NBSIR 76-1070

Evaluation of Backflow

Prevention Devices:

A State-of-the-Art Report

Grover C. Sherlin

Robert W. Beausoliel

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

June 1976

Final Report

Prepared for Water Supply Division

Environmental Protection Agency

Washington, D. C. 20460

NBSIR 76-1070

EVALUATION OF BACKFLOW

PREVENTION DEVICES:

A STATE-OF-THE-ART REPORT

Grover C. Sherlin

Robert W. Beausoliel

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

June 1976

Final Report

Prepared for Water Supply Division

Environmental Protection Agency

Washington, D. C. 20460

U.S. DEPARTMENT OF COMMERCE, Elliot L. Richardson, Secretary

Edward O. Vetter, Under Secretary

Dr. Betsy Ancker-Johnson. Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

CONTENTS

Abstract 1

1. Introduction 2

1.1 Purpose and Scope 2

1.2 Fundamentals of Backflow 3

2. Background Information 7

2.1 Historical Background and Recorded Incidents

of Backflow through Backflow Connection and

Cross-Connections 7

2.2 Navy Study of FCCCR Certification Procedures 9

2.3 A.S.S.E. Concern for Backflow Problems 10

2.4 Backflow Prevention Devices and Piping

Arrangements 12

3. Elements in the Evaluation of Backflow Prevention Devices... 18

3.1 The Product Standards 18

3.2 The Plumbing Codes 19

3.3 The Manufacturers of Backflow Prevention Devices 23

3.4 Testing Laboratories 23

3.5 A Conceptual Model Cross-Connection Control

Program 36

/ 4. Evaluation of Devices 39

4.1 Design Considerations that Affect Reliability 39

4.2 Methods that Test Appropriate Attributes 45

5. Summary of Findings 56

5.1 Air Gap (AG) 56

5.2 The Reduced Pressure Backflow Device (RPBD) 56

5.3 Fail-Safe Devices 56

5.4 Realistic and Useable Test Methods 57
6. Conclusion and Recommendations .....58

6.1 Conclusions 58

6.2 Recommendation 59

7. Abbreviations and Definitions 62

8. References 71

9. Acknowledgement 75

10. Appendix 76

10.1 Vacuum Dissipation Calculations 76

10.2 Navy Survey Form 79

10.3 Procedures for a National Voluntary Laboratory

Accreditation Program 83

10.4 Hose Connection Vacuum Breaker Test 100

10.5 Reduced-Pressure Backflow Prevention Device Test .104

10.6 Analysis of Test Methods in A.S.S.E. Standards

for Backflow Prevention Devices 108

10.7 Units of Measure and S.I. Conversion Factors 137
EVALUATION OF BACKFLOW PREVENTION DEVICES:

A STATE-OF-THE-ART REPORT

by

Grover C. Sherlin and Robert W. Beausoliel

ABSTRACT

A significant potential for potable water supply contamination

exists within all water supply systems due to backflow and crossconnections. Surveillance of the water supplies to protect from such

hazards requires continuing vigilance by the administrators of cross- connection control programs, and continuing upgrading of technical

criteria and methods of evaluation.

The Environmental Protection Agency assists local (usually

municipal) authorities, through the State water supply agency, in

establishing and operating cross-connection control programs.

Essential to these programs are (1) information on the suitability of

commercially available devices for use in potentially high-hazard

locations, and (2) practical and effective standardized test methods

for evaluation of devices. The National Bureau of Standards investigation reported herein addresses the two needs identified.

This study includes a systematic review of the literature,

together with consultations and visits with water purveyors, plumbing

officials, laboratory officials and researchers in this field. Emphasis

has been placed on those devices, test methods, and laboratory

practices considered most essential to an effective assessment of the

state-of-the-art. Also, test development needs were identified in a few areas of greatest concern.

Key Words: Backflow; backflow preventers; back pressure; backsiphonage; cross-connections; health hazard; potable water; vacuum

breaker; water supply.

1
1. INTRODUCTION

1.1 Purpose and Scope

5 As approved Dec. 16, 1974, Public Law 93-523 (called the "Safe

Drinking Water Act") marks the first time a national commitment has been

made to safeguard public drinking water supplies. It provides that the

Federal Government - U.S. Environmental Protection Agency (EPA) - set

national standards, and that the states enforce those standards and

10 otherwise supervise public water supply systems and sources of drinking

water. The Act gives EPA responsibility for setting minimum national

drinking water standards for all public water systems throughout the

United States having at least 15 service connections or regularly

serving at least 25 people. EPA is also authorized to help States

15 improve their drinking water programs by providing technical assistance,

employee training and financial support.

Although the Safe Drinking Water Act is primarily concerned with

the contaminants — that must be processed out of the raw water by those

20 persons who own and operate a public water supply system, EPA has long

been concerned with contaminants that may enter a potable water system by

backflow from a consumer's pipeline through a cross-connection.

In this particular concern, EPA assists local (usually municipal)

25 authorities, through the State water supply agency, in establishing and

operating cross-connection control programs. Essential to these programs

are (1) up-to-date information on the suitability of various types of

commercially available protective devices for use in potentially highhazard locations, and (2) practical and effective standardized test

30 methods for use in evaluating such devices. The collective experience

of EPA, other federal agencies, and state agencies has shown that a significant potential for potable water supply contamination exists within

all water supply systems, and that minimization of such hazards requires

continuing vigilance by the administrators of cross-connection control

35 programs, and continuing upgrading of the state-of-the-art in matters

of technical criteria and methods of evaluation. EPA has requested the

National Bureau of Standards (NBS) to provide assistance in meeting the

needs identified above.

NBS has undertaken to perform the tasks of (1) producing a state40 of-the-art survey and report, drawing upon available NBS laboratory

findings to evaluate existing or modified test procedures, and (2) of

developing guide criteria for the laboratory evaluation of backflow

protection devices and examining protocols required for evaluation

purposes.

45

This report assesses the state-of-the-art for the evaluation of

devices used to protect potable water supplies against backflow con- tamination. Backflow contamination of a water supply can arise in — A number of terms and abbreviations have been defined in section 7.

2
either of two plumbing system configurations. In the first configuration

a so-called " direct cross-connection" exists where the potable water

supply piping is mechanically joined to piping or pressurized devices

which may contain potential contaminants. Examples of direct cross-con- nections are inter-connections between dual-purpose water distributing

systems (potable system and a protection system, laboratory water system,

etc) ; completely submerged inlets from water supply lines to closed

plumbing fixtures, tanks or vats; and continuous water connections

between supply and drain systems, pump priming lines, etc.

In the second configuration, an " indirect cross-connection" or a "potential cross-connection" exists. This is one in which the interconnection is not continuous and the completion of the cross-connection

depends upon certain possible occurrences. Examples: water closets with

direct flush valve supply, bathtubs or lavatories with faucet openings

that may become submerged, etc. [1, 2], 2/

In either case, i.e., direct or indirect cross-connection, backflow

results from an adverse pressure differential across the cross-connection

Thus, the necessary conditions for potable water contamination by backflow are the simultaneous occurrence of events which produce (a) a crossconnection, (b) an adverse pressure differential across the connection,

and (c) the presence of a contaminant on the normal downstream side of

the cross-connection. If prevention of conditions (b) and (c) above

could be assured, special backflow prevention devices would not be

necessary. However, many of the types of events which give rise to

either the presence of a contaminant or an adverse pressure differential

or both appear unexpectedly beyond human control; therefore, there are many design situations where adequate backflow protection devices must

be used.

This study has involved collection of information from a number of sources. These include a systematic review of the literature, together

with consultations and visits with water purveyors, plumbing officials,

laboratory officials and researchers in this field. To the extent that

the scope of these investigations was restricted by the resources available for this study, emphasis has been placed on those devices,

test methods, and laboratory practices considered most essential to an effective assessment of the state-of-the-art. Also, test development

needs were identified in a few areas of greatest concern.

1.2 Fundamentals of Backflow

Backflow can result when either a direct or an indirect cross- connection to a potable water supply experiences an adverse pressure

differential. In other words, backflow can occur when the pressure in

the potable water system is, or momentarily becomes, less than that in

2/ Numbers in brackets refer to sequential listing of references in

section 8.
the system to which it is connected. For example, consider the hypothetical and typical illustration of a backflow situation depicted on figure 1. Here an upfeed water supply riser serves a number of fixtures

in a tall building. Assuming that all fixtures are closed and the

line supplying water to the building is broken in the street, the column

of water in the riser will fall to a level of approximately 33 feet to

balance the atmospheric pressure on the broken end of the pipe thus

creating a vacuum in the upper levels of the riser. Then if, as shown

on this figure, the water supply faucet of fixture "A" (with hose submerged in laboratory sink) were opened, the contents of the sink would,

under the atmospheric pressure, be "sucked" or back-siphoned into the

riser. This volume of non-potable liquid would be distributed to other

water outlets in the building after the water service was restored;

consequently, a health hazard for occupants of the building served by

that riser would result. It is conceivable that this slug of non-potable

liquid could travel through the riser and the service piping to the

street main where it would subsequently be transferred to the service

piping of other premises and thereby create a widespread health hazard.

Dawson and Kalinske have demonstrated that a column of water in a closed riser as shown in figure 1 would fall to its final position shown

in about seven seconds [3]. The falling column of water would first ac- celerate, then decelerate to zero velocity at the 33-foot level shown.

Therefore, it is seen that the potential back-siphonage hazard can occur

quite rapidly. It is interesting to note that a subatmospher ic condition

would exist temporarily inside the riser as the water column fell even

if the riser were completely open at the top. This condition would occur because the atmospheric air flowing into the riser would experience a loss of pressure due to the entrance loss (frictional loss) and also a loss of pressure in the direction of flow due to pipe friction and

velocity head. Therefore, even if means were developed to completely

vent a riser, some degree of back-siphonage potential would exist during

the transient period when the water column was falling. Of course, if

the riser were vented, all of the water in the riser would flow into the

excavation shown and no potential back-siphonage hazard would exist after

flow ceased.

If, as indicated by figure 1, a faucet "B" were open at the instant

the water main were broken, air would immediately begin entering the

riser as the water fell from the riser. This, of course, would greatly

reduce the peak magnitude of the vacuum in the riser as well as its

duration. Assuming that the volume of vacuum was initially about 7 1/3

gallons (internal volume of the pipe) , the method of Dawson and Kalinske

[3] indicated that the time to dissipate the vacuum from 29 inches of

mercury to atmospheric pressure would be 4.6 seconds through a 3/8- inch

diameter opening at the faucet. See Appendix Section 10.1 for details

concerning the sample calculation and applicable equation.

Referring again to figure 1, we may assume that faucets "A" and "B"

were closed and the interconnection "c", a check valve between the heating

system and the water system, was leaking. Then chemically treated heating
2" DIA. STD. WT. GALVANIZED

STEEL PIPE (RISER) CLOSED AT TOP

POTENTIAL BACK-SIPHONAGE

FROM CONTAINER IF VALVE IS OPENED WHILE THE CONNECTING

HOSE IS SUBMERGED IN LIQUID

PARTIAL VACUUM (WATER.

VAPOR AT 0.3 PSIA)

WITH ALL FAUCETS CLOSED WATER.

FALLS FROM TOP OF RISER TO THIS LEVEL WHEN THE STREET MAIN IS BROKEN

STREET EXCAVATION

AIR FNTERS RISER

IF FAUCET IS OPEN

BUILDING WATER

SUPPLY RISER

75'

RADIATORS

WATER IS AT ATMOSPHERIC

PRESSURE

STREET MAIN IS BROKEN

IN THE EXCAVATION >

Figure 1. Illustrating Two Examples of Backflow: (A) by Backsiphonage

and (C) by Back Pressure

5
system water would backflow into the riser from the back pressure caused

by the circulating pump and/or boiler. When the break in the street main

was subsequently repaired and service restored, the slug of chemically

treated water could be distributed through all potable water outlets

within the riser and perhaps to other premises connected to the street

main.

There are, of course, many other more common situations which can

give rise to adverse pressure differentials of the types shown on figure

1. For example, back-siphonage in cross-connections can occur by way

of a vacuum generated in the potable water piping of any building as follows

a. Draining of hot water heaters and/or a water supply system

without venting air into the system can create vacuums within

the system.

b. "Imperfections of workmanship at tee connections or couplings

may produce restrictions which would cause high water velocities with consequent reduction in pressure. The pressure may

be reduced sufficiently so as to produce a negative pressure

at the side outlet of the tee and consequent siphonage from

the submerged inlet fixture to which the side of the tee is

connected." [3] Excessive water demand can result in equally

high velocities in the main line and excessive reduction in

pressure in branch piping with similar back-siphonage.

This section has indicated that the possibility of backflow depends

on a number of factors usually unique to a particular cross-connection

situation. Unfortunately, very little data are known to exist on the

f requency-of-occurrence of adverse pressure differentials, contaminant

presence, or both, with or without backflow prevention devices installed.

Therefore, no means exist presently to predict backflow hazard potential

or hazard reduction through use of backflow prevention devices. If such

data were available, analyses of this type would be straightforward and

quite useful not only in identifying high risk cross-connection situations,

but also in predicting the relative effectiveness of alternative methods

of backflow protection.
2. BACKGROUND INFORMATION

2.1 Historical Background and Recorded Incidents of Backflow Through

Backflow Connections and Cross-Connections

5 The previous section has given an overview of the mechanisms of

the cross-connection problem. This section presents some actual backflow

incidents chronologically and gives indication of what is being done

presently to prevent such incidents.

10

A highly publicized and investigated incident involving backflow

resulted in an outbreak of amoebic dysentery in a hotel during the World's

Fair in Chicago in 1933. This epidemic brought world-wide attention to

Chicago and stands as a landmark in the development of cross-connection

15 control efforts. The most important outcome from the Chicago incident

was the recommendation that air-gap separation be used for preventing

contamination of the potable water supply [4] . Vacuum breakers were not

available during the Chicago epidemic era, but by 1945 vacuum breakers

had been developed and approved for use [4].

20

"Craun and McCabe [5] conducted a review of the causes of water

borne-disease outbreaks occurring in the U.S. during 1946-70. During

this 25 year period, there were 358 recognized outbreaks of disease or chemical poisoning attributed to contaminated drinking water. These

25 outbreaks affected 72,358 individuals and resulted in 36 deaths....

The majority of the outbreaks (71 percent) resulted from con- tamination of private, individual water systems; but most of the illnesses

(83 percent) occurrred as the result of outbreaks in community water

30 systems. The major cause of outbreaks in community water systems was contamination of the distribution system, primarily through cross- connections and back siphonage; however, few illnesses resulted from this source because the contamination was confined to rather small areas."

[6] Table 1 lists some of the more sensational, recently recorded,

35 incidents of backflow.

The U.S. Environmental Protection Agency publication, "CrossConnection Control Manual," cites a number of interesting incidents

including the following concerning the sill faucet or hose bibb [7].

40

"A California laborer had been using an aspirator, attached

to a garden hose, to spray a driveway with weed killer

containing arsenic. Sometime while he was at the job, the

water pressure reversed. Taking no notice of the incident,

45 the man disconnected the hose and, feeling thirsty, drank

from the bibb of the hose connection at the house. Arsenic

in the waterline killed him."

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Hutchinson, speaking to the American Water Works Association [8]

and earlier to the American Society of Sanitary Engineering [9] , stated

that there is no organized cross-connection incident reporting system.

It is conceivable that if some mechanism for reporting such incidents

5 existed, it would be found that the number of backflow and cross- connection incidents is actually many times larger than current knowledge

indicates. If practical, a reporting system would be invaluable in

setting priorities for device usage and for pinpointing and correcting

causes. Such a system might include records of low water pressure and

10 vacuum in the water piping to hazardous premises such as sewage treatment plants and industrial plants. Recurring low pressure would indicate

system deficiencies requiring correction.

During a cross-connection survey in Calhoun County, Michigan, [10]

15 pressure-vacuum recording gages were installed in some 45 different

locations. A total of ninety (90) charts were obtained during the survey

and sixteen of these showed low or negative pressure. The existence of

low pressure in the potable water supply indicates potential for backflow.

20 2.2 Navy Study of FCCCR Certification Procedures

During World II, according to Navy Technical Note N-1169 [11]

there were numerous backflow occurrences caused by docked Naval and

and merchant vessels accidentally pumping harbor water through on-shore

25 water lines. Sanitary protection of the water supply was frequently

neglected due to the urgency of wartime schedules. As a result, a group

of individuals concerned with backflow prevention proposed in 1944 to

establish a foundation 3/ at the University of Southern California to

study the problem. On 14 September 1944, the Board of Trustees of the

30 University established the FCCCR as a formal arm of the University.

The FCCCR adopted definitions and specifications for backflow

prevention devices as early as 1948 when Paper Number 5 [12] was published. In 1959, an expanded set of definitions and specifications was

35 published as USCEC Report 48-101. [13] Shortly thereafter, a joint

committee representing numerous Southern California water utilities

expanded USCEC Report 48-101 into what became known as the Manual for

Cross-Connection Control - Recommended Practice. [14] This manual, which

contains additional information on the application of backflow pre40 venters, was first published in 1960. The 2nd and 3rd Editions were

published in 1965 and 1966, respectively , with minor revisions. During

1967 and 1968, the manual (particularly Section 10 covering specifications) was thoroughly reviewed by a committee representing water utilities, local health authorities, manufacturers, and the Foundation.

45

3/ At the time of the Navy report the name was Foundation for CrossConnection Control Research (FCCCR)

9
The major changes which resulted were incorporated in the 4th Edition

of the Manual, [15] published in 1969.

Navy Technical Note N-1169 [11] resulted from the need to under5 stand better the impact of a change in certification procedure by FCCCR.

The Naval Civil Engineering Laboratory at Port Hueneme, California con- ducted a survey of authorities concerned with backflow prevention, including persons in city, county, state and federal governments. Responses

from 62 localities are summarized in Table 2. The column headings in the

10 table are of necessity cryptic, but by following the arrangement of the

survey questions (reproduced here as Appendix 10.2) possible confusion

of meanings is minimized. Nearly half of those responding indicated that

the reduced pressure principle backflow preventer was the minimum

protection required for a health hazard to the potable water supply.

1~* Although the Navy has relied heavily on certification procedures to

assure that the very best protection would be provided at its bases and

docks, it may find that periodic field testing of devices is more

certain assurance of best protection.

20 2.3 The A.S.S.E. Concern for Backflow Problems

The American Society of Sanitary Engineering (A.S.S.E.) was

founded in Washington D.C. in 1906, eight years prior to the advent of

the first U.S.PHS standards for drinking water. Although the member25 ship of the society for many years was small, the yearbooks indicate that

active members concerned themselves with many aspects of water supply

and waste disposal with primary concern for public health.

In the NBS file is a collection of three papers prepared by

30 William C. Groeniger, [16, 17, 18] who in the early thirties was for

several years Chairman of the Research Committee of A.S.S.E., and earlier

an Ohio State inspector of plumbing. He and the Research Committee

pioneered activities toward solution of cross-connection problems. In

1932, Major Groeniger, in the capacity of Chairman of the Research

35 Committee, served as Chairman of an A.S.S.E. conference on "Cross Connections" [19] held at NBS on February 24 and 25. The conference

registration list of 54 included a broad sampling of concerned persons:

physicists, engineers, plumbing contractors, plumbing component manufacturers, and public health officials. Of particular interest was the

40 presence of H. H. Matthieson, Chief Sanitary Engineer of the Los Angeles

Health Department because other authors have indicated that Los Angeles

was early the center of activity in testing and evaluating mechanical

backflow preventers — as early as 1934.

45 The first national standards for devices to prevent or to control

backflow (ASA A40.4 - 1942 "Air Gaps" and ASA - A40.6 - 1943 "Backflow

Preventers in Plumbing Systems" were published by the American Standards

Association (ASA). A.S.S.E. did not have representatives on the A40

committee of ASA but became a sponsor with the American Society of

50 Mechanical Engineers (ASME) when part of A40 was changed to A112,

Committee on Standardization of Plumbing Material and Equipment, in 1958.

10
2. Results of a Survey Made by the Naval Civil Engineering Laboratory

and Reported in Navy Technical Note N 1169

ABBREVIATIONS:

RP = Reduced pressure zone backflow preventer

DCV = Double check valve assembly

C = The water user or

1.

Type

of

Agency:

CN

Protection

Required

for

Health Hazard:

1

3.

Certification

or

approval

required

for

devices:

4.

Will

new

FCCR

1-yr.test

program

be

accepted?

5.

If

cert,

not

renewed,

exist,

devices

will

be: |

6.

Purchase

&

install.

costs

borne

by:

7.

Make

of

RP

Device

installed

8.

Inspect

.,

Test

and

Maint.

Policy:

9.

Failures

and

problems

experienced

with

devices:

10.

Other

Comments

s

DCV

customer

U = The utility supplying water

L = An agency, test lab or person certified

by the Utility A = As required

|Clty,

County

or

Port

Auth.

State

COu

01 TJ

01 d.|Air

Gap

|R.P.

Device

|DCV

Assembly 1

Other

Protection

|No

Protection

Specified

Full

Approval

by

FCCCR

Provis.

Approv.

by

FCCCR j

Other

Approval

None

Required

Yes 0

2;

Replaced

ASAP

Accepted

as

Orig.

Approv. |

Water

Utility

Customer

BEECO CRANE

CLA-VAL

Other

1

Freq.

of

Inspections

(mo. )1

Freq.

of

Tests

(mo.)

Freq.

of

Maint.

(mo.)

Inspection

Performed

by

Test

Performed

by

Maint.

Performed

by

Inspection

Paid

by

Test

Paid

by

Maint.

Paid

by

0

u

CRANE

CLA-VAL

OTHER

1

Freeze

Protection

Policy

Change

in

Future

|

62 AGENCIES SURVEYED - Total 55 5 3 9 2 9 14 5 4 9 7 19 7 15 0 u 13 0 2 7 28 14 15 ]. i 1 7 1 15 2 2 5 1. Alabama State Docks

2. Baltimore, Md.

XX ::X X x

3. California

4. Charleston, S.D. X

.-. X

X X

X X X X

12

6

12

A AA U U

c

c

: U

C

c :: x 5. Chicago, 111.

6. Cleveland, Ohio

XX

X XXX X X X A A A U U

: X X X X X

v 7. Corpus Christi, Texas

8. Dallas, Texas

X

X X

X

X X X X X

612

612

AAu U

u c U c X x

9- Denver, Colo.

10. Detroit, Mich.

X

:•: X

X

X XX

X X X X X X 24 A A u a U u X X 11. Duluth, Minn.

12. Duluth, Seaway Port

X

X

X

X X 13. Galveston, Texas

14. Hawaii State Harbors

XX

. X

X X 1 1

15. HEW Inter. Carrier Br.

16. HEW Nat. Inst, of Health

.XX X

X X X

X X X X 12 12 3b c c c c c c X X x X 17. Honolulu, Hawaii

18. Houston, Texas

X

X X

X ;•: X X X X X X 12 12 60 L L c c c X

19- Houston, Port Nav. Dist.

20. Indianapolis, Ind.

Xx X X

21. Jacksonville, Fla.

22. Jersey City, N.J.

X

X X X

X

X X X

12 12 A X 23. Long Beach, Calif.

24. Los Angeles, Calif.

XX

XX

<X

X

X

(X

::X

X

X

XXXX

12

12

1212AAL

[, L

L

L

c cc e

c

c

c XX XX 25. Louisville, Ky

26. Maryland Port Authority

X

(

:•: X 24 x 27- Massachusetts Port. Auth.

28. Minneapolis, Minn.

... X

X X

29. Milwaukee, Wise.

30. Mobile, Ala.

XXX X

X X X

31. New Orleans, La.

32. New Orleans Port Board

XX

XX

XX X

X

XXX

X

XX

XX X6

6

6

6

A 1

U c c c c X

33. New York Port Authority

34. Newport Mews, Va.

XXX

X

X X X 12 X

35. Norfolk, Va.

36. Oak Ridge Nat ' 1 Lab.

X X XX

X

< X

X

X

X

XX A

12

A12A c u X X

X 37. Oakland, Richmond, Calif.

38. Ohio State Dept. Health

X

X X X X

X

X X X

X

X

X

X

X

X

1212

12

12

A u c c 0 c c X X

X 39. Oregon

40. Philadelphia, Pa. X

X X X

X X X X 12 12 A i, L c A c

:•; X 41. Phoenix, Ariz.

42. Portland, Ore.

X

X XX X

X XX X

1

12

A

12

AA

u

u

u

II uu

0

c C c X

43. Providence, R.I.

44. Richmond, Va.

X

X

X

X 45. Sacramento, Calif.

46. St. Louis, Mo.

(X

X

X X

X

X X X

XX 24 24 A L L c c c c

X

X 47. St. Paul, Minn.

48. San Diego, Calif.

XX X

A X X X X X X X 6 6 6 U U w 11 II II X

49. San Jose, Calif.

50. San Jose Water Works

X

X

X XX

X

X X XX

X 12

12

6

12 A L L L c c c X

51. San Francisco, Calif.

52. Savannah, Ga.

X

X

X

X X

X X

X X X 12 A " U c 11 II c X

53- Seattle, Wash.

54. Seattle, Port of

X

X

X

X

X

X

X X X XX

X 12 12 A L A u 0 c X XX

X

55- So. Carolina

56. S. Carolina St. Port X

X X

X

X X X

57. Tacoma, Wash.

58. Tampa, Fla.

X

X

X

X

X X X X X X X 12 12 A U u c 11 1 c X X

59. Virginia St. Ports Auth.

60. Washington, D.C.

X

:•: X

X

X

X X

X

X 61. Washington State

62. Wilmington, Del. X

X X X X XX

13

3 3 u u c c X

X

11
The first output of the A.S.S.E. Standards Committee on May 1966, A.S.S.E.

1001, "Pipe Applied Atmospheric Type Vacuum Breakers," received approval

of the American National Standards Institute — A112 Committee to become

ANSI A112.1.1 - 1971. [20]

5

The A.S.S.E. 1002 covering standards and tests procedures for

water closet flush tank anti-siphon ball cocks was issued in October

1964 and revised in 1968 but has not yet met the approval of ANSI.

10 More recently the Standards Committee has focused its attention

on five additional standards for backflow preventers and has published

them as A.S.S.E. 1011, 1012, 1013, 1015, and 1020 [21, 22, 23, 24, 25].

All of these are now being considered by the ANSI A112 Committee for

adoption . 15

Backflow preventers include devices and arrangements such as the

air gap, the barometric loop, double check valve assemblies, reduced

pressure zone back pressure backflow preventers, and vacuum breakers.

Each of these types will be described and categorized.

20

2.4 Backflow Prevention Devices and Piping Arrangements

Figure 2 shows two applications of an air gap whereby protection

against back siphonage can be assured as long as there is no tampering

25 with the gap. For example it is quite possible to slip a short length

of rubber tubing or rubber hose into the faucet of the lavatory, or sink without anticipating the hazards. The hose could lie in the stopped sink filled to the overflow outlet with contaminated wash water,

and the faucet could be partially opened to supply water for a contin30 uously flowing wash operation. Should a sudden vacuum occur on the

water supply line contaminated wash water would back-siphon out of the

sink into the potable system.

When water is needed to be under pressure for a particular ap35 plication water is delivered to a tank through an air gap as illustrated

in Figure 2 and a booster pump, located between the tank and point of

use, can provide the necessary pressure. However, when the booster pump

fails to operate and repair or replacement is not immediately possible,

maintenance men have piped across the air gap to make use of the pressure

40 in the potable supply line. Such an action could be more hazardous to

human life than the act of putting a copper penny behind a blown

electrical fuse.

V

45 — Founded in 1918 as the American Engineering Standards Committee, it

became the American Standards Association (ASA) in 1928, the United

States of America Standards Institute (USASI) in 1966 and now American

National Standards Institute (ANSI) since October 1969.

12
OUTLET AT AN ANGLE AN AIR GAP IS PROVIDED BETWEEN THE FLOOD RIM OF A FIXTURE AND THE SUPPLY FAUCET

35 FEET OR MORE

POTABLE WATER

BUTTERFLY VALVE y

TO CHEMICAL PROCESS OR OTHER NON POTABLE

USE FIXTURE

AN AIR GAP SEPARATES POTABLE WATER AND

PROCESS WATER THAT MUST BE UNDER PRESSURE BAROMETRIC LOOP MADE BY THE ELEVATION OF A LOOP OF PIPE

Figure 2. Showing Examples of the Air Gap and the Barometric Loop

13
Work began in 1938 to develop a national standard for air

gaps in water distribution piping systems suitable for all water-connected devices and fixtures. The initial American Standard ASA 40.4 - 1942 for air gaps was recently updated to be ANSI A112.1.2 - 1973. [26].

5

A sketch of a barometric loop is also shown in Figure 2.

Following the principle of operation, an elongated U-bend in the water

piping is extended to a height beyond which siphonic action can not

occur. In practical application the top of the U-bend would be about

10 35 feet above the highest outlet supplied by the water piping.

De Roos and Michaelsen [27] studied the barometric loop and

particularly the air-lift effect — which, should it occur in the simple

loop, could make the piping arrangement ineffective at preventing back15 siphonage. In their experiments they installed an air-water separator

in the base of the loop on the downstream side and vented the separator

through 1/2-inch copper tubing to the top of the downstream leg of the

loop. Properly designed, it appears from that research that air entering

the piping downstream of the separator will be removed by the separator20 vent arrangement and will not enter the downstream leg of the loop to

create the air-lift effect.

25

30

Additional matters of concern were not explored by the experiments but were noted by the authors:

1. It was not determined whether or not diffusion caused

a transfer of contaminants from the downstream to the

upstream side of the loop.

2. Any effect temperature gradients might have on the

transfer of contaminants over the loop was not determined,

and

3. Unanswered is the question of the amount of contamination

transferred over the loop by air separated from water

near the top of the loop.

For specific applications the barometric loop could be an inexpensive way to protect against backsiphonage. It can not be used

when there is any possibility of back pressure occurring on the downstream side.

On the air-lift effect, air enters the downstream leg of the loop

through an open outlet or leaky connection. An air bubble of sufficient size may form to rise in the pipe and lift a quantity of water

over the U-bend into the potable water.

14
2.4.1 Backflow prevention devices

A backflow preventer has been defined as any mechanical device,

whether used singly or in combination with other controls, that will

5 automatically forestall the possibility of an unintentional reverse flow in a potable water distribution system. Depending upon the degree

of redundancy desired, each backflow preventer is comprised of one or more check valves, atmospheric relief valves (air inlet valves) or pressure differential relief valves, together with test cocks and gate

10 valves. Among the less complicated devices are the vacuum breakers

which are used primarily to protect against the hazard of back-siphonage.

Three standards for vacuum breakers have originated with the

American Society of Sanitary Engineering (ASSE) to cover the pipe15 applied atmospheric-type [20], the hose-connection type [21 J and the

pressure-type [25] vacuum breakers. The International Association of

Plumbing and Mechanical Officials (IAPMO) has published a standard for

backflow prevention devices [28] which includes design and operational

specifications together with laboratory and/or field test procedures

20 for the pipe-applied atmospheric type, the single check valve pressure

type and the double check valve pressure-type vacuum breakers. Also in

the fifth edition of the Manual of Cross-Connect ion Control [29]

published by the Foundation for Cross-Connection Control and Hydraulic

Research (FCCCHR) , specifications and test procedures for pressure

25 type vacuum breakers have been included for the first time.

A.S.S.E. also has published a standard for Water Closet

Anti-siphon Ball Cocks [30], in this standard the anti-siphon device

may be an air gap or a vacuum breaker.

30

In Figure 3, sketches and schematic drawings are used to aid

the reader in the differentiation of the several types of vacuum

breakers using combinations of atmospheric relief valves, check valves,

and gate valves. The pipe-applied atmospheric type and the hose-con35 nection type are designed for use downstream of the last flow control

valve. With the pressure type vacuum breaker a control valve may be

located downstream of the device.

Test cocks are an integral part of the device in some designs.

They are required for double check valve assemblies and for reducedpressure principle backflow prevention devices.

Table 3 summarizes the sizes, working pressures , temperature

services, operational features and applications for each type of

45 backflow preventer identified by an illustration and the corresponding

A.S.S.E. standard number.

50

15
FLOW | FLOW |

PRESSURE TYPE VACUUM BREAKER PIPE-APPLIED ATMOSPHERIC TYPE VACUUM BREAKER

FLOW |

^

FLQW |

o o a o o o SINGLE CHECK VALVE PRESSURE VACUUM

BREAKER WITH TEST COCKS DOUBLE CHECK VALVE ASSEMBLY

FLOW |

BACKFLOW PREVENTER WITH INTERMEDIATE ATMOSPHERIC VENT —

DOUBLE CHECK VALVE PRESSURE VACUUM BREAKER

ASSEMBLY WITH TEST COCKS FLOW >

REDUCED-PRESSURE ZONE PRINCIPLE BACK PRESSURE BACKFLOW PREVENTER FLOW }

SINGLE CHECK VALVE PRESSURE VACUUM BREAKER IN TANDEM WITH A REDUCEDPRESSURE ZONE

PRINCIPLE BACK PRESSURE BACKFLOW PREVENTER (SEE B O C A. -1975 SECTION P1605.11.8 "CONNECTIONS SUBJECT TO BACK PRESSURE

LEGEND: ^

-C^Ch -W- HXI- -1-

GATE VALVE CHECK VALVE PRESSURE ATMOSPHERIC 5 DIFFERENTIAL RELIEF VALVE TEST COCKS

RELIEF VALVE

Figure 3. Schematic Drawings of Backflow Prevention Devices that Utilize

Check Valves, Gate Valves, Relief Valves and Test Cocks

16
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111 

17
3. ELEMENTS IN THE EVALUATION OF BACKFLOW PREVENTION DEVICES

3.1 The Product Standards

The first widely used standards for backflow preventers appears to

5 be those of the Foundation for Cross-Connection Control Research at the

University of Southern California. The other entries in the standards

field were A. W.W. A. [31], A.S.S.E. [20,21,22,23,24,25,30] and

I.A.P.M.O. [28].

10 3.1.1 Foundation for Cross-Connection Control and Hydraulic

Research (FCCCHR)

The 5th edition, (March, 1974) of the Manual of Cross-Connection

Control [29] incorporated editing of Section 10 to make the original

15 intent of the formulating committee a bit clearer. Also in Sections 9

and 10, the pressure type vacuum breakers were included for the first

time. The Manual is a volume of 150 pages compiled to provide for uniform

cross-connection control practices as they impact upon health agencies,

water purveyors, water users (consumers) and inspectors of backflow

20 prevention devices. The following subjects are included:

° A statement of policy 0 Cross-connection control

o n jv-t-.^' c practices Responsibilities of purvey25 ors, consumers and officials ° Samples of standard letters

o j. . . . . c j , and forms Definitions of words and

phrases ° Field testing procedures

30

° Examples of cross connections ° Specifications for devices

° Results of noncompliance ° Case histories

The survey made by the Navy [11] in 1968, summarized in Table 2

gives some idea of the extent of use of this particular cross25 connection control manual throughout the United States.

3.1.2 American Water Works Association (AWWA or A. W.W. A.)

The A. W.W. A. has a standard, C 506-69, [31] for two types of

devices that are designed especially for protection of water in the

water mains. The work toward development of the standard appears to

have started in 1959 with the first output being a manual: "AWWA M14 - Recommended Practices for Backflow Prevention and Cross-Connection

Control."

The subsequent AWWA standard C 506-69"Backf low Prevention Devices - Reduced Pressure Principle and Double Check Valve Types" describes

essentially the same devices as does A.S.S.E. 1013 and 1015.

50

18
3.1.3 American Society of Sanitary Engineering (ASSE or A.S.S.E.)

In 1953 the Standards Committee of A.S.S.E. was appointed. The

output of backflow prevention standards began in 1964 with A.S.S.E.

1001 [20] and A.S.S.E. 1002 [30], followed later in 1970 by A.S.S.E.

5 1011 [21], in 1971 by A.S.S.E. 1013 [23], in 1972 by A.S.S.E. 1012 [22]

and A.S.S.E. 1015 [24]; and the latest A.S.S.E. 1020 [25] in 1974. The

Canadian Standards Association voted to adopt these standards as the

basis for their standards.

10 3.1.4 International Association of Plumbing and Mechanical Officials

(IAPMO or I.A.P.M.O.)

The IAPMO standards are related to the need for backflow preventer

standards in the IAPMO Plumbing Code. In the development of the IAPMO

15 Specification PS 31-74 [28] many of the advisors to the FCCCHR programs,

including Dr. Springer, aided in formulating the standard. Four types of

backflow preventers are identified with criteria and test requirements

Reduced-pressure principle backflow prevention device, Double check

valve assembly, Single check valve pressure vacuum breaker, and Double

20 check valve pressure vacuum breaker assembly.

3.1.5. Summary of Applications of Product Standards

Table 4 is a matrix arrangement of the information found in plumb25 ing codes and various other publications relating the type of backflow

preventer (identified by standard when available) to the type of hazard

at a cross-connection. This table illustrates how these complex relationships can be visually presented. When the environmental, engineering and

economic considerations are sharply defined for each specific application,

39 the blanks and the small squares (indicating acceptable applications)

and the large squares (indicating primary applications) might fit into

different cells from those shown in table 4. The absence of a square,

therefore, does not necessarily mean that such application is undesirable.

35 3.2 The Plumbing Codes

Some regulation of cross-connection hazards is provided by the

ordinances or the state laws that adopt model plumbing codes. Model

plumbing codes have been developed by the following sponsors:

40

American Society of Plumbing Engineers (ASPE) with the

National Association of Plumbing-Heating-Cooling Contractors

1016 20th Street, N.W. , Washington, D.C. 20036 (NAPHCC)

19
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tanks,

or

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handling

sewage

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Direct

connection

through

steam

lines

and

boilers

to

toxic

substances

Direct

connection

in

car

wash

installation

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type

connection

in

greenhouse

Direct

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to

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tanks,

lines,

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boilers

involving

only

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to

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to

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containing

toxic

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outlets

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with

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attachments

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to

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(nontoxic

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sprinkler

systems

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connections

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valve

toilets

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to

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fighting

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injection

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20
Building Officials and Code Administrators International

Inc. (BOCA or B.O.C.A.)

1313 East 60th Street, Chicago, Illinois 60637

International Association of Plumbing and Mechanical

Officials (IAPMO or I.A.P.M.O.)

5032 Alhambra Avenue, Los Angeles, California 90032

Southern Building Code Congress International, Inc

3617 Eighth Avenue, South, Birmingham, Alabama 35222

In those localities where plumbing codes have been adopted into

law, plumbing inspectors are employed to effectuate the requirements

of the code. As technology and economics interact, products such as backflow prevention devices are modified or new ones are introduced.

In either case the compilers of plumbing codes are called upon to make

changes in the codes so that acceptable innovations may be passed by the

1 ^ plumbing inspector. The procedures for making changes varies with

each of the sponsors and is a time consuming operation.

At the Annual Meeting of the A.S.S.E. in 1974 representatives of

the four model codes gave the following brief descriptions of procedures

20 for making code changes as recorded in the 1974 A.S.E.E. Yearbook:

Milton Snyder, Chairman of the Joint NAPHCC-ASPE Plumbing Code

committee stated:

10

25

30

'Changes and additions to the National Standard Plumbing Code can be

made upon initiation by Code Committee members or can be initiated by

any interested party. There are public meetings at least once a year.

Chairmanship of the committee rotates between the National Association of

Plumbing Contractors and the American Society of Plumbing Engineers.

Actions of the committee are submitted to our Board of Directors and

annually the actions of the Board are submitted to the entire membership.

Since our membership has a broad base of Contractors, Engineers, and

Inspectors — all of whom vote — we cannot conceive that any model code

has a broader base of members with full voting privileges. And there is

35 of course another review by any locality using our information."

Clarence R. Bechtel, Managing Director of BOCA spoke to the point:

40

45

50

"Code changes can be submitted by anyone on forms supplied by BOCA.

The Plumbing Code is not changed by staff, only BOCA members change BOCA

codes. The Plumbing Code changes are reviewed in a public hearing and

followed by a vote of active members. The approved changes are then

incorporated into the code.

The code is established and maintained according to National

Standards and practices, that is a system or device acceptable in a distant community should be acceptable in another community providing the

performance can be proven to be identical. The local or regional influence is minimized.

21
The responsibility for enforcement lies solely and ultimately with

the local municipality.

The individuals with the duty and responsibility of enforcing the

code in the local level have a voice and a vote in determining the

content of the code by a democratic process.

Our technical staff provides the necessary back-up services such

as code interpretations, plumbing code seminars and a plumbing code

correspondence course to enhance the officials knowledge and use of

the code.

R.E. Sullivan, Director of Education for Southern Building Code

Congress International spoke as follows:

" We believe that a code can best be written and amended by those

people who use it from day to day, utilizing the advice and assistance

made available from industry and the architectural and engineering proffessions. Consequently, every member of the Southern Building Code

Congress is afforded the opportunity to participate in the revision

process at every annual research conference, and to vote on code changes

recommended by our code revision committee."

Neil A. Mac Lean, Executive Vice President of I.A.P.M.O.

"Our code changes procedure is not much different from that of any

other code agency other than the fact that - and this may be true of the

other agencies but it wasn't brought out - we will accept a code change

from anyone in the world, anyone. When we receive a code change to the

Uniform Plumbing Code, it is printed just the way it is submitted to us by the photocopier. We don't take a chance that in retyping that we may

change your words. We use a photocopier to reproduce enough copies

of these code changes for the code changers committee. We have a deadline of March 1st of each year, and all code changes that have come in

prior to March 1st, usually by the 1st of April are reviewed by a cross section of the code changing committee; still having the only voting

privilege are people who have a nonvested interest, the inspectors from

our jurisdiction. The code change receives a recommendation at that

point, a recommendation to either accept, reject, or hold for further

study. Within 30 days prior to the annual conference - but more actually,

usually within 30 days after that code changes committee - all of these

code changes are then printed in a code changes document and mailed out

to our entire membership, or to anyone else if they have an interest in

the Uniform Plumbing Code - they may not be a member. These changes are

then voted on at the conference, and we have remained anonymous in these

code changes."
10

"We specify that a code change has to be done In a specific manner,

and if a stranger to our code-changes procedure submits a code change

to us, and it is incorrect, we inform him of how to do it correctly

and assist him to do it correctly. We then make it anonymous.

3.2.2 Backflow prevention requirements in model plumbing codes

The plumbing codes determine the utilization of backflow preventers

in a building at the time of the design of the structure. An effective

cross-connection control program must encourage the designers to install

suitable devices , where needed, at the time of construction to obviate

the resistance to change later.

Table 5 presents a listing of paragraphs from four model plumbing

codes pertinent to specific types of cross-connections.

3.3 The Manufacturers of Backflow Prevention Devices

A complete listing of manufacturers of all backflow prevention

devices is beyond the scope of this document. In table 6 the names of

manufacturers have been compiled from the latest listings of approved

devices of the American Society of Sanitary Engineering and from a similar list of the Foundation for Cross-Connection Control and Hydraulic Research. Additional names were obtained from advertisements

found in recent technical publications and magazines.

25 In table 7, the matrix presentation is only as up-to-date as our source of information.

3.4 Testing Laboratories

15

20

30

35

40

There currently exist two modes for the certification of backflow

prevention devices. The Foundation for Cross-Connection Control and

Hydraulic Research tests for compliance of backflow prevention devices

with criteria published in its Manual of Cross-Connection Control [29].

The American Society of Sanitary Engineering has working arrangements

with three testing laboratories to test devices and to authorize a seal

of approval. Just recently a procedure for accrediting testing

laboratories was established within the Department of Commerce, effective February 25, 1976. The complete procedure, as published in the

Federal Register of Wednesday, February 25, 1976 has been arranged by

the authors of this document to provide sidenotes and a special format

as explained in Appendix Section 10.3.

Each of the above procedures will be discussed in the following

paragraphs

45

23
Table 5. A Listing of Paragraphs from Four Model Plumbing Codes Pertinent

to Specific Types of Cross Connections

Pcints of Contact Where a Potable Water System May Become Contaminated by Backflow from a Non-potable Source

n r\ rt a D. U. 0 . A. 1973 Code

Pai'agraphs

1. A. P. M. 0. 1973 Code

Paragraphs

PHCC-ASPE

1973 Code

Paragraphs

S.B.C.C. 1973 Code

Paragraphs

Water Closet Flushometer Valves ; Urinal Flushometer Valves 1605.117 1003(a), (c) 10.5-5A 1205.1

Water Closet and Urinal Tanks 1605.117 1003(b) 10.5-5A 1205.2

Over Rim Supplies to Plumbing Fixtures 1605 . Ill 1003(d) 10.5.2 1205.3

Direct Connections Between Potable Water Piping and Sever Connected Wastes 1605.3 1003(e) ic 5.3.5c

Connections Between Potable Water Piping and the Inlet

Side of a Fixture Trap ,

1003(e)

Inlets to Tanks, Vats, Sumps and other Receptors I605.II6 1003(g) 10.5.3.1

Lawn Sprinkling Systems l605.117 1003(h) 10.5.9 1205.4

Fixture Inlets or Valved Outlets with Hose Attachments 1605 . 117 1003(i) 10.5.3.3 1205.5

Medical, Therapeutic, Surgical, Mortuary or Similar Equipment 1403. 6;.

1003(d) 14.27; .26

Water Cooled Compressors, Degreasers or any other Water

Cooled Equipment

1003 (k) 10.5.3.4

Water Cooled Equipment Subject to Continuous Flows for

Periods of Twelve Hours or More 1003(k) 10.5.3.4

Aspirators Connected to the Inlet Side of a Fixture Trap 1403.6 1003(1) 10.5-5A

Steam Boilers, Pumps, etc. that May Create a Higher Pressure

in the Non-potable Line than Exists in the Potable System

1605.117 1003(n)(o) 10.5.3.5 1205.6

Cup Beverage Vending Machines 1605.117 10.5-5A

Dishwashing, Garbage Can Cleaning, and Laundry Machines 1605.117 10.5-5A 1204.3

Hose Bibbs 1605.117 3-1.3 1205.5

Mobile Homes in Trailer Parks E 25 18.5.8 C 8(c)

High Pressure Units such as Used in Car Washes to Supply Water and Detergent Under High Pressure

Dwg. 11

NOTE: B.O.C.A. is Building Officials and Code Administrators International. Inc.

I.A.P.M.0. is International Association of Plumbing and Mechanical Officials

PHCC-ASPE is National Association of Plumbing, Heating, Cooling Contractors

joined with the American Society of Plumbing Engineers.

S.B.C.C. is Southern Building Code Congress International, Inc.

24
Table 6. An Alphabetical Listing of Manufacturers of Backflow Prevention

Devices. (Relate to Table 7)

AMA Enterprises, Inc. 444 Hempstead Turnpike

West Hempstead, New York 11552

(516) 483-1166

Alsons Products Corp

525 East Edna Place

Covina, Calif. 91722

(213) 966-1668

American-Standard, Inc.

P. 0. Box 2003

New Brunswick, New Jersey 08903

(201) 885-1900

Badger Meter, Inc. 4545 W. Brown Deer Road

Milwaukee, Wisconsin 53223

(414) 355-0400

Beacon Valve Company

P. 0. Box 478, 2 Jackson St. Waltham, Mass. 02154

(617) 893-0011

Belvedere Products, Inc. 725 Columbia Avenue

Belvidere, Illinois 61008

(815) 544 3131

Bidoro Manufacturing Co. 229 Bellerose Avenue

East Northport, N. Y. 11731

(516) 261-5050

Buckner Sprinkler Co

909 W. Nielson Avenue

Fresno, California 93706

(209) 269-5561

Burlington Brass Works

4QQ Pine Street

Burlington, Wisconsin 53105

(414) 763-3534

A. W. Cash Valve Mfg. Corp.

666 E. Wabash Avenue

Decatur, Illinois

(217) 422-8574

Champion Brass Mfg. Co. 1460 Naud Street

Los Angeles, California 90012

(213) 221-2108

Chicago Faucet Co. 2100 S. Nuclear Dr. Des Plains, Illinois 60018

(312) 298-1140

2

Chicago Speciality Mfg. Co. 7500 Linder Avenue

Skokie, Illinois 60076

(312) 674-7500

Cla-Val Co. Backflow Div.

Post Office Box 1325

Newport Beach, California 92663

(714) 548-2201

Clayton Mark & Co. 1900 Dempster Street

Evanston, Illinois 60204

(312) 864-9100

Consolidated Brass Co.

P. 0. Box 247

Mathews, North Carolina

(704) 847-9191

Coyne & Delany Co

1565 Avon Street Extended

Charlottesville, Virginia 22901

(804) 296-0166

Crane Company

300 Park Avenue

New York, N. Y. 10022

(212) 752-3600

Eastman Central D Div.

U. S. Brass Corp. P. 0. Box 37 Piano, Texas 75074

(214) 235-4531

Fluidmaster Inc. 1800 Via Burton, P. 0. Box 4264

Anaheim, California, 92803

(714) 774-1444

Frost Company

14th Ave. at 65th Street

Kenosha, Wisconsin 53140

(414) 658-4301

G. C. G. Mfg. Co. Ltd.

173 Glidden Road, BRAMPTON,

Ontario, Canada L6W 3L9

(416) 453-8120

H. L. Gee Mfg. Co. 9292 Santa Monica Blvd. P. 0. Box 5285

Beverly Hills, California 90210

(213) 275-5376

Griswold Controls

124 E. Dyer Road

Santa Ana, California 92707

(714) 546-3844
Table 6. (Continued)

Hamilton Industries Division

American Hospital Supply Co. Two Rivers, Wisconsin 54241

(414) 793-1121

Hersey Products Inc. 250 Elm Street

Dedham, Massachusetts 02026

(617) 326-9400

ITT Grinnell Corp.

260 W. Exchange Street

Providence, Rhode Island 02901

(401) 831-7000

Jaco , Inc

2945 W. Maple Road

Troy, Michigan 48084

(313) 647-0115

Johns-Manville Corp

Greenwood Plaza

Denver, Colorado 80217

(303) 770-1000

Josam Manufacturing Co

Corymbo Road

Michigan City, Indiana 46360

(219) 872-5531

Kirkhill, Inc. 12021 Woodruff Avenue

Downey, California 90248

(213) 773-3492

Kohler Company

44 High Street

Kohler, Wisconsin 53044

(414) 457-4441

Lawler ITT 3500 N. Spaulding Avenue

Chicago, Illinois 60618

(312) 267-1600

Lear Siegler, Inc. 6331 E. Jefferson Avenue

Detroit, Michigan 48207

(313) 259-2095

Mansfield Sanitary, Inc.

P. 0. Box B Perrysville, Ohio 44864

(419) 938-5211

Modern Faucet Mfg. Company

1700 East 58th Place

Los Angeles, California 90001

(213) 582-6286

Mueller Steam Specialty Company

72 Jericho Turnpike

Mineola, New York 11501

(516) 747-8300

L. R. Nelson Corporation

7719 N. Pioneer Lane

Peoria, Illinois 61614

(309) 692-2200

Nepture Water Meter Company

30 Perimeter Park

Atlanta, Georgia 30341

(404) 458-8111

Nibco, Inc. 500 Simpson Avenue

Elkhart, Indiana 46514

(219) 295-3000

Nidel Company

P. 0. Box 418

Grand Haven, Michigan 49417

(616) 842-2650

Powers Regulator Company

3400 Oakton Street

Skokie, Illinois 60076

(312) 673-6700

Rain Bird Sprinkler Mfg. Co. 7045 N. Grand Avenue

Glendora, California 91740

(213) 963-9311

Rockwell International Corp.

P. 0. Box 487

Uniontown, Pennsylvania 15401

(412) 438-3501

Sloan Valve Company

10500 Seymour Avenue

Franklin Park, Illinois 60131

(312) 671-4300

Surgical Mechanical Research, Inc. 960 W. 16th Street

Newport Beach, California 92663

(714) 646-4405

Taco , Inc

1160 Cranston Street

Cranston, Rhode Island 02920

(401) 942-8000

Tempstat Corporation

Monument Road

Hinsdale, New Hampshire 03451

(603) 256-6001

26
Table 6. (Continued)

T & S Brass And Bronze Works, Inc. 119 Magnolia Avenue

Westbury, L. I., New York 11590

(516) 334 5104

Toro Technology

1709 La Costa Meadows Drive

San Marcos, California 92069

(714) 744-5650

Twentieth Century Products Corp.

3600 South Jason Street

Englewood, Colorado 80110

(303) 789-0418

Water Saver Faucet Company

701 W. Erie Street

Chicago, Illinois 60610

(312) 666-5500

Watts Regulator Company

10 Embankment Street

Lawrence, Massachusetts 01842

(617) 688-1811

Wolverine Brass Works

648 Monroe Avenue, N. W. Grand Rapids, Michigan 49502

(616) 451-2581

Woodford Mfg. Company

1626 Delaware Avenue

Des Moines, Iowa 50317

(515) 262-5638

Zurn Industries, Inc. 1801 Pittsburgh Avenue

Erie, Pennsylvania 16512

(814) 455-0921

27
A Matrix Presentation Relating Manufacturers with the Types of

Backflow Prevention Devices that Each Manufactures.

Types of Backflow

Preventers

Air

Gap

Atmospheric Type Vacuum Breakers Pressure Type Vacuum Breakers

Backflow Preventers

Intel medi

ate

Double

Check

Reduced Pressure Principle

Representative

\ Standards

Makers of Backflow \.

Preventers \.

ANSI

A

112.1.2

1973

Pipe

Applied

ANSI

A

112.1.1

1971

Antisiphon

Ball

Cock

A.S.S.E.

1002

1963

Hose

Connection

A.S.S.E.

1011

1970

Single

Check

Valve

IAPMO

PS

31

1974

Single

Check

Valve

A.S.S.E.

1020

1974

Double

Check

Valve

IAPMO

PS

31

1974

Double

Check

Valve

A.S.S.E.

1020

1974

Atmospheric

Vent

A.S.S.E.

1012

1972

Valve

Assemblies

IAPMO

PS

31

1974

Valve

Assemblies

A.S.S.E.

1015

1972

IAPMO

PS

31

1974

A.S.S.E.

1013

1971

Alsons Products Corp AMA Enterprises

American Standard , Inc

.

Badger Meter, Inc.

N

N

N

N

& Beacon Valve Company

Belvedere Products , Inc. Bidoro Manufacturing Co. Buckner Sprinkler Co.

N

#N

N Burlington Brass Works, Inc.

A. W. Cash Valve Mfg. Corp.

Champion Brass Mfg. Co. Chicago Faucet Company

// &

#

N

& &

Chicago Specialty Mfg. Co. Cla-Val Co., Backflow Div. Clayton Mark & Co. Consolidated Brass Co. # &

N

&

// //

Coyne & Delany Company

Crane Company

Eastman Central D Div.

Fluidmaster, Inc.

N

N

NN

N

N

//

Frost Company

G. C. G. Mfg. Co. ,Ltd.

H. L. Gee Mfg. Co. Grinnell Company, Inc.

N

f

&

1 Griswold Controls

Hamilton Industries Div.

Hersey Products, Inc. Jayco, Inc.

N

N

//

& &

Meaning of Symbols: // = FCCCHR Listed & = A.S.S.E. Listed N = Advertized but not listed

2°
Table 7 (Continued)

Types of Backflow

Preventers

Air

Gap

Atmospheric Type Vacuum Breakers Pressure Type Vacuum Breakers

Backflow Preventers

Inter medi

ate

Double

Check

Reduced Pressure Principle

Representative

N. Standards

Makers of N. Backflow N. Preventers n.

ANSI

A

112.1.2

1973

Pipe

Applied

ANSI

A

112.1.1

1971

Antisiphon

Ball

Cock

A.S.S.E.

1002

1963

Hose

Connection

A.S.S.E.

1011

1970

Single

Check

Valve

IAPMO

PS

31

1974

Single

Check

Valve

A.S.S.E.

1020

1974

Double

Check

Valve

IAPMO

PS

31

1974

Double

Check

Valve

A.S.S.E.

1020

1974

Atmospheric

Vent

A.S.S.E.

1012

1972

Valve

Assemblies

IAPMO

PS

31

1974

Valve

Assemblies

A.S.S.E.

1015

1972

IAPMO

PS

31

1974

A.S.S.E.

1013

1971

Johns-Manville Corp. Josam Manufacturing Co. Kirkhill.Inc.

Kohler Company

N

N

N

N

# # & &

Lawler ITT Lear Siegler, Inc. Mansfield Sanitary, Inc. Modern Faucet Mfg. Co. JL

it

N

N &

& &

Mueller Steam Specialty Co.

L. R. Nelson Corporation

Neptune Water Meter Co. Nibco, Inc.

&

&

&

&

& &

Nidel Company

Powers Regulator Co. Rain Bird Sprinkler Mfg. Co. Rockwell International Corp.

N

// &

&

& & &

&

&

& Sloan Valve Company

Surgical Mech. Research, Inc. Taco, Incorporated

Tempstat Corporation

# &

#

# #

&

T & S Brass & Bronze Works

Toro Technology

Twentieth Century Products Water Saver Faucet Company

N

#

&

N N

Watts Regulator Company

Wolverine Brass Works

Woodford Mfg. Company

Zurn Industries, Inc.

# & £>

&

&

&

N & &

Meaning of Symbols: # = FCCCHR Listed & = A.S.S.E. Listed N = Advertized but not listed

29
3.4.1 Foundation for Cross-Connection Control and Hydraulic Research

10

40

45

It was mentioned in Section 2.2 that the Foundation for CrossConnection Research was established as an arm of the University of

Southern California in 1944. In a publication dated April, 1948 it was stated that the Research Foundation for Cross-Connection Control

established at the University of Southern California is properly

equipped to make all the necessary studies and tests on antisiphon

and backflow prevention devices and has been engaged in the work since

1944. [12]

The name of the foundation was later changed to appear in the

fourth edition of the Manual of Cross-Connection Control [15] as Foundation for Cross-Connection Control Research (FCCCR) . In the latest

edition of the Manual the name is given as Foundation for Cross15 Connection Control and Hydraulic Research (FCCCHR) . As reported by

Bibbens [11]

"A financial grant originally equipped the FCCCR laboratory and

provided staff salaries for the first few years. Laboratory equipment

20 and instrumentation were expanded and improved in following years

through gifts from water equipment manufacturers. There is now a written agreement with the Southern California Water Utilities Association which provides financial support for the Foundation in the form

of annual membership subscriptions by water utilities, cities, and

25 county, state, and federal agencies. Memberships range from $50 to

$500 per year, depending on utility size. The Southern California

Water Utilities Association is a non-profit organization which supports

an educational institution (the FCCCR)." [11]

30 "The FCCCR laboratory was originally located on the USC campus but

was removed in the mid-1960' s to make way for other campus expansion.

Being without laboratory facilities for a few years, the FCCCR contracted for the use of private facilities when laboratory tests were

required. In, 1968, the laboratory was reestablished in an old pumping

station on Riverside Drive in Los Angeles. The FCCCR currently conducts backflow evaluation tests and other related research at this

facility. Pressures of 45 and 150 psi are available directly from the

city's water supply system. Headers up to 16" are installed for

testing the various sizes of devices. A 200 HP diesel engine driven

pump will soon be included in the system to provide a 4600 gpm recirculating flow capacity. The Foundation's laboratory was inspected

by the NCEL Project Engineer in June 1969 and was found to have

facilities adequate for the testing of backflow preventers as prescribed

by the 4th Edition of the "Manual." During this inspection, it was

observed that extensive equipment modification and improvement were

underway and much new instrumentation was being installed in the laboratory. Half of the laboratory space was occupied by the Los Angeles

Department of Water and Power for meter flow testing, but the remaining

30
half of the laboratory had enough space for considerable future

expansion by the FCCCHR for further testing or research." [11]

10

Summarizing from Dr. Springer's paper [32] for testing under the

FCCCHR procedures, a proposer must:

11 (a) Submit a complete set of drawings and specification to

FCCCHR for review. If the review discloses that the

design is weak or contradicts the specifications of FCCCHR,

FCCCHR will make these weaknesses or non-compliance aspects

known to the proposer.

20

(b) If the manufacturer or proposer passes step (a) , he must

then submit one device or preferably three devices to

FCCCHR for laboratory evaluation. The device is inspected

to see that it is in compliance with FCCCHR' s specification and the manufacturer's drawings. The manufacturer

is invited to have his representative present to witness

the evaluation procedure and results.

(c) If the device(s) pass the hydraulic laboratory evaluation,

the manufacturer must next arrange for the installation of

at least three (3) devices of this same model and size in

the field. The field location must be approved by FCCCHR

(Such location(s) cannot be on fire service where static

conditions may exist continuously from one year to the

25 next). Also, a service where the flow is maximum continuously is not acceptable. Also the device under test cannot

be placed in a position where it would be expected to

protect the potable water supply against potential backflow of any hazardous materials or contaminant. Such contaminant could backflow if the unproven device failed.

Also, the device cannot be placed in a water supply that

cannot be shutoff temporarily as may be required during

the field evaluation.

(d) The field installed devices are tested monthly: — The tightness of each check valve for double check valve

assemblies is determined by test to see that each check

will hold a 1 psig differential in the direction of flow,

30

40

45

— The opening pressure differential of the relief valve,

the pressure differential across number one check

valve, and the drip tightness of number two check valve

are all checked for the RPBD device."

(e) If any type of malfunction is observed during the field test,

the test is terminated and such devices are returned to the

manufacturer for corrective measures.

31
(f) After the device has been corrected or redesigned, the device

must go through the complete hydraulic laboratory evaluation

again just as though it were a completely new device. Then if

a successful laboratory test is again realized, the device is

field tested a second time. When the device satisfies FCCCHR

requirements, the manufacturer receives a "Certificate of

Approval" for the particular model and size of device passing

5 the tests.

10

15

20

3.4.2 Laboratories testing in the A.S.S.E. Seal Program

The American Society of Sanitary Engineering (A.S.S.E.) was established in 1906 with its main endeavor being in the field of Plumbing

and Sanitary Research. A.S.S.E. main office is located in Cleveland,

Ohio [21].

The A.S.S.E. has authorized three independent testing laboratories

to test products for compliance with the A.S.S.E. Standards mentioned

previously in this report. These laboratories are:

(a) The Twining Laboratories, Incorporated,

Fresno, California

(b) The National Sanitation Foundation,

Ann Arbor, Michigan

2^ (c) Factory Mutual Research Corporation,

Norwood, Massachusetts.

30

35

When a product is approved in one of these authorized laboratories

the A.S.S.E. seal may be displayed on the product. The seal indicates

that the product has been certified to be in compliance with the appropriate

A.S.S.E. standard as a result of satisfactory laboratory tests. Authorization for the use of the seal is obtained from the Seal Control Board

at the A.S.S.E. Central Office.

The seal is issued for a period of five (5) years but must be

renewed annually by the manufacturer. The manufacturer must prove to the

satisfaction of the Seal Control Board that the product has not been

changed or modified in any way that would affect compliance with the

requirements under which it was tested. Extension of the seal usage

40 beyond five years may be negotiated with the Seal Control Board. The

manufacturer makes all arrangements for testing at an A.S.S.E. approved

laboratory and defrays all costs involved. If the manufacturer changes

or alters his product without notification, the Board will cancel the

manufacturer's right to display the seal.

45

32
3.4.3 Procedures for a National Voluntary Laboratory Accreditation

Program

During the fall and winter of 1972, R.W. Beausoliel visited five

laboratories in expectation that such visits would provide critical

5 information needed to perform an evaluation of each laboratory. We know

now that in the half-day alloted for each of the visits, we did not and

probably could not have obtained the essential information needed for

such evaluations. We know that the business of evaluating laboratories

is a complex one, for we have become aware of the work being done by

10 others at NBS to define an acceptable laboratory evaluation program.

The evaluation and accreditation program is now established and is

presented in detail , with special formatting, in the Appendix,

Section 10.3.

15 Concisely, the ten steps needed to develop a list of accredited

laboratories to test backflow prevention devices are as follows:

(1) Some person or organization must request the Secretary of

Commerce to find that there is a need for accrediting

2Q laboratories to test backflow prevention devices (Sec. 7. 4 (a))

(2) Such request will have to show:

(a) that standards and test methods exist for the evaluation

of backflow prevention devices,

(b) the number of testing laboratories believed desiring to

25 be accredited to test backflow prevention devices,

(c) and the number of anticipated users of the testing

laboratories service. (Sec. 7.4(b))

(3) Public hearings will be held to provide a forum for any and

2Q all opinions to be expressed. (Sec. 7.4(f))

(4) Based on the expressions that come from the hearings, the

Secretary of Commerce will either decide to proceed or to

withdraw. (Sec. 7.4(g)).

35 (5) If the Secretary proceeds he will form a National Laboratory

Accreditation Criteria Committee for Backflow Prevention

Devices. (Sec. 7.4(h)(3)).

(6) The Committee will be directed by the Secretary of Commerce

to develop and recommend to him, general and specific criteria

40 to accredit testing laboratories that serve backflow

prevention devices. (Sec. 7.6(d)).

(7) When the specific and general criteria have been prepared for

the Secretary of Commerce, he will consider them and invite

45 comments from the public. (Sec. 7.8(a))

(8) The input from the hearings will be turned over to the

Criteria Committee to evaluate and to advise the Secretary of

Commerce (Sec. 7.8(c)).

33
(9) Should the Secretary of Commerce accept the Criteria

Committee's work, the criteria will be accepted and

laboratories will be invited to apply for accreditation.

(Sec. 7.10(b))

5 (10) The Secretary of Commerce will report to the public monthly,

via the Federal Register, all actions which grant, revoke,

terminate, or result in the withdrawal of the accreditation

of a laboratory. (Sec. 7.17(c)).

In the above procedures, the initiating action requires that

10 standards and test methods exist for the evaluation of the devices.

The A.S.S.E. standards have been submitted to the American National

Standards Institute (ANSI) for consideration by the A 112 Committee.

For only two of these has the approval process progressed to the

stage of final approval.

15

The correlation of A.S.S.E. standards with the ANSI numbers are:

A.S. S. E. 1001 . . ANSI A 112. 1. 1 - 1971

A.S. s. E. 1011 ANSI A 112. 1. 3 - 1976

A.S. s. E. 1012 . . ANSI A 112. 1. 4 - A.S. S. E. 1013 ANSI A 112. 1. 5 - A.S. s. E. 1015 . . ANSI A 112. 1. 6 - A.S. s. E. 1020 ANSI A 112. 1. 7 - 1976

2^ Also required to exist for the initiating action is information

on the number of testing laboratories desiring to be accredited. To

explore the possibility of developing such information, reference was made to the 1976 Directory of the American Council of Independent

Laboratories, Inc., 1725 K Street, N.W. , Washington, D.C. 20006.

30 (202) 659-3766.

The Directory has a classified index of its membership wherein

those laboratories doing qualification testing, hydraulic testing,

hydrostatic testing, and also carrying out certification programs

35 are identified by the page number of their advertisement in the

directory. All laboratories identified as being in each of the four

classifications were selecting for listing here. With the names of

the laboratories and three others taken from our files, table 8 was compiled.

45

34
Table 8. A List of 2k Independent Tes

ested in Testing Backflow P

Applied Research Laboratories of Florida, Inc. Florida Industrial Research Park SR 27 43650 S.W. 232 Avenue, Dade County .Florida

P.O. Drawer 1, Homestead, Fla. (305) 245-3660

Approved Engineering Test Laboratories , Inc

15720 Ventura Boulevard, Suite 420

Encino, California 91436

(213) 783-5985

Associated Testing Laboratories, Inc.

9 Brighton Road

Clifton, New Jersey 07012

(201) 473-6455

Bowser - Morner Testing Laboratories , Inc

420 Davis Avenue P.O. Box 51

Dayton, Ohio 45401

(513) 253-8805

C T L Engineering, Inc. 2860 Fisher Road

Columbus, Ohio 43204

(614) 276-8123

Detroit Testing Laboratory, Inc. 8720 Northend Avenue

Oak Park, Michigan 48237

(313) 398-2100

Electrical Testing Laboratories, Inc.

2 East End Avenue

New York, New York 10021

(212) 288-2600

Engineers Testing Laboratories, Inc. 3737 East Broadway

Phoenix, Arizona 85040

(602) 268-1381

Froehling and Robertson, Inc. 814 West Cary St. P.O. Box 27524 Zip 23261

Richmond, Virginia 232 20

(804) 644-3025

General Environments Corp.

6840 Industrial Road

Springfield, Virginia 22151

(703) 354-2000

Arnold Greene Testing Laboratories, Inc. East Natick Industrial Park

6 Huron Drive, Natick, Mass. 01760

(617) 235-7330

Arnold Greene Testing Laboratories of P.R.,

167 Quisqueya Avenue Inc. Hato Rey, Puerto Rico 00917

(809) 763-3910

ing Laboratories Potentially Inter-

'evention Devices. (See Sec. 3.^.3)

Institute for Research, Inc. 8330 Westglen Drive

Houston, Texas 77063

(713) 783-8400

Law Engineering Testing Company

P.O.Box 98008, 2000 Century Parkway

Atlanta, Georgia 30329

(404) 325-3933

Shilstone Engineering Testing Laboratory, Inc. 1714 Memorial Drive

Houston, Texas 77007

(713) 224-2047

Skinner and Sherman, Inc. 227 California Street

Newton, Massachussetts 02195

(617) 332-8300

Smith - Emery Company

781 East Washington Boulevard

Los Angeles, California 90021

(213) 749-3411

Southwestern Laboratories,

222 Cavalcade Blvd. P.O. Box 8768

Houston, Texas 77009

(713) 692-9151

Testing Consultants, Inc. 525 East Mississippi Avenue

Denver, Colorado 80210

(303) 777-1771

Twining Laboratories of Southern California, Inc. 3310 Airport Way P.O. Box 47 Long Beach, California 90801

(213) 426-3355

United States Testing Company, Inc. 1415 Park Avenue

Hoboken, New Jersey 07030

(201) 792-2400

Value Engineering Laboratory

2550 Huntington Avenue

Alexandria, Virginia 22303

(703) 960-4600

Wingerter Laboratories, Inc. 1820 N.E. 144th Street Drawer L North Miami, Florida, 33161

(305) 944-3401

York Research Corporation

One Research Drive

Stamford, Connecticut 06904

(203) 325-1371

35
3.5 A Conceptual Model Cross -Connection Control Program

In recent months a conceptual model for a realistic cross- connection control program has been evolving. The necessary elements

are even now developing, with a minimum of input from the authors.

The model is shown as figure 4.

I. In the model, credit is given to EPA as being the source of

activity needed to bring all elements together into a workable program.

The line of action indicates that EPA would provide guidelines to state

or municipal authorities who would in turn develop the appropriate

legislation or ordinance to establish the cross-connection control

program.

II. The enabling laws will require funds for the operation of the

program. The funding would pay for two activities:

(a) An inspection program that:

1. Authorized installation of particular backflow prevention devices where needed.

2 . Inspected the installation of the device at time of

construction

3 . Carried out a regular schedule of reinspection and

testing to determine that backflow protection devices

were performing adequately.

(b) A contractual arrangement with an independent testing

laboratory to

1. Audit or monitor the cross-connection control program

on a annual or semi-annual basis to assure that the

program was being carried out under (a) above as required by law, and

2 . To provide technical guidance and training to the

inspection staff as needed and as contracted for.

III. To be qualified to make decisions or judgments on suitable

backflow protection devices the inspection staff will need technical

guidance for the approval of devices. Such guidance could come from:

1 . Knowledge that suitable devices are available in a competitive market to fill needs in most applications.

2 . Knowledge of existence of nationally recognized product

standards that assure quality and dependability for

the several types of devices

3. Knowledge of the existence of a certification program

that verifies on a continuing basis that devices claiming to meet the requirement of the standards actually

do so.
37
IV. The existence of a competitive market depends upon a demand for

the devices. The demand may be expected to increase as the number of

cross-connection control programs increase. The demand could then be

expected to motivate new designs - utilizing new materials - and

necessitating evaluation of the new products.

5 V. The product standards currently in existence need to be improved

from the present stage to assure that testing and certification may be

carried out uniformly by any certified independent testing laboratory.

To provide for approval of suitable innovative devices, the requirements

for backflow protection devices need to be stated in performance

10 language. Another document of NBS, NBSIR 76-1020 "Guide Criteria for

Laboratory Evaluation of Backflow Prevention Devices for Protection of

Potable Water Supplies" by Grover C. Sherl in, Robert W. Beausoliel, and

Lawrence S. Galowin will aid in the develop of the performance

language.

15

VI. Certification of the backflow protection devices would be carried

out by authorized independent testing laboratories who receive compensation for such certification from the manufacturers. Authorization of

the certifying laboratories could be accomplished through the U.S.

20 Department of Commerce Accreditation Program.

VII. The National Voluntary Laboratory Accreditation Program is now

available to accredit testing laboratories to test backflow prevention

devices. In Section 3.4.3 a concise listing is given of steps required

25 to initiate the program. The complete program is presented as Appendix

Section 10.3.

38
4.0 EVALUATION OF DEVICES

4.1 Design Considerations that Affect Reliability

4.1.1 Air Gaps

5

The design of air gaps in a potable water distribution line

depends upon the size of the effective opening and the distance

between the supply fitting outlet (spout or faucet) and a near-by

wall. Above one-inch diameter of effective opening the length of

air gap is specified to be twice the diameter; except when affected

±0 by a near-by wall it is to be three times the diameter. See figure 3.

The primary function of the air gap may be defeated by attaching

a hose , a pipe , or a tube between the potable water outlet and a non- potable source. Possible means to prevent such practices are by

]_5 designing or modifying outlets of faucets to discourage the attachment

of hoses and by initiating educational programs to apprise the public

that attachment of such hoses can create potential health hazards

4.1.2 Barometric Loops

20

The Environmental Services Branch, National Institutes of

Health, in cooperation with the Division of Environmental Health and

Safety, University of Minnesota Health Service investigated the

barometric loop [27] . The investigation showed that air bubbles

25 could transfer contaminated water through the loop when back-siphonage

occurred. They developed an air-water separator that proved effective

in preventing such transfer. Additional studies were recommended to

determine the effect diffusion might have in the transfer of con- taminants through the. loop. There are no data on how widely

30 barometric loops are used or on how many loops are used with airseparators. The use of the separators with loops does not appear

in the model plumbing codes.

4.1.3 Pipe Applied Vacuum Breakers

35

The pressure type vacuum breakers (PVB) and the atmospheric

type vacuum breakers (AVB) are vulnerable to air port blockage by

rags, etc. Such blockage would render the device ineffective.

Suggested countermeasures are educational efforts to explain the

40 need to keep the air ports or air inlets of the vacuum breakers open,

and frequent periodic inspection, test and repair. Although PVB

has means for testing the device in line, standards do not require

similar test arrangement for AVB.

45

39
4.1.4 Hose Connection Vacuum Breakers

10

20

25

There are two types of hose connection vacuum breakers (HCVB)

One type has a diaphragm to seal the air inlets but does not have a check valve to seal the water inlet. This type of HCVB is essentially

a special design of AVB which is not intended to be subjected to back

pressure. The other type of HCVB has both a diaphragm and check valve,

For such devices a nationally recognized standard ASSE 1011 specifies

the following test requirements which are unique for vacuum breakers

° The outlet of the device is subjected to a back pressure

created by a ten-foot column of water within an elevated

garden hose. Backflow through the check must not take

place under this pressure.

° Leakage of water from the hose through the HCVB at the rate

of 1/4-pint per minute is permitted to flow through the vent

ports to the ambient in order to relieve back pressure

caused by the column of water in the hose. (The check

valve prevents backflow into the inlet of the device when

the water is discharged from the vent ports)

The objectives of these two tests conflict with the principles

set forth by two authorities concerned with vacuum breakers . For

instance, the following attitudes were found concerning the first

and second test methods respectively:

HCVB exposure to back pressure is not allowed under AWWA's

Pacific Northwest Sections Manual [1]. The Manual depicts

this HCVB (with the check valve) as an AVB which the

manual states is not effective against backflow due to back

3Q pressure.

° Dawson and Kalinske have said that the air inlets of vacuum

breakers should not be used to convey water as lime deposits

may cause closure of the air inlets. Also the air inlets

35 should not be placed where they would get exposed to

polluted water [3].

A third test method concerns the fouling of the check with a wire (a common test for vacuum breakers) [20] to simulate check valve

40 leakage resulting from check material failure or a foreign substance

lodged between the check and its seat. The test is summarized as follows

The back-siphonage test with vacuum applied at the inlet

45 to HCVB requires the check to be fouled.

40
° In the back pressure portion of the test method, the check

valve is not fouled. (The standard does not say that

backflow will occur if the check leaks)

It seems reasonable that if the device effectively prevents

backflow under back-siphonage conditions with a fouled check , the

device should also effectively prevent backflow due to combined

back-siphonage and back pressure because the standard indicates that

the device effectively relieves back pressure . The standard does

not consider the simultaneous application of both vacuum at the

inlet and back pressure at the outlet. Such likely conditions could

occur when filling a back yard swimming pool with an elevated garden

hose. Because the standard test methods did not address this likely

condition, a simple test, as explained in Appendix Section 10.4, was carried out to see how effective the device would be in relieving

back pressure and preventing backflow with the simultaneous application

of vacuum at the inlet and back pressure at the outlet with the check

fouled in the manner of the standard test method. Backflow occurred

at 0.2 gpm. The test results indicate that backflow remained constant

with increasing elevation of the terminal end of the hose (increasing

back pressure) . Such a constant backflow rate into the inlet of the

device does indicate that the device is effective in relieving back

pressure. However, the results also indicate that a tight check

valve is required to prevent backflow under these conditions. It

would seem reasonable that the standard consider this limitation of

the device

It appears that the HCVB which includes the check valve is

superior to the type that does not have a check valve . The use of garden hoses with HCVB naturally subjects HCVB to back pressure.

The HCVB without a check valve can not resist back pressure. A

simple test by the National Bureau of Standards in accordance to

ASSE 1011 [21] showed that the device would backflow when subjected

to atmospheric pressure at the inlet and a three -foot head of water

at the outlet. Because of this, NBS believes that HCVB without a check should not be used with garden hoses. It is possible to

overly criticize this relatively inexpensive device (present cost

about four dollars) because obviously a garden hose installation

is safer with HCVB than without it. Alternatives to present HCVB

installation for garden hose applications could be the use of the

pressure vacuum breaker in the hose supply or, perhaps, a redesign

of the water supply piping such that the terminal end of a garden

hose under normal use would not be elevated above HCVB or other

vacuum breaker. Such approaches would tend to increase the

cost of the installation; but it must be

41
10

20

25

remembered, however, that garden hose installation can cause deaths

as shown by the example in section 2.1 of this report and the best

protection must be provided. It may be that HCVB is quite adequate if

the check valve does not leak. A study should be carried out to

determine the following:

° Will the air ports of the HCVB become blocked with

lime deposits as mentioned by Dawson and Kalinske [3]?

0 Is there, in reality, a high risk of contamination

at the air ports of HCVB with the check valve ?6/

° How reliable is the check valve under service

conditions?

0 Would the HCVB give additional protection if it

15 were installed at the nozzle end of the garden

hose or at both the faucet end and nozzle end?

30

With any such change (s) , the manufacturers and/or administrative

authorities should make the general public aware of the importance and

function of HCVB and other devices (perhaps TV coverage from time to

time and informative literature concerning backflow potential included

with the water purveyors bills)

4.1.5 Double Check Valve Assemblies

The double check valve assembly (DCVA) gives no visual indication

of check-valve failure. Protection depends entirely on tight check

valves. Good preventive maintenance will tend to preclude check-valve

leakage

6/ It is interesting to note that if a 50-foot length of 1/2 -inch

diameter garden hose was used to fill an elevated swimming pool such

35 that water would backflow from the hose through the vent ports to

the surrounding atmosphere at the rate allowed in the standard, 1/4-

pint per minute (approximately 29 cubic inches per minute) , all of the

water in the hose (about 118 cubic inches) would flow through the ports

in about five minutes. At the end of this time, possibly non-potable

40 swimming pool water would be flowing in the hose and vent ports

42
4.1.6 Backflow Preventers with Intermediate Atmospheric Vent

Since the backflow preventers with intermediate atmospheric

vent are relatively new, no feedback from installation experience

was found

5

4.1.7 Reduced-Pressure Principle Back Pressure Backflow Preventers

Some authorities declare that a reduced-pressure principle

backflow preventer (RPBD) will permit backflow when its upstream and

downstream check valves both leak when there is vacuum at the inlet

10 and back pressure at the outlet. In light of such statements, and

in view of the fact that existing standards for RPBD do not have tests

for back-siphonage , a limited NBS laboratory test of a 3/4-inch device

was conducted to determine if it would permit backflow. See Appendix

10.5 for details. With the check valves fouled with 0.042 -in

3-3 diameter wires in the manner normal during vacuum breaker tests [20] , with a vacuum of 11 centimeters of mercury absolute (about 25 inches

of mercury gage) at the inlet, and with low back pressure of 1.31 psig,

and zone pressure of one inch of water column gage, an average backflow

rate of 0.029 gpm into the inlet of the device occurred. The relief

20 valve was open under these conditions and discharged water from the zone to drain at only 1.85 gpm indicating that the zone was not

overloaded (this rate was well below the 5 gpm allowed by the

standards) . It was noted that the soft rubber check valve material

used in the upstream check of this particular model of RPBD tended

25 to slowly seat around the wire thus preventing backflow into the inlet.

The results above are in agreement with those for a similar

test of a 3/4-inch RPBD made at NBS over 20 years ago. 7/ During

that test the check valves of RPBD were fouled with 0.027-inch

30 diameter wire. The supply piping to the device was subjected to

vacuum up to 18-inches of mercury gage, and at the same time a positive water pressure of 25 psig was maintained in the piping

downstream of the device. The final paragraph concerning the test

results stated the following: "In none of the vacuum tests described

35 above was there any indication whatsoever of backflow. Apparently

the resilient nature of the main valve seat and the force of the

spring, which aids in closing the valve, are responsible, at least

in part, for good results obtained. Even when the piece of wire

40

7/ National Bureau of Standards Report on Test of Backflow Preventer

Requested by the Federal Security Agency, National Institutes of

Health, U. S. Public Health Service, Washington, D. C. on January 31,

1952. Prepared by R. S. Wyly.

43
was placed between the main valve and its seat, there was no apparent

backflow of either air or water. Inspection of the valve showed that

the wire had merely been pressed into the valve seat , and when the

unit was disassembeled , the wire fell out, leaving only an insignificant mark on the valve seat . " The final conclusion of the report

5 states. "It is obvious that under extreme conditions, backflow could

take place in the unit tested; for example, with the check valve and

the main valve very poorly seated or held open, simultaneously with

a high vacuum in the supply line. However, no backflow preventer

or vacuum breaker known at this time is entirely perfect or foolproof.

It is believed that in the great majority of cases serious imperfections

10 in valve seating will develop gradually; hence, in the device tested,

visual evidence of this fact would be at hand long before any real

danger of backflow exists."

There appear to be four reasons for backflow during the test

15 presented in Appendix Section 10.5

( i) The fouling wires used were 0.042-inches in diameter

versus 0.027-inches in diameter for the earlier NBS

test. The smaller diameter would favor check valve

20 seating into the soft check material.

( ii) A vacuum of 11-centimeters of mercury absolute was

used in this work (about 25-inches of mercury gage)

which is somewhat more severe than the 18 inches of

25 mercury gage used in the earlier NBS test.

(iii) The device used in this work was installed in a vertical line (as sanctioned by the manufacturer)

with the direction of normal flow "Down" . The older

30 device was installed in a horizontal line.

( iv) There were differences in manufactures designs, i.e.,

internal shape and size of the zone, discharge port,

etc

35

It\ seems likely, that had the 0.042-inch diameter fouling wire been

used during the earlier test, backflow probably would have occurred.

It must be said also that the rate of backflow occurring during the

test presented in Appendix 10.5 was very low. The likelihood of

40 such fouling of the device is probably remote because the manufacturer

requires the use of a strainer upstream of the device and the upstream

check valve has two seats that have to be fouled simultaneously.

Considerable difficulty was experienced during initial efforts to get

the wire to remain in position across both seats simultaneously.

45

44
Additional tests should be carried out concerning RPBD of other

sizes and from other manufacturers. Preliminary information

obtained from such tests would be of value in the development

of a back-siphonage test for a RPBD. The present standards for

RPBD do not have back-siphonage test methods or requirements;

5 however, the device is relied upon by many users to give effective

protection against back-siphonage.

It was beyond the scope and resources of this project to

determine the probability of the two check valves of an RPBD leaking

simultaneously or whether any RPBD of other manufacturers would

10 allow backflow or whether the size or configuration of the device

contributed to the backflow failures. An attempt was made to get

information from the Los Angeles Department of Water and Power (DWP)

concerning the number of times in any one year period on an average

that RPBD experiences the failure of both check valves. DWP has

15 computer records of inspection, test, and performance data on over

3,000 backflow preventers [11]; however, a computer program would

have to be developed to retrieve this information. The Department

of Public Utilities, City of Tacoma, Washington provided data for

yearly tests conducted on RPBD and double check valve assemblies

(DCVA) for the past 2 1/2 years. Data collected from 114 RPBD tests

showed several failures of the RPBD relief valves; however, only

one RPBD was found to have both check valves leaking simultaneously.

This condition occurred because of debris under the checks. Only

two DCVA were found to have both checks leaking simultaneously out

25 of 59 tests of DCVA conducted during that period. Factory Mutual

Fire Insurance Companies inspected 1,032 sets of DCVA and only four

sets were found out of this number to have both checks leaking

simultaneously [34]. The use of strainers ahead of RPBD may be a precaution to reduce risk of check leakage due to debris. ASSE

30 Standard 1013 for RPBD recommends the use of strainers but other

standards do not. It is believed by some that strainers introduce

excessive pressure drop.

The U. S. Navy has reported that on certain docks and piers

35 the relief valves of RPBD have frozen. Such failures have become

an expensive and not completely solved problem [11]. Repiping for

installation of a RPBD within a heated space could be a solution.

20

40

4.2 Assessment of Standard Test Methods

In this section the test methods given in standards for the

backflow prevention devices will be evaluated against the following

criteria

45

45
5 (a) Understandable, Usable and Fair: Can any normally

equipped laboratory perform the tests as described

in the standard? Can innovative devices be accepted

under the test method described or would such

devices be restricted from approval?

IQ (b) Methods that test appropriate attributes (life cycle

phenomena) : Are the test methods realistic? Do they

expose devices to water supply conditions of temperature,

pressure, flow, chemistry, water borne inclusions, and

actual or test contaminants that could pollute the

20 potable water?

(c) Repeatability and Accuracy: Are the test data repeatable

and how many runs of test data are taken? How accurate

are the measured data?

25

(d) Limit testing, Failure Modes, Maintainability, and

Field Testing: Are tests used to determine common modes of device failure? Is level of maintenance

determined? Do laboratory tests assure satisfactory

30 field performance?

(e) Cost/effectiveness: Are test methods periodically

reviewed to determine if instrumentation techniques

or other newly developed techniques might substantially

35 reduce the cost of testing and improve data quality?

By the formulation of these criteria there has been established

a "yard stick" against which the test methods may be evaluated. In

tables 9 , 10 and 11 the tests methods are summarized with comments

40 as appropriate. In the following subsections the tests methods will

be discussed in terms of the above criteria.

In Appendix 10.6 each of the ASSE Standards have been

analysed in great detail to identify the test requirements, test

45 setup and preparation for testing, test procedure, observations

records and computations and basis for rejection of device. The

matrix format used facilitates the identification of missing

elements

50 4.2.1 Understandable, Usable, and Fair Test Methods

The ASSE Standards have test setups and test methods for a laboratory to follow which are understandable and usable. The FCCCHR

and IAPMO Standards imply identical hydraulic laboratory tests but

46
Table 9 Summary of Test Methods Found in Current Standards for Atmospheric Types

of Backflow Preventers - with Comments

Devices and

Standards

Test Methods Comments

Air Gap (AG)

ANSI A112.1.2 1973 [26]

° Measurement of the length of

the air gap between the flood

level rim of a plumbing fixture or tank and the effective

(minimum) diameter of the

water supply outlet

Adequate test methods

Atmospheric

Vacuum

Breaker (AVB)

A.S.S.E. 1001,1970

ANSI A112.1.1 1971 [20]

° Nontoxic certification

° Positive pressure test

* Air port shield examination

° Air flow test

° Water rise test

Test methods are indirect,

that is, a tracer .yielding

quantitative results is

not used to simulate

contaminants

.

Antisiphon

VI£ XUail nch VaVd-LVC 1 VP Ball Cock (AFVBC)

A.S.S.E. 1002,1968 [30]

° General requirements

° Vacuum breaker equipped

° Air gap equipped ball cock

Barometric Loop (BL) (No test methods) This device has features

into the installation to make it reliable and costeffective.

Backflow Preventers

with Intermediate

Atmospheric Vent (BPIA)

A.S.S.E. 1012,1972 [22]

ANSI A112.1.4 - 1976

0 Noise

0 Hydrostatic test - total

° Hydrostatic test - check valve

° Tightness of downstream check

° Tightness of inlet check

° Atmospheric vent valve leakage

° Backflow through inlet check

0 Atmospheric vent, opening

pressure

° Back— s iphonage

° Flow and pressure loss

° Flow with low supply pressure

The standard does not have

a test method to cover .the likely condition of simultane'ous vacuum at the inlet and back pressure at the outlet

A tracer to simulate con- tamination could be used

to give quantitative measurements of check valve

leakage. The colored water

tracer called for can give

only a qualitative value.

Hose Connection

Vacuum Breakers (HCVB)

A.S.S.E. 1011,1970 [21]

ANSI A112.1.3 - 1976

° Resistance to hydrostatic test

0 Noise

° Water flow capacity

° Leakage from vent ports

° Water hammer shock resistance

0 Backflow due to back pressure

° Backflow due to back-siphonage

° Resistance to bending

° Ability to resist and relieve

back pressure

° Deterioration in hot and cold

water.

Although the test method

for backflow, section

2. 1.6, requires the use of

a colored water tracer,

this is a qualitative test

only which depends on visual ability to detect

the presence of the tracer.

A measureable tracer is

not used.

47
Table 10 Summary of Test Methods Found in Current Standards for Double Check Valve

Assemblies and for Pressure Type Vacuum Breakers - with Comments

Devices and

Standards

Test Methods Comments

Double Check

Valve Assembly (DCVA)

A q Q F 1015 1972 r 2 4

ANSI A112.1.6 - 1976

0 Hydrostatic test - full

° Hydrostatic back pressure test

of check valves

° Tightness of check valves

against upstream pressure

of 1 psi.

° Rated flow and pressure loss

Lacks realistic test for

performance under backsiphonage conditions, i.e., vacuum vacu 1<s -L o not" 11UL annH ClL/UlJ.Cu pH fL. n\J the inlet of the device.

Double Check

Valve Assembly (DCVA)

FCCCHR - 1974 [29]

IAPMO PS 31-74 [28]

AWWA C506 - 69 [31]

° Specifies similar requirements

as in A.S.S.E. 1015

° Also specifies but without a test procedure:

- shock and water hammer

- hydrostatic test on all

barriers

- 12 months field performance

- no backflow under all conditions of pressure differential

- tolerance to sand, scale and

other interfering materials

- devices for elevated temperatures to be so tested

The FCCCHR and IAPMO test requirements are very similar. The AWWA is less

developed

Test requirments must have

test procedures to be

useful broadly

Periodic testing of devices in a cross- connection control program

may economically substitute for field testing.

Antisiphon

Pressure Type

Vacuum

Breakers (PVB)

A.S.S.E. 1020,1974 [25]

ANSI A112.1.7 - 1976

° Hydrostatic test , internal , total

° Hydrostatic test, check valve

back pressure

° Check valve force loading

° Atmospheric vent , opening

pressure

0 Air passageway areas

° Back-siphonage prevention

° Rated flow and allowable

pressure loss

Test methods are indirect,

that is, a tracer .yielding

quantitative results, is

not used to simulate

contaminants.

Pressure Type

Vacuum

Breaker

Assemblies (PVB)

FCCCHR - 1974 [29]

IAPMO PS 31-74 [28]

° Specifies similar requirements

as in A.S.S.E. 1020

0 Also specifies but without a test procedure:

- shock and water hammer

- hydrostatic test on all

barriers

- 12 months field performance

- tolerance to sand, scale and

other interfering materials

- devices for elevated temperatures to be so tested

The FCCCHR and IAPMO test requirements are very

similar. IAPMO definitely

single and double check

valve types. FCCCHR (?)

Test requirements must

have test procedures to be useful broadly.

Periodic testing of devices in a cross- connection control program

may economically substitute for field testing.

48
Table 11 Summary of Test Methods Found in Current Standards for Reduced Pressure

Principle. Back Pressure Backflow Prevention Devices - with Comments

Devices and

Standards

Test Methods Comments

Reduced

Pressure Principle

Backflow Prevention

Device (RPBD)

A.S.S.E. 1013,1971 [23]

ANSI A112.1.5 - 1976

° Hydrostatic test - full

° Hydrostatic test - outlet only

° Outlet check valve, drip

tightness

0 Rated flow and allowable

pressure loss

° Zone pressure versus inlet

pressure (flowing status)

0 Zone pressure versus inlet

pressure (static status)

° Relief discharge rate

(backflow condition)

° Relief valve opening and

closing

° Relief valve discharge versus

inlet pressure surge

Lacks realistic test for

performance under backsiphonage conditions, i.e., vacuum is not applied to the inlet of the device.

Does not require a field

evaluation after the

device has passed the

laboratory tests.

Test methods are indirect,

that is, a tracer yielding

quantitative results is

not used to simulate

contaminants.

Reduced

Pressure Principle

Backflow Prevention

Device (RPBD)

FCCCHR - 1974 [29]

IAPMO PS 31-74 [28]

AWWA C506-69 [31]

° Specifies similar requirements

as in A.S.S.E. 1013

° Also specifies but without a test procedure:

- shock and water hammer

- hydrostatic test on all

barriers

- 12 months field performance

- no backflow under all conditions of pressure differential

- tolerance to sand, scale and

other interfering materials

- devices for elevated temperatures to be so tested

The FCCCHR and IAPMO test

requirements are very similar. The AWWA is less

developed.

Test requirements must

have test procedures to be useful broadly.

Periodic testing of devices in a cross- connection control program

may economically substitute for field testing.

49
they do not give test methods. Field test setups and field test

methods are given by FCCCHR and IAPMO, but these are not clear

concerning test site selection. ASSE Standards do not require

a field test but do invite the manufacturers to furnish recommendations for field testing upon request. The field test appears

5 to be a major difference between requirements of some standards.

The field test is an aspect of backflow preventer testing that

requires further study.

The standards are for particular product types and are generally prescriptive concerning functional parts. The standards

10 do not have a mechanism that would allow test of an innovative

device that may be entirely different than the particular products

covered which makes those standards difficult if not impossible

to apply to innovative devices.

15 4.2.2 Methods that Test Appropriate Attributes

4.2.2.1 Backflow Prevention

Although authorities claim the RPBD and DCVA prevent

20 back-siphonage , the standards for RPBD and DCVA do not have backsiphonage requirements or back-siphonage test methods. No standard

test requires that vacuum be applied to the inlet of RPBD and DCVA.

The standards do not give emphasis to the ability of RPBD to prevent

backflow due to back-siphonage. In fact, the opposite impression

is given. The foreword to ASSE 1013 for RPBD states the following:

"This standard covers only the type of device which is identified

as a Reduced- Pressure Principle Backflow Preventer which is designed

primarily for the prevention of backflow due to back pressure .

(Underline added for emphasis).

30

ASSE 1012, Backflow Preventers with Intermediate Atmospheric

Vent, requires a back-siphonage test for the very inexpensive

device, about $17.00, as compared to RPBD which would cost several

hundred dollars. This device has two independently operating check

35 valves separated by an intermediate chamber with provision for

automatically venting it to the atmosphere. Therefore, although

it does not incorporate a relief valve, it is similar to RPBD in

configuration. ASSE standard 1012 has a test method to determine

that no back-siphonage will occur if both check valves leak when

vacuum is applied to the inlet of BPIA and the downstream pressure

is atmospheric. (A basic purpose of this device is to protect the

potable water supply against backflow where contaminants located

within the outlet piping are under pressure from such equipment as ^ a low pressure residential heating boiler). In light of the fact

40

50
that back pressure will exist continuously during normal operation

of the device, it would seem that the above mentioned back-siphonage

test method would be more realistic if it were performed with back

pressure on the downstream side in lieu of atmospheric pressure.

5 The test method concerning HCVB was discussed in section

4.1.4. The basic conclusion concerning HCVB (without check valves)

is that it would not pass the backflow test of HCVB (with check

valves) ; consequently, it would not be approved under ASSE 1011

test methods . The device is a special AVB that should as a minimum

be tested under the procedures of ASSE 1001. The test methods for

10 HCVB (with check valve) concerning backflow due to back-siphonage

and back pressure appear adequate. However, the tests would be

more realistic if a quantitative tracer could be used that relates

to insecticides, herbicides, car wash soap, swimming pool water and

perhaps other substances that are associated with garden hose

15 application.

The water rise test for AVB and PVB appears to be generally

effective but could be improved upon if a quantitative tracer could

be used that relates to sewage and other commonplace contaminants.

20 The ASSE Standards do not apply the water rise test to AVB, HCVB

or BPIA when the devices are at operating temperatures. IAPMO

has no such test for PVB. It seems reasonable that moving parts of

devices might bind due to material expansion or contraction which

could cause device malfunction.

25

Additional backflow test improvements concerning all devices

would encompass tests that show the device to meet all of the

operating requirements. These are as follows:

30 ° Functional operation under dynamic conditions

° Functional operation at design pressure temperature

combinations

35 ° Functional operation would , of course , be under exposure

to vacuum at the inlet, pressure at the outlet and

combinations of vacuum and back pressure

Generally standards for devices do not test the devices for failure

modes. RPBD failure is generally indicated by water flowing from

the zone. However, the device does not have a means to warn of

failure unless someone actually sees the water discharging from the

zone. A remote -indicating device for RPBD located in hazardous

areas such as sewage treatment plants would be an improvement

No standard for other devices considers failure detection.

51
4.2.2.2 Nontoxic Materials

Devices should be constructed of nontoxic materials. ASSE

Standards are the only standard that consider nontoxic materials.

However, ASSE looks for a statement from the manufacturers that all

materials in contact with the potable water are nontoxic. No

criteria such as that given in the U. S. Public Health Service

Drinking Water Standards §/ is mentioned. No standard cites a test method for this important parameter. FCCCHR, IAPMO, and AWWA

Standards do not have requirements concerning toxicity of materials.

The standards should address this aspect of devices definitively

because one of the most important attribute of devices is nontoxicity.

4.2.2.3 Design Temperature

The standards are not consistent concerning test methods at

design temperatures. For instance, ASSE has design temperature

tests for AVB but no design temperature tests for RPBD and DCVA.

On the other hand, FCCCHR and IAPMO have tests for RPBD and DCVA if

the design temperature exceeds 110°F. Such tests are important for

all devices because of possible binding of moving parts at elevated

operating temperatures . It seems reasonable that standards should

not be inconsistent concerning temperature tests.

4.2.2.4 Rated Flow and Allowable Pressure Loss and Hydrostatic

Pressure Resistance

The standards (ASSE, AWWA, FCCCHR and IAPMO) agree on the

acceptable flow rates for RPBD and DCVA. ASSE test methods for

pressure drop versus flow rate are defined and appear adequate.

AWWA does not have test methods, FCCCHR and IAPMO have implied

tests but their methods are not defined. ASSE has acceptable flow

rate and allowable pressure loss test methods for all devices

except AVB. It would seem reasonable that acceptable flow rates

and an acceptable test method be given for AVB.

— Under the Safe Drinking Water Act, Public Law 93-523, National

Interim Primary Drinking Water Regulations were promulgated

December 24, 1975 to become effective 18 months later.

52
ASSE, FCCCHR, and IAPMO have hydrostatic pressure tests for

devices. However, there is some inconsistency in the duration of

the time that internal pressure of two times working pressure

(2 x 150 psig) is applied. FCCCHR and IAPMO require at least two

minutes. ASSE requires a ten minute application. The basic purpose

of this test is to observe any leaks in valve bodies and check

valves or distortion of parts. The test time should be standardized.

ASSE requires that AVB be subjected to a hydrostatic test at design

temperature extremes (32°F and 212°F for hot water devices and 32°F

and 110°F for cold water devices) but other devices such as RPBD

which has identical operating requirements is not tested at a design

temperature

4.2.2.5 Water Hammer

The standards are inconsistent concerning test methods for

water hammer. ASSE has water hammer tests for HCVB but no tests for

RPBD and DCVA. FCCCHR and IAPMO indicate water hammer tests but do

not give the methods for RPBD and DCVA.

Water hammer results in overpressure that could occur

periodically. In light of this, devices should be exposed to a certain number of cycles of water hammer to determine possible

failure of parts. A similar test method is used on shock absorbers

that prevent water hammer. This test method is detailed in the

standard for water hammer arresters [35]

4.2.2.6 Noise

ASSE has a noise test method for HCVB and BPIA but does not

mention a test for RPBD and DCVA. The method basically depends on

the hearing ability of the test personnel. FCCCHR considers that

RPBD and DCVA should not "chatter" which implies noise but no test

method is given. It is important that these devices not be noisy.

Users may defeat them or have them removed from service. Study

would be required to develop quantitative techniques to detect

noisy devices.

4.2.2.7 Resistance to Actual Contaminants or Simulated Contaminants

Under Laboratory Conditions

No standard test method requires that contaminants such as sewage or other toxic substance or an appropriate nontoxic tracer be

used to demonstrate quantitatively the ability of the devices to

prevent backflow of contaminants under realistic conditions. For

example, such performance standard should include a tracer test for

functional performance under various steady state normal flow, and

dynamic flow conditions (water hammer , etc . )

53
10

15

20

Although the standards for devices do not consider these

realistic conditions, such tests have been performed on one model

of RPBD by the Oak Ridge National laboratory (ORNL) using the

procedures of activation analysis [36] . The RPBD passed this test

which had a sensitivity of about 0.2 parts per billion of manganese.

The nonradioactive test was generally as follows:

(a) The water supply at the test setup was first sampled

to determine the threshold level of manganese, if any.

(b) The manganese tracer was introduced down stream of the

device and the device subjected to pressure differentials,

fluctations water hammer, etc.

(c) The upstream side of the device was next sampled to

determine if manganese had backflowed. The samples were

irradiated in a nuclear reactor in order to determine

the amount of manganese present. The upstream samples

did not indicate backflow. That is, the manganese

concentration upstream did not increase over the

threshold value

No correlation was made between manganese tracer and other

hazardous substances. Further work is needed to validate and

develop the practical application of this promising test method.

25 4.2.3 Repeatability and Accuracy

With the exception of ASSE 1001 and ANSI A112 . 1 . 1 . 1971

(pipe Applied Atmospheric Type Vacuum Breakers) , no other standards

require data repeatability (the average of three test runs are required) or measure accuracy. However, an acceptable value of data

30 repeatability is not mentioned (departure from the average)

4.2.4 Limit Testing, Failure Modes, Maintainability and Field

Testing

35 The standards do not require that devices be cycled to

failure over operating conditions of temperature, pressure, and flow

in order to detect failure modes. The standards do not require that

devices fail safe or that devices indicate when they have failed

(except for RPBD) . RPBD discharges water from its ports on failure

40 of check valves or relief valve but this does not necessarily mean

such failure would be observed or detected. As noted earlier, no test methods determine whether a device can prevent backflow of a pollutant when subjected to conditions of backflow under operating

conditions of temperature , pressure , and flow . Guidelines and tests

45

54
for mean time between failure, mean time to maintain, mean time

to repair, level of spare parts required, availability of repair

parts are not considered.

FCCCHR and IAPMO Standards require a twelve-month field

test of RPBD and DCVA. Although the standards do not go into

detail concerning the tests, the following is the general procedure

as given in an unpublished FCCCHR paper [32]: See Section 3.4.1.

(a) One or more units of each size and model are submitted

from the manufacturer's stock. These devices

shall pass the laboratory test prior to the field

evaluation

(b) The manufacturer arranges for the placement of at

least three devices, of each size and model tested

in the laboratory in the field installation. FCCCHR

approves of the selected field location. The location

must not be on a fire service where normally a no-flow

condition exists almost continuously. The devices

must not be placed where the flow is maximum all of

the time. Also, an RPBD under test must not be placed

in a pipeline where there is potential for hazardous

backflow if the RPBD should fail during the field

test. The devices must be located in pipelines where

the water supply can be turned off for short periods

of time as required by test procedures

(c) The field evaluation consists of a monthly test of all

of the devices on the field test program.

The field test purpose is to assure that a device will function

under actual operating conditions . ASSE Standards do not require

a field test and as a result their standards do not give assurance

of satisfactory performance under operation conditions. Field

testing is presently performed only for RPBD, DCVA and PVB. AVB

is not field tested. It appears that this aspect of testing

requires additional study. Certainly, assurance should be given

that all devices will perform in the field.

55
5. SUMMARY OF FINDINGS

The following is a summary of findings concerning backflow

protection devices, test methods, and laboratories.

5.1 Air Gap (AG)

An air gap provides positive protection against backflow of

liquid and solid contaminants. However, authorities recognize that an air gap may be defeated through attachment of by-passes [ 1] . This

attribute of AG is no different than that of other devices such as the electric fuse which can be defeated in households by use

of coins or other means that result in burned wiring and houses.

5.2 The Reduced Pressure Backflow Device (RPBD)

The RPBD provides good protection against backflow in high risk

situations. This device is in its weakest mode of operation when

subjected to both back pressure and back-siphonage conditions simultaneously. NBS tests have demonstrated that one RPBD would backflow

when the check valves leaked under such conditions. The standards

for RPBD do not have requirements or test methods for back-siphonage.

However, one manufacturer's literature states that the RPBD is

absolute protection against back-siphonage conditions. Administrative

authorities use RPBD for protection against both back-siphonage and

back pressure within the water service lines to hazardous locations

such as sewage treatment plants. The probability of simultaneous back

pressure and back-siphonage conditions is unknown but is presumed to

be much smaller than the likelihood of either event singly. Thus,

RPBD's clearly do provide protection. The RPBD's only means of

protection under simultaneous conditions of both back-siphonage and

back pressure is the tightness of the check valve on the upstream side

of the zone. For this reason, a periodic test and maintenance

program is essential for RPBD (some authorities test RPBD at least

annually) [1]. The use of strainers is considered helpful by some,

but others feel that strainers can cause excessive pressure drop

(ASSE's standards require strainers ahead of both RPBD and DCVA but

FCCCHR does not).

5.3 Fail Safe Devices

No device currently used to prevent backflow provides a positive

indication of the device function or malfunction in the way that a fuse

or circuit-breaker protects an electrical circuit. An RPBD can be

observed to discharge fluid as an indicator only if an informed person

happens to be near the device at the time the backflow condition exists

56
The ASSE standard 1001 does not consider means to test AVB for

malfunction in the field [20]

Although Barometric Loops are used in large laboratory complexes

to protect against backflow of potentially hazardous substances, there

are questions concerning its adequacy to protect against transfer of

contaminants by air bubbles if an air water separator is not used.

Additional studies concerning transfer of pollutants by diffusion and

by air have been recommended by the National Institutes of Health

[27] .

HCVB with a check valve is in its weakest mode of operation

when subjected to back pressure which occurs when the terminal end

of the garden hose is elevated above the HCVB. In this situation the

device does give protection as long as the check valve does not leak.

More protection could occur if the devices were located above the

terminal end of the hose, though such an arrangement may not be

practical in many cases. The HCVB without the check valve should

not be used on garden hoses because this type of HCVB does not prevent

backflow caused by back pressure. This type HCVB (without a check

valve) is merely a special AVB and should be tested under ASSE type 1001

methods

5.4 Realistic and Usable Test Methods

The AWWA standard for RPBD and DCVA does not contain test

methods or implied tests. FCCCHR and IAPMO indicate the type of tests

that are to be performed but do not give details of the test methods or test setups for hydraulic laboratory tests. ASSE standards specify test

methods and test setups.

In the case of RPBD, the current standards do not consider

back-siphonage conditions and yet the device is used for this condition

in actual practice. Similarly RPBD tests do not involve actual demonstration of functional performance i.e., prevent backflow of actual

contaminants under simulated use conditions.

The RPBD standards are not consistent concerning the necessity

for field test. ASSE does not require a field test and FCCCHR and

IAPMC require a twelve month field test. Further, FCCCHR and IAPMO

standards do not provide definitive detail concerning how to perform

the tests. Although PVB is field tested, AVB is not field tested.

The standard for HCVB (check valve type) tests the device with

water discharging from its air inlet ports. This is reasonable in

light of the fact that the device is designed to relieve back pressure

through its ports. However, some authorities, Dawson and Kalinske, [3]

have said that one of the main requirements to good vacuum breaker

57
design and installation is to prevent the discharge of water from the

air inlet ports. Such discharge is alleged to cause blockage of the

ports by a build up of lime deposits. Further study is required to

determine if this condition will occur with HCVB. Port pollution

possibilities should also be studied.

No standard requires the use of actual or simulated

contaminants or an appropriate tracer to demonstrate quantitatively

or qualitatively the ability of the devices to prevent backflow. All

present tests are indirect in that they show that valves do not leak

or that relief valves function. The water-rise test for AVB is the

most realistic test, but it is not concerned with upstream measurements

to determine if a contaminant (air, aerosol, etc.) has passed into the

inlet of the device

With the exception of the ASSE/ANSI Standard for AVB, no other

standard specifies data repeatability or measurement accuracy.

Limit testing to determine failure modes or other tests to

determine mean-time -to -maintain or to-repair , and level of spares required

or availability of spares are not considered by standards. Many of

these devices are very expensive, costing thousands of dollars.

The standards do not explicitly require periodic review of

test methods/equipment.

6, CONCLUSIONS AND RECOMMENDATIONS

6.1 Conclusions

1. Existing backflow prevention devices do provide protection

against backflow. However, insufficient data appears to exist to

evaluate quantitatively the effectiveness of these devices, the risks

associated with various types of system designs, or the relative

advantages of various devices in particular installations.

2. None of the existing devices is fool proof. Most do not provide

positive indication of failure, when it occurs, or device usage when

backflow conditions arise; nor are any of the devices used fail-safe.

There is some apparent misconception of the test methods regarding the

capabilities of the RPBD and HCVB (with check valves) in particualr

concerning functional performance under all normal service conditions

(i.e., combined back pressure and back-siphonage conditions and

possible lime deposits blocking HCVB air ports) . HCVB (without a check) should not be used with garden hoses.

58
3. A.S.S.E. Standards are the only standards that have detailed

test methods, i.e., definitive test procedures and test setups. However,

the standards are inconsistent concerning the application of realistic

tests. For instance (other examples are in section 4.2), if a device

is designed to operate in water that is 32°F, the device should be

tested to demonstrate the ability to prevent backflow at that temperature. AVB's are tested at their operating temperatures for leaks and

distortion of parts but not back-siphonage . RPBD's do not have test

methods that show the device will operate at design temperatures.

Although both AVB's and RPBD's are used to protect against backsiphonage, AVB's are tested with vacuum and RPBD's are not. In fact no standard of FCCCHR, IAPMO, or AWWA specifies performance for RPBD

under vacuum conditions simulating back-siphonage. FCCCHR and IAPMO

require a twelve month field test, but ASSE does not. Some standards

do not explicity spell out test methods or equipment. Others are prescriptive and provide no means for testing of innovative devices.

No existing standards test devices for functional performance under

full actual or simulated service life conditions. The test methods,

however, do show that devices provide protection. These test methods

could be much improved by the use of realistic service condition

simulation

4. In fairness to the backflow prevention device industry and the

standards to which they adhere it is appropriate to note

(a) The backflow prevention device industry provides an extremely valuable National service in the manufacture

and sales of devices which adhere to recognized standards.

The purpose of this work was not to discredit any party

concerned, but to present constructive criticism

when required.

(b) Although the devices of a particular manufacturer may be

recognized in this report, tests presented and discussed

here do not in any way discredit specific products.

6.2 Recommendations

6.2.1 First Order Priority

(a) It is recommended that a study be carried out concerning

the reliability of devices that have been field tested

versus the reliability of devices that have not been field

tested in order to resolve the apparent controversy

concerning whether to require field test or not.

59
(b) It is recommended that a functional performance test and

performance standard based on using a quantitative tracer

(pollutant) be developed that would be applicable for

testing all classes of devices including innovative devices

under simulated life cycle conditions. During the test,

the devices would be subjected to a program of various

water supply operating conditions including backsiphonage to determine the ability of the device to

prevent the backflow of the tracer or simulated

contaminant. See Section 4.2.2.7.

(c) It is recommended that a program be undertaken to

develop a positive fail-safe means of indicating or calling

operator attention to any backflow condition particularly

in high-hazard locations. Ideally a device

corresponding to an electrical fuse or circuit breaker

would be desirable.

6.2.2 Second Order Priority

(a) It is recommended that means be developed that would allow

the homeowner or plumbing inspectors a ready means to

determine whether or not an AVB or HCVB or similar device

is functioning properly and has not failed.

(b) It is recommended that manufacturers provide definitive

data concerning reliability, maintainability, mean-timeto-maintain, and mean-time-to-failure on their devices

for various locations and water type, etc.

(c) It is recommended that a study be conducted to determine

the level of barometric loop usage and whether or not the

barometric loops in use are using air-water separators

[19].

(d) It is recommended that a study be carried out concerning

the use of strainers ahead of RPBD, DCVA, PVB, and AVB.

Such strainers would tend to prevent the passage of

particles that could foul the checks of devices.

(e) It is recommended that a back-siphonage detection

monitoring system be developed. This should include

sampling at statistically selected high-hazard

locations such as sewage treatment plants, hospitals,

and hazardous industrial and commercial locations. Such

information would define the magnitude of the problem and

pinpoint recurring low pressure conditions in the water

60
supply system that must be corrected. Better data on backflow incidents is needed to provide a basis for

developing and evaluating alternative program options

in this field.

It is recommended that a rational approach be developed

to determine the order of magnitude of the risk presented

by any particular type of hazard on a premise as related to

other premises and the water utility itself. For instance,

hazardous condition on a premise of a given type located

in the middle of a highly populated metropolitan area would present a greater risk in terms of population

density alone than the same condition on a premise

located outside the metropolitan area where the population

density is very much lower. This method would provide a means of establishing priorities for the installation of

devices of various types. This approach would be based

on information on adverse water pressure fluctuations

and backflow incidents reported in paragraph (e) above.

It is recommended that the HCVB's be studied to obtain

answers to the following questions:

(i) Will the air ports become blocked with lime

deposits to make them ineffective.

(ii) Is there a high risk of contamination at the

air ports?

(iii) Would the device give greater protection

installed at the nozzle end of the hose

instead of the sillcock end?

61
7. ABBREVIATIONS AND DEFINITIONS

The following Abbreviations have been used in this report. The source of

definitions are identified at the end of the section.

Air Gap AG

American National Standards ANSI

Institute

American Society of Mechanical ASME

Engineers

American Society of Plumbing ASPE

Engineers

American Society of Sanitary A.S.S.E.

Engineering or ASSE

American Standards Association A.S.A.

or ASA

American Water Works A.W.W.A

Association or AWWA

Antisiphon flush valve ball cock AFVBC

Atmospheric Type Vacuum Breaker AVB

Backflow Preventer with BPIA

Intermediate Atmospheric Vent

Ball Cock BC

Barometric Loop BL

Building Officials and Code B.O.C.A.

Administrators International, or BOCA

Inc

Critical Installation Level C-I-L

Double Check Valve Assembly DCVA

Environmental Protection EPA Agency

Feet or foot ft

Foundation for Cross-Connect ion FCCCHR

Control and Hydraulic Research

Foundation for Cross-Connection FCCCR

Control Research

Gallons per minute

Hose Connection Vacuum

Breaker

Inch or inches

International Association

of Plumbing and

Mechanical Officials

Iron pipe size

Library of Congress "Science

Policy, a working Glossary"

Los Angeles Department of

Water and Power

Milliliters

Minute

National Association of

Plumbing-HeatingCooling Contractors

National Bureau of Standards

National Sanitation

Foundation

National Standard

Plumbing Code

Oak Ridge National

Laboratory

Pounds per square inch

Pounds per square inch, gage

Pressure type vacuum

breaker

Product Standard

g.p.m.

or gpm

HCVB

in

I.A.P.M.O.

or IAPMO

l.p. s. or ips

LCSPWG

DWP

ml

min

NAPHCC

NBS

NSF

NSPC

ONRL

p. s. i. or psi

psig

PVB

PS

P.educed Pressure Principle RPBD or Backflow Prevention Device or RP

62
7.2 Definitions

Administrative Authority ; The individual official, board, department,

or agency established and authorized by a state, county, city or other political subdivision created by law to administer and enforce the provisions of the plumbing code or of a cross-connection

control program. (NSPC & NBS)

Air Gap : An air gap in a potable water distribution system is the un- obstructed vertical distance through the free atmosphere between

the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture or other device and the flood level rim of

the receptacle. (NSPC)

Air Gap Separation : The physical separation between the free-flowing

discharge end of a potable water supply pipeline and an open or non-pressure receiving vessel. The width of separation shall be

at least that specified in ANSI A112.1.2 - 1973 (FCCCHR & NBS)

Air Inlet : The opening or series of openings through the body of a vacuum breaker connecting the free atmosphere with the liquid

passageway of the device (ASSE 1001)

Ambience (noun) : The surroundings or environment of a place or thing

used in experimental research to indicate, e.g. the temperature,

humidity pressure, gases, and radiation in the space surrounding

the object of an experiment. (LCSPWG)

Analysis : The action of taking something apart and examining its

components. (The very extent of the use of the term may seem to

deprive the word of much of its meaning. It is employed in a great many different senses, and in many combinations. The meaning seems to depend somewhat on the discipline connected with

its use.)

The notion that analysis is an identifiable and describable

process independent of the discipline involved or the item being

analyzed is suggested by the large number of compound words

hyphenated with it, for example: value-, failure-, costeffectiveness-, operations-, systems-, stress-, reliability-,

maintainability-, etc. (LCSPWG & NBS)

Atmospher ic Air : Air of the surrounding atmosphere and at its existing" pressure. (ASSE 1013)

Backf low : The unintentional reversal of flow in a potable water

distribution system which may result in the transport of harmful

materials or substances into the other branches of the distribution system. (NBS)

Backf low Connection : The point of joining of potable water piping with

equipment, fixtures, or other piping that may be contaminated. (NBS).

63
Backflow Preventer : Any mechanical device, whether used singly or in

combination with other controls, that may automatically forestall

the possibility of an unintentional reverse flow in a potable water

distribution system. (ASSE 1001)

Backflow Preventers with Intermediate Atmospheric Vent : These devices have

two independently operating check valves separated by an intermediate

chamber with a means for automatically venting the chamber to the

atmosphere. 1 The check valves are force loaded to a normally closed

position and the venting means is force loaded to a normally open

position. These devices can operate under continuous or intermittent

pressure conditions. (ASSE 1012)

Backflow Preventers, Reduced Pressure Principle, Back Pressure : These devices

consist of two independently acting check valves, internally force

loaded to a normally closed position, and separated by an intermediate

chamber (or zone) in which there is an automatic relief means for venting

to atmosphere, internally force loaded to a normally open position. These

devices are designed to operate under continuous pressure conditions.

(ASSE 1013)

Backflow Preventers, Double Check Valve Type, Back Pressure : These devices

consist of two independently acting check valves internally force loaded

to a normally closed position and designed and constructed to operate

under intermittent or continuous pressure conditions.' (ASSE 1015)

Back Pressure : Pressure created by any means in the water distribution system

on the premises, which by being in excess of the pressure in the water

supply main could cause backflow. (NBS)

Back-Siphonage : The backflow of possibly contaminated water into the potable

water supply system as a result of the pressure in the potable water

system becoming unintentionally less than the atmospheric pressure in the

plumbing fixtures, pools, tanks or vats that may be connected to the

potable water distribution piping. (NBS)

Ball Cock : A water supply valve opened or closed by means of a float or

a similar device and used to supply water to a tank. (ASSE 1001)

Ball Cock, Antisiphon : A ball cock that contains an antisiphon device

in the form of an approved air gap or a vacuum breaker which is an integral part of the ball cock unit and which is positioned on the

discharge side of the water supply control valve. (ASSE 1001)

Check Valve Assembly : A combination of spring and weight loaded check

valves with resilient discs for the intended purpose of preventing

back pressure backflow in a water supply line. Assembly is usually

furnished with test cocks for field testing the tightness of the check

valves. Some assemblies include a vacuum breaker to admit atmospheric

air downstream of the assembly. (ASSE 1013)

64
Community Water System : A public water system which serves at least

15 service connections used by year-round residents or regularly

serves at least 25 year-round residents. "Non-community water

system" means a public water system that is not a community water

system (EPA 141.2. (e)) (see public water system).

The purpose of defining "Community water system" is to allow

appropriate regulatory distinction between public water systems

which serve residents on a year-round basis and public water

systems which principally serve transients or intermittent users. The possible health effects of a contaminant in drinking water in

many cases are quite different for a person drinking the water for

a long period of time than for a person drinking the water only

briefly or intermittently. Different monitoring requirements are appropriate for the two types of systems. (EPA 141.2(e))

Constraint : A limiting condition to be satisfied in the design or operation of a system. For example: the total cost may be a constraint, or the percentage of system life consumed in downtime, or the compatability of a system with other systems.

(LCSPWG)

Contamination : The admission of contaminants into a potable water

supply (ASSE 1013)

Contaminants (as applicable to standards for backflow prevention

devices) : Materials (solids or liquids or gases) which may be

added unintentionally (or intentionally) to the potable water

supply and cause it to be unfit for human or animal consumption.

(ASSE 1013)

Contaminants (as applicable to the Safe Drinking Water Act) ; Any

physical, chemical, biological, or radiological substance or matter in water. (EPA 141.1(6))

This definition, in the. review of Section 141.2 of the National

Interim Primary Drinking Water Regulations of December 24, 1975, was critized for its breadth. The term as defined includes

virtually any constituent in water, including constituents con- sidered to be harmless or even beneficial. The definition was

taken directly from Section 1401(6) of the Safe Drinking Water Act.

It is not intended to suggest that all constituents of water are undesirable, but rather is intended to permit the regulation of any

constituent which may be harmful. (see definition of maximum

contaminant level)

65
Control Valve : A valve that is operated each time water is supplied to or shut off from a receptacle or plumbing fixture. Familiar examples

are faucets and sill cocks. (ASSE 1001)

Cost/Benefit Analysis ; The relation between social benefits and social

costs associated with the operations of a technical system under

study. The benefits and the costs include direct and indirect

effects. Monetary equivalents are sometimes assigned to the nonmaterialistic values for the purpose of comparison and to clarify

the relationships between benefits and costs. (LCSPWG)

Cost/Effectiveness : This is a term widely used in systems analysis, and

has been carried over into budgeting analysis. It signifies the

ratio, over an explicit and finite time-span, of cost in dollars

and other tangible values to effectiveness. In the military area,

in which cost/effectiveness analysis originated, the payoff was defined in terms of the effectiveness of the military system. In

the civilian area, "effectiveness" is replaced by "benefit."

Admittedly, benefits in social systems are even more difficult to

define than effectiveness in military systems. (LCSPWG)

Criterion (plural Criteria) : A standard or an explicit measure by which

to evaluate any activity or thing. Criteria may be quantitative or qualitative and objective or subjective. In effectiveness analysis,

criteria are the elements to be measured to determine costs and

benefits. (LCSPWG)

Critical Installation Level : A designated operational limitation prescribing a safe height on installed vacuum breaker above the floodlevel rim of the fixture or receptacle served. In the absence of a physical mark on the device, indicating a height measurement reference point, the extreme bottom of the device shall be considered

the height reference point. (ASSE 1001)

Cross Connection : Any physical connection or arrangement between two

otherwise separate piping systems, one of which contains potable

water and the other either water of unknown or questionable safety

or steam, gas, chemicals or other substances whereby there may be

a flow from one system to the other, the direction of flow depending

on the pressure differential between the two systems. By-pass

arrangements , jumper connections, removable sections, swivel or changeover devices and other temporary or permanent devices

through which or because of which backflow can or may occur are considered to be cross-connections. (FCCCHR)

Cross Connection, Point of : The specific point or location in a potable

water distribution where a cross connection exists. (FCCCHR)

66
Effectiveness : In system analysis, the term effectiveness is an aggxegative expression intended to encompass all performance

qualities of a system that is likely to be judged as relevant.

The term describes a condition in which a system or program

possessing it has been designed to satisfy at some pre -determined

level all criteria selected as relevant. The term does not imply

perfection but essential adequacy in all significant categories

of performance. An effective design will result from the total of

design decisions among options, selecting the optimal trade-off

at each decision point, to satisfy all conceivably relevant

internal and external criteria, quantitative and qualitative,

tangible and intangible of performance and environmental compatibility.

The concept includes such obvious criteria as cost, efficiency, and

reliability. It also involves total life cost, maintainability,

maintenance of the state-of-the-art modernity, compatibility with

expected operating environment, recycle or scrap value, and such

other criteria as the design engineer and the customer (or sponsor)

consider relevant. (LCSPWG)

Flood Level Rim : That level from which liquid in plumbing fixtures,

appliances or vats could overflow to the floor when all drain and

overflow openings built into the equipment are obstructed. (NBS)

Hazard: A possible source of danger or peril; also a condition that

tends to create or increase the possibility of loss or harm. (NBS)

Hazard, Health : An actual or potential threat, of contamination or pollution of a physical or toxic nature to the potable water system

to such a degree that there would be a danger to health. (FCCCHR)

Hazard, Minimal : A connection made to the potable water system whereby

the risk from backflow occurring would entail the contamination of

the potable water with objectionable but non-toxic substances such

as steam, air , food, beverage etc. (NBS)

Hazard, Plumbing : A plumbing type cross-connection in a consumer's

potable water system that has not been properly protected by a vacuum breaker, air gap separation, or other suitable device. (FCCCHR)

Health Agency : The organization established by law to have jurisdiction

over the water supply quality. (FCCCHR)

In the National Interim Primary Drinking Water Regulations, "State"

means the agency of the State government which has jurisdiction over

public water systems. During any period when a State does not have

primary enforcement responsibility pursuant to Section 1413 of the

Safe Drinking Water Act, the term "State" means the Regional Administrator, U. S. Environmental Protection Agency. (EPA 141.2(h))

67
Maximum Contaminant Level : The maximum permissible level of a contaminant in water which is delivered to the free flowing

outlet of the ultimate user of a public water system, except

in the case of turbidity where the maximum permissible level

is measured at the point of entry to the distribution system.

Contaminants added to the water under circumstance controlled

by the user, except those resulting from corrosion of piping

and plumbing caused by water quality, are excluded from this

definition. (EPA 141 . 2 (c)

)

Model: A simplified description of a process or system, or the

interaction of either with its environment. (LCSPWG)

Potable Water : Water from any source which has been approved for

human consumption by the health agency having jurisdiction.

(FCCCHR)

Potable Water: Water that meets the maximum contaminant level

requirements of the National Interim Primary Drinking Water

Regulations and which has been approved for human consumption by

the health agency having jurisdiction. (EPA)

Pollution : As used in this report the word is equivalent to

contamination in the sense that substances in the water are either undesirable or harmful. FCCCHR credits the California

State Health and Safety Code with differentiating the two words:

contamination of water creates health hazards (q.v.) and

pollution of water creates minimal hazards (q.v.). (NBS)

In view of the EPA definition of a contaminant, the word

"pollutant" may provide the means of defining or designating

the "contaminants" that are undesirable or harmful.

Pressure, Absolute : Pressure measured on a scale having a zero value

approximately 14.7 lb/in^ below normal atmospheric pressure.

Pressure, Atmospheric : The pressure exerted in every direction at

any given point by the weight of the atmosphere.

Pressure, Hydrostatic : Pressure exerted by or existing within a liquid at rest with respect to adjacent bodies.

Public Water System : A system for the provision to the public of

piped water for human consumption, if such system has at least

fifteen service connections or regularly serves an average of

at least twenty-five individuals daily at least 60 days out of

the year. Such term includes (1) any collection, treatment,

storage, and distribution facilities under control of the

operator of such system and used primarily in connection with

68
such system and (2) any collection or pre-treatment storage

facilities not under such control which are used primarily in

connection with such system. A public water system is either

a "Community Water System" or a "Non-Community Water System"

(EPA 141.2(e))

Service Connection: The point at or near the water main where the

water purveyor delivers potable water to the consumer's water

system. Usually the water purveyor loses jurisdiction and

sanitary control over the water at the service connection.

Trade -off : The foregoing of some portion of one benefit in order to

achieve some unused portion of another benefit: (or) foregoing

some portion of a benefit in order to achieve a reduction in some portion of a cost: (or) accepting an increased portion of one cost in order to receive a decrease in the portion of another

cost. Other more complicated permutations of this concept can be

suggested. The term is in wide usage. (LCSPWG)

Toxic : Poisonous [see Code of Federal Regulations, Title 21, Food and

Drugs Parts 170 to 299, 21 CFR 170.1, Section 191.1, Hazardous

Substances. Definitions.] (ASSE 1011)

Vacuum : Any space in a water-supply system from which water has been

displaced by water vapor, air, or other gases, and in which the

pressure is less than the prevailing atmospheric pressure.

(RP 1086)

Vacuum Breaker, Atmospheric Type : A back-siphonage prevention device

which is designed to operate under pressure only when water is

flowing through the system and not under static, standing

conditions. Must be installed upstream of any shut -off or control

valve or means. (ASSE 1011)

Vacuum Breaker, Pressure Type : A back-siphonage prevention device

which can be subjected to continuous pressure, flowing, static, or both. (ASSE 1011)

Vacuum Breaker, Hose Connection Type : A backflow prevention device

designed to be attached to an outlet having a hose connection

thread. It may be either atmospheric or pressure type. (ASSE 1011)

Water Hammer: The term used to identify the hammering noises and

severe shocks that may occur in a pressurized water system when

flow is halted abruptly by the rapid closure of a valve or faucet.

(NBS)

Water Purveyor: The owner or operator of the public potable water

system supplying an approved water supply to the public. The

69
purveyor operates under a valid permit from the State Department

of Public Health or the local health agency having jurisdiction.

(FCCCHR)

Water Supply Approved : Any public potable water supply which has

been investigated and approved by the State Department of Public

Health or the local health agency having jurisdiction. The

system must be operating under a valid health permit. (FCCCHR)

Sources of definitions are identified by code as follows:

ASSE 1001

ASSE 1011

ASSE 1012

ASSE 1013 and 1015

-Standards of the American Society

of Sanitary Engineering

see reference in Section

[20] [21] [22] [23] [24]

EPA EPA, Water Programs, Part 141,

National Interim Primary Drinking

Water Regulations, dated Dec. 24, 1975

FCCCHR Foundation for Cross Connection Control

and Hydraulic Research, see Reference [2 9]

LCSPWG Library of Congress "Science Policya Working Glossary" see Reference [37]

NBS When used alone, the definition was generated by the authors, when used jointly,

the definition was modified from one published by the other source.

NSPC- -National Standard Plumbing

Code Reference [38]

RPI086- -Hunter, Golden, and Eaton

Reference [2]

70
8. REFERENCES

[ 1] "Accepted Procedure and Practice in Cross Connection Control

Manual , " Prepared and edited by the Cross Connection Control

Committee of Pacific Northwest Section, American Water Works

Association, Published by Pacific Northwest Section, AWWA,

October 1971.

[ 2] Hunter, R. B. , Golden, G. E., and Eaton, H. N. "Cross-Connections

in Plumbing Systems" National Bureau of Standards (U. S.)

Research Paper RP 1086, Vol. 20, April 1938.

[ 3] Dawson, F. M. and Kalinske, A. A. "Report on Plumbing CrossConnections and Back-Siphonage Research" State University of

Iowa, National Association of Master Plumbers of the United

States, Inc., (now NAPACC) Washington, D. C, Tech. Bulletin

No. 1, 1938.

[ 4] Nielsen, L. S. Standard Plumbing Engineering Design , (McGraw-Hill

Book Company, Inc., New York, N . Y . , 1963.)

[ 5] Craun, G. F., and McCabe, L. J., "Review of the Causes of

Waterborne Disease Outbreaks . " Journal American Water Works

Association, Vol. 65, 74 (1973).

[ 6] Craun, G. F. "Microbiology - Waterbourne Outbreaks" Journal

Water Pollution Control Federation, Vol. 46, No. 6, June 1974.

[ 7] "Cross-Connection Control Manual," U. S. Environmental Protection

Agency, Office of Water Programs, Water Supply Division, 1973,

EPA-430/9-73-002.

[ 8] Hutchinson, Gary D. "The Problem of Cross-Connections , " Presented

at AWWA Cross-connections Control Seminar, Atlanta, Ga., March

28, 1972.

[ 9] Hutchinson, G. D. "Cross-Connection Control Policy and

Recommendations" American Society of Sanitary Engineers, 1970

Yearbook, Vol. 48, pp 96-98.

[10] Stockton, E. L. "Cross-Connection in Calhoun County, Michigan,"

The University of Missouri Bulletin, Engineering Series,

Engineering Experiment Station Bulletin No. 32, 1943.

[11 ] Bibbens, R. N. "Backflow Prevention Devices for Potable Water

Systems at Naval Shore Facilities, Investigation through

January 1971," Naval Civil Engineering Laboratory, Port

Hueneme, Calif., Technical Note N-1169, May 1971.

71
[12] Vivian, R. E. and Reynolds, K. C. "Objectives, General Testing

Procedure, Specifications, Results of Tests," The Research

Foundation for Cross-connection Control, University of Southern

California, Los Angeles, Calif., Paper No. 5, April 1948.

[13] Springer, E. K. and Reynolds, K. C. "Definitions and Specifications

of Double Check Valve Assemblies and Reduced Pressure Principle

Backflow Prevention Devices," University of Southern California,

School of Engineering, Report 48-101, January 30, 1959.

[14] Reynolds, K. C. "Manual of Cross-Connection Control Recommended

Practice," Research Foundation for Cross-Connection Control,

University of Southern California, Los Angeles, California,

August 1960.

[15] Springer, E. K. "Manual of Cross-Connection Control" Foundation

for Cross-Connection Control Research, University of Southern

California, Los Angeles, Calif., March 1969.

[16] Groeniger, W. C. , "Insurance Against Water-Born Diseases Through

Plumbing Fixtures," Plumbers and Heating Contractors Trade

Journal, September 1, 1927.

[17] Groeniger, W. C. "The Contamination of Water Supply Through Cross

Connections," Plumbers and Heating Contractors Trade Journal,

January 1, 1929.

[18] Groeniger, W. C. "Cross Connections," Read at Twenty-Fourth

Annual Convention of the American Society of Sanitary

Engineering, Detroit, Michigan, September 3, 1929.

[19] "Cross Connections" The American Society of Sanitary Engineering,

Minutes of the Conference held at the Bureau of Standards at

Washington, D. C. on February 24 and 25, 1932. Reported and

Prepared by Henry B. Weaver, Washington, D. C.

[20] ANSI - A112.1.1 - 1971 "Performance Requirements for Pipe-Applied

Atmospheric Type Vacuum Breakers," (A.S.S.E. 1001), American

Society of Sanitary Engineering, 228 Standard Building,

Cleveland, Ohio.

[21] A.S.S.E. 1011, "Hose Connection Vacuum Breakers," American Society

of Sanitary Engineering, 228 Standard Building, Cleveland, Ohio,

June 1970.

[22] A.S.S.E. 1012, "Backflow Preventers with Intermediate Atmospheric

Vent," American Society of Sanitary Engineering, 228 Standard

Building, Cleveland, Ohio, May 1972.

72
[23] A.S.S.E. 1013, "Performance Requirements for Reduced Pressure

Principle Back Pressure Backflow Preventers," American Society

of Sanitary Engineering, 228 Standard Building, Cleveland, Ohio,

June 1971.

[24] A.S.S.E. 1015, "Double Check Valve Type Back Pressure Backflow

Preventers," American Society of Sanitary Engineering, 228

Standard Building, Cleveland, Ohio, May 1972.

[25] A.S.S.E. 1020, "Performance Standard for Vacuum Breakers, Antisiphon, Pressure Type," American Society of Sanitary

Engineering, 228 Standard Building, Cleveland, Ohio, November

1974.

[26] ANSI - A112.1.2 "Air Gaps in Plumbing Systems," American Society

of Mechanical Engineers, 345 East 47th St., New York, N. Y .

,

January 1973.

[27] DeRoos, R. L. and Michael sen, G. S. "Use of Barometric Loop for

Protection of Potable Water Systems," Air Conditioning, Heating

and Ventilating, pp 99-103, June 1969.

[28] PS 31-74, "Specification for Backflow Prevention Devices"

International Association of Plumbing and Mechanical Officials,

Los Angeles, California, 1974.

[29] Springer, E. K. "Manual of Cross -Connection Control," Foundation

for Cross Connection Control and Hydraulic Research, University

of Southern California, Los Angeles, California, 1974.

[30] A.S.S.E. 1002 "Standards and Test Procedures for Water Closet Flush

Tank Ball Cocks" American Society of Sanitary Engineering 228

Standard Building, Cleveland Ohio, Oct. 1964 (Rev Oct. 1968).

[31] AWWA C506-69 "Backflow Prevention Devices - Reduced Pressure

Principle and Double Check Valve Types," American Water Works

Association, New York, 1969.

[32] Springer, E. Kent "The Protection of Potable Water Systems from

Contamination or Pollution by Backflow" A paper presented to

the Medford Water Commission, Medford, Oregon, Nov. 16, 1971.

FCCCHR, University of Southern California, Los Angeles, Calif.

[33] "Oxygen Pressure Method for Accelerated Aging Tests of Rubber

Compounds" Bulletin of Research No. 16 June 1940. Underwriters

Laboratorie s , Chicago , 111.

73
[34] Angle, G . J. "Cross-Connections and Backflow Prevention" AWWA

Supplementary Reading Library Series, No. S106, American

Waterworks Association New York, N. Y. Dec 31, 1970.

[35] ANSI A112.26.1 "Water Hammer Arresters" American Society of

Mechanical Engineers, New York, N. Y. 1969.

[36] Baird, J. N. ; Sanford, W. R. and Cristy, G. A.; "Reduced Pressure

Principle Backflow Preventer Evaluation and Use at Oak Ridge

National Laboratory" "Health Physics" Pergamon Press, 1965

Vol. 11, pp. 743-757.

[37] Huddle, F. P.; Boesman, W. C, and Rothberg, P. F. "Science Policy:

A Working Glossary", Science Policy Research Division, Library

of Congress July 1973.

[38] National Standard Plumbing Code - 1975 Co-sponsored by National

Association of Plumbing-Heating-Cooling Contractors and the

American Society of Plumbing Engineers, (National Association

of Plumbing Heating - Heating-Cooling Contractor, Washington,

D. C. , June 1975)

74
9.0 ACKNOWLEDGMENT

The authors acknowledge the critical reviews of Roger D. Lee,

James A. Warren and Thomas N. Hushower in the Water Supply Division

of the Environmental Protection Agency and the equally valuable

work of William G. Street in the NBS Center for Building Technology.

Also the informal contribution of Thomas P. Kruzic with Naval

Facilities Engineering Command was appreciated.

The list of other individuals who contributed material for

the updating of this paper is long, including many sales engineers,

plumbing officials, laboratory personnel and code writers. The

authors are grateful for the cooperation of each person

75
10. APPENDIX

10.1 Vacuum Dissipation Calculations

Dawson and Kalinske present the following useful equations in

their report on "Plumbing Cross-Connections and Back-Siphonage

Research," pages 28 and 29 [3]. The introductory paragraph concerning

these equations is as follows:

"In order that some idea may be had of the time required

to dissipate vacuums in different-size volumes, an analysis

will be made of this particular problem. It is to be

remembered that the rate of air flow in pounds per second

through any given opening remains constant for any vacuum

greater than 14 inches of mercury. Therefore, the time

required for a vacuum in a volume V to be reduced to the

critical pressure of 14 inches of mercury vacuum, can be

obtained from the following expression :

Equation (11)

Where: t^ = seconds of time required.

W = weight of air per cubic foot at critical

pressure P . (lbs/ft 3

) c P = 0.53P = 14 inches of mercury vacuum. W

c a, q is ton>e determined by considering adiabatic

expansion from Pq to P . P = atmospheric

pressure (lbs/ft*) ° a

= Unit weight of air at initial pressure and

temperature in the volume into which air is

flowing, (lbs/ft 3 )"

Q

a

= pounds per second of air flow into the vacuum

for vacuums exceeding 14 inches of mercury.

Q = 50CA, where C = the discharge coefficient

or the opening through which air enters the vacuum. A = the area of the opening in square

feet.

76
The unit weight of air after adiabatic expansion from atmospheric

pressure to any pressure, P, can be determined from the following

formula:

W = W / P \ 3 rr)

3 Where: W = unit weight of atmospheric air (lbs/ft ) k = 1.4 for air

The time to dissipate vacuums less than 14 inches mercury is given by

Dawson and Kalinske as follows:

t

1 = 0.00086 V Equation (15)

CA

They give the following example:

"Taking an example where V is 10 gallons or 1 and 1/3 cubic

feet, find the time required to dissipate the vacuum from

29 inches of mercury to atmospheric pressure if air flows

in through a 3/4-inch circular opening having a flow co- efficient of 1/2. From equation (11), the time required

to reduce the vacuum from 29 inches to 14 inches is 0.8

seconds. To reduce the vacuum from 14 inches of mercury

to atmospheric pressure required about another 0.8 seconds.

Therefore, the total time for dissipation of the vacuum is

1.6 seconds. The persistence of a vacuum for such a short

time would obviously prevent the maximum back-siphonage

effect. A 10 gallon volume is equivalent to about 100 feet

of 1 1/2-inch pipe. The time required for vacuum dissipation in other volumes would be in proportion."

From Dawson and Kalinske's equation above, (11) and (15), a simplified

equation for the dissipation of vacuum to atmospheric pressure can be

developed as follows for the total time t

fc

.

t

t = C

l

+ H

t = W - W.)V + 0.00086 V

t c i

CA

By substitution of the parameters of the above example into equation

11, it can be shown that (W - W.) = 0.0460 for Dawson and Kalinske

assumed conditions. Substituting this value into the above equation

gives:

77
t 0.Q460 V 0.00086 V

1 = 50x1/2x0.785 D +

1/2x0.785 T)2

t 0.00234 V , 0.00219 V 0.00453 V

f- «b» + —

2 2 2

D D D

Where D = diameter in feet,

For a diameter d in inches

t _ 0.00453 V x 144 ^ 0.65232 V

t

2 2 d d

For example in section 2.1 of this report, where V = seven and one third gallons = 0.98 ft^ and d = 0.375 inches, the total time is as follows

t 0.65232 x 0.98 4.547 seconds

0.1406

78
10.2 The Navy Survey Form

The Navy survey form is reproduced here to aid in the

interpretation of the data gathered for table 2 on page 11.

BACKFLOW PREVENTION POLICY

SURVEY FORM

NAVAL CIVIL ENGINEERING LABORATORY

Port Hueneme, California 93043

Mechanical and Electrical Engineering Department

Work Unit: YF38.534.006.01.007, Backflow Prevention Devices

BACKFLOW PREVENTION SURVEY

The following questions concern policies and regulations governing

the protection of a potable water source which supplies a customer

having a known or potential cross-connection to a health hazard. Of

specific interest are the requirements for backflow preventers at

vessel watering points at piers and wharves.

Responding Agency

Name :

Address:

Phone : Respondent: Name/Title

Please complete this questionnaire by checking (/) the appropriate

answer to each question that applies to your backflow prevention

policies.

l.a. What is the minimum backflow prevention you require where a health

hazard exists?

( ) Air gap separation required (reduced pressure devices and

double check valve devices not allowed).

( ) Reduced pressure principal backflow preventer required.

( ) Double check valve assembly required.

( ) Other protection.

( ) No protection specified.

79
l.b. What minimum protection do you require at vessel watering points

at piers and wharves? _____

2. If reduced pressure principal devices are used, what certification

or approval of the device do you require prior to its installation?

( ) Full approval by the Foundation for Cross-Connection Control

Research at the University of Southern California.

( ) Provisional approval by the above Foundation.

( ) Laboratory test only by the above Foundation.

( ) Other certification or approval. (Please specify and list

devices approved.)

( ) No certification or approval required.

3. The Foundation for Cross-Connection Control Research has recently

changed the field test requirement, before granting full approval, from

a three-year test to a one-year test with more frequent inspection. If

you currently require full or provisional approval will you:

t

( ) accept all devices approved under the new one year test

program.

( ) accept only those devices previously approved under the

three-year test program.

( ) provide an alternate policy. (Please specify)

A. If devices now in service were previously approved by a certifying

authority, and if they do not have their certification renewed, or if

it is rescinded by that authority, what will your policy be?

( ) Replace these devices at the earliest possibility with an

approved device.

( ) Replace these devices at the first sign of malfunction with

an approved device.

( ) Accept the device as originally approved.

( ) Other policy. (Please specify)

5. The cost of purchasing and installing a backflow prevention device

is borne by the:

( ) water utility.

( ) customer.

80
6. Please list the manufacturer, model, and size of reduced pressure

principal backflow preventers which have been installed in your water

system. Reduced pressure devices have been used for how many years?

Manufacturer Model Size No. Installed

7. Please indicate your maintenance and inspection policy regarding

reduced pressure principal devices.

i. Frequency of inspection

b. Frequency of scheduled testing

c. Frequency of scheduled maintenance

d. Work required during scheduled maintenance

e. Wh.o performs inspection

testing

maintenance

f. Who pays for inspection

testing

maintenance

8. Please describe any malfunctions, failures, or problems encountered

with reduced pressure preventers, including the make, model, and size

of unsatisfactory units, the date of installation, and length of

operation before malfunction.

81
9. Repeat question 8 for double-check valve assemblies.

10. Is freezing a problem in your area?

How are these units protected from freezing?

What are the effects from freezing on reduced-pressure devices and

double-check valve assemblies?

11. Do you foresee any changes in your existing backflow prevention

policy in the near future?

12. Other comments. (Please attach a copy of any regulations

applicable to this survey.)

82
10.3 Procedures for a National Voluntary Laboratory Accreditation

Program.

The National Voluntary Laboratory Accreditation Program was promulgated by the publication of procedures in the Federal Register

on February 25, 1976. It was stated that the goal of this program

is to provide in cooperation with the private sector a national

voluntary system to examine upon request the professional and technical competence of private and public testing laboratories that serve regulatory and nonregulatory product and certification needs.

The program is also intended to accredit those laboratories that

meet the qualifications which will be established under these

procedures

The program has been set up as Part 7 of Title 15 in

Commerce and Foreign Trade. For this reason the document is

divided into eighteen sections numbered from 7.1 through 7.18.

Because some of the sections are quite lengthly and tedious to

read, a format with sidenotes has been chosen for the presentation

of Part 7 in this paper. Also the format incorporated the following arrangements

1. The first line of the first sentence in a paragraph is

indented

2. Subsequent sentences in the same paragraph are not indented

but, after a line space, begin at the margin.

3. A small circle marks the location of each sentence and a dash through a circle represents supporting statements or phrases for a previous sentence.

4. Where sentences are long, the ideas are separated by

breaking the line and continuing after a single line space.

83
7.1 Purpose

The purpose of this part is to establish procedures

under which a National Voluntary Laboratory Accreditation

Program will function.

7.2 Description and goal of program

7.2(a)

This system would

examine competence

of testing laboratories

This program establishes a national voluntary system that

would examine the professional and technical competence of

testing laboratories that serve regulatory and non-regulatory

product evaluation and certification needs.

Laboratories that meet

qualifications would

be accredited

o Laboratories that meet the qualifications established pursuant

to the procedures set out below would be accredited.

Periodic checks and

examinations will be

required

This program will also require those laboratories that are accredited to maintain their qualification status through

periodic checks and examinations.

7.2(b)

Program will make

maximum use of all

existing activities

o The program will seek through coordination and consultation, to maximize benefits derived from other laboratory

examination and accreditation activities.

Would avoid

duplication of

other programs

In this way, it is intended that the program will avoid

duplication of other laboratory examination or accreditation programs conducted by the public and private

sectors.

Secretary will insure

close coordination

and consultation

To this end, the Secretary will insure that close and

continuing coordination and consultation is undertaken

and maintained with interested representatives of Federal,

State and local governments and of the private sector,

including those from professional and trade associations

and societies.

7.2(c)

To serve needs of

industry, consumers

and the Government

The intended goal of this program is to serve, on a timely basis, the needs of industry, consumers, the Government,

and others by accrediting this nation's testing laboratories.

To promote technical

competence

The achievement of this goal would be sought by fostering

and promoting a uniformly acceptable base of professional

and technical competence in testing laboratories

To establish a background of

experience

and by establishing a background of experience necessary

to the orderly evolution of a laboratory accreditation

system designed to serve national needs as they develop.

7.3 Definitions

7.3(a)

Secretary

The term "Secretary" means the Secretary of Commerce or his designee.

7.3(b)

Product

The term "Product" includes the plural thereof and means

a type or a category of manufactured goods, constructions,

installations and natural and processed materials or those

associated services whose characterization, classification or functional performance determination is specified by standards.

84
The term "Criteria Committee" means a National Laboratory

Accreditation Criteria Committee appointed by the Secretary

under these procedures.

The term "person" means associations, companies, corporations, educational institutions, firms, government agencies at the Federal. State and local level, partnerships and societies,

as well as divisions thereof, and individuals.

The term "testing laboratory" means any "person," as defined above, whose functions include testing, analyzing or inspecting "products," as defined above, and/or evaluating the

designs or specifications of such "products" according to the

requirements of applicable standards.

The term "general criteria" means those characteristics

of a testing laboratory commonly found in, and generally

expected of, such a laboratory serving the product under

consideration. See in this connection Sec. 7.7(a).

The term "specific criteria" means those detailed

requirements deemed essential to assuring an acceptable

examination and evaluation of the testing function performed

by a testing laboratory in performing specific tests related

to identified standards for the product under consideration.

See in this connection Sec. 7.7(a).

.4 Finding of need to accredit testing

laboratories

Any person may request the Secretary to find that there

is a need to accredit testing laboratories which render

services regarding a specific product so that it may be

ascertained whether such product meets the requirements of

applicable standards.

Such a request shall be in writing and will include the

following:

& (1) Identification of the product;

i (2) Text of an applicable standard;

& (3) Text of a test method, if not included in the

applicable standard identified in paragraph (b)(2)

of this section; and

i (4) Basis of need for accrediting testing laboratories

that serve the product identified in paragraph (b) (1)

of this section.

<b The basis will provide information relative to the items

set out in Sec. 7.5 and will include, where appropriate,

documentary evidence on such items as:

(i) the number of testing laboratories that is believed

will want to be accredited to serve the product

identified in paragraph (b)(1) of this section; and

(ii) the number of users of testing laboratories that

is believed will desire services of testing laboratories

accredited to serve the product identified in paragraph

(b)(1) of this section.

85
7.4(c)

Secretary may ask

for more information

Secretary may

decline to act upon the request

Secretary must

respond in 10

working days

7.4(d)

Should a request be

made that may affect

accreditation program

of a Federal agency,

Secretary shall seek

views of such agency.

Should the affected

agency object in

writing within 30

days, the Secretary

shall cease further

actions

And the Secretary

shall notify the

requester of such

actions

o The Secretary may ask for more information to support

a request made under paragraph (a) of this section if he

feels it is necessary to do so.

o If on the basis of the information provided or because of the

lack of resources, the Secretary is unable to justify the

making of a preliminary finding of need, he will decline to act further on the request.

o The Secretary shall in that event notify the requester in

writing within ten (10) working days after making a decision

and shall state the reasons for so declining.

o If a request received under this section is believed to affect an existing or developing testing laboratory examination

or accreditation program of a Federal regulatory agency, the

Secretary shall seek from the head of such agency its views

relative to the Secretary's making a preliminary finding of

need.

o If within thirty (30) days after receipt of the Secretary's

solicitation of views, or such extension of time as may be

agreed to by the Secretary, the head of the affected Federal

regulatory agency explains, in writing, his objections to the

Secretary's making a preliminary finding of need, the

Secretary shall cease to act further on the making of such

finding.

o In that event, the Secretary shall notify the requestor

of such objections and of his declination to act on the

request pursuant to paragraph (c) of this section.

7.4(e)

Should Secretary find

that a need exists

he will publicize in

the Federal Register

and provide at least 30 days

for written comments

o If, on the basis of the information provided to him, the

Secretary finds that a need exists to accredit testing

laboratories that serve a specific product, he shall publish

a notice in the Federal Register indicating that such finding

is a preliminary finding.

The notice shall include a statement as called for in Sec. 7.

as to the basis for the Secretary's finding and shall provide

at least a thirty (30) day period for the submission of written

comments thereon.

Should a public

hearing be held,

time for written

comments shall be

extended to hearing date

7.4(f)

Persons desiring to be

heard shall notify the

Secretary in 15 days

If requested, informal

hearings will be held

for oral presentations

In the event that a public hearing or hearings are held on this preliminary finding as authorized under paragraph (f)

of this section, the period allowed for the submission of

written comments shall be extended to the date on which such

hearing or hearings are held.

Interested persons wanting to express their views in an informal hearing shall notify the Secretary of that desire

within fifteen (15) days after the notice is published in

the Federal Register.

Upon receipt by the Secretary of such request, informal

public hearings shall be held so as to give all interested

persons an opportunity for the oral presentation of data,

views, or arguments, in addition to the opportunity to make

written submissions.

86
If appropriate

hearings may be

held at two places

with notice published

in Federal Register

All comments will

be on file in the

Commerce Building

o If deemed appropriate by the Secretary, such hearings may be

held at two locations, one of which shall be east of the

Mississippi River and the other west thereof.

o Notice of such hearings shall be published in the Federal

Register at least twenty (20) days in advance thereof.

o A transcript shall be kept of any oral presentation.

i (1) All written and oral comments will be filed in

the Central Reference and Records Inspection Facility,

Room 7068, Commerce Building, 14th Street between E Street

and Constitution Avenue, N.W. , Washington, D.C. 20230,

and will be available for public inspection at that

location.

7.4(g)

By a notice in the

Federal Register the

Secretary shall make

a final finding of need

or shall withdraw his

preliminary finding

And shall state the

basis for such finding

After evaluating the comments received, the Secretary

shall publish a notice in the Federal Register making a final finding of need or withdrawing his preliminary finding

of need to accredit testing laboratories that serve a specific product.

The notice shall state the basis for the Secretary's final

finding of need or for the withdrawal of his preliminary

finding.

7.4(h)

If notice sets out

the final finding of

need, it will include:

(1) identification of

product

(2) identification of

standards and test methods

(3) statement that

separate notice in Federal

Register will advise that

a NLACC will be formed or

else an existing criteria

committee will be used

o The notice published under paragraph (g) of this section,

if it sets out the Secretary's final finding of need, will

also include:

(1) Identification of the product for which testing

laboratories will be accredited to serve;

(2) The identification of applicable standards,

including the test methods involved; and

(3) A statement that the Secretary is publishing

simultaneously with this notice,

a separate notice in

the Federal Register advising that pursuant to the

provisions of the Federal Advisory Committee Act (Pub.

L. 92-463, dated October 6, 1972) the Secretary will

form a National Laboratory Accreditation Criteria

Committee pursuant to Sec. 7.6 or will utilize an existing

Criteria Committee previously established under that

section.

Such separate notice

will state duties of

Committee, its size and

basis for selection of

committee members.

Except where the Secretary utilizes an existing Criteria

Committee such separate notice will outline the functions

and duties of the Committee, its size, and the basis for

selection of the members thereof.

87
7.5 Statement of the basis for a preliminary finding of need.

Basis for preliminary

finding of need are:

o The statement setting forth the basis for the preliminary finding

of need referred to in Sec. 7.4(e) shall as a minimum address

the following items:

7.5(a)

The establishment of

criteria must benefit

public interest

7.5(b) A National need extends

beyond that served by

any existing program

7.5(c)

An existing product

standard is deemed

suitable by the

Secretary

7.5(d)

Existing testing

methodology is

determined by the

Secretary to be

valid

Whether the establishment of general or specific criteria

and other conditions for accrediting testing laboratories

that serve a specific product would benefit the public interest

Whether there is a national need to accredit testing

laboratories for the specific product involved beyond that

served by any existing laboratory accreditation programs in

the public or private sector;

Whether for the specific product involved, there is in

existence a standard that is deemed by the Secretary as being

of importance to commerce, consumer well-being, or the public

health and safety;

Whether there is in existence a valid testing methodology

as determined by the Secretary for ascertaining conformity to

to the standard of the specific product involved; and

7.5(e)

Secretary determines

that accreditation

is feasible and

practical

o Whether it is feasible and practical to accredit testing

laboratories that serve the specific product involved.

7.6 Establishment and functions of a National

Laboratory Accreditation Criteria Committee.

7.6(a)

When the Secretary

establishes a Criteria

Committee he will:

o The Secretary will establish a Criteria Committee and

appoint the Chairman and members thereto following:

(1) publish a notice

in the Federal Register

according to Sec. 7.4(h)(3)

(2) and file a charter

setting forth purpose

and nature

(1) Publication of the separate Federal Register

notice referred to in Sec. 7.4(h)(3) that announces the

Secretary's intention to form a Criteria Committee,

as distinguished from an announcement of intent to utilize

an existing committee; and

(2) The filing of a charter setting forth the purpose

and nature of the Criteria Committee.

7.6(b)

Membership of Criteria

Committee is chosen

broadly from interested

groups

The membership of the Criteria Committee will be composed

of employees of the Department of Commerce, other Federal

agencies, and qualified representatives chosen from among

producers, distributors, users, consumers, testing laboratories

academia, and general interest groups,

including State and

local governmental bodies and agencies affected by the

Secretary's finding of need to accredit testing laboratories

serving a specific product.

88
Equitable balance of

members that represent

all interested groups

7.6(c)

Criteria Committee

shall be governed

by the Federal Advisory

Committee Act

The membership of each Criteria Committee shall be selected

so as to provide an equitable balance that represents the

interests affected by the Secretary's finding of need.

The establishment and functioning of each Criteria

Committee formed and utilized by the Secretary under these

procedures shall be governed by the applicable provisions

of the Federal Advisory Committee Act, cited earlier herein.

Committee members may

be paid per diem and

travel expenses

7.6(d)

Criteria Committee will

develop and recommend

criteria to the Secretary

Secretary will define

a time period for

development of criteria

7.6(e)

Criteria Committee may

consult with other

public and private

parties to develop

criteria

Persons selected to serve on a Criteria Committee may be paid

travel expenses and per diem, provided authorized travel is

involved.

Upon formation of the Criteria Committee, the Secretary

will request it to develop and recommend to him general and

specific criteria to accredit testing laboratories that serve

a specific product.

The Secretary, in a written communication to the Chairman of

the Committee, shall designate a time period for the

development of general and specific criteria.

When developing general or specific criteria, the Criteria

Committee may, where it deems such action to be appropriate,

consult with other interested public and private parties,

including Federal, State and local agencies and private

standards bodies.

and evidence of such

consultation will be

made a matter of public

record.

Exchanges of correspondence, memorandums and other evidence

of such consultation will be made a matter of public record.

7.7 Development and recommendation of

criteria for accrediting testing

laboratories

7.7(a)

Secretary and Criteria

Committee will be

guided in Criteria

development by factors

such as these:

o The Secretary, and the Criteria Committee acting at the

request of the Secretary, in developing general and specific

criteria to accredit testing laboratories that serve a specific

product shall consider factors such as:

4 (1) For general criteria pertaining to testing

laboratories

for general criteria (i) Organization;

(ii) Staff:

(iii) Physical plant;

(iv) Operational processes;

(v) Control procedures;

(vi) Quality assurance; and

(vii) Professional and ethical business

practices, as appropriate.

(2) For specific criteria pertaining to testing

laboratories

and for specific criteria (i) Personnel and equipment qualifications

required of the testing laboratory function;

(ii) Requirements applicable to proficiency

sample programs;

89
7.7(b)

Criteria in existing

standards will be used

when appropriate, but

where none are found

Criteria Committee will

undertake development of

criteria

7.7(c)

Instructions for making

application shall be

included in criteria

together with conditions

to be followed in the

program:

(1) examination and audit

(2) payment of fees

(3) limitation on advertising

(iii) Application requirements;

(iv) Initial and periodic examination and audit

procedures; and

(v) Professional and technical qualifications of

personnel who examine testing laboratories.

o The general and specific criteria developed under this

section for accrediting testing laboratories will be based

upon criteria found in existing standards where such existing

criteria are deemed appropriate.

o Where appropriate existing criteria cannot be found, the

Criteria Committee will, at the request of the Secretary,

undertake to develop and recommend to him such appropriate

general and specific criteria as may be needed.

o The criteria shall contain instructions for making

application by testing laboratories serving the product

involved and

shall require that each testing laboratory

that desires to participate in this program must agree

to conditions that include but are not limited to the

following

& (1) Be examined and audited, initially and on a continuing basis;

i> (2) Pay accreditation fees and charges; and

4 (3) Avoid reference by itself and forbid others

utilizing the services of an accredited testing

laboratory from referencing its accredited status

in consumer media and in product advertising or on product labels, containers and packaging or the

contents therein.

7.7(d)

Accreditation by this

program does not relieve

laboratories from

observing any existing

statutes, or regulations

7.7(e)

This section does not:

(1) prohibit accreditation

solely on basis of

organizational association

or for being a foreign firm

(2) provide for development

of product standards or test methods

The criteria shall contain a statement that compliance

by testing laboratories with the general and specific

criteria and other conditions established by the Secretary

and which are accredited by him under these procedures

shall in no way relieve such laboratories from the necessity

of also observing and being in compliance with any existing

Federal, State and local statutes, ordinances, and regulations

that may be applicable to the operation of such laboratories,

including consumer protection and anti-trust laws.

In carrying out the activities authorized by this

section

6 (1) No action will be taken or criteria developed

that would prohibit the accreditation of a testing

laboratory solely on the basis of that laboratory's

association or nonassociation with manufacturing,

distributing or vending organizations,

or because the

testing laboratory is a foreign firm;

4 (2) No action will be taken under this program to develop a product standard or test method standard;

90
(3) establish procedures

to modify a product standard

or a test method standard

(4) propose to promulgate

criteria considered to be impractical or contrary

to the public interest

(3) No action will be taken under this program to modify a product standard or a test method standard

where such a standard is in existence;

(4) No general or specific criteria will be promulgated unless compliance with such criteria and its

implementation has been determined by the Secretary to be feasible and practical and not contrary to the

public interest ; and

(5) want or accept business

data, trade secrets, etc.

7.8(a)

Criteria Committee shall

forward its recommendations

to the Secretary

f> (5) The Secretary, under this program, will not ask

for or accept confidential business data, trade secrets

or other proprietary information.

7.8 Publication of proposed criteria.

Upon its development of the general and specific

criteria for accrediting testing laboratories under Sec. 7.7,

the Criteria Committee shall forward its recommendations for

such criteria to the Secretary for his consideration.

Secretary will publish

it in Federal Register

The

Secretary, after consideration of such criteria will publish

in the Federal Register a notice giving the complete text of

the proposed general and specific criteria,

inviting written

comments within

forty-five (45)days

7.8(b)

Request for a hearing

can be made by

interested persons

within 15 days

o and inviting any interested persons to submit written

comments on such proposed criteria within forty-five (45)

days after its publication in the Federal Register, unless

another time limit is provided by the Secretary.

o Interested persons wanting to express their views in an informal hearing shall notify the Secretary of that desire

within fifteen (15) days after such proposed criteria are published in the Federal Register.

If requested, informal

hearings will be held

for oral presentation

Upon receipt by the Secretary of such request, informal

public hearings shall be held so as to give all interested

persons an opportunity for the oral presentation of data,

views, or arguments, in addition to the opportunity to make written submissions.

If appropriate,

hearings may be

held at two places

with notice published

in Federal Register

written and oral

comments will be

filed and available

for inspection

o If deemed appropriate by the Secretary, such hearings be

held at two locations, one of which shall be east of the

Mississippi River and the other west thereof.

o Notice of such hearings shall be published in the Federal

Register at least twenty (20) days in advance thereof.

o A transcript will be kept of any oral presentation.

i (1) All written and oral comments will be filed in

the Central Reference and Records Inspection Facility,

Room 7068, Commerce Building, 14th Street between E Street and Constitution Avenue NW. , Washington, D.C.

20230,

and will be available for public inspection

at that location.

91
7.8(c)

Criteria Committee

will evaluate comments

and make recommendations

to the Secretary

Secretary will act

upon the Criteria

Committee's recommendations in one of

three alternatives:

o The Secretary upon receipt of all written and oral

comments will request the Criteria Committee to conduct

and return to him in writing, within a time period specified

by the Secretary, its evaluation and recommendations with

respect to such comments.

o After considering the Criteria committee's evaluation

and recommendations, the Secretary will prepare his evaluation

and publish in the Federal Register a notice;

(1) to announce the

final general and

specific criteria <

(1) Announcing the final general and specific

criteria that testing laboratories must meet in order

to be accredited and the date when such final criteria

shall go into effect which shall not be less than thirty

(30) days after the date of publication of such notice;

(2) to postpone action

for further development

(2) Stating that the proposed general and specific

criteria will be further developed before final

publication; or

(3) to withdraw the

criteria from

consideration

(3) Withdrawing the proposed general and specific

criteria from further consideration.

7.9 Coordination with Federal agencies,

7.9

Secretary will consult

with interested Federal

agencies for meaningful

cooperation

As a means of assuring effective and meaningful

cooperation, input, and participation by those Federal

agencies that have an interest in and may be impacted

by the laboratory accreditation program carried out under

these procedures,

the Secretary shall undertake to communicate and consult with appropriate officials at policy making levels within those agencies.

Opportunities for

Federal agency

representatives to serve on Criteria

Committees

These coordination efforts will include opportunities for

representatives designated by those agencies to serve on each Criteria Committee established by the Secretary in

which those agencies have an interest.

7.10 Establishment of fees and charges.

7.10(a)

Secretary shall

establish fees and

charges for examining,

accrediting and

auditing

Fees shall be calculated to maximize the

self-sufficiency of

the accrediting program

Notice in the Federal

Register will give

criteria of Sec. 7.8(a)

o The Secretary in conjunction with the use of the

Working Capital Fund of the National Bureau of Standards,

as authorized by section 12 of the Act of March 3, 1901,

as amended (15 U.S.C. 278b),

for this program shall establish

fees and charges for examining, accrediting, and auditing

testing laboratories.

o The fees and charges established by the Secretary, which may

be revised by him when he deems it appropriate to do so, shall be in amounts calculated to maximize the selfsufficiency of this program.

o A separate notice will be published in the Federal Register

simultaneously with the notice of proposed general and

specific criteria referred to in Sec. 7.8(a).

92
and a tentative

schedule of fees

and charges

so that public may

evaluate criteria

against fees charged

7.10(b)

Upon the announcement

of final general and

specific criteria

a separate notice in

Federal Register will

list final schedule

of fees

o Such notice will set out a schedule of estimated fees and

charges the Secretary proposes to establish.

o The notice would be furnished for informational and guidance

purposes only in order that the public may evaluate the

proposed criteria in light of the expected fees to be charged.

o At such time as the Secretary publishes the notjce

announcing the final general and specific criteria referred

to in Sec. 7.8(c)(1),

he shall simultaneously publish a separate notice in the Federal Register setting forth the

final schedule of fees that will be charged testing

laboratories that serve a specific product.

to become effective

on date criteria

becomes effective

o The effective date of such final schedule of fees shall be

the same as the date on which the final general and specific

criteria are to take effect.

7.10(c)

Subsequent revisions

to be published in

Federal Register - to gecome effective

in not less than thirty

(30) days

o Revisions, if any, to the fees and charges established

by the Secretary under paragraph (b) of this section shall

be published in subsequent Federal Register notices

and shall

take effect not less than thirty (30) days after the date

of publication of such notice.

o Mention of such revisions shall also be published in the

appropriate quarterly reports referred to in Sec. 7.17(a).

7.11 Participation of testing

laboratories

7.11(a)

Each laboratory may

initiate an application

for accreditation

7.11(b)

Secretary will notify

applicant and NBS of

requirements and fees

Each testing laboratory serving a product for which

final general and specific criteria have been promulgated

under Sec. 7.8(c)(1),

and desiring to be accredited under

this program, will notify the Secretary of its desire pursuant to the provisions of such criteria.

After receipt and evaluation of the testing laboratory's

application and information contained therein,

the Secretary

shall, upon the acceptance thereof, notify the applicant

testing laboratory

and the National Bureau of Standards in

writing of the specific applicable examination requirements

for accreditation and

the fees and charges for such

examination and accreditation.

Rejected applicant may

reapply after he has

corrected deficiences

Rejected applicant may

request a hearing

If the application is not accepted, the Secretary shall

notify the applicant testing laboratory of the reasons for

rejection of its application,

and such testing laboratory

may reapply under Sec. 7.13(d) after correcting the

deficiencies set out in the Secretary's notification of

rejection.

Alternatively, the applicant testing laboratory shall have

thirty (30) days to request a hearing pursuant to 5 U.S.C.

556.

93
Secretary's rejection

would be stayed until

the hearing

7.11(c)

Applicant laboratories

must meet general and

specific criteria

7.11(d)

National Bureau of < Standards, on behalf

of Secretary, will

arrange for examination

of applicant laboratory

National Bureau of

Standards will assure

that examiners possess

qualification of Sec. 7.8(c)(1)

If NBS conducts examination, the resulting

report will be sent to the Secretary

If testing is prepared

by contractor, NBS will

review it before sending

to Secretary

In the event, however, that the applicant testing laboratory

requests a hearing within that thirty (30) day period the

Secretary's rejection shall be stayed until the hearing held

pursuant to 5 U.S.C. 556.

A testing laboratory desiring to be accredited under

this program to serve the product identified by the Secretary

in his final finding of need under Sec. 7.4(g) in accordance

with the standards and test methods identified by the

Secretary in that finding must meet the general and specific

criteria promulgated by him.

Upon receipt by the National Bureau of Standards of the

applicant testing laboratory's written request for examination

and of the fees and charges specified in paragraph (b) of

this section,

the National Bureau of Standards on behalf of

the Secretary, will arrange for by contract or will itself

conduct, the examination requirements of the Secretary.

In all cases where testing laboratories are examined, the

National Bureau of Standards will assure that the personnel

used by the contractor

or by the National Bureau of Standards

possess the professional and technical qualifications set out

in the specific criteria promulgated under Sec. 7.8(c)(1).

If the National Bureau of Standards conducts the examination,

the resultant examination report will be forwarded to the

Secretary.

In cases where the examination report was prepared by a contractor, the National Bureau of Standards, before making

payment thereunder

or forwarding the report to the Secretary,

will review the report to assure that the contract terms

have been fulfilled.

7.11(e)

Secretary will grant

or propose to deny

accreditation within

20 working days after

receiving report.

or will notify

applicant in writing

with reason for delay

Secretary's determination

of status will be given

in writing

and if he proposes to deny the accreditation

he will state reasons

The Secretary, after reviewing the examination report

furnished under paragraph (d) of this section, will make a determination granting or proposing to deny accreditation

to the applicant testing laboratory, not later than twenty

(20) working days following the date on which the report

is received by him.

If the determination is not made within such time limit, the

Secretary shall notify the applicant testing laboratory in

writing of the reasons for the delay.

Upon making his determination, the Secretary will notify

the testing laboratory in writing of its accreditation

status

If the Secretary proposes to deny accreditation to an applicant testing laboratory, the notification will state

the reasons for such proposed denial.

94
7.11(f)

and the applicant

shall have thirty

(30) days from

receipt of notice

to request a hearing

If appeal is not

made in required

period the Secretary's

proposed denial will be

made final in a written

notification

o If an applicant testing laboratory is notified by the

Secretary that he proposes to deny accreditation, the testing

laboratory shall have thirty (30) days from the date of

receipt of such notification to request a hearing under the

provisions of 5 U.S.C. 556.

o The Secretary's proposed denial shall become final through

the issuance of a written decision to the applicant in the

event that the applicant does not appeal such notification

by the end of that thirty (30) day period.

However, if hearing

is requested, proposed

denial shall be stayed

until hearing

o In the event, however, that the applicant testing laboratory

requests a hearing within that thirty (30) day period, the

Secretary's proposed denial shall be stayed until the hearing

held pursuant to 5 U.S.C. 556.

7.12

Advertising by the

accredited laboratory

is limited in scope

7.13(a)

Secretary may find cause to revoke the

accreditation of a laboratory

7.13(b)

If so notified by

the Secretary such

laboratory may

request a hearing

Revocation would

become final should

hearing not be

requested in 30 days

Should a hearing be

properly requested

the proposed revocation

shall be stayed

7.12 Reference to accredited status.

o Except as limited under Sec. 7.7(c)(3), a testing

laboratory accredited under this program may use the following

statement on its letterheads and in professional, technical

and trade publications:

i> "Accredited by the Department of Commerce, National

Laboratory Accreditation Program for (appropriate

wording as authorized by the Secretary's notification

under Sec. 7.11(e))."

7.13 Revocation or termination of

accreditation of a testing laboratory.

o If the Secretary finds that a testing laboratory which

he has previously accredited has violated the terms of its

accreditation

or the provisions of these procedures, he may,

after consultation with such testing laboratory, notify that

testing laboratory that he proposes to revoke its accreditation.

o Upon receipt of a notice from the Secretary of the

proposed revocation, which notice shall set forth the reasons

for such proposed revocation,

the accredited testing

laboratory shall have thirty (30) days from the date of

receipt of such notification to request a hearing under the

provisions of 5 U.S.C. 556.

o The Secretary's proposed revocation shall become final through

the issuance of a written decision to the testing laboratory

in the event that such testing laboratory does not appeal

the proposed revocation within that thirty (30) day period.

o In the event, however, that the accredited testing laboratory

requests a hearing within that thirty (30) day period, the

Secretary's proposed revocation shall be stayed until the

hearing held pursuant to 5 U.S.C. 556.

95
7.13(c)

A laboratory may end

participation with a written notice to the Secretary

Receipt of notice

would terminate

processing of

application

or terminate

the accreditation

when acknowledged

by the Secretary

7.13(d)

A laboratory may

reapply should

accreditation be

denied, revoked

or terminated

7.14(a)

Secretary may cease laboratory accreditation

for a specific product

Notice of preliminary

finding in Federal

Register

Shall address those

items of Sec. 7.5

covered by original

finding.

7.14(b)

Minimum period of

60 days to submit

written comments

Should public

hearings be held

written comments

accepted up to hearing date

7.14(c)

Twenty (20) days

allowed for the

request for hearing

o A testing laboratory may at any time terminate its

participation and responsibilities under this program or withdraw its application for accreditation by giving written

notice to the Secretary.

o Upon receipt by the Secretary of such notice, he shall

terminate further processing of the testing laboratory's

application for accreditation.

o If such testing laboratory has been accredited, the

Secretary shall terminate that testing laboratory's

accreditation.

o The Secretary shall notify the testing laboratory that its

accreditation has been terminated pursuant to its request.

o A testing laboratory whose application has been rejected or whose accreditation has been denied, revoked or terminated or which has withdrawn its application prior to being accredited

may reapply for and be accredited if it meets the applicable

general and specific criteria promulgated by the Secretary

under Sec. 7.8(c)(1) and

agrees also to meet the conditions set out under Sec. 7.7(c)

and the provisions of Sec. 7.12.

7.14 Cessation of accreditations.

o The Secretary may cease the accreditation of testing

laboratories that serve a specific product if he finds that

there is no longer a need to accredit such laboratories.

o An action to cease such accreditations shall commence with

the issuance of a preliminary finding which shall be

published in the Federal Register.

o Such notice shall set forth the Secretary's reasons for his

preliminary finding and shall,

as a minimum, address those

relevant items listed in Sec. 7.5 which formed the basis for

his original finding of need to accredit testing laboratories

serving a specific product.

o The notice published under paragraph (a) of this section

shall provide at least a sixty (60) day period for the submission of written comments on the Secretary's preliminary

finding.

o In the event that a public hearing or hearings are held on

this preliminary finding as authorized under paragraph (c) of

this section,

the period allowed for the submission of written

comments shall be extended to the date on which such hearing

or hearings are held.

o Interested persons wanting to express their views in an informal hearing shall notify the secretary of that desire

within twenty (20) days after the notice is published in the

Federal Register.

96
Public hearings

may be held to get views of all

concerned

Hearings may be

held east and west

of the Mississippi

Twenty (20) days

advance notice in

Federal Register

o Upon receipt by the Secretary of such request, informal public

hearings shall be held so as to give all interested persons

an opportunity for the oral presentation of data, views, or arguments, in addition to the opportunity to make written

submissions.

o If deemed appropriate by the Secretary, such hearings may be

held at two locations, one of which shall be east of the

Mississippi River and the other west thereof.

o Notice of such hearings shall be published in the Federal

Register at least twenty (20) days in advance thereof.

A transcript shall be kept of any oral presentation.

all records of

hearings will be

available at Commerce Building

(1) All written and oral comments will be filed in

the Central Reference and Records Inspection Facility,

Room 7068, Commerce Building, 14th Street between E Street and Constitution Avenue N.W., Washington, D.C.

20230,

and will be available for public inspection at that location.

7.14(d)

Notice of Secretary's

decision shall be in

Federal Register

After evaluating the comments received, the Secretary

shall publish a notice in the Federal Register making a final finding,

or withdrawing his preliminary finding, that

there is no longer a need to accredit testing laboratories

that serve a specific product.

together with basis

for his decision

Cessation date shall

be not less than 60

days after publication

of notice

o The notice shall state the basis for the Secretary's final

finding or for the withdrawal of his preliminary finding.

o If the notice sets forth the Secretary's final finding that

there is no longer a need to accredit testing laboratories

that serve a specific product,

such notice shall also state

the effective date of such final finding which shall not be

less that sixty (60) days after the publication of the notice.

7.14(e)

Cessation of accreditation affects all

those previously

accredited for a product.

If the Secretary ceases the accreditation of testing

laboratories that serve a specific product as provided for

in this section, ,he shall withdraw the accreditation

previously issued to all those testing laboratories serving

the same specific product.

Such accredited

laboratory may seek

to serve another

product

o Any testing laboratory whose accreditation to serve a specific

product has been withdrawn by the Secretary under this subsection may seek to be accredited to serve a different specific

product under these procedures,

and may be accredited

by meeting provisions

of Sees. 7.7(c), 7.8(c)l

and 7.12

o and may be so accredited if it meets the general and specific

criteria promulgated by the Secretary under Sec. 7.8(c)(1) that are applicable to that different specific product

and if it

agrees also to meet the conditions set out under Sec. 7.7(c)

and the provisions of Sec. 7.12.

7.14(f)

Accreditation may be

reinstituted by procedures of Sec. 7.4

o The Secretary may reinstitute the accreditation of testing

laboratories that serve a specific product which he previously

ceased accrediting under this section.

97
o In that event he shall follow the same procedures set out

under Sec. 7.4 relative to the finding of need to accredit

testing laboratories that serve a specific product.

7.15 Refund of fees and charges.

7.15(a)

Some fees will be

refunded should the

laboratory withdraw

its application for

accreditation

7.15(b)

No refunds made

when laboratory

terminates

participation

If a testing laboratory withdraws its application for

accreditation after it has submitted the required examination

fees and provides written notice to the Secretary of such

withdrawal prior to the issuance of an accreditation or the denial thereof,

the testing laboratory will be refunded

such fees except

for the application fee, if any, and for any

other costs that have been incurred relative to its application.

If a testing laboratory terminates its participation and

responsibilities under this program at any time after it has

been accredited or after it has been notified by the

Secretary that it is not being accredited, no part of the

fees and charges paid by the testing laboratory will be

refunded

7.15(c)

No refunds made

when accreditation

is revoked under

Sec. 7.13

If the accreditation of a testing laboratory is revoked by

the Secretary under Sec. 7.13, no part of the fees and charges

paid by the testing laboratory will be refunded.

7.15(d)

Some fees will be

refunded when the

accreditation ceases

as in Sec. 7.14

If the Secretary ceases the accreditation of testing

laboratories that serve a specific product under Sec. 7.14

and withdraws the accreditation of a testing laboratory to test a specific product under that section,

such testing

laboratory will be refunded the unexpended part of the

examination fees or charges paid by such testing laboratory

to maintain its accredited status under this program:

PROVIDED, HOWEVER, That no such testing laboratory will be

refunded its original application fee, if any, to be

accredited to serve a specific product.

7.16 Amendment or revision of criteria.

7.16

Provisions are made

for amendments or revisions to previously promulgated criteria

The Secretary, or a Criteria Committee acting at the

request of the Secretary, may undertake the development of

amendments or revisions of any applicable general or specific criteria previously promulgated by the Secretary

by following the same procedures pertaining to the original

development of such criteria.

98
7.17 User education and reports.

7.17(a)

Secretary will publish

a quarterly report of

actions involving each

specific product

For each specific product for which the Secretary has

made a final finding under these procedures that a need exists

to accredit testing laboratories that serve such product,

he

will publish a quarterly report noting all action taken by him

regarding such matters as accreditations, revocations, the

establishment of fees and charges, the promulgation of general

and specific criteria and any amendments or revisions to such

criteria.

Such report to state

clearly that accreditation does not relieve

the laboratories from

any legal responsibilities

Such publications shall clearly state that testing laboratories

accredited by the Secretary under these procedures are in no manner immune from the necessity of being in compliance

with

all legal obligations and responsibilities imposed by existing

Federal, State, and local laws, ordinances, and regulations,

including those related to consumer protection and antitrust

prohibitions

7.17(b)

Secretary's annual

report shall list

all laboratories

accredited during

the year

7.17(c)

Secretary shall report

monthly in the

Federal Register

all actions involving

status change

The Secretary will also prepare an annual report

summarizing all activities carried out under these procedures

which shall include a listing of all testing laboratories

accredited by the Secretary during the year to which the

annual report relates.

As a means of giving prompt notice to the public of

accreditation actions taken by the Secretary, he shall, in

addition to the reports called for under this section,

publish

in the Federal Register all actions taken by him during the

preceding month which grant, revoke, terminate or result in

the withdrawal of the accreditation of a testing laboratory.

with name and address

of laboratories

concerned

Such notice shall include the name and address of the testing

laboratory concerned, and a brief explanation of the action

taken by the Secretary with respect to that laboratory.

7.18 Support function.

Secretary shall

provide necessary

support

o The Secretary shall make provisions for administrative

and technical support and staff services as may be needed to carry out this program.

99
10.4 Hose Connection Vacuum Breaker Tests at NBS

A test was conducted to see how the HCVB would respond to

simultaneous back-siphonage and back pressure (due to garden hose

elevation) when the check valve was fouled with a wire in the manner

presented in ASSE standard No. 1011 for the back-siphonage test

method

10.4.1 Test Procedure and Results

The basic test procedure was as follows and as depicted in

figure 5

(a) Fill Pail "A" to some level (measured from the floor)

as shown in setup #1, figure 5. (Pail "A" simulates

a contaminated source - swimming pool)

(b) Weigh Pail "B" (tare weight) on weighing platform shown

in figure 6, Appendix 10.5 (Water flows out of the vent

ports down the outside of the hose and into Pail "B")

(c) Open spring loaded hose nozzle submerged to bottom of

Pail "A".

(d) Open vacuum valve "C" (make sure Pail "B" is dry) . The

purpose of Pail "B" is to collect vent port discharge.

(e) Simultaneously open quick-closing valve "D" and start

time interval recorder

(f) Read vacuum manometer and record vacuum (absolute value)

(g) When the sight glass is half full with water, shut valve

"D" and simultaneously stop time interval recorder.

(Water collected in the sight glass is backflow)

(h) Weigh Pail "B" to get weight of water plus weight of

bucket

(i) Remove the hose from HCVB and blow water (compressed air

from sight glass through HCVB into a graduated cylinder

(milliliters) . Record the volume of water as milliliter

of back-siphonage

For each setup shown in figure 5, make triplicate runs.

100
101
The average results are presented in Table 12 . The average

vacuum was 11.7 centimeters of mercury, absolute. The above average

rate results were quite repeatable even though vacuum fluctuations of

about + 2 cm of mercury occurred sporadically throughout each run. The last observed vacuum reading before closing valve "D" was recorded

as the running vacuum and these values were averaged. This variation

is judged to be normally caused by water movement through the atmospheric vents of the HCVB. Water movement being somewhat variable

since air is attempting to enter the vents simultaneously as water

tends to escape.

10.4.2 Discussion of Results

Even though vacuum varied somewhat, the back-siphonage rate

tended to remain quite constant. The volumes collected generally

were several hundred milliliters and these volumes tended to be repeatable within + 20 milliliters during any set of three runs for a given

setup. Out of fifteen runs only one run was off by + 50 milliliters.

The back-siphonage rate did not vary appreciably with increasing back

pressure condition. The device is designed to relieve back -pressure

through the ports and data shows that it does this quite effectively.

Although back-siphonage rate remained relatively constant with increasing back pressure, the vent discharge increased considerably as back pressure head was increased. A constant back-siphonage rate

indicated that back pressure at the HCVB must be relatively constant

regardless of the back pressure head potential imposed by the elevated

hose

102
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103
10.5 Reduced-Pressure Backflow Prevention Device Tests at NBS

A test was conducted to determine if the RPBD would allow backsiphonage, when checks were fouled with wires in the manner used for

testing vacuum breakers.

10.5.1 Test Procedure and Results

The basic test procedure was as follows:

(a) Mount the device in its normal operating position as recommended by the manufacturer, using test setup shown in

Figure 6.

(b) Apply water pressure to the device and conduct the three

tests described in AWWA publication No. S106, pages 21 and

22 [34] to determine that the checks are tight and that the

relief valve is functioning according to specifications.

(c) With check valve seats fouled with 0.042 inch diameter wire,

apply vacuum to the inlet and back-pressure to the outlet

of the device simultaneously. (Down stream check appears

to be open more than 0.042 inches because of its design).

(d) Measure zone pressure in inches of water column and record.

(e) Read back pressure at pressure gage P and record reading.

(f) With start of the run referenced to the initial application

of vacuum, time the run for an interval of 60 to 70 seconds

and close inlet and outlet valves simultaneously.

(g) Measure the volume of backflow (back-siphonage) collected

during the time interval and also the weight of water in

the zone discharge. Calculate flow rates in gpm.

(h) Tabulate results as follows:

RUN VOLUME OF

# BACK-SIPHONAGE

COLLECTED - ml

130

125

110

TIME TO

COLLECT

- Sec.

60

70

70

BACK-SIPHONAGE

RATE

- gpm

0.034

0.028

0.025

104
r

OPEN TO ATMOSPHERE

INCHES

SCALE

, PIEZOMETER TUBE FOR MEASURING

ZONE PRESSURE

FOR CONNECTION

TO DRY COMPRESSED ^^z£><]=

AIR FOR FORCE DRAINAGE

OF SIGHT GLASS

MILLILITER GRADUATED

CYLINDER TO MEASURE /

VOLUME OF BACKFLOW /

COLLECTED /

CONNECTED TO VACUUM

SUPPLY TO SIMULATE .BACK SIPHONING

SIGHT GLASS

VISUAL INDICATION OF BACKFLOW

V777777777777Z

VACUUM GAGE ABSOLUTE

TYPE- CENTIMETERS OF

MERCURY

VENT AND GAGE _

BLOW DOWN USING

COMPRESSED AIR

CENTIMETER SCALE

INVERTED WATER

MANOMETER

UPSTREAM SIDE OF RPBD UPSTREAM CHECK FOULED WITH

A 0.042 IN. DIA. WIRE (paper clip) UNDER SEATS

DISCHARGE FROM ZONE

VIA PIPE ELBOW

WEIGHTING TANK AND

WEIGHING PLATFORM

I I I I I 777777777777

DIGITAL READOUT OF

WEIGHT COLLECTED

VENTURI FOR

MEASURING RATE OF WATER FLOW

INTO THE RPBD

+777777?

ELECTRIC TIMER FOR

DETERMINING RATE OF

BACKFLOW AND ZONE

DISCHARGE RATE

Figure 6. A Diagram of Apparatus Used in the Testing of the ReducedPressure Backflow Prevention Device.

105
The average of three (3) runs of data are as follows:

(a) 1.85 gpm backflow rate (also zone discharge rate for all

practical purposes). Well below the rate specified in the

standards for a 3/4" safe RPBD.

(b) 0.029 gpm back-siphonage rate (rate into inlet of the

device)

(c) Zone pressure one (1) inch of water column.

(d) Backpressure 1.31 psig (36 1/4" head).

(e) Vacuum, 11 centimeters of mercury absolute (at inlet during

back-siphonage)

10.5.2 Discussion of Results

The relatively low backflow rate appeared close to the cutoff

condition when backflow would not occur (not exactly defined since such

information would serve no useful purpose at this time because the purpose was merely to test at some reasonable condition). The rubber

check material tended to seal itself around the fouling wire and backsiphonage rate decreased with time. Unfortunately, it was beyond the

scope of this effort to investigate this phenomenon. It was noticed

that backflow rate tended to fall off with time after initial installation of the fouling wires. The preceding backflow data illustrates

a slight change and trend during the runs. The three runs were taken

in about one hour (approximately 20 min./run).

After the device had been idle for several weeks with fouling

wires in place, it was noticed that only about 10 ml was collected

during a one minute period. The short term effect (one hour) appears

to be the seating of the soft rubber upstream check valve material

around the wire (self repairing, sealing tendency). The long term

effect (several weeks) appears to be the self repairing tendency plus

the effect of wire diameter reduction caused by corrosion. After

several weeks the wire diameter was reduced to about 0.020 inch

diameter in that portion under the seat of the upstream check. It was

not determined if complete sealing would result in time due to the

seating effect. Some reduction in backflow rate must have occurred

due to reduction in wire diameter.

106
The flow rates imposed on the zone were well below the value set

in the RPBD standards (five gpm^. Zone pressure with or without backsiphonage were well below the 1.5 psig maximum allowed by the RPBD

standards (appeared to be the same with or without vacuum at inlet to

the RPBD). Zone pressures and flow rates were checked as follows:

ZONE FLOW RATE

1.85 gpm

4.27

4.88

BACK PRESSURE

1.3 j>sig

2.5

5.0 '

ZONE PRESSURE

1" of water

2.5" of water

4.0" of water

At the end of the test, the fouling wires were removed and the

device tested in the usual field test manner using a differential

gage .8/ The test was conducted with 60 psig of water pressure. The

opening differential pressure of the relief valve was 6.5 psig which

was the same as that obtained at the beginning of the test. This test

and zone pressure tests demonstrated that the device was operating in

a satisfactory manner.

The reason why backf^ow took place is simply that the zone was

full of water at a pressure superior to that at the inlet, and the

inlet was separated from £he zone by the leaking check which allowed

water to flow from the high pressure zone into the low pressure inlet.

One of the basic problems is that water flowing from the relief valve

port blocks air that tends to enter the zone to vent the vacuum in the

inlet. In other words, this RPBD acts like a submerged vacuum breaker.

If it had adequate zone shape and configuration with independent zone venting and drainage such that the air inlet was not submerged and the

upstream check were exposed only to the entering air during backsiphonage , backflow of the liquid would be prevented.

8/

The differential gage was a special manufactured kit especially

designed and sold for use with RPBD.

107
10.6 Analysis of Test Methods in ASSE Standards for Backflow

Prevention Devices

While seeking a means of evaluating the tests methods that

apply to existing standards for backflow protection devices, it was noted that the recent ASSE Standards could be analyzed into

(a) Test requirement

(b) Test Setup and Preparation for Testing

(c) Test Procedure

(d) Observations , Records , and Computations

(e) Basis for Rejection of Device

The results of such analyses to the ASSE Standards 1001,

1002, 1011, 1012, 1013, 1015 and 1020 are documented herewith on

tables 13 through 19. A uniformity of style has become established

with the more recent output. The uniformity of style or format is

sharply defined in table 20 wherein the numerical sequence of

paragraph of ASSE 1013 were matched with comparable subject matter

(where possible) to be found in ASSE 1001, 1011, 1012, and 1015. Such

analysis is expected to be helpful in the development of criteria.

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133
Table 20 Descriptive Cataloging of Five Backflow Prevention Devices Indexed

to Comparable Paragraphs of the Respective A.S.S.E. Standards

A.S.S.E. No. 1001

October, 1970

2.6 Claused in this group of devices ere only those that perforin the single function of back-3lphona».;e preventlon;not included

are the atmospheric types ueed In conjunction with other controls(such as on antl-slphon ballcocf.) or vacuum relief valve6.

U.lt The basic function of the device is accomplished by

ans of a check valve

and an air relief valve.

2-3

It is designed to operate

only on the discharge side of a control valve.

3.7.5

It must not leak or spill water even under conditions of minimum flow and/ or flow pressure.

1.2

It must be Installed with

the C-I-L point at least

6" above the flood level rim of the receptacle

served.

Pine Api-lted Atn.iSK.erK Type Vacuum Srenxers

llor.o Connection Vacuum Hreaxera

U.5 and Fig. 2 Sites 'are 1/6" , l/V , 1/2"

3/V,l",l-l/V, 1-1/2",

2", 2-1/2", 3" and V.

3.2.1 and 3-2-2 Devices for cold water

supply lines only have a working temperature range from 32*F to 110°F. For

use with either hot or cold water the temperature

range Is from 32*F to 212

*F.

3.2 and U.2 The hydrostatic working

pressure is 125 pel

3-1 The entire assembly shall

be certified by the manu- facturer to be of nontoxl

materials, when used with

potable water.

3.2.1. and U.2 Must withstand 3 ten-minute hydrostatic teats at 3C*F and also 3 ten-min- ute tests at 110'F for cold water service at 1^5 pel.

A.3.3.B. No. 1011

June, 1970

1.1.1

The desl-'n ami-races a check valve na.-D.ijer foroe- louded.or biased, to a closed position and an atmospheric vent valve, or means, force-loaded to an open position when the device is not under

pressure.

1.1.2

The device is intended for

the protection of the po

.able water supply against contaminants which could

otherwise enter the water system by back-slphonage

cr bock-pressure backflow

through the hose-threaded

outlets.

1.1.1

It is designed to be in- stalled on the discharge

side of the control valve

Foreword

To be effective it must be so Installed that the air ports connot be submerged

1.2.2 The two sizes have 3/V

and i" hose connection

threads.

1.2.1 and 2.1.10

It must be suitable for both he. and cold water

service. The working temp- erature range is i2°F to 190°F.

1.2.3

The TM-iri-iinini working pressure is 125 psl.

1.3.1 All material in contact

with t!.e water flowing

through the device which

can, in any way, contaminate the water so that it may be Injurious to per- sons consuming It, are prohibited

L'OCkl'low Preventerj wi tii Interaetllata

A.3.3.E. No. 1012

May, 1972

1.1.1.1

Such devices r.ave two in- dependently cieratiiv

cneck valves separate.: by

an lntercediate chaxcer

witli a means :'or eutcr.a- tlcally ventliug it tc the atmosphere. The check

valves are force loadei to a normally-clcsed position

and the venting means Is force loaded to a norr-al- ly-open position.

1.1.2 Should not be used fcr building Isolation, but

may be used back-pressure backflow and/or back-si- phonage involves contaminants of low hazard.

1.1.1.1

The device can operate un- der continuous :>r inter- mittent pressu-j condltlons.

1.7-1

It must not be '. stalled

In a concealed i • inaccessible location where venting of watt! would be objectionable, t

1.1.1.2

Inlet and cutlet ; lpe sizes are l/V, \ (?", 1/2", and 3/V1.1.1. It The temperature

U0*F to 220*F.

2.1.1

Must withstand for a 5- mlnute period a hydrostatic test of ^ tlacs the rated working pressure.

ige is

i 1.1.1.3 \ The working pressure i at be not less than 150 ;i I.

1.1*.

All material in cont

with the water flowli through the device wr. can, in any way, conto

nate the water so tna \ It cay be inj uric us to p \ sons or animals consult, are prohibited

2.2

Must withstand for a 5 \ minute period a hydros', tic tec-', of tw-„ tines

rated warning pressure.

134

Heuuced Prooaure

Principle buck Pressure

l<ackl'low Pro-venters A.S.8.G. No. 1013

June, 1971

1.1.1.1

Tne device consists of two

lndeper iently actim; check valves Internally force- loaded to a normally

closed position and sepa- rated by an lntercediate chamber or zone In which

there is an automatic re- lief means for venting to atmosphere. Such means is internally force-loaded to a normally-open position.

Foreword and 1.1.1.1

It is designed primarily

for the prevention of backflow due to back pres- sure and to operate under

continuous pressure condi- tions.

Foreword of A.S.S.E. 1012

The device is considered

to be the best available

for building isolation

or for high health hazard

conditions

1.3-7

The design must incorporate provision for bleeding trapped air from the

device.

1.1.1.2 Connection pipe sizes are: 1/2", 3A", 1", 1-l/V,

1-1/2", 2", 2-1/2", 3", V,

6", 8", 10", 12", 1U", and 16".

l.l.l.U

For cold water service

the temperature range is 33*F to llO'F and for hot water service the range

is above 110'F.

1.1.1.3

The working pressure must

be at least 150 psl.

1.U.7

All material In contact

with the water flowing

throuv^h the device which

can, in any way, contaminate the water so that it may be injurious to percons consuming it, are prohibited

2.1

It must withstand for 5 minutes a hydrostatic test

at two times the rated working pressure ar plied

at the Inlet.

tViuble Check Valve

Type Back Prescure

Pockflow Preventers

A.S.S.E. No. 1015

May, 1972

1.1.1.1

The device consists of

two Independently operating check valves, inter- nally loaded to a normal- ly-closed position.

1.1.1.1

It cay be used under In- termittent or continuous

pressure conditions.

1.1.2 This type of device is considered suitable for

use only where there is

no health hazard.

1.1.1.2

The sizes shall be 1/2",

-•/K", 1", 1-1/V', 1-1/2", i", 2-1/2", 3", U", 6", 3", 10", 12", IV, and l6".

l.l.l.U

For cold water service

the temperature range is 53'F to 110'F and fcr hot

water service the range

is above 110'F.

1.1.1.3 The working pressure cust

be at least 150 psl.

1.U.3

All material in contact

with the water flowing

through the device which

can, in any way, contaminate the water so tnat it may be injurious to persons consuming it, are prohibited

2.1

It must withstand a 5-nin- ute hydrostatic test at two times the rated working pressure which is 150 psl minimum.
Table 20 Descriptive Cataloging of Five Backflow Prevention Devices Indexed

to Comparable Paragraphs of the Respective A.S.S.E, Standards

a.s.s.e. No. iaa

October, ly70

3. £.2.. and 4.C

ftuet withstand 3 ten-min- ute hydrostatic tests at 32°F and also 3 ten-minute tests at ^Lc°F for hot water service at 125 psl.

Pipe Applied Atmospheric Type Vacuum Breakers Hose Connection Vacuum B) eakerj

A.S.S.E. No. 1011

June, 1970

2.1.3

At the minimum flows (gp=.) given in table 1, the pressure loss must not exceed 25 psi.

2.1.1* At 3 P*l Inlet pressure

ther must be no leakage from vent port. Below 3 psl, leakage must not exceed 1/4 pint per minute.

2.1.9

With the device connected

as in Fig. 10 to 50 ft. of

1/2" hose at rated pressure, if the pressure at the Inlet drop3 suddenly

to 0 psl, the pressure In

the hose must dissipate

quickly through the vent

porta.

BuckI'low Preventers

With Intermediate Atmospheric Vent

A.S.S.E. No. 1012

May, 1972

2-3 The outlet check valve

must withstand for a 5- mlnute period, two times

the rated working pressure on the downstream side with atmospheric on up- stream side.

2.4 and 2.5 Each check valve must be drip tight when not less than 1 psi is applied to upstream side and atmosspherlc pressure to down- stream side.

2.10

At rated flow (gpm from

table 4) the pressure loss shall not exceed 25 psl.

2.6 There must be no leakage from the vent port when

the supply valve Is opened regardless of the rate at

whicli it is opened, nor

any leakage at any flow

rate up to the 'capacity rating of the device.

lie-iueed Pressure

Principle bacK Frc^ure

Backflow Pre-. enters

A.S.S.E. No. 1013 June, 1971

:.2 The outlet checu valve

must with3tai.d for 10 minutes, two tires the rated working pressure on the downstream side with atmo6 pheric pressure In the in- let and Intermediate chambers.

2.3 The outlet check valve

must be drip ti-Tht when

the intermediate pressure

is 1 psl and the outlet

pressure is atmospheric.

2.4

At rated flow (-ri and psl from table 2; the pressure

loss must not exceed the maximum allowable.

2.5 Under either static or

flow conditions the Inter- mediate zone pressure must be at least 2 psi lower

than the Inlet.

2.6 During static operating

condition, s:.ouid supply

pressure fall tc 2 psi

then pressure in the zone must become atmospheric.

2.7a

During backflow condition with supply pressure 2 psl or more, the zone must dis- charge to at=ospi.ere at rate shown In taile 3 and zone pressure must be at least 0.5 psi below the supply pressure.

2.7b During backflow condition

with supply pressure less

than 2 psl, the zone must

discharge to atrx sphere at rate shown In table 3 and the zone pressure must not exceed 1.5 psl.

i.a

The atmospheric vent valve

must start tc open when

pressure In zone is at least 2 psi lower than

pressure in Inlet. It must open and close positively.

2.9

The relief valve must not discharge water jider supply pressure fluctuations of l-i/2 psl maximum

variation.

A.S.S.E. No. 1015

May, 1972

2.2 Each check valve must withstand two times the rated working pressure on downstream side and atmos- pheric on upstream side for a 5-mlnute period.

2.3 Each check valve must be

drip tight when not less

than 1 psi is applied to upstream side and atmospheric to downstream side.

2.4

At rated flow (gpm from

table 2) the pressure loss must not exceed 10 psi.

Double Chick Valve- Type I'.'iek Prcceure

Backflow Preventers

135
Table 20 Descriptive Cataloging of Five Backflow Prevention Devices Indexed

to Comparable Paragraphs of the Respective A.S.S.E. Standards

Pipe Applied Atnospherlc Type Vacuum breukera

Hoee Connection

Vtici.um breakers

buckllow Preventers

With Intern-Mlute Atnospherlc Vent

ReluceJ Pressure

Principle tack Pressure

I'ockflow Preventers

Double Check Valve

Type Back. Pre^uure Backflow Prcventero

A.3.3.E. No. 1001 October, 1970

A.S.S.E. No. 1011

June, 1970

2.1.6 With the air porta sealed,

the device must prevent backflow during 5 -minute testa at 0.22,l.oi, I.96,

2.82, 2.o6, and I*. 33 psi back pressure on the in- let check valve.

3-5 and 4.5 With the check valve seat fouled with a test wire, the inlet connected to a vacuum line, and the out- let connected by a sight tube extenilng downward

6 Inches into a water sur

face, as varying vacuuraa are applied to the inlet water rise in the sight tube must not exceed 3"-

2.1.7

With the inlet check valve

fouled by a test wire, the device must withstand

back-8lphona_;e vacuums of

25 inches of mercury

column applied to the in- let either gradually cr

rapidly alternating from

0" to 25" to 0" etc.

2.1.10 When tested ( see fig 9) with hot water flowing at

5 to 7 gpm for 10 days of

8 hours each at temperatures of 190°F 5°F, the nonmetallic materials in

the device must not be adversely affected.

2.1.5

Hist withstand a water hammer test of four shocks each at 25 psi and at 100

psi flowing pressure

A.S.S.E. No. 1012

May, 1972

2.7 With the vent outlet

sealed closed and the out< let check held partially

open, the must be no leak age through the inlet check as pressures of 0.2

15 and rated psi are ap- plied successively for 5 minutes each at the out- let of the device.

2.6

The atmospheric vent must

be open when the supply pressure is 20$ less than downstream.

2.9 With a vacuum at the in- let and atmospheric pressure at the cutlet, and both check valve seats

fouled, there must be no back-slphonage to the inlet.

2.11 With a supply pressure of

10 psi the flow rate must

be not less than 20$ of rated capacity.

A.S.3.E. No. 1013

June, 1971

A.S.&.E. No. 1015

May, 1972

2.1.8

When tested for 3 minutes

as shown in Fig. 3, the device must withstand a torque of 300 in- lb while pressurized to at least

100 psi.

3.1* and The effective airway must be equal to or greater than the effective water- way through the device.

3-3 and U.3 Air port shields must ex- tend to the bottom of the lowest air port opening

and clearance of 3/1''" between shield and body must be maintained.

2.1.2

Must not produce objec- tionable noises at ec" flow rate up to maximum

capacity, at any pressure

u; to itc r«*.ed mux 1 sua ralntaincd at the Inlet.

2.1 Must not produce oblec- ticnhle nois-e at u,.. fl jw r*\*.e U" tn mn'iEuir. capa'it/, at any pressure

>i|' to its rateU maxlmuc. maintained at the Inlet. 136
10.7 Units of Measure and S. I. Conversion Factors

In NBS Document LC 1056, revised August 1975, guidelines were established to reaffirm

and strengthen the commitment of NBS to the greatest practicable use of the International

System of Units (S. I.) in all of its publications and also in all of its dealings with

the science and engineering communities and with the public. In this report the measurements are those of the U. S. Customary units as they appear in the referenced standards,

in order that the readers may give full attention to discussions and the compilation of

data in this state-of-the-art report on backflow preventers. Notwithstanding the immediate

objectives of this report, subsequent actions leading to the updating of backflow preventer

standards should establish the metric system to the fullest extent possible.

The following conversion factors are appropriate for the units of measure that appear

in this report:

Length -

1 inch (in ) = 0.0254 meter (m)

1 foot (ft ) = 0.3048 meter (m)

Mass -

1 pound-mass (lbm) * .4535924 kilogram

Temperature -

1 1 Degree Fahrenheit (°F) = (1.8) kelvin (K) or (°K)

Temperature Fahrenheit (°F) - (459.67 + temp. °F)/1.8 kelvins (K)

Time -

1 hour (h) = 60 minutes (min) = 3600 seconds (s)

Velocity -

1 foot per second (fps) = 0.3048 meter per second (m/s)

Force -

1 pound-force (lbf) = 4.448222 newtons (N)

Pressure -

1 pound-force per square inch (psi) 6894.757 pascals (Pa)

6.894757 kilopascals (kPa)

1 inch of water column at 60°F » 248.84 pascals (Pa)

Volume - 11 1 U.S. liquid gallon (gal) - 0.003785412 meter (m ) - 3.785412 liters (1)

Flow Rate -

1 U.S. gallon per minute (gpm) - 0.0000630902 meters^/second

3 = 63.0902 centimeters /second (cm /s) = 0.0630902 liters/second (1/s)

137
NBS-114A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 76-1070

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Evaluation of Backflow Prevention Devices:

A State-of-the-Art Report

5. Publication Date November 1976

6. Performing Organization Code

7. AUTHOR(S)

Grover C. Sherlin and Robert W. Beausoliel

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. 4624190

•

I • Cv—Urtnf 11 1. rnrf 1 Btl//Cimnf >~I I dill llU. Wf\ EPA-IAG-0170(D)A

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

Environmental Protection Agency

Water Supply Division

Washington, D.C. 20460

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

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

bibliography or literature survey, mention it here.) A significant potential for potable water supply contamination exists within all

water supply systems due to backflow and cross connections. Surveillance of the water

supplies to protect from such hazards requires continuing vigilance by the administrators of cross-connection control programs, and continuing upgrading of technical

criteria and methods of evaluation.

The Environmental Protection Agency assists local (usually municipal) authorities,

through the State water supply agency, in establishing and operating cross-connection

control programs. Essential to these programs are (1) information on the suitability

of commercially available devices for use in potentially high-hazard locations, and

(2) practical and effective standardized test methods for evaluation of devices. The

National Bureau of Standards investigation reported herein addresses the two needs

identified.

This study includes a systematic review of the literature, together with consultations and visits with water purveyors, plumbing officials, laboratory officials and

researchers in this field. Emphasis has been placed on those devices, test methods, anc laboratory practices considered most essential to an effective assessment of the stateof-the-art. Also, test development needs were identified in a few areas of greatest

concern.

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

Backflow; backflow preventers; back pressure; back-siphonage; cross connections;

health hazard; potable water; vacuum breaker; water supply.

18. AVAILABILITY [* Unlimited

|

' 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. C13

|X I Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS 21. NO. OF PAGES

(THIS REPORT)

UNCLASSIFIED ^.41

20. SECURITY CLASS 22. Price (THIS PAGE)

UNCLASSIFIED $6.00

U8COMM.DC 29042-P74