CM o o CN

XXX

XX

mm

X

XXX

XXXXXX

X

X

m in

X

XX

XX

X

rd

C CN ID <N VO o CM CM

O rO r- i—CO o rO o o CM CN UO UO U0 vo vo vo •H rH ^r 1—

in i—

i—

as r- as in ro as r-~ as r- uo uo rH i—

r- rH rH rH

T3

—

CN CN (N CN CM ro ro rH rH i—i—i—

rH i—

i—

rH

r—

CM CM ro ro ro ro ro CN CN CN

Size ( o O

OOO o OO o o o o O o o o O o OOO o o o OOO

CO<D * * * £ CO CM CM CM oc a:

0)

WCMWCM

rH * * CM CM

wi—

rH •K * *

•H o rH ro rH ro 1 i—

w i | CM * * * 00 \ c i 1 1 i i—

X X H~ •f- i—

rH H- H- CM CM

XX CM CM

w* p •H rH rH i—

i—

X vo vo CM CM 1 1 CN CM X X ID VO X X X r~ ro CN

0)

XXX

X 5T 1—

rH

X CMX CM CM CMX CM

X CM 1—

rH 00 00 00

XXX

X)

X CN <H4 \ W

O

X

O

X

XX

O

X

O

XW

WW\CN CN CM e " i—

f—i—

1 1 1—

in in rH as i—

as r- VO rH as i—as i—rH uo UO ro ro ro •—

1—

i—

2 =«= =& =#= =H= H4= =tc- # # # #.

=#= =& =#= =#= =&

rH rH i—rH

0) 01 0) rH 1—

—

i—

i—i—i—

i—i—rH

0) 0) 0 0) 0) 0 e 0 0 0 0 0 0 0 w a -P -p 4J 0) 0 0 0 0 0 0 0 0 0 CO 1—

rH

co co co in

a -p -P •Paa

a

a

a

a rd 0 0 P in CO CO CO CO CO CO CO in CO p 0 0

0) •o

a

a

a c t T) t Td CO CO 0 rd rd rd cd Td r0 T5 T) TJ T3 TJ T5 T5 Td s. -P 0) 0 0 0 rd rd rd rd rd rd rd rd rd rd t - *. CO as as as as 0 OJ 0 0 0 0 0 0 0 0 rd mi id

<d

a E a E aa

aaaa cd rd rd

a -p -p

aa •—

1—

rH

a 0 0

rd rd rd rd 0) mi T) T< T5 T3 T3 Td T5 Id TJ 0 0 E a

rH rH i—rH 0)

G

CGG c c GG c c 0 0 TS

a

a

a

a -pG P pG

ppppp

p

aa

C

aa 1—

rH in o O o o o o o o o n i—1 rH CO rH rH rH

m P rd rd

«. 0 o a

aa

a

a

a

aa (!) Cl) 0 Cl) 0 o i—1 rH 3 3 3 3 0 0) 0 0 0 0 0 «. a a a

<u 0) 0 0 0)

a -pa

aaa

a

aaa

ap

p

pp CO in rH 3 3 3 s IS IS IS IS 3 w

wa CO CO CO rH

v

v •* >1 o o o o o 01 0) 0 0 0 0 0 0 0 0 n o 3 3 3

Eh co CO in CO »»

ap

p

p

pppppppa

a 0 0 0

-p

a

u o o o o o o u

ua

a

a -p

aa

p P P

Cn Cn Cn tn rH rH 0) CO CO CO CO CO CO CO CO CO CO rH rH 0 1—

i—

rH 0 o D o c <s G c 0 0 c o o c 0 0 o c CO a CO

•r| •H •r| •H

aaa

m •rHaaa •H

a

a

a

a S3

CA 'O t t HU t -C SS mi T5 Td

aaa acntu o 0 o o o o 0 o n o tr> im o tr> im tm

O o o 0

rd rd rd rd <d <d rd o o o 0 o 0 o n o o rd rd «d rd rd rd rd

n o 0

Eh

H

H tHaa s

r» s £ IS

a PJ £ a

a

a £ 5 IS 12

d) rH N 'tr CM CM CN CM

rd -H \ w

w \ \ \\\ c a r-. 1—1 •—

rH •a*

a rH 00 00 i—1 i—

rH rH i—1 •H c 1 l | \\ 1 1 \ \ 1 1 \ i 1 | e aj •H rH rH rH •

i i—1 CM CM ro ro i—1 rH in UO rH rH ro rH i—1 CN CM o a S -Ha

p

a)(ma

a)

ffi 0

cu

>1

Eh cpaaa

a

CO 1—

. p 0 a * 0 0 rH * CL a a H CL a 0 p p U • 0 0 • > CL CL > id rH CL CL i—

0

rd 0 O rd

a

au

U

a rdp 0 0 0 0 0

rH rH 1 1 i—

MH o o o 0 p a a a a 0a

CM CN i—

CM tr>

** c

CL, CL CL CL •rH rd rd rd rd Td p p p p G a a a a rd a CO CO CO m

inP0

S3

in0

•H -P w a) -P rH w n 0 o

-P 0 0

rH <D i—I r-H Pi rH (0 X3

<: s; eh * * +- *

28

tests

incorporated

washers

and

three

did

not
Table

2.

Fire

p

fa

p

p

u

p CA o 1—1 in in o o o o in to

OO

O o Oh o O P 6

•• o H ^ rH o o o ro in o o ro in

r—1 *H c •• fd • • • • •• • • •• •H Eh •H o fa ro to r*" Oh Oh Oh Oh 00 o CM ro tr

(d £ CN i

1 pH i1 i1 CM

Pm

— 02 p u LO P If)

O ^ ^ o o to to r- in

H1 00 o o

fa

O i—1

fa i

1 i1 (N CN o o r- ro Oh o 00 to

0) 3 CN P tO tO t£> tO in in in LO cm in in in to CN

fa fa rH P P •H '—1 P fd •H 0) fa Oh fa ch o in in CN CN in in rH in in rH to to o p a o 1—1

fOfOHH ro ro rH •—i

ro Oh to o CN in o

fa e 1— 0 i—1 i—H i—1 i—1

Oh Oh

O o in oh o ro in o 2 rH iH rH i—1 i—1 •—i 1—1

Eh

in p- o to p- Oh to in CM CN r- p- CM CM

ro

m ^ to oh in to CO in i—i i—i

to to CM rH rH ro ro tr to co in to 00 in h1 i—1 rH to to CN i—1

rH

T) r-H

r

—1

CM

fdo CA LO in o o O LO o o in o o o o o O

O o

fa ra pO LO

O CN uo o CN o in in in in

O LO in

i—1

rH rH CN f-H •

i CN r-H rH CN CNr—i rH in CM CN

CN CN 00 00 00 CO CM CM CM CM CN CM LO in in in in

CM CN o o o o CN CN CN CM to to ro ro ro ro ro • • • • g CN CN in in in in CM CN CN CN r- to to to to to ' o1 X X X X X X X X X X X X X X X X X

Oh Oh in in in in Oh Oh Oh Oh in in Oh Oh Oh Oh Oh H1 ro ro ro ro H* ro ro H1 H1 H1 H' in in to to to to in in LO • in to to in in in in in

CN CM CM CN CN \ \ \ \ \ 00 00 00 00 00 00 rH H rH rH 1—1 \ \ CM CN CM CM \ \ \ \ ro ro 1 1 | | 1 e p- p- X X X X r- p- r- X X CM CM CM CN CN •H X X H1 H1 H1 — X X X X X X X X X 

CM CN

w

w CN CN CN CN

w CM CN CN CN CM

rH rH i—1 i—1 rH i—1 rH i—1 rH i—1 i—1 i—1 i—1 i—1 i—1 i—1 i—1 =8= =8-‘ =8= =8= =8= =#= 88 =8= =8= =8= =8=

P3 'U T3 P3 C C c C c C P -p fa -P -P P P rH i—1 1—1 1—1 p P p P rH rH fd fd P fd fd O 0 d> d) d) d) o O o O d) P •—i i—i i—1

rH i—i fa fa d) p d) <U fa fa fa fa P P Cm Cm fa fa Cm

fa fa fa fa fa fa - co - CO co co co co U) (A (A - tn co co ** i—1 1—1 " rH *“ i—1

*» rH

p 5 CO S CO

U) s (A CA ^ U) £ 0) £ P & P & p P

a, d)

p

p

p . * " (U cd 0) fd d) fd e p *. * CD d) 0) P P P p

p <U P

fau Sh fa fa fa fanpr SH

Un

u Sh

u Sh

M fa fa

U -Pp fa Sh fa Sh faU fa

Eh

a « o m i—i i—t

rH rH

u CQ o CQO CQ

U CQ rH i—1 U CQ o COU COO CO

u CO CO CO 0 o O 0 CO co CO co 0 0 CQ CQ CO CO CQ

**

m co cq

m •* •»mm

T3 rs

r

aU PJ T3 TS

p

p

p

p T3 PJ PS PI PS 0 P O P tm tr> tn Cr> o fd O fd 0 fd 0 P CP CP 0 P 0 p 0 P 0 P 0 p 0 P 0 P P P p p o (D O a) o cu o e p p O P o p O P 0 P 0 p £ fa £ K fa fa fa fa S K S k s & fa fa fa S fa |2 K £ fa £ fa X

Q) r—I N

fd *H

—

G CQ

G

•H *H £O Ch S *H

CQ * *h1

h<\m

•K\ *

CN CN CM CM

Oh * C Oh Oh

Sh P •H

C c p Dr « •H •H

Oh Dr CA « 2 c O p p fa p p •—1

fd

U rH rH -H i—1 i—1 p iH rH 2 0 O fa 0 o > p p p T5 K X u X CQ •H > >

a,p > H •H

>i fa CM i—l-K CM

MHH CQ s s

Eh P CnH s s CQ CQ

ShC - d ** 0 -H Dr P Dr Dr • Dr • fa MH PI P D. P > P > P > •H -p fa

>H

C fa Dr P rH P rH P 1 1 rH •H •H P P fa 0 fa P fa p fa P Dr i—1

rH

fa CQ CQ

U CO CD co o CQ

O CO Dr Dr

CQ CQ PO Oh Oh O^ Oh Oh Oh

Sh fa; fal fal fa fa fa 3 fa fa fa fa fa fa 0 rH in rH in H in rH in h in rH in

CQ r- r- ca P- CA r- ca P- CA P" CA o . fa o • fa O • fa o . fa o . fal O . fa

fa r- .—i -H rH -H r- i—i *h i—1 *H P** i—1 *H P^ i—1 *H

fd 1 ro Sh 1 ro fa 1 to fa 1 to fa 1 ro fa 1 (O fa pK 1 1 CJ CM '— CJ CM O CM CJ CM ^ CJ CM s— (J

fa • CA D rH CM

m in to

Q) Z

Eh * ** 29

MI

is

an

abbreviation

for

Malleable

Iron. 1

in

(2.54

cm)

diameter

pipe, 7

ft

(2.13

m)

long

suspended

between

hangers

spaced 5

ft

(1.52

m)

apart

with

load

uniformly

distributed

on

pipe.
Table

3.

Load

Failure

Tests

33

ai MH

m 44 2 4H MH UH o o o o 0 (0 CU cu cu cu o d)

0) 4-1 P 4-) a; 4-> 44 4-1 44 44 44 44 <u d) <u T3 id U (0 u id O id o id id id 44 44 44 O rH rH CU rH (1) rH cu 33 -a 03 i—

i—rH 03 0 0 0 2 2 a2 2 2 2 PH 2 CU 0) dJ PH 2 2 03 C Td 01 01 L S4 P £ rH rH rH CU CU (U d) cu PQ m m

<u 2 iO 4-> 2 4-> 4-> 2 44 i—

rH i—

44 44 44 rH OJ I—

rH i—

P C rH PS id c id g id P P P C PS C rH 1—

rH rH 03 03 03 3 cu u a) cu d) 2 CM 2 d) dl (3 P 44 p p P id (3 <0 rH E 03 E E TO e Tl E 03 E 03 C4 id PU PH PH cu cu <u •H jE2 K r2 a) ,2 <u ,2 (U w w w 2, 0) d> 2 CU as 2 2

id o o o 2 o 44

u 44 s s U 44

U 44O 44 cu s 13 £

Cm cd 2 (0 o id

U id

O <u 0) d) id

U idO idO d) 44 <u <U (U 44 44 44

4->

O 2 id -P id 4J id P p

p 44 id 44 id 44 id

L 0 IH Sh P 1 1 1 1 1 1 2 H 2 p 4-> p 4J p o CJ a 44 p 44 p 44 P O p U o o n 0 0 c PQ < u < u < u CO CO CO < U < U < U CO m CO CO CO PQ m m

ro ro in o o CO CO o m vo 00 00 00 <T\ VO cm

m

in vo vo CO ro ro o CM r- o o ^r 1—

CM rH r- rH 2 vo r- r- G\ CM CM 00 VO CM 00 o ro CM VO in V—

vo in VO in VO vo vo VO VO VO vo in vo ro in in

TJ CM ro cm

id i—

i—l i—

0

in in

O inO o o o O

O o o o LO in in in o o w CTv CM vo o o in rH o r- co 00 r- ro in 2 H1 CM in ro •^r •^r in in m rH in D i—

•—

CO o r- rH i—

rH rH i—

i—rH rH •—

•—

rH i—

i—

rH rH rH CM ro cm

p

<D AW

id £ o

IS o

IS o£ oIS WWW

(D CD CD ^ >H WWW<D <D <D >H >H WWWCD CD CD >H >-i >-1

p

(DG

<D •PW

id fa

tr CO 00 00 ^ ^LD in LD

r

X

in

X

in

rrX

<j\

in

rrX

CTi

LO

coX

in

roX

in

coX

in

X

•^r in

X

cr>

in

^rX

ro co ro XXX in in in

ro ro ro

vo vo vo

CM CM CM XXX ^ ^ ^

O'* O'* O'*

r-* r- r* o o o

rHI rH rH XXX'vr ^ o> ^

r* r- rX

roI X

CM

roIX

CM

X

XX

roIX

CM

roI i—

X

CM

roIX

CM

H i—I i—

I I I XXX^ ^

rlH i—

XXX vo vo vo \in Win in

-P 44 44 44 44 44 44 44 44 44 rH i—1 rH

id id id id id id id id id id CU d) cu •—

rH rH rH i—

i—rH rH •—

•—

CU CU d) 2 2 2 2 2 2 2 2 2 2

rH rH 1—

1—

l—

•—

-p -p -p

CO CO CO

** cu cu d) CU CU cu S 3 s s s s 5 3 cu cu CU cu CU <u

cu

<u <u CU <U cu <u cu d) CU CU 44 44 2 2 2 2 2 2 2 H rH H rH H rH P 2 H i—

P 2 P 2 P rH p 1—P rH 2 2 2 CO 2 2 rH rH rH

CH o cu

u <u o cuO d)

u cuO d) o cu

u cu o cu

u cu 0 O 0

I>1 CO 0) CO 0) 2 <U CO CD CO <D 2 <U CO Q) 2 CU CO CD CO (D <*. •k

V «.

m

mm Eh 44 44 44 44 44 -P -p 44 -p -p 44 44 2 2 2 2

Co 2 C32 22 2 2 22 2 2 Cr> co 2 2 22 2 2 rH 1 1 rH rH rH 1—

cu cu cu

G c PSC c G c C PS

G o O o o o n

C PS PS •H ** •H ^ •H ** •H ** •H •H *• •H ^ •H * •H •H *• 2 2 2 2 2 2 •H *H *H

CH 03 203 2 03 203 203 203 201 201 203 203 2 2 2

CH <3 2 nl 2 13 2 13 2 13 2 13 2 c3 2 13 2 f3 2 13 Cn CJ> tr> 2 2 2 U

V

U

(3 CU (3 CU 13 <U 13 CU (3 d) 13 <U (3 CU (3 CU c3 CU 13 CU id id id id id id Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 Eh 2 2 2 2 2 2 2 s s a

p

<D

tr» G

id SU

(D rH N

Cd *H r-v c w c

•H *H S <U o a 2 -H2

•<r \I—

I

'S’ \I—

I \ \rHI

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30
Table

3.

Load

Failure

Tests

(continued) P0c0

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10

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CO S3 CO S3 CO

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k CO fak CO 4H CO 4H fa® fa fa o 0 o 0 0

(fa 3 (fa 3 fa 3 & 0 a (fa fa 3 fa 3 fa 3 fa > fa 3 fa 3 3 fa fa £ fa 3 fa

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31
Table

3.

Load

Failure

Tests

(continued)

s IS s s s 33 33 33 33 33 33 33 33 33

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Table

3.

Load

Failure

Tests

(continued)

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Iron.
Table

3.

Load

Failure

Tests

(continued)

Xi 0 0 0 C 3 3 3

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XX

X

00 CO 00 1—1

rH 1—1

CM CM CM CM CM CM CM CM CM

X CO CO CO CO ro CO 1—1 1—1 1—1 1—1

1—1 1—1 1—1

rH rH

0)c0

ro ro ro in in in =8= =8= =8= =8= =tt =8= HP =8= =8=

-p0

rd Eh 1—1 1—l 1—1 3 3 3 3 3 3 T) Td ra X) T3 X -P -p G G c G c G

XX

X 1—1 rH 1—l

1—1 1—1 •—1

rH 1—1 1—1

CO CO CO 3 3 3 3 p

p 0 0 0

a; 0 <u <u <u cu cu 3 3 0 n 0 n Cl 0 1—1 1—1 1—1

a; 0 0) cu 3 cu cu 3 3 •» **

a

Xa PCa

XX

XX

X

X

X

XXXXX -p

X

X

X 3 in in in CO CO CO CO CO CO 1—1 1—1 1—1

*» 0 s 0 S 0 s 0 s 0 - 0 s 1—1 s 1—1

*- rH

Oh 0 0 0 0 3 0 3 0 3 0 3 0 3 3 3 3 3 3 3 3

>1 ** •* *• *> *• *- ** •* 03 cu 03 3 0 3 0 3 0 3 0 3 0 3 3 3 3 3 3 3 3

EH

XX -p

XXX

XX

X

X

XXX

X

X

XXX

X

XXXXXX

X

X 1—1 l—l »—i

rH 1—1

rH 1—1 1—1 1—1 3 3 3 t) 03

O CQ

O

X

U

X 0 X

O

X

O CO 0 CO 0 CO 0 0 0 0 0 0 0 n n G c C CO W CO CO CO CO CO w CO X 03 X x m 03 P3 IX) 03 •H •H •H s s s s s s s s

TU TD XS Xl TU X} Td 'P T3 ^ ^ T3 Hd ^ 'd ^ 'd Td

CP CP CP Cp CP CP CP O' O'

uu

a 0 0 0 0 0 0 0 0 0 0 0 3 0 0 O 0 0 3

rd rd rd rd 0 0 0 0 0 0 0 0 n 3 0 3 0 3 0 3 0 3 0 3 0 3 0 3 O 3 X X X X X X X X X 2 2 2 £ X S X s X s X s X S X & X S X S X 1—1 0N

rd •H CM CM CM CM CM CM G w c

•H •H 1—1 1—1 1—1

rH

g 3 —

1 1 1 1 1 1 o a 1—1 1—1

rH rH 1—1 1—1

£2 •H * K * * * *

PU * -K * +-

p P * * * p X! H3 nd T3 "d t XI 'd 0 3 3 3 3 3 3 3 3 3

Cp * X 3 X 3 X 3 X a)

X 3 X 3 X 0 X 3 X 3 C H H H H H H H H H H H M 3 T) 3 T3 3 Xj 3 TJ 3 Xi 3 TU 3 TS 3 Xi 3 TU

rd 222 2 2 2 2 2 2 2 2 2 X •H

X •HX •HX •H

X •HX

X

X

H

X

H

X -X 3 0 d) cu 3 3 0 & 0 3 0 3 O 3 0 3 0 3 0 3 O 3 0 3

cu 3 3 3 3 3 MH MH CM MH MH MH MH MH MH 1—1 1—1

1—1 1—1

rH rH 1—1 1—1

rH rH 1—1 1—1 X - X s X s X - X - x = p = P P = 0 0 0 0 0 0 0 0 0 0 0 0 3 nr 3 H1 3 ht 3 *4T 3 0 3 0 ^ 0 ^ X X tc X x SB EG sc EG BG X X Oh \ Oh X \ X X \ X

ro CO ro ro ro CO ro ro ro

pH 1—1 l—l 1—1

rH 1—1 rH iH rH iH 1—1 rH Si s s s s s s s 0 CP S O' S CP S CP s CP s CP - c^ s CP s CP “

CM ** ** *»

C

X c X c X

GX

GX

C

X c X (Gp

G P

CM CM CM CM CM CM U-i Ux P-i CX CXi Q-t •H 3 H 3 •H 3 *H 3 •H 3 •H 0 0 0 •H 0

ro ro rd ro 0 0 0 0 0 0 0 0 t a, -a Oh'C Oh cvt OhTJ

X "d cva CVCS Oh P P P P P X X X X X X X G Dh c Uh c a c x e Dh C ft G a c Oh C Oh

-P -P -P -P -P -P •P

X

X

XX

X 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 O 0 0 1n

co in CO CO CO CO CO

C/3 CO CO CO 03

U 03u

X 0 CQ

a

x

u

X

u

X 0 X

u

X

u coxH3I—I

XI33

(0 2XO

XIcoHX3

•H>3

1-1 XIXI

id • 04

04 a;X 3 0 X Cn 0 -H

tn m-i Hm a)cu 3 to 3 —

(03

XI<Xo

0) XSXcnoX

<u xu3xx<* +- * 34

Attached

to

bottom

of

beam
Table

3.

Load

Failure

Tests

(continued)

c/i d) 1—1 0M

<u 03 CN 03

03 0) dJ 0 M M cu (3 (3 3 2 rd d) fat d) 3 d)

d> 43 0 3 d) 43

(1) 43w

M (U 43 tn

M CO rd 03 44

W 3 3 s w £

rH tn tn to tn •H C 03 C fa C 03

<d •H c •H

H 3

fa 03 3 g 03 3 C O 3 O C O

rd P rd

M 3 3 m < 03 44 « c

00 LO

O

CO C' 2 rH CM

CM CM CM

03

rd0

PI . o O

O

w LO 03 rH

43 LO LO pH

M

<D

W

w

43 d) aj d) w X X X

rd s

00 00 00 S o o o g • • t o lo LO LO X X X

03

LO LO LO

0) • • •

•H

co

(3 •H1—1 CM CM CM X X X

CM CM CM

M i—1

rH rH

0) =#= =tt= =8= c

CD

4-> w

rd fa

44 44 44

rd 3 rd rH iH rH

fa fa fa

D rH 1—1 K rH

fa £ d) dJ is tu >1 d) d) 01 <3 d) <D

E-t

M 44

p 44 S3 44

U CO 0 c/)

u CO aj 03 CO K •k V T3 rO rO rO 5 rd 0 rd 0 3 p <D 0 dj O <3 £ XSffiSK

0) 1—1 N

rd

H

— CMC H •H g <U 0 (fa 2 H

fa

p 4- +- +•

a) 03 03 03 tn <3 d) 0) d> 0) d) c 4-1 03 44 03 44 03

rd rd •H rd •H rd *H » u s p S3 S 0 o o

4H

r 4-1r 4H = p P -O' <u \ cu \ dJ \ fa CO fa fO fa ro

d) tn tT> tn * a c p C p 3 V4 •H aj •H d) •H (D i —t

(fa 03 (fap

a

C Ifa c •ifa <3 (fa rd 0 rd o to 0

03

u 03

O 03U

a\

d)L3

•rH

4-1

d)

d)Wg

tao

£1<wogo

-p

44o

43O

44rd

0) 43o

(0

4-> 4J<

35
Table

4.

Excess

Load

Factors

(Strap

Fasteners)*

in3 VX) rH cn in 3 5 1 6 ON CN ["• in

4-1 • • • • • 4-1 co co CO ^ 0 0 1 0 O rH CN rH rH rH

in * tjl u c

iH 0 -H

•PO

O e

•o

a VO

p cp VO

TJ P CO on in in rH 4 6 2 6 O CO ON 00 00 ID

RJ 0 —

• • • • • • • • • • • • • • 0 cr 4-> CO CO co in 0 0 1 0 rH rH CN rH rH rH J c 4-1 rd <0 2 CN

in0) >i rH O XI X r-*. K e

CO

00

r- rH 4 7 6 9 ON o 00 rH • • • • • '

1 ^f r* 0 0 1 0 rH rH CO rH CN rH

A-> 4H

IX)

rHO r- io 7 2 9 2 rr rH CO ^F rH rH 5 • • • • • (d 2 cn 00 CO CN in rH CN in ON ON CO CO N* | 0 co r- co vo vo o O) i—

in co 00

H ^

a) xi in in oo in O'* *3* co VO ID ID rH in CO

t7> in vo VO CN CN rH CN rH CN CN CN P p

01 3 in on o in cn CN

hO co 00 CO CO cn in > rM Si ID o rH ON CN H ^ H 00 ON VO CN

rH *=f in in ooH CN in CO in co o n1 in in

rd

— i—i i—

rH CN rH

Cm ** e cn in in vr 8 2 5 0 ai 00 CN ID 00

ID <u ft • • • • • C in 2 ft i—1 rH rH ON 00 rH rH OS ON •H on CO ON 00 •H • ' •H CO CO CO 00 00 CO CO ID 00 p co 00 ^F 00 o ftf 00 rH rH 00 in 00 rH CO 00 co r- cn ^ in

rd

rH CN CN CN rH rH CN CN CN

p rH rH rH rH rH

a.

cp a) ft

+j— a> r- cn CN VO 2 7 2 6 ID ft rH CO in ON CN P MM W p 0 • • • • • <d Si CP rH ON on on C" rH O'. CN ON u o co oo in

tn in rH rH r- r- ^ in rH Is* co

O ON oo cn in

C

rd EC

rH io co ^ *3* in ID CO CO CN co CO

Em rH 00 oo o 2 1 8 7 O

O ^ CN

XI e • • • • • VX) r-v r- r- r- co i r*'* O rH ON CN CO o vo 2 00 CN CN co ON 00 CN rH CO ON CN N- 00 ON

in • VO ON on uo

N1 ID ON rl uo CN ID CN CO ^

CM CO rH rH rH CN rH rH rH CN CN rH rH rH rH rH w

4- , , p ~ CO rr r- 7 3 4 1 r- rH IO 00 00

mm in • • • • • P SI ON CO co on in o* co io ON O o o in

<D IN rH l"** co co io co co i ID ON ID 00 rH CO P rH ' co ^ in CO CO N1 N* in CN CO CN CO CO

rd £+

aj ^-s CN co co 00 4 2 3 6 00

O ON ON C'N1 a, e • • • • • •H co ^ o o O CN CN O O CN rH ID O h CN

ft oo 2 O CN CN CN

O

O CN rH CN

O ID 00^0 ' • in in oo co ^ in vo 00 CN CO rH CN CO

rH rH i—

rH i—rH rH rH i—rH rH i—rH rH rH

•P£

on •H -P ~ 00 00 00 00 00 00 00 o 00

O CO in in 00

a> M-l 0) • • • • • £ XI ^ rH rH O'* CN ^ rH CO ON O P- in o cn 1—1 VX> rH rH O O'* rH VO O r- o vo 00 ON

in CO CO CO CN CO CO co CN co CN CN r*"

CD rH N

rd *H c cp c CN CN •H •H \ N w N \ S <u s—

rH rH ^ rH rH rH 00 rH

O ft 1 i \ i i \ 1 \ i 2 -P i—1 rH rH CN CO rH i—1 i—

CN CO rH in rH rH

Pi

rH

<D

<u (U

<u a) CD -P <D

K rH rH rH CO rH

Em 0 rH o 0 0

O' ec <u ECC 2 • 2 P c 1 <D 1 o i -a 1 a

•H CN HJ rH J-H CN -P CN

On os CP

H rH c N - p - p

rd -p

a • a • • ft ft a) EC •H (0 > 3 E> iH fd •

<TJ ft rH P rH JH rH (—

p a p ft

CM -P 3 •P (0 3 P 0 -P 0

CP CP CJ3 IPOS co o CP

u

36

NFPA

13

Load

supporting

requirement

disregarding

the

spacing

requirement.

The

NFPA

13

Load

requirement

is

based

on

the

weight

of

12

feet

of

water

filled

pipe

1-1/4

inches

in

diameter

or

smaller

or

15

feet

of

water

filled

pipe

1-1/2

inches

in

diameter

or

larger,

times 5

plus

250

pounds.

Highest

average

hanger

mode

failure

load.
Table 5.

Excess

Load

Factors

(Copper

Banding) *

+JG

cde

CDG

•HG01 CDG

tnC

•Ho

<0cuw

CD £p

tn

x

G • rH •H XI 'Orin gfloro

tT> • rH (DOIT G U3 w in || •H

T3 II -pG

•P -p CD G G £

CL) <D

X S e O

CD XIG

g o X

•H

G P G P G

C-P

CD (0 £ G O

CD -P TJ T) P g •H O o cn X

rH

gG < 0 O

Ph 4-1 4-1 ixs 'O T3 G G 0 0 O p rH rH

ro 0) CD g G G G G 0 iH rH •H •rl (N G G

4H 4H

440 CD CD Cn tP 0 G G G G

-P CD CD

<0 > >

IX < < * * +“
Table 6. Pilot Hole Sizes (Axial Loading)

Screw

Size

No.

Body

Diameter

(in)

Estimated

Root

Diameter

(in)

70%

Root

Diameter

(in)

Nearest

Drill

Size

(in)

Nearest

Drill

No.

6 0.138 0.092 0.064 0.635 52

7 0.151 0.101 0.071 0.0700 50

8 0.164 0.109 0.077 0.0760 48

9 0.177 0.118 0.083 0.0820 45

10 0.190 0.127 0.089 0.0890 43

12 0.216 0.144 0.101 0.1015 38

14 0.242 0.161 0.113 0.1130 33

16 0.268 0.179 0.125 0.1285 30

18 0.294 0.196 0.137 0.1360 29

20 0.320 0.213 0.149 0.1495 25

24 0.372 0.248 0.174 0.1730 17

38
Table

7.

Pilot

Hole

Sizes

(Lateral

Loading)

Body

Drill No. 31 30 27 23 19 12 co

C fa fa fa o in o o o o o o o o o rH o 00 •O’ O’ VO CO co O’ p- rH CO

U rH 0 ^ CN <N N*

m vo 00 rH CO U0 00 CN id'H N c rH 1—1

rH rH rH rH CN CM CM CN CO

CDU -H -H • • • t 0 0 0 0 0 0 0 21 D W ^ o o o o o o O o o o o P

CD rH <N O’

m VO O'! CM in p- o vo

>i -P ^ <N CO •O’ in VO 00 rH co in 00 CN

00 fQ (D

C rH rH rH rH rH I—1

CM CM CM CN CO \ 0 6 -H • • • # 0 0 0 0 0 0 0 r' W nj'-' o o o o o o O o o o o

•HQ t0 i—1

CD rH • VO CO rH O’ o 00 CN CO CO U -H 0 •O' O’ co CO CO CN CN rH rH

siu sa

E-I

Q o o o o o in in

O o o o

rH 1—1

CO VO O’ 1—1

00 o r- CO uo co

H i—1 CD ^ 00 00 CO o rH CM O’ in r- 00 rH 0 -H N C o O o rH rH rH rH rH rH rH CN 0 P -H -H

£1Q c/)

w o O o o o o o o o o o P0 rH 00 in CO rH VO rH vo CN p" p" PD- 00 00 co o rH CN •O’ in P" 00 rH

00 0 0 C o o o rH rH rH rH i—1

rH rH CN \ 0 6 -H 0 p* fa to ^ o o o o o o o o o o O •HQ 0 P

-P 0 CN rH CO 00 p- O’ i—1

Co VO co 00

fO -P -P —s co o O rH CN O’ vo r~ CO rH of e o 0 c o rH rH i—1

rH rH rH rH rH CN CN •H 0 6 -H 0 0 -P fa 0 ^ o o o o o o o o o O o W -H

faQP0 00 i—1 'O’ i-" o VO CM 00 •O’ o CN >i-P — CO uo VO [" CO rH of vo CO CN P" T3 0 d rH rH rH rH rH CN CN CN CN CO CO 0 & -H

cq

a o o o o o OOOO o o

•HQ£0 0 P N VO p- 00 CO o CN •O’ VO 00 o of O -H i—1 rH 1—1 1—1 1 1 CM CN

fa CO

39
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLIC A LIGN OR RHPORT NO. NBSIR 77-12822. Gov’t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

Investigation of the Suitability of Light Duty Pipe

Hangers for Use in Residential and Care Type

Sprinkler Systems

5. Publication Date October 1977

6. Performing Organization Code

7. 'Warren) D. Hayes, Jr. and Richard L. P. Custer 8 . Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4928671

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Division of Energy, Building Technology and Stds.

Office of Policy Devlpment and Research, U.S. Dept

of Housing and Urban Development

Washington. D.C.. 20410

13. Type of Report & Period Final Report

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) Several sizes of various types of commonly available light

duty hangers for pipe, cable and conduit were subjected to load

failure tests and while under load to exposure to 70 to 140 pound

(31.8 and 63.5 kg, respectively) crib fires. In addition, hangers

made from thin strap metal were tested for effect on performance

of undersized screws and for benefit obtained from the use of

washers. All sizes of the two-hole or two-fastener hangers met

the NFPA No. 13 Standard for the Installation of Sprinklers load

requirement, while only the nominal 1-1/4 inch size of the onehole hangers met the requirement. Washers improve the performance

of hangers made of thin strap metal.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Automatic sprinklers ; care type occupancies; fire

endurance; load failure; pipe hangers; residential occupancies.

18. AVAILABILITY Uni imited c For Official Distribution. Do Not Release to NTIS

] Order From Sup. of Doc., U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. Cl 3 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCL ASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

44

22. Price

$4 . 50

USCOMM-DC 29042-P74