NATIONAL BUREAU OF STANDARDS REPORT

7736

PROGRESS REPORT NO. 1

ON

FLUID DYNAMICS OF PLUMBING

by

R.S. Wyly* and R.W. Beausoliel

For Use of Sponsor, Project Advisory Committee,

and Project Staff Only.

Not for Publication or Distribution

<NB§>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent

with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; invention and development of devices to serve special needs of the

Government; and the development of standard practices, cbdes, and specifications. The work includes basic

and applied research, development, engineering, instrumentation, testing, evaluation, calibration services,

and various consultation and information services. Research projects are also performed for other government

agencies when the work relates to and supplements the basic program of the Dureau or when the Bureau’s

unique competence is required. The scope of activities is suggested by the listing of divisions and sections

on the inside of the back cover.

Publications

The results of the Bureau’s research are published either in the Bureau’s own series of publications or

in thfe journals of professional and scientific societies. The Bureau itself publishes three periodicals available from the Government Printing Office: The Journal of Research, published in four separate sections,

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•nd Technical Notes. A complete listing of the Bureau's publications can be found in National Bureau of Standards Circular

460, Publications of the National Bureau of Standards, 1901 to June 1947 (SI. 25), and the Supplement to National Bureau of Standards Circular 460, July 1947 to June 1957 (SI. 50), and Miscellaneous Publication 240,

July 1S‘57 to June 1960 (Includes Titles of Papers Published in Outside Journals 1950 to 1959) (S2. 25); available from the Superintendent of Documeuts, Government Printing Office, Washington 25, D, C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT

1005-12-10615

NBS REPORT

October 31, 1962 77 ^ A

PROGRESS REPORT NO. 1

ON

FLUID DYNAMICS OF PLUMBING

by

R.S. Wyly and R.W. Beausollel

for

The National Association of Home Builders

For Use of Sponsor, Project Advisory Committee,

and Project Staff Only.

Not for Publication or Distribution

NATIONAL BUREAU OF STA

Intended for use within the G

to additional evaluation and re listing of this Report, either li the Office of the Director, Nat however, by the Government i to reproduce additional copiei

IMPORTANT NOTICE

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

ogress accounting documents

rtally published It Is subjected

eproduction, or open-literature on Is obtained in writing from

iuch permission is not needed,

irepared If that agency wishes

<^BS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

CONTENTS

Page

1. Introduction 1 1.1 Purpose of Investigation 1 1.2 Authorization 1 2. Preliminary Activity 1 3. Accomplishments 2

3.1 Procurement of Equipment and Supplies 2

3.2 Test Structure 3

3.3 Piping Plans 3

3.4 Fluid Flow and Pressures in a 2-in. Test Stack 3

3.5 Methods for Assigning and Imposing Test Loads 8

4. Proposed Work for Next Reporting Period 9

5. Expenditures 10

6. Appendix 10

6.1 Outline of Proposed Investigation 10

6.2 Plans for Full-Scale Drainage and Vent Systems 13

ABSTRACT

This progress report, che first in a series, presents a summary of plans for a study of the fluid dynamics of residential plumbing

systems for sanitary drainage. Preliminary results and accomplishments

are given. Perhaps the most important information in the report is that

concerning proposed methods for applying test loads, and that giving results of flow tests in a laboratory apparatus simulating a 2-in. stack.

1* Introduction

1.1 Purpose of Investigation

The purpose of the investigation is to study aspects of the fluid

dynamics of plumbing systems such as installed in one- and two-story

houses, which have not been covered adequately by previous research.

Particular emphasis is to be placed on the study of venting phenomena.

New or additional factual information could lead to improvement in rational, economic design, and provide data useful in the preparation of

plumbing codes and standards.

1.2 Authorization

The project was approved by the National Bureau of Standards under

the Grants-in-Aid Program on Dec. 21, 1962, as outlined in a letter from

Dr. R.D. Huntoon, Deputy Director of the National Bureau of Standards,

to Mr. John R. Dickerman, Executive Vice President, National Association

of Home Builders. Financial support in the amount of $25,000 was provided by NAHB on May 10, 1962, and acknowledge by NBS in a letter dated

May 28, 1962, from Mr. D.E. Parsons, Chief, Building Research Division,

to Mr. Dickerman. It was understood that the cost of the work would not

exceed $25,000 per year over a period of about two years.

2 . Preliminary Activity

An advisory committee was organized for the purpose of reviewing

the work at appropriate stages, making recommendations, and furnishing

advice on questions raised by the project staff. The functions of the

committee are advisory only. The committee comprises the following

persons

Mr, Ralph Johnson, Technical Director,

National Association of Home Builders.

Mr. Robert Schmidtt, Chairman,

NAHB Research Committee.

Mr. James Simpson, Chief,

Standards and Technical Studies Section,

Architectural Standards Division,

Federal Housing Administration.
.

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Mr. Malcolm Hope, Assistant Chief,

Division of Environmental Engineering,

Department of Health, Education, & Welfare.

Mr. Douglas Parsons, Chief,

Building Research Division,

National Bureau of Standards.

Mr. John French, Hydraulics Engineer,

Fluid Mechanics Section,

Mechanics Division,

National Bureau of Standards.

Mr. Robert Wyly, Hydraulics Engineer,

Building Research Division,

Codes and Safety Standards Section,

National Bureau of Standards.

The Advisory Committee met on May 16, 1962, and discussed in some

detail the following items:

1. Project scope,

2. hydraulic and pneumatic performance criteria,

3. problems to be studied,

4. nature of measurements required, and

5. instrumentation.

A summary of the committee's recommendations has been included in

this progress report as section 6.1. It was suggested by the project

staff that the following tasks be emphasized in the initial phase of

the investigation:

1. Measurement of performance of small -diameter vents for certain

conventional systems,

2. measurement of effects, on air demand and stack pressures, of

(a) type of stack fitting, (b) stack and fixture branch diameters, and (c) stack length,

3. preparation of recommendations for obtaining data on time distribution of fixture use and on minimum residual trap seals in

service, and

4. a review of the literature relating to items (i), (iii), (vii),

and (viii) as outlined in section 6.1c (2).

3 . Accomplishments

3 . 1 Procurement of Equipment and Supplies

Purchase orders were placed for pipe, plumbing fixtures, and instruments. Test systems will be constructed for the most part of castiron 8 oi 1 pipe, galvanized-8teel pipe and methyl -methacrylate plastic
; ,

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pipe . Residual trap seals will be measured with glass or clear plastic

piezometers in combination with short graduated scales. Fluctuating or rapidly changing pneumatic pressures and water depths will be measured

with strain gage or magnetic reluctance pressure transducers and a multichannel recording oscillograph, most of this instrumentation having been

purchased on NBS funds. Miniature pitot -static pressure probes will be

used to sense air movement in vent pipes. Air pressures and water heads • will be transmitted to transducers or indicating devices through sidehole taps or pressure probes, depending on requirements in the particular test to be made. Fluctuating phenomena can be measured on a sixchannel basis with the instruments available for this project.

3 .2 Test Structure

Work is nearing completion on a multi-deck wooden test structure

simulating two stories and a basement. A horizontal space of approximately 33 ft x 16 ft is being provided at the first floor level, and

approximately 17 ft x 16 ft at the second story level. A longer space

is available at the basement level. Split-level arrangements can be accommodated by the use of a portable platform above the first floor deck,

if this should be necessary.

3 .3 Piping Plans

A portion of the experimental program is to involve hydraulic tests

on full scale piping systems taken from house plans furnished through

NAHB. House plans were received for 23 different houses, furnished by

five different builders. The states represented are California, Indiana, Maryland, New York, and Texas. Piping plans were furnished for one

of the California houses and two of the Maryland houses. From these

plans, tentative plans for drainage and vent piping have been prepared

by the project staff for four test systems. These are shown in section

6.2. System 1 is from a 1-story, 1-bath house with kitchen and automatic clothes washer all on one floor. Systems 2 and 3 are from 1-story,

2-bath houses with kitchens and automatic clothes washers all on one floor. System 4 is from a two-bath house with bathrooms and kitchen on the first floor and a laundry tub in the basement. It is believed that

the sequence of the plan numbers also indicates the relative order of

complexity of the piping from the standpoint of testing. For this reason System 1 probably should be tested first.

The project staff will welcome any constructive suggestions from

NAHB or the advisory committee regarding these proposed piping plans.

3.4 Fluid Flow and Pressures in a 2-in. Test Stack

Equations similar to eq (55) of NBS Mono. 31 [1], or eq (9) proposed by Dawson and Kalinske [2] are commonly employed in estimating air
.
14.

Figure 1. Test system for study

of fluid flow in 2-in.

stack

1 Bouyancy compensator 15

2 Inverted steel drum 16

3 Lead counter weights 17 4 Low-friction pulleys

5 500 gal.- wooden box 18

6 Steel cable 19

7 Water line 20

8 Simulated stack vent

9 Quick-opening valve

10 Gate valve

11 Thermometer 21

12 Long -turn T-Y water

inlet fitting, recessed 22

drainage type 23

13 10-ft length of 2-in, 24

plastic pipe on 1/4-in. /ft 25

slope

14 Stilling box S A-G

Supply line to stilling box

Orifice meter

Connection to constant -head

water supply

Water manometer

Flange union

Plastic dash pot to prevent

water from entering tubing to pressure sensing devices.

44" length of 2" diameter

standard weight wrought iron pipe

Air gap at bottom of 22 ft stack

funne

Turnbuckle

Valved connection to compressedair supply

Pressure tap in stack vent

Pressure taps below water -inlet

5

maintaining the stack full of water under conditions of substantially

steady pipe flow. Computed values of the Darcy-Weisbach friction factor based on these measurements are shown in table 1.

Referring to table 1, it will be seen that the friction factors

are somewhat lower than those ordinarily suggested for use with commercial iron pipe. Possibly this may be attributed in part to errors in

measuring flow rates and pressure drop, particularly for low rates. The'

data strongly indicate that the test pipe was actually smoother than the

M commercial" pipe referred to in textbooks and handbooks, characterized

by roOghness magnitutes based on materials as manufactured at least 20

years ago.

Figure 2 shows data for air flow as a function of water flow, obtained with the apparatus shown in figure 1. For comparison, curves representing the equations

and

0

(1 ‘r

s> = 0 = 2&.9(r )

2/3 (l-r )(D.) 873

w

^ a s si (la)

1 - 5Qv

(1 'rs) - Q, = 40.3(r<! ) 2/3

(l-r KDp 873

(lb)

< r

s> are shown. These equations were developed in the same manner as eqs (53)

and (55) of Mono. 31, based on an assumed absolute roughness of 0.001 ft.

A value of V^/V^ of 1.0 was assumed in eq (la), and a value of 1.5 in cq

(lb). For other values of absolute roughness, air flow and water flow

rates should vary in inverse proportion to the 1/6 power of the absolute

roughness for any given value of r . The terms have the following meanings when used in eqs (la) and (lb;:

Q is the volume rate of water flow in gpm

w

Q is the volume rate of air flow in gpm

a r is the ratio of area of cross section of water stream in the

g stack to total area of cross section of stack

V is the mean terminal velocity of the water in fps, in accorw

dance with the equation

2/3/Di \ 1/6

Vw = 3.21(rB

) ( 2 )
-

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Table 1. Experimental values of Darcy-Weisbach friction factor

for

2 -in. galvanized

iron stack shown in figure 1

Water

flow rate

Reynolds Number x 10

"3 Friction

gpm

19 25.6 0.0266

35 47.2 .0213

50 67.5 .0200

64 , 86.4 .0192

80 108 .0194

*The corresponding average value of absolute roughness is approximately 0.00025 ft, which is 1/2 the value given by Rouse for new galvanized iron pipe

150

140

830

820

MO

100

90

80

70

60

50

40

30

20

10

0

VOLUME RATE OF WATER FLOW,

GPM

;ure 2.

r Air demand as a function of water flow rate and vent pressure,

for 2-in. test stack shown in figure l.
. -

.

.
-6

where dimensionally consistent units are used (Eq (2) is derived from eq (44) of Mono. 31)

V is the mean velocity of the air in the stack, in fps

a

is the stack diameter in inches

k

1 is the absolute roughness of the stack material

Experimental air flow rates for atmospheric pressure in the stack

vent were intermediate between values predicted from eqs (la) and (lb)

over a range of water flow between 10 and 55 gpm (see intermediate data

curve, figure 2) . For water flow rates less than 10 and greater than 55

gpm, air flow rates exceeded those predicted from eq (lb) . In this connection, the criterion for stack capacity given in Mono. 31 indicates

that a 2-in. stack should not be used for water flow rates in excess of

about 25 gpm.

Air flow rates for vent pressures of +1 and -1 in. of water indicate

the extent to which air demand may be affected by stack vent pressure.

As an example, if the stack vent were long enough to allow a pressure

drop along its entire length of 1 inch of water gage for a water flow

rate of 20 gpm, the air rate would be 30 gpm. On the other hand, if a very short vent is used so that the vent pressure remains substantially

atmospheric the air demand would be 70 gpm. Positive vent pressures,

as shown in the upper data curve, may occur in a stack vent during a strong down draft on a windy day, and may occur in a vent at an intermediate or low level on a multistory stack as a result of "piston" action

when a slug of water is discharged at some higher elevation.

The theoretical values for air flow indicated by eqs (la) and (lb)

are slightly less than those by eq (55) and of Mono. 31. The reason for

this is that eq (55) of Mono. 31 was based on a value of absolute roughness of 0.00083 ft, while eqs (la) and (lb) of this report are based on

an arbitrary value of k^ = 0.0010 ft, this being twice the value suggested by Rouse for new galvanized wrought iron pipe [3]. It can be

shown that the coefficient in the equations varies inversely as the 1/6

power of the absolute roughness for any given value of r . As shown in

table 1, measurements in the current investigation indicate that the test

stack had an apparent roughness of about 0.00025 ft, this being only

about 1/4 as great as assumed in eqs (la) and (lb) . If this is taken

into account, both the air flow and the water flow values on the theoretical curves in figure 2 would be increased by the factor/'D .0010 \ 1/6

,

\0. 00025/

or by about 26 percent. Had the coefficients in the equations been based

on the lower value of roughness, close agreement between eq (la) and the

experimental values of air flow would have been obtained for rates of water flow from 20 to 30 gpm. The agreement is probably affected also by

length of stack, type of inlet fitting, and other factors.
.

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The data on "shut off" head shown in figure 3 were obtained from

the test system in figure 1 by closing the stack vent completely and

measuring the pressure in the vent for several different rates of water

flow. The significance of this data is that the omission of a stack

vent can reduce pressures so much that trap seals may be lost. For example, figure 3 indicates that a 2-in. trap seal connected to the test

stack at or above the elevation of the water inlet would have been lost

or seriously reduced for a water flow rate of 15 gpm, this being less

than the normal rate of discharge obtained by removing the cup strainer

from a kitchen sink half full of water. The curve shown in the figure

for comparison with the experimental data represents the equation

p

= -0.0028 (Q ) 5/2

, (3) w

where p is the vent pressure in inches of water, and is the volume

rate of water flow in gpm. The facts that (1) the pressure above the

water inlet in the absence of an air supply was approximately proportional to a power function of the volume rate of water flow, and (2)

that the power was approximately 5/2, are consistent with earleir findings under somewhat different conditions [1, 2, 4, 5]. In the earlier

studies, pneumatic pressures within a vented horizontal branch or within

a stack were roughly proportional to a power function of the water flow

rate over a practical range, and the value of the power appeared to approach a maximum of 5/2 in inverse ratio to the extent of venting relief.

[3] Elementary mechanics of fluids, Hunter Rouse, John Wiley and Sons,

Inc., New York, N.¥. (1946).

[4] Tests on the hydraulics and pneumatics of house plumbing, Harold

E. Babbitt, Engineering Experiment Station Bulletin No. 143, University of Illinois, Vol. XXI, No. 47 (1924).

[5] Tests on the hydraulics and pneumatics of house plumbing, pt II,

Harold E. Babbitt, Engineering Experiment Station, Bulletin No. 178,

University of Illinois (1928).
. .. .

•

. I
0 5 10 15 20 25

VOLUME RATE OF WATER FLOW.,

GPM

Figure 3. Shut-off head In stack vent as a function of water flow rate,

for 2-ln. test stack shown in figure 1.
<

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Figure 4 shows stack pressures below the elevation of water Inlet

for several rates of water flow, measured by means of sidewall taps along the stack. The greatest reductions In pressure occurred just below

the elevation of water Inlet. It Is evident that pressure reductions

for all except the lowest water rates were sufficient to destroy trap

seals connected to the stack through unvented drains within at least one

branch interval below the water inlet.

The data in figures 2 to 4 are exploratory in nature. Theory indicates that air flow and air pressure for a given water flow are affected

by stack diameter. This parameter should be varied over the range 1-1/2

to 3 inches in this investigation. Other parameters known or believed

to be significant, and which should be varied, include type of water

inlet fitting, length of stack, and diameter of branch. The effect of

introducing the water as a short -duration surge rather than as steady

flow should be investigated, although preliminary indications are that

this effect may not be significant insofar as design air flow or vent

pressure in concerned. Finally, the effect of introducing water simultaneously at two or three elevations on the stack, rather than at a single

elevation, should be investigated since this may occur under service conditions .

3 .5 Methods for Assigning

and Imposing Test Loads

In many plumbing tests the test loads have been more or less arbitrary. In some cases the extreme view has been taken that the proper

test load is that arbitrary combination of number and sequence of fixtures in operation found by trial to produce the worst conditions. Unfortunately, this approach has led to wide differences in opinion as to

what constitutes a reasonable test load. The problem is further complicated for the experimenter because if more than perhaps three or four fixtures are involved, an excessive amount of experimentation may be requi.jd

in trying to determine the worst test combinations, and he may not be certain that the worst combination has been found. Then the question arises

as to whether such a load is a reasonable one.

Another method of assigning test loads is being considered for possible use in this project. This method is to use mathematically predetermined random operating programs applied independently to each fixture

either by manual or automatic means. Automatic punched-tape readers are

obtainable for simultaneous handling of predetermined programs on a large

number of independent channels. A shop-made program timer operating on

a similar principle has been developed by the project staff for limited

use on 8 channels or less. If only 4 or 5 fixtures are involved, manual

push-button control might be sufficient.

Where random sequences are utilized, the programs will be prepared

by automatic high speed computer, each program to be capable of running
'

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•

.

;
Figure 4. Stack pressure as a function of water flow rate and distance

below water Inlet, for 2-ln. test stack shown In figure 1.

-9-

for a period of time as long as desired without repeating the sequence*

Programs will be prepared for values of p = 0.01 - 0.10 by 0.01' s, p

=

0.

15 - 0.25 by 0.05's, and for p = 0.50, where p is the probability of

the fixture being in operation if observed at an arbitrary instant. Undoubtedly the use of these programs would greatly simplify the task of

choosing reasonable test loads, since it would only be necessary to

choose a conservative value of p for each fixture and then allow the test

to proceed automatically for a sufficient time so that peak pressures,

discharges, etc. approach the design values predicted mathematically.

This latter requirement, however, requires some further study. In any

event, it should be well worthwhile to make a comparison between the

results of applying arbitrary programs and mathematically predetermined

programs

4. Proposed Work for Next Reporting Period

It is expected that the test structure described in section 3.2

will be completed and that the drainage and vent system described as system 1 in section 6.2 will be installed on the test structure. Further

work will be done in devising means for applying test loads and for measuring significant parameters in connection with System 1. Present plans

call for measuring the following qualities:

1. Discharge rates and time sequence as related to the various fixtures,

2. air velocities in stack vent and branch vents,

3. air pressure in fixture drains,

4. water depths in building drain near its junction with branch

from water closet, and also in building sewer, and

5. residual trap seals.

Among the independent variables in System I which probably should

be varied over a range are (a) effective diameter of various vents, (b)

magnitude and sequence of test loading, (c) slope of building drain, and

(d) method of joining intermediate stacks to building drain -i.e. from

the side or the top. Finally, it may be worthwhile to plan to investigate the performance of an alternate piping arrangement in which fewer

vents are employed through the use of stack venting for the bathroom

group, and per^haps also through the use of a combination waste-andvent system for the kitchen sink and the clotheswasher

It is expected that some further results will be obtained from the

apparatus for studying fluid mechanics of stacks as described in section

3.4 and figure 1. The next two items to be studied with this apparatus

are (1) effect of branch diameter, and (2) effect of stack fitting type,

1.

e. sanitary tee or long-turn T-Y.
new

i

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10 -

Further information will be sought with reference to practical

means for collecting field information on time distribution of fixture

use and other items, and the literature will be examined with reference

to data of value in the current project.

5 . Expenditures

The sum of approximately $6800 was spent or obligated during the

first four months of the fiscal year. A relatively large proportion of

this sum was applied to the purchase of supplies and equipment. As the

project continues relatively less will be charged to supplies and equipment and more to labor.

6. Appendix

6 . 1 Outline of Proposed Investigation

a. Scope

The investigation will cover hydraulics and pneumatics, with particular reference to drainage and venting of residential plumbing systems. It will be restricted to problems for which meaningful measurements can be obtained. Problems dealing with the development of

fouling, scaling, or corrosion over a period of time under service conditions; with the performance of different specific piping materials;

with water conservation; or with redesign of fixtures will not be studied.

b. Hydraulic and Pneumatic Performance Criteria

The fundamental performance requirement for drainage and venting

systems is that waste water and fecal matter must be conveyed to a public sewer or other acceptable point of disposal without nuisance, health

hazard, or excessive maintenance. Experience has shown that this can

be accomplished by designs based on the following considerations:

(1) The use of a water-seal trap for each plumbing fixture to prevent passage of sewer gases or vermin. A trap with a seal

depth of at least 2 in. is considered adequate.

(2) Minimization of pneumatic -pressure fluctuations inside each

fixture drain to avoid serious loss or disturbance of trap

seal and excessive drainage noise. A residual trap seal of

at least 1 in. is considered adequate.

(3) Minimization of peak hydrostatic pressures in the drainage piping resulting from the discharge of fixtures to avoid forcing

waste water or fecal matter back into fixtures or their traps.

Water depths not in excess of one half pipe diameter above the

Inverts of horizontal drains are considered satisfactory.

11 -

(4) Provision for adequate, uniform cross-sectional areas of piping and for self -cleansing liquid velocities to reduce the incidence of sluggish drainage and stoppage. Mean longitudinal

liquid velocities of not less than 2 fps are considered adequate .

c . Suggested Problems for Study

The following list of problems is by no means complete nor is it

Intended to indicate the relative importance of the various problems.

Furthermore, it may include a larger number of problems that can be stud

led within the time to be alloted to the proposed investigation. The

purpose of the list is to indicate some of the problems which could be

investigated under the proposed program.

(1) Type 8 of Problems

(1) Effects of flow resistance on dynamic performance. Resistance

may depend on size, length, and slope of pipe, on number and

type of fittings; or on smoothness of certain pipe-system components .

(ii) Effects on dynamic performance produced by certain modifications

in pipe -system geometry.

(iii) Dynamic performance as affected by magnitude and sequence of

test loading.

(iv) Effects on dynamic performance produced by detergents and solids

in the discharge.

(v) Dynamic performance of plumbing systems under service condition?

(2) Some Specific Problems

(i) Hydraulic characteristics of residential plumbing fixtures, including wall-hung water closets.

(ii) Minimum sizes of vents for certain conventional systems.

(iii) Safe loads for single-story wet-vented and stack-vented systems.

(iv) Safe loads for two-story wet-vented and stack-vented systems.

(v) Performance of venting systems for island fixtures.

(vi) Performance of standpipe receptors and floor drains receiving

indirect wastes.

(vii) Safe unvented lengths of fixture drains and floor drains .
\

• .Vi W’ ....

•; ii

:

'

.

• ‘

. •'

''

,

'

’

*

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(viil) Evaporation of trap seals.

(lx) Effect of tailpiece length on performance of traps.

(x) Effects, on air demand, of type of stack fitting, of stack

diameter, and of vertical drop.

(xl) Fundamental mechanisms of air movement within vertical drains,

horizontal drains, and branching systems of vents.

(xll) Time distribution of fixture use and trap seal losses In service .

d. Types of Tests

(1) Tests on typical, full-scale drainage and venting systems under

laboratory conditions. Systematic Investigation over a range

of variables Is generally too time consuming by this method,

but quick empirical data on certain practical problems can be

obtained

(2) Tests on selected components of piping systems under laboratory conditions. Fundamental facts and rational design data

over a range of conditions are most advantageously obtained In

this way.

(3) Tests on actual plumbing systems In service. Probably these

tests should be limited to the measurement of time distribution

of fixture use, of trap seal losses, and of fixture flow rates.

Such tests should be useful In Indicating typical loads and In

checking field performance of specific piping systems.

e. Measurements

In general, the geometry and dimensions of test systems will be

fully described, and test loads will be described by water discharge

rate sequence, spatial distribution, physical composition, and temperature. Dependent variables to be measured as required Include:

(1) Residual trap seals.

(2) Pneumatic pressures In fixture drains and other critical places.

(3) Water depths and longitudinal velocities at selected sections In

sloping drains.

(4) Longitudinal velocity of air flow In vent pipes.

f. Instrumentation

(1) Predetermined test loads for laboratory tests will be applied

through the use of electrical circuitry controlled either
- • “Sir.' .
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manual ly by push buttons or automatically by a program timer,

depending on the complexity of the test load.

(2) Residual trap seals will be measured with piezometer tubes

equipped with graduated scales. Visual observations will be

recorded manually.

(3) Peak values of slowly changing pneumatic and hydrostatic pressures will be measured with sensitive gages where feasible, and

maximum gage readings recorded manually. Where a number of simultaneous or sequential measurements must be recorded, a multichannel electrical recorder will be utilized.

(4) Rapidly changing pressures and water depths produced simultaneously or in rapid sequence at a number of stations will be

measured and recorded electrically on a multi-channel basis as required

(5) Air and water velocities will be measured by use of miniature

velocity head pickups and recorded either through the use of

mechanical pressure gages, manometers, or electrical instruments,

depending on the number of stations involved and on the acceleration or deceleration of the fluid stream. Where essentially

steady, uniform flow is involved, velocities may be calculated

from simple volumetric measurements and data on cross-sectional

areas

(6) Air and water temperatures will be measured with mercury thermometers or electrically, as required.

(7) Time distribution of fixture discharge under service conditions

will be indirectly obtained through the use of electrical or photographic instruments which give a chronological record of

the passage of suitably small volume increments through one or more water meters appropriately placed in water-supply piping.

6.2 Plans for Full-Scale

Drainage and Vent Systems

Figures A-l through A-8 have been prepared showing possible piping

arrangements to accommodate fixtures called for in four different house

plans. Figures A-l, A-3, A-5, and A-7 are plan views showing the plumbing fixtures, taken directly from house plans. The piping arrangements

shown in figures A-2 and A-8 were furnished by the builders, while those

shown in figures A-4 and A-6 are proposed by the project staff. It

should be understood that in all cases several alternative piping arrangements could be readily devised. No attempt has been made to explore the

range of possibilities in this connection. The purpose of showing certain

piping arrangements here is to indicate the nature of one or more possible
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test systems for use In the initial stages of the invest igation, and to

stimulate constructive suggestions before such a test system is actually

completed.

USCOMM-NBS -DC
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Figure

A-l.

System

1,

fixture

plan

I

C.

WASHER

BUILDING DRAIN

Figure

A-3.

System

2,

fixture

plan

Figure A*4. System 2 , pipe isometric*

Figure

A-5

.

System

3

,

fixture

plan

Figure

A-6.

System

3,

pipe

Isometric.

Figure A-7. System 4, fixture plan.

BUILDING

DRAIN

U. S. DEPARTMENT OF COMMERCE

Luther II. Hodges, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In general, each section carries out specialized research, development, and engineering in the field indicated by

its title. A brief description of the activities, and of the resultant publications, appears on the inside of the

front cover. WASHINGTON, U. C.

Electricity. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements

Dielectrics. High Voltage.

Metrology. Photometry and Colorimetry. Refractomctry. Photographic Research. Length. Engineering Metrology.

Mass and Scale. Volumetry and Densimetry.

Heat. Temperature Physics. Heat Measurements. Cryogenic Physics. Equation of State. Statistical Physics.

Radiation Physics. X-ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological Equipment.

Nucleonic Instrumentation. Neutron Physics.

Analytical and Inorganic Chemistry. Pure Substances. Spectrochemistry. Solution Chemistry. Standard Refer- ence Materials. Applied Analytical Research, Crystal Chemistry.

Mechanics. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Rheology. Combustion

Controls.

Polymers. Macromoleculcs: Synthesis and Structure. Polymer Chemistry. Polymer Physics. Polymer Characterization. Polymer Evaluation and Testing. Applied Polymer Standardsand Research. Dental Research.

Metallurgy. Engineering Metallurgy. Microscopy and Diffraction. Metal Reactions. Metal Physics. Electrolysis

and Metal Deposition.

Inorganic Solids. Engineering Ceramics. Glass. Solid State Chemistry. Crystal Growth. Physical Properties.

Crystallography.

Building Research. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials.

Codesand Safety Standards. Heat Transfer. Inorganic Building Materials. Metallic Building Materials.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics. Operations Research.

Data Processing Systems. Components and Techniques. Computer Technology. Measurements Automation.

Engineering Applications. Systems Analysis.

Atomic Physics. .Spectroscopy. Infrared Spectroscopy. Far l lltraviolet Piiysics. Solid Slate Physics. Electron

Physics. Atomic Physics* Plasma Spectroscopy.

Instrumentation. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical Instru- ments. Basic Instrumentation.

Physical Chemistry. Thermochemistry. Surface Chemistry. Organic Chemistry. Molecular Spectroscopy. Elementary Processes. Mass Spectrometry. Photochemistry and Radiation Chemistry.

Office of Weights and Measures. BOULDER, COLO.

Cryogenic Engineering Laboratory. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Cryogenic Technical Services.

CENTRAL RADIO PROPAGATION LABORATORY

Ionosphere Research and Propagation. Low Frequency and Very Low Frequency Research. Ionosphere Research. Prediction Services. Sun-Earth Relationships. Field Engineering. Radio Warning Services. Vertical

Soundings Research.

Radio Propagation Engineering. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements.

Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

Radio Systems. Applied Electromagnetic Theory. High Frequency and Very High Frequency Research. Fre- quency Utilization. Modulation Research. Antenna Research. Rndiodctcrmination.

Upper Atmosphere and Space Physics. Upper Atmosphere and Plasma Physics. High Latitude Ionosphere

Physics. Ionosphere and Exosphere Scatter. Airglow and Aurora. Ionospheric Radio Astronomy.

RADIO STANDARDS LABORATORY

Radio Physics. Radio Broadcast Service. Radio and Microwave Materials. Atomic Frequency and Time-Interval

Standards. Radio Plasma. Millimetei^Wave Research.

Circuit Standards. High Frequency Electrical Stnndnrds. High Frequency Calibration Services. High Frequency

Impedance Standards. Microwave Calibration Services. Microwave Circuit Standards. Low Frequency Calibration

Services.