csa-b64.10 selection and installation of backflow

B64.10-07/B64.10.1-07

Selection and installation of backflow preventers/Maintenance and field testing of backflow preventers

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Update No. 1B64.10-07/B64.10.1-07July 2008Note: General Instructions for CSA Standards are now called Updates. Please contact CSA Information Products Sales or visit www.ShopCSA.ca for information about the CSA Standards Update Service.

Title: Selection and installation of backflow preventers/Maintenance and field testing of backflow preventers — originally published July 2007

The following revisions have been formally approved and are marked by the symbol delta (Δ) in the margin on the attached replacement pages:

CSA B64.10-07/B64.10.1-07 originally consisted of 146 pages (x preliminary and 136 text), each dated July 2007. It now consists of the following pages:

• Update your copy by inserting these revised pages.• Keep the pages you remove for reference.

Revised Figure E.1

New None

Deleted None

July 2007 iii–x, 1–60, and 63–136

July 2008 61 and 62

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© C

anadian Standards Association

July 2008

Selection and installation of backflow preventers

Figure E.1 (Concluded)

Table 1Authorized functions listMunicipality of _________________Bylaw number __________________

Item Authorized function

Professional engineer with tester’s licence

Certified engineering technologist with tester’s licence*

Licensed master plumber with contractor’s and tester’s licence

Journeyman plumber with tester’s licence†

Apprentice plumberwith tester’s licence‡

Fire system sprinklerfitter with a tester’s licence

Lawn irrigation system installer with tester’s licence

1 Carry out cross- connection survey

✓ ✓ ✓ ✓ — — —

2 Install, relocate, or replace backflow preventer

— — ✓ ✓ ✓ — —

3 Repair backflow preventer

✓ ✓ ✓ ✓ ✓ — —

4 Test backflow preventer ✓ ✓ ✓ ✓ ✓ — —

5 Complete Items 1, 2, 3, and 4 in relation to fire protection systems

✓ ✓ ✓ ✓ ✓ ✓ —

6 Complete Items 3 and 4 in relation to lawn sprinkler systems

✓ ✓ ✓ ✓ ✓ — ✓

*Required to be under the direction of a professional engineer.†Required to be employed by a licensed plumbing contractor or licensed fire sprinkler contractor.‡Required to be employed by a licensed plumbing contractor and under the direct supervision of a journeyman plumber or master plumber.

Δ

61

(Replaces p. 61, July 2007)

Licensed for/Autorisé à Jeff Whitaker, Utilities Kingston, Sold by/vendu par CSA on/le 4/8/2009. Single user license only. Storage, distribution or use on network prohibited./Permis d'utilisateur simple seulement. Le stockage, la distribution ou l'utilisation sur le réseau est interdit.

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B64.10-07/B64.10.1-07

CSA Standards Update Service

B64.10-07/B64.10.1-07July 2007

Title: Selection and installation of backflow preventers/Maintenance and field testing of backflow preventersPagination: 146 pages (x preliminary and 136 text), each dated July 2007

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Published in July 2007 by Canadian Standards AssociationA not-for-profit private sector organization

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CSA Standards

B64.10-07/B64.10.1-07Selection and installation of backflow

preventers/Maintenance and field testing of backflow preventers

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© Canadian Standards AssociationSelection and installation of backflow preventers/

Maintenance and field testing of backflow preventers

July 2007 iii

ContentsTechnical Committee on Backflow Preventers and Water Pressure Reducing Valves vii

Preface ix

B64.10-07, Selection and installation of backflow preventers

1 Scope 31.1 Application 31.2 Exclusions 31.3 Terminology 31.4 Measurement 3

2 Reference publications 3

3 Definitions, abbreviations, and symbols 43.1 Definitions 43.2 Abbreviations 93.3 Symbols 93.3.1 Backflow preventers 93.3.2 Vacuum breakers 103.3.3 Other symbols 11

4 Backflow prevention methods and devices 124.1 Air gap 124.1.1 General 124.1.2 Hazardous installations 124.1.3 Use 124.2 Barometric loop 124.2.1 General 124.2.2 Use 134.2.3 Limitations 134.3 Mechanical backflow preventers 144.3.1 Available types 144.3.2 Vacuum breaker backflow preventers — General 154.3.3 AVB devices 154.3.4 PVB devices 174.3.5 SRPVB devices 184.3.6 HCVB and HCDVB devices 204.3.7 DCAP and DCAPC backflow preventers 214.3.8 RP and RPF backflow preventers 244.3.9 DCVA and DCVAF backflow preventers 254.3.10 DuC and DuCF backflow preventers 274.3.11 LFVB devices 274.3.12 DuCV backflow preventers 284.3.13 SCVAF backflow preventers 29

5 Selection of backflow preventers 295.1 General 295.2 Categories of hazards 305.3 Principal ways of providing protection 305.3.1 General 30

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B64.10-07/B64.10.1-07 © Canadian Standards Association

iv July 2007

5.3.2 Individual protection 315.3.3 Zone protection 315.3.4 Premises isolation 325.4 Selection guide 335.5 Backflow from fire protection systems 345.6 Backflow from water fill stations 365.7 Backflow from temporary water services 365.8 Backflow from irrigation systems 365.8.1 Above-ground irrigation systems 365.8.2 In-ground irrigation systems 36

6 Installation of backflow preventers and vacuum breakers 376.1 General requirements 376.1.1 Accessibility 376.1.2 Clearances 376.1.3 Support and restraint 376.1.4 Bypasses 376.1.5 Field testing at installation 386.1.6 Installation of DCAPC backflow preventers 386.1.7 Flushing 386.2 Sizing 386.3 Working pressures and temperatures 386.4 Shut-off valves and test cocks 386.5 Strainers 396.6 Location 396.7 Parallel service 396.8 Connections to drains 396.9 Thermal expansion 406.10 Installation orientation 406.11 Enclosures and protection from freezing 40

AnnexesA (informative) — How backflow can occur 42B (informative) — Guide to the assessment of hazards 45C (informative) — Water-hauling equipment and backflow devices 55D (informative) — Conversion tables 56E (informative) — Model backflow prevention bylaw 57

Tables1 — Types of backflow preventers and vacuum breakers and applicable CSA Standards 142 — Selection guide for backflow preventers 343 — Selection guide for backflow preventers for fire protection systems 354 — Clearances, mm 37

Figures1 — Air gap 122 — Barometric loop 133 — Typical AVB device 154 — Use of AVB devices 165 — Typical PVB device 176 — Use of PVB devices 187 — Typical SRPVB device 198 — Use of SRPVB devices 19

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July 2007 v



9 — Typical HCVB device 2010 — Use of HCVB and HCDVB devices 2111 — Typical DCAP backflow preventer 2212 — Use of DCAP backflow preventers 2213 — Typical DCAPC backflow preventer 2314 — Typical RP backflow preventer 2415 — Use of RP backflow preventers 2516 — Typical DCVA backflow preventer 2617 — Use of DCVA backflow preventers 2618 — Typical DuC backflow preventer 2719 — LFVB devices 2820 — Typical DuCV backflow preventer 2921 — Typical enclosure 41

B64.10.1-07, Maintenance and field testing of backflow preventers

1 Scope 65

2 Reference publications 65

3 Definitions, abbreviations, and symbols 65

4 Devices to be field tested, frequency, and reporting 664.1 Devices to be field tested 664.2 Frequency of field testing 664.3 Reporting 66

5 School accreditation and tester certification and licensing 695.1 School accreditation 695.2 Tester certification and re-certification 705.3 Tester licensing and registration 70

6 Maintenance 716.1 General 716.2 RP backflow preventers 716.3 DCAPC backflow preventers 71

7 Test gauges and kits 727.1 Accuracy 727.2 Verification and calibration 727.3 Units 72

8 Field test requirements and pass/fail criteria 728.1 PVB devices 728.1.1 General 728.1.2 Air inlet valve 728.1.3 Check valve 728.1.4 Static line pressure 738.2 RP and RPF backflow preventers 738.2.1 General 738.2.2 Relief valve 738.2.3 Check valve 1 738.2.4 Check valve 2 748.2.5 Static line pressure 74

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vi July 2007

8.3 DCVA, DCVAF, and SCVAF backflow preventers 748.3.1 General 748.3.2 Check valve 1 748.3.3 Check valve 2 758.3.4 Static line pressure 758.4 HCDVB devices — Manual field test of downstream check valve 768.4.1 Test requirement 768.4.2 Test set-up 768.4.3 Test procedure 778.5 SRPVB devices 778.5.1 General 778.5.2 Air inlet valve 778.5.3 Check valve 778.5.4 Static line pressure 77

AnnexesA (informative) — Field testing procedures 78

Tables1 — Field test requirements for backflow preventers 76

Figures1(a)—Sample testing and inspection report for DCVA backflow preventers and PVB devices 671(b)—Sample testing and inspection report for RP backflow preventers 681(c)— Sample testing and inspection report for RP and DCVA backflow preventers and PVB and SRPVB

devices 69

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July 2007 vii

Technical Committee on Backflow Preventers and Water Pressure Reducing Valves

M. Birks The Birks Company,Moffat, Ontario

Chair

J.W. Green City of Calgary,Calgary, Alberta

Vice-Chair

R. Armstrong City of Saint John,Saint John, New Brunswick

W. Ball Woodford Manufacturing Company,Colorado Springs, Colorado, USA

S. Breda Breda & Associates Ltd.,Downsview, Ontario

C. Caruana CSA International,Toronto, Ontario

Associate

R.W. Castle Honeywell Water Solutions,Warwick, Rhode Island, USA

S.L. Cavanaugh Cavanaugh Consulting,Burbank, California, USA

D. Dolan City of Coquitlam,Coquitlam, British Columbia

W.C. Dunmire FEBCO, a division of Watts Water Technologies, Inc.,St. Pauls, North Carolina, USA

Associate

W.C. Evans British Columbia Institute of Technology,Burnaby, British Columbia

R. Funderburk Conbraco Industries, Inc.,Pageland, South Carolina, USA

D. Hanna Ontario Backflow & Plumbing Service Ltd.,Oshawa, Ontario

E. Ho IAPMO Research & Testing,Markham, Ontario

Associate

K.S. Hui Ontario Ministry of Municipal Affairsand Housing,Toronto, Ontario

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viii July 2007

L. Kendall Hamilton, OntarioRepresenting the United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry of the United States and Canada

A. Knapp A. Knapp & Associates,Toronto, OntarioRepresenting the Canadian Copper and Brass Development Association

N. Kummerlen Moen Incorporated,North Olmsted, Ohio, USA

Associate

B. Lagueux Saint-Nicolas, QuébecConsumer representative

M. Légaré Régie du bâtiment du Québec,Québec, Québec

F. Lemieux Health Canada,Ottawa, Ontario

S. MacDonald Halifax Regional Water Commission,Halifax, Nova Scotia

B. Maddock Humber College,Toronto, Ontario

B. Noll Wilkins, a Zurn Company,Paso Robles, California, USA

P. Paré Watts Industries (Canada) Inc.,Burlington, Ontario

S. Rawalpindiwala Kohler Co.,Kohler, Wisconsin, USA

Associate

S. Remedios Delta Faucet Company,Indianapolis, Indiana, USA

Associate

R. Sochowski Capital Regional District Water Services,Victoria, British Columbia

C. Spagnuolo City of Brampton,Brampton, Ontario

Associate

R. Tomuschat Alberta Municipal Affairs and Housing,Edmonton, Alberta

G. Veltman City of Toronto,Toronto, Ontario

A.I. Murra Canadian Standards Association,Mississauga, Ontario

Project Manager

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July 2007 ix

Preface

This volume contains the fifth edition of CSA B64.10, Selection and installation of backflow preventers, and the second edition of CSA B64.10.1, Maintenance and field testing of backflow preventers. CSA B64.10 supersedes the previous editions published in 2001 (under the title Manual for the Selection and Installation of Backflow Prevention Devices), 1994, 1988 (as part of the CAN/CSA-B64 Series), and 1981. CSA B64.10.1 supersedes the previous edition, published in 2001 under the title Manual for the Maintenance and Field Testing of Backflow Prevention Devices.

This edition of CSA B64.10 includes the following:(a) new definitions and requirements for

(i) zone and area protection; (ii) different classes of fire protection systems; and(iii) spill-resistant pressure vacuum breakers (SRPVB);

(b) updated hazard categories;(c) new requirements for the prevention of backflow from water fill stations and for temporary water

services;(d) a revised and expanded guide to the assessment of hazards in Annex B, which presents information in

two separate tables for greater clarity; and(e) the addition of a model backflow prevention bylaw in the new Annex E.

The new edition of CSA B64.10.1 now includes field testing procedures for spill-resistant pressure vacuum breakers and testing procedures using a 5-valve differential pressure gauge.

Both Standards have been extensively edited to improve consistency and clarity.The two Standards are intended as a guide for designers of potable water supply and plumbing systems

in the selection of the proper type of device, for installers and owners in the installation and maintenance of the devices, and for inspection authorities in the testing of the devices after they have been installed. The Standards provide information on other methods of preventing contamination of potable water by backflow from back siphonage or back pressure.

CSA B64.10 and CSA B64.10.1 provide selection criteria, installation and maintenance procedures, and techniques that represent the general state of the art, but should not be construed as all-inclusive, especially where procedures and techniques must be altered to meet special conditions. Where there are problems with a specific installation, it is suggested that the manufacturer of the backflow preventer be consulted.

These Standards were prepared by the Technical Committee on Backflow Preventers and Water Pressure Reducing Valves, under the jurisdiction of the Strategic Steering Committee on Plumbing Products and Materials, and have been formally approved by the Technical Committee. They will be submitted to the Standards Council of Canada for approval as National Standards of Canada.

July 2007

Notes: (1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.(2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains

the responsibility of the users of the Standard to judge its suitability for their particular purpose.(3) This publication was developed by consensus, which is defined by CSA Policy governing standardization — Code of

good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this publication.

(4) CSA Standards are subject to periodic review, and suggestions for their improvement will be referred to the appropriate committee.

(5) All enquiries regarding this Standard, including requests for interpretation, should be addressed to Canadian Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6.

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x July 2007

Requests for interpretation should(a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;(b) provide an explanation of circumstances surrounding the actual field condition; and(c) be phrased where possible to permit a specific “yes” or “no” answer.Committee interpretations are processed in accordance with the CSA Directives and guidelines governing

standardization and are published in CSA’s periodical Info Update, which is available on the CSA Web site atwww.csa.ca.

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CSA Standard




B64.10-07Selection and installation of backflow

preventers

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© Canadian Standards Association Selection and installation of backflow preventers

July 2007 3

B64.10-07Selection and installation of backflow preventers

1 Scope

1.1 ApplicationThis Standard specifies requirements for the selection and installation of backflow preventers. Additional information on how backflow due to back siphonage and back pressure occurs, and how to select and apply specific devices, is included in Annexes A, B, and C.

1.2 Exclusions

1.2.1This Standard does not specify requirements for materials, construction, or performance tests of backflow preventers. Such requirements are specified in the CSA B64 Series, in ASME A112.18.1/CSA B125.1, and in CSA B125.3. See Table 1.

1.2.2This Standard does not specify requirements for maintenance or field testing after the initial installation. Such requirements are specified in CSA B64.10.1.

1.3 TerminologyIn CSA Standards, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; “should” is used to express a recommendation or that which is advised but not required; “may” is used to express an option or that which is permissible within the limits of the standard; and “can” is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.4 MeasurementThis Standard is written in SI (metric) units. For conversion tables, see Annex D. Vacuum is expressed in pressure below ambient.

2 Reference publicationsThis Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below.

CSA (Canadian Standards Association)B64 Series-07Backflow preventers and vacuum breakers

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B64.10-07 © Canadian Standards Association

4 July 2007

B125.3-05Plumbing fittings

ASME/CSA (American Society for Mechanical Engineers/Canadian Standards Association)ASME A112.18.1-2005/CSA B125.1-05Plumbing supply fittings

ASSE (American Society of Sanitary Engineering)1060-2006Performance Requirements for Outdoor Enclosures for Fluid Conveying Components

CGSB (Canadian General Standards Board)CAN/CGSB-24.3-92Identification of Piping Systems

National Research Council CanadaNational Building Code of Canada, 2005

National Plumbing Code, 2005

3 Definitions, abbreviations, and symbols

3.1 DefinitionsThe following definitions apply in this Standard and in CSA B64.10.1:

Air break — the unobstructed vertical distance between the lowest point of an indirectly connected waste pipe and the flood level rim of the fixture into which the waste pipe discharges. See Fixture.

Air gap — the unobstructed vertical distance through air between the lowest point of the water supply outlet and the flood level rim of the fixture or device into which the outlet discharges.

Area protection — protection provided for a section of a piping system with potable and non-potable connections (that may or may not be considered cross-connections) downstream of a backflow preventer.See Zone protection.

Auxiliary water supply — any water supply on or available to the premises other than the purveyor’s approved public water supply.Note: The auxiliary water supply can include water from another purveyor’s public water supply or from any natural source, such as a well, lake, spring, river, stream, or harbour; auxiliary water can also include used water or industrial fluids.

Back pressure — a pressure higher than the supply pressure.

Back siphonage — backflow caused by pressure below atmospheric in the supply system.

Backflow — a flowing back or reversal of the normal direction of flow.

Backflow preventer — a device that prevents backflow.

Double check valve (DCVA) — a backflow preventer that consists of two force-loaded, independently acting check valves and two resilient-seated shut-off valves located at each end of the DCVA backflow preventer and is fitted with resilient-seated test cocks. DCVA backflow preventers are designed for use under continuous pressure.

Double check valve for fire protection systems (DCVAF) — a DCVA backflow preventer specifically designed for use on fire sprinkler and standpipe systems.

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Dual check valve (DuC) — a backflow preventer that consists of two independently acting, force-loaded, soft-seated check valves in series. DuC backflow preventers do not have a relief port or test cocks. They are designed for use under continuous pressure.

Dual check valve for fire protection systems (DuCF) — a DuC backflow preventer specifically designed for use on residential fire sprinkler and standpipe systems.

Dual check valve with atmospheric port (DCAP) — a backflow preventer that consists of two independently acting check valves separated by an intermediate chamber with an atmospheric port. DCAP backflow preventers are designed for use under continuous pressure.Note: A chamber pressure higher than the supply pressure is required to open the port when there is a positive pressure on the supply side.

Dual check valve with atmospheric port for carbonators (DCAPC) — a backflow preventer specifically designed for use in carbonated beverage dispensing machines that consists of two independently acting check valves biased to normally closed positions and separated by an intermediate chamber with an atmospheric port. DCAPC backflow preventers are designed for use under continuous pressure.Note: A chamber pressure higher than the supply pressure is required to open the port when there is a positive pressure on the supply side. An integral strainer at the inlet ensures that debris does not foul the device’s check valves or enter the carbonated beverage dispensing machine.

Dual check valve with intermediate vent (DuCV) — a backflow preventer that consists of two independently acting check valves biased to a closed position. Between the check valves there is an atmospheric vent that is biased to an open position. DuCV backflow preventers are designed for use under continuous pressure.

Reduced pressure principle (RP) — a backflow preventer that consists of a mechanically independently acting, hydraulically dependent relief valve located in a chamber between two independently operating, force-loaded check valves. RP backflow preventers are designed for use under continuous pressure.Note: The intermediate chamber pressure is always lower than the supply pressure when there is a positive pressure on the supply side. RP backflow preventers include resilient-seated test cocks and resilient-seated shut-off valves at each end.

Reduced pressure principle for fire protection systems (RPF) — an RP backflow preventer specifically designed for use on fire sprinkler and standpipe systems.

Single check valve for fire protection systems (SCVAF) — a backflow preventer that consists of one force-loaded, independently acting check valve, including resilient-seated shut-off valves located at each end of the SCVAF backflow preventer and fitted with resilient-seated test cocks. SCVAF backflow preventers are designed for use under continuous pressure on fire sprinkler and standpipe systems.

Backflow prevention device tester — a person who is certified to test backflow preventers by an accredited organization acceptable to the regulatory authority.

Confined space — an enclosed or partially enclosed space that has restricted access and egress and that because of its design, construction, location, atmosphere, and contents or work activity therein, is or can become hazardous to the worker.

Critical level (CL) — the level of submergence at which a vacuum breaker ceases to prevent back siphonage.

Cross-connection — any actual or potential connection between a potable water system and any source of pollution or contamination.Note: Bypass arrangements, jumper connections, removable sections, swivel or changeover devices, or any other temporary or permanent connecting arrangements through which backflow can occur are considered cross-connections.

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Cross-connection control program (CCCP) — a program initiated by a regulatory authority to administer and regulate the selection, installation, testing, and maintenance of backflow preventers.

Enclosure — an above-ground structure, designed to accommodate a backflow preventer, that incorporates positive drainage to prevent submergence of the backflow preventer, provide security, increase accessibility for testing and repair, and possibly provide freeze protection.

Fire protection system (class types) — an assembly of pipes and fittings that conveys water from the water service pipe to the fire sprinkler or standpipe outlets.

Class 1 system — a fire protection system that has direct connections only from public water mains, has no pumps, tanks, or reservoirs, and has all sprinkler drains discharging to atmosphere, dry wells, or other safe outlets.

Class 2 system — a fire protection system that is the same as a Class 1 system but also includes a booster pump in the connection from the municipal water supply system.

Class 3 system — a fire protection system that has direct connections from the municipal potable water supply system, elevated storage tanks (either open or closed), fire pumps taking suction from above-ground covered reservoirs or tanks, and pressure tanks. In Class 3 systems, storage facilities are only filled from, or connected to, the municipal potable water supply system, and the water in the tanks is maintained in a potable condition. Class 3 systems resemble Class 1 systems in all other respects.

Class 4 system — a fire protection system that has direct connections from the municipal potable water supply system (similar to Class 1 and Class 2 systems) and an auxiliary water supply dedicated to fire department use and available to the premises, such as an auxiliary supply located within 500 m of the pumper connection.

Class 5 system — a fire protection system that has direct connections from the municipal potable water supply system and that is also interconnected with an auxiliary water supply.

Class 6 system — a fire protection system that is a combined industrial and fire protection system and is supplied from the municipal potable water supply system only, with or without gravity storage or pump suction tanks.

Residential “full flow through” system — a fire protection system that is fully integrated into the potable water supply system to ensure a regular flow of water through all parts of both systems.

Residential “partial flow through” system — a fire protection system in which flow (during non-functioning periods of the fire system) only occurs through the main header to a water closet located at the farthest point of the system.

Fire service pipe — a pipe that conveys water from a municipal potable water supply system or private water supply system to the inside of a building for the purpose of supplying a fire protection system.

Fixture — a device that receives water, waste matter, or both and directs these substances into a sanitary drainage system.

Hazard —

Minor hazard (MH) — any type of cross-connection or potential cross-connection that involves a substance that constitutes only a nuisance and that results in a reduction in only the aesthetic qualities of the water. This category includes all connections described in Clause 5.1.3.2 involving water that might have been heated or cooled and connections that cannot create a danger to health.

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July 2007 7

Moderate hazard (MoH) — any minor hazard (MH) connection that has a low probability of becoming a severe hazard. This category includes, but is not limited to, connections involving water where the aesthetic qualities of the water have been reduced and, under certain conditions, can create a danger to health.

High or severe hazard (HH) — any type of cross-connection or potential cross-connection described in Clause 5.1.3.2 involving water that has additives or substances that, under any concentration, can create a danger to health.

Horizontal — a plane perpendicular to a plumb line ± 2°.

Individual protection — protection provided at the connection to a fixture or appliance.

Irrigation — artificial watering of land to sustain plant growth.

Irrigation system, above-ground — a system of pipes and valves, installed above grade, that carry water for various irrigation uses: examples include garden and soaker hoses, portable lawn or garden sprinklers, and manually controlled micro/drip irrigation systems.

Irrigation system, in-ground — a system of pipes and valves that carry water to various types of sprinklers for distribution over the surface of the soil (piping located underground).

Pit — a hole or cavity constructed to house a backflow preventer in the ground, and not capable of being physically entered by a person.

Port — an aperture for the passage of a fluid that can allow a connection to be made.

Atmospheric port — a port that allows air to enter or water to be discharged.

Relief port — a port that discharges water from a relief valve.

Vent port — a port that vents water (not from a relief valve).

Potable water — water safe for human consumption.

Potable water system materials — any material acceptable under the National Plumbing Code or a provincial plumbing code for use in a potable water distribution system.

Potable water system materials, not acceptable — any material that is not acceptable under the National Plumbing Code or a provincial plumbing code for use in a potable water distribution system.

Premises isolation — protection provided at the entrance to a building or facility.

Readily accessible — capable of being reached for operation, renewal, servicing, or inspection, without requiring the climbing over or removal of an obstacle or the use of a portable ladder.

Regulatory authority — a federal, provincial, or municipal ministry, department, board, agency, or commission that has responsibility for regulating by statute the use of products, materials, or services.

Residential (applied to a building) — intended for residential occupancy as defined in the National Building Code of Canada or a provincial building code.

Vacuum breaker — a backflow preventer that prevents backflow from back siphonage, i.e., when pressure upstream of the vacuum breaker falls below atmospheric pressure. Air is only admitted downstream of the device.

Atmospheric vacuum breaker (AVB) — a vacuum breaker designed to be under pressure only when water is being drawn from the water supply system and for short, intermittent periods of time.

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Hose connection dual check vacuum breaker (HCDVB) — a vacuum breaker that consists of two independently acting check valves, force-loaded or biased to a closed position. Located between the checks is a means of venting to atmosphere that is force-loaded or biased to an open position. HCDVB devices(a) are designed to be under pressure only when water is being drawn from the system and for

short, intermittent periods of time; (b) incorporate a means to manually test the operation of the downstream check valve; and(c) are designed to be used where the back pressure generated by an elevated hose is equivalent

to 3 m of head pressure or less.Note: If there is no flow through the HCDVB device, the check valves are closed and the vent is open.

Hose connection vacuum breaker (HCVB) — a vacuum breaker that consists of a single force-loaded check valve biased to a closed position. Downstream of the check valve is a means of automatically venting to atmosphere that is force-loaded or biased to an open position. HCVB devices are designed to be under pressure only when water is being drawn from the water supply system and for short, intermittent periods of time.Note: If there is no flow through the HCVB device, the check valve is closed and the vent is open.

Laboratory faucet vacuum breaker (LFVB) — a vacuum breaker that consists of two independently acting check valves force-loaded or biased to a closed position. Between the check valves there is an atmospheric vent that is force-loaded or biased to an open position. Note: When the laboratory faucet is off, the check valves are closed and the atmospheric vent is open; when the faucet is on, the check valves are open and the atmospheric vent is closed.

Pressure vacuum breaker (PVB) — a vacuum breaker that contains an independently acting check valve force-loaded or biased to a closed position, and an independently operating air inlet valve force-loaded or biased to an open position and located downstream of the check valve. PVB devices are(a) equipped with resilient-seated test cocks and resilient-seated shut-off valves located at each end

of the vacuum breaker; and (b) designed for use under continuous pressure.

Spill-resistant pressure vacuum breaker (SRPVB) — a vacuum breaker that contains an independently acting check valve force-loaded or biased to a closed position, and an independently operating air inlet valve force-loaded or biased to an open position and located downstream of the check valve. A diaphragm separates the flow from the atmospheric vent. SRPVB devices are equipped with a resilient-seated test cock, a bleeder, and resilient-seated shut-off valves located at each end of the device. SRPVB devices are designed for indoor use under continuous pressure.

Vault — a room or space that is constructed to house a backflow preventer and that is capable of being entered by a person. See Confined space.

Vertical — a plane parallel to a plumb line ± 2°.

Water distribution system — an assembly of pipes, fittings, valves, and appurtenances that conveys water from the water service pipe or private water supply system to water supply outlets, fixtures, appliances, and devices.Note: In the CSA B64 Series, water distribution systems are also referred to as water systems or water supply systems.

Water service pipe — a pipe that conveys water from a public water main or private water source to the inside of the building.

Zone protection — protection provided for sections of a piping system within a building or facility with no potable connections downstream of a backflow preventer. See Area protection.

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3.2 AbbreviationsThe following abbreviations are used in this Standard and in CSA B64.10.1:

3.3 Symbols

3.3.1 Backflow preventersThe following symbols for backflow preventers are used in this Standard and in CSA B64.10.1:

(a) Double check valve (DCVA)

(b) Dual check valve (DuC)

Term Abbreviation

Air gap AG

Backflow preventers:Double check valve Double check valve for fire protection systemsDual check valveDual check valve for fire protection systemsDual check valve with atmospheric portDual check valve with atmospheric port for carbonatorsDual check valve with intermediate ventReduced pressure principleReduced pressure principle for fire protection systemsSingle check valve for fire protection systems

DCVADCVAFDuCDuCFDCAPDCAPCDuCVRPRPFSCVAF

Check valve CV

Critical level CL

Cross-connection control program CCCP

HazardHigh or severe hazardMinor hazardModerate hazard

HHMHMoH

Thermal expansion relief (valve) TER

Vacuum breakers:AtmosphericHose connection Hose connection dual checkLaboratory faucetPressureSpill-resistant pressure

AVBHCVBHCDVBLFVBPVBSRPVB

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(c) Dual check valve with atmospheric port (DCAP)

(d) Dual check valve with atmospheric port for carbonators (DCAPC)

(e) Dual check valve with intermediate vent (DuCV)

(f) Reduced pressure principle (RP)

(g) Single check valve for fire protection systems (SCVAF)

3.3.2 Vacuum breakersThe following symbols for vacuum breakers are used in this Standard and in CSA B64.10.1:

(a) Atmospheric vacuum breaker (AVB)

(b) Hose connection dual check vacuum breaker (HCDVB)

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(c) Hose connection vacuum breaker (HCVB)

(d) Laboratory faucet vacuum breaker (LFVB)

(e) Pressure vacuum breaker (PVB)

(f) Spill-resistant pressure vacuum breaker (SRPVB)

3.3.3 Other symbolsThe following symbols are used in this Standard and in CSA B64.10.1:

(a) Check valve (CV)

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(b) Shut-off valve

4 Backflow prevention methods and devices

4.1 Air gap

4.1.1 GeneralAir gaps shall be installed in accordance with the local plumbing or building code to permit atmospheric air, instead of a contaminated or polluted liquid, to enter the potable water system.Note: In theory, a well-designed and properly maintained air gap is the best means available for protection against backflow. However, an air gap is not always practical and is vulnerable to bypass arrangements that can nullify its effectiveness.

4.1.2 Hazardous installationsIn extremely hazardous installations, an air gap separation is recommended.

4.1.3 UseThe proper use of an air gap shall be as illustrated in Figure 1 (see Clause 6.6.1).

Figure 1Air gap

(See Clause 4.1.3.)

4.2 Barometric loop

4.2.1 GeneralA barometric loop is a piping arrangement designed to make use of the principle that a vacuum can only lift water approximately 10 m against atmospheric pressure. The piping arrangement shall be formed by constructing a loop in the service line that rises 10.7 m or more above the service line, or 10.7 m or more above the highest fixture or device being served. See Figure 2.

Supply valve

Flood level rim

Air gap

Fixture

Water supply

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Figure 2Barometric loop

(See Clause 4.2.1.)

4.2.2 UseA properly installed barometric loop is effective against back siphonage only. If there is any possibility of back pressure, a backflow preventer suitable for back pressure type backflow shall be used.

4.2.3 LimitationsThe barometric loop is not recommended for backflow prevention because it is difficult to protect it from freezing, and bypasses nullify its effectiveness. A barometric loop shall not be installed without the approval of the regulatory authority.

Meter

Meter

Water main

Barometric loop

Barometric loop

Irrigation system

Irrigationsystem

10.7 m

10.7 m

Waterservicepipe

Water main Water

servicepipe

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4.3 Mechanical backflow preventers

4.3.1 Available types

4.3.1.1 GeneralThe types of mechanical backflow preventers that shall be used for cross-connection control are listed in Table 1.

Table 1Types of backflow preventers and vacuum breakers

and applicable CSA Standards(See Clauses 1.2, 4.3.1.1, and 4.3.6.2.)

4.3.1.2 Plumbing supply fittingsWhere a plumbing supply fitting requires backflow protection, it shall be provided in accordance with ASME A112.18.1/CSA B125.1 or CSA B125.3 or be equipped with a backflow preventer in accordance with the CSA B64 Series.

ApplicableCSA Standard Type Abbreviation

B64.1.1 Atmospheric vacuum breaker AVB

B64.1.2 Pressure vacuum breaker PVB

B64.1.3 Spill-resistant pressure vacuum breaker SRPVB

B64.2 Hose connection vacuum breaker HCVB

B64.2.1 Hose connection vacuum breaker with manual draining feature

B64.2.1.1 Hose connection dual check vacuum breaker HCDVB

B64.2.2 Hose connection vacuum breaker with automatic draining feature

B64.3 Dual check valve backflow preventer with atmospheric port DCAP

B64.3.1 Dual check valve backflow preventer with atmospheric port for carbonators DCAPC

B64.4 Reduced pressure principle backflow preventer RP

B64.4.1 Reduced pressure principle backflow preventer for fire protection systems RPF

B64.5 Double check valve backflow preventer DCVA

B64.5.1 Double check valve backflow preventer for fire protection systems DCVAF

B64.6 Dual check valve backflow preventer DuC

B64.6.1 Dual check valve backflow preventer for fire protection systems DuCF

B64.7 Laboratory faucet vacuum breaker LFVB

B64.8 Dual check valve backflow preventer with intermediate vent DuCV

B64.9 Single check valve backflow preventer for fire protection systems SCVAF

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4.3.2 Vacuum breaker backflow preventers — GeneralBackflow preventers that provide protection from back siphonage are referred to as vacuum breakers. Currently available vacuum breakers usually contain a check valve that prevents backflow and also prevents the entrance of air upstream of the vacuum breaker. If a suction pressure develops upstream of the vacuum breaker, this pressure is equalized by air entering through the atmospheric vents. In the case of atmospheric and hose connection vacuum breakers, when a slight positive differential pressure occurs downstream of the vacuum breaker, water spills out of the atmospheric vent. Although these vacuum breakers do contain check valves, they are not intended to withstand back pressure caused by thermal or mechanical means.

4.3.3 AVB devices

4.3.3.1 GeneralAVB devices contain a valve that acts as a check valve against back siphonage when the supply pressure drops to atmospheric pressure or lower. When the valve opens the atmospheric vent, it allows air to enter and equalize the pressure. The check valve also seals the atmospheric vent under normal flow conditions (see Figure 3).

AVB devices are intended only to prevent back siphonage and not backflow due to back pressure, even though a check valve is present.

Figure 3Typical AVB device

(See Clause 4.3.3.1.)

Atmospheric vent

Outlet

Inlet

Stop

Seat

Check valve

Shield

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4.3.3.2 UseAVB devices are used to isolate minor or moderate hazards (see Figure 4). If used for severe hazards, zone or area protection shall also be used (see Clause 5).

Figure 4Use of AVB devices


4.3.3.3 Limitations

4.3.3.3.1AVB devices do not provide adequate backflow protection when(a) back pressure can be developed on the downstream side of the device;(b) the device is located in an area subject to flooding; and(c) the device is under line flow pressure continuously for more than 12 h.Note: Codes recognize Item (a) by requiring that atmospheric vacuum breakers be located downstream of the last valve in the water supply system, and Item (b) by requiring that the critical level of a back siphonage preventer be located above the flood level rim of the fixture. See Clause 4.3.3.4.

4.3.3.3.2When water flows through an AVB device for long periods of time (12 h or more), the check valve can become stuck in the open position, thus rendering the device inoperative as a back siphonage preventer. Therefore, another type of device, such as a pressure type vacuum breaker (PVB) or a reduced pressure principle type backflow preventer (RP), shall be used whenever extended periods of flow could occur.

4.3.3.4 Critical levelAVB devices shall be installed with their critical level at least 25 mm above the flood level rim of the fixture, container, or appurtenance.

When the critical level is not marked on an AVB device, the critical level shall be taken as the lowest point on the device.

Watersupply AVB device

Critical level of the AVB device

See applicable plumbing code andClause 4.3.3.4 for minimum distance

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4.3.4 PVB devices

4.3.4.1 GeneralPVB devices (see Figure 5) are similar to AVB devices, except that PVB devices can be subject to continuous full line static pressure. The check valve in a PVB device is force-loaded to the closed position, usually by a spring, while the air inlet valve is usually float-operated. The check valve is not intended to resist back pressure caused by thermal or mechanical means. PVB devices are normally available in sizes NPS-2 and smaller.

Figure 5Typical PVB device


4.3.4.2 UsePVB devices are used to isolate minor, moderate, or severe hazards (see Figure 6). Careful consideration shall be given to the possibility of improper use of a PVB device, e.g., when a downstream connection is made that would permit back pressure to occur. (See Clause 5.)

Test cock 1

Test cock 2

Shut-off valve 1

Shut-off valve 2

Checkvalve

Air inlet valve

Outlet

Inlet

Atmospheric vent

Shield

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Figure 6Use of PVB devices


4.3.4.3 Critical levelPVB devices shall be installed with their critical level at least 300 mm above the flood level of the fixture, container, or appurtenance.

When the critical level is not marked on a PVB device, the critical level shall be taken as the lowest point on the device.

4.3.5 SRPVB devices

4.3.5.1 GeneralSRPVB devices (see Figure 7) are similar to PVB devices, except that they include a spill-resistant membrane. The check valve in SRPVB devices is force-loaded to the closed position, usually by a spring, while the air inlet valve is float-operated and force-loaded to the open position. The check valve is not intended to resist back pressure caused by thermal or mechanical means. One test cock and one bleeder are provided for periodic testing.

4.3.5.2 UseSRPVB devices are used to isolate minor, moderate, or severe hazards (see Figure 8). Careful consideration shall be given to the possibility of improper use of SRPVB devices, e.g., when a downstream connection is made that would permit back pressure to occur. (See Clause 5.)

Watersupply

PVBdevice

Critical level of the PVB device

See applicable plumbing code and Clause 4.3.4.3 for minimumdistance

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Figure 7Typical SRPVB device


Figure 8Use of SRPVB devices


Test cock

Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve

Shut-off valve 2

Check valve

Shut-off valve 1

Inlet

Outlet

Shield

Watersupply

SRPVB device

Critical level of the SRPVB device

See applicable plumbing code and Clause 4.3.5.3 for minimumdistance

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4.3.5.3 Critical levelSRPVB devices shall be installed with their critical level at least 300 mm above the flood level of the fixture, container, or appurtenance.

When the critical level is not marked on an SRPVB device, the critical level shall be taken as the lowest point on the device.

4.3.6 HCVB and HCDVB devices

4.3.6.1 GeneralHCVB and HCDVB devices (see Figure 9) are subgroups of AVB devices and(a) are intended to be installed on the discharge side of a shut-off valve;(b) are designed so that when the shut-off valve is turned off, the check valve closes, opening the

atmospheric vent and allowing air into the downstream;(c) incorporate a check valve that is force-loaded to the closed position; and(d) incorporate a vent to atmosphere on the outlet side of the check valve that is force-loaded or biased

to the open position.

Figure 9Typical HCVB device


4.3.6.2 HCVB devicesHCVB devices are specifically intended for minor hazard installations such as on a hose bibb to which a garden hose can be attached (see Figure 10). If used for moderate or severe hazards, zone or area protection shall also be used (see Clause 5.4). HCVB devices shall be installed so that the atmospheric vents cannot be submerged in water (see Figure 10).Notes: (1) HCVB devices are intended to withstand the small amount of back pressure that can occur if the end of the hose is

higher than the hose bibb when it is shut off. Some leakage may occur when the hose bibb is first opened.(2) HCVB devices that can be drained to prevent damage to the shut-off valve under freezing conditions are available (see

Table 1).

Atmospheric vent

Vent valve

Inlet

Outlet

Check valve

Spring

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Figure 10Use of HCVB and HCDVB devices


4.3.6.3 HCDVB devicesHCDVB devices incorporate a means to conduct a field test to verify the operation of its downstream check valve.

4.3.7 DCAP and DCAPC backflow preventers

4.3.7.1 DCAP backflow preventers

4.3.7.1.1 GeneralDCAP backflow preventers consist of two independently acting, internally loaded check valves and an intermediate atmospheric port (see Figure 11). The check valves are force-loaded to a closed position and the atmospheric port is force-loaded to an open position. During normal operation, the atmospheric port is closed by the deflection of a diaphragm seal. During backflow conditions, the diaphragm seal is displaced, allowing air to enter the area between the check valves or leakage from the downstream check valve to be discharged to the atmosphere. DCAP backflow preventers are not equipped with test cocks.

4.3.7.1.2 UseDCAP backflow preventers are intended to prevent backflow due to back siphonage and back pressure where a minor hazard exists (see Figure 12), such as with a low-pressure, single-family residential heating boiler (where no chemical additives are used). If used for moderate hazards, zone or area protection shall also be used (see Clause 5.4).

Swimming pool

Grade

Install HCVB or HCDVB device at this point

Building

Hose

Watersupply

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Figure 11Typical DCAP backflow preventer

(See Clause 4.3.7.1.1.)

Figure 12Use of DCAP backflow preventers

(See Clause 4.3.7.1.2.)

4.3.7.1.3 LimitationBecause DCAP backflow preventers have no test cocks and are not intended for protection from severe hazards, they shall not be used in place of reduced pressure principle (RP) backflow preventers.

Inlet

Secondary check valve

Outlet

Atmosphericport

Air inlet valve

Primarycheck valve

Watersupply

DCAP

Air gap

Low-pressure boiler — single-family residential(no inhibitors added)

To domestic hot water system —single-family residential

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4.3.7.2 DCAPC backflow preventersDCAP backflow preventers for carbonators (DCAPC) consist of two independently acting check valves that are normally biased in the closed position. An atmospheric port is located between the check valves (see Figure 13). DCAPC backflow preventers are intended to provide backflow protection when installed on the water supply connection of carbonated beverage dispensing equipment. In the event of a downstream (secondary) check valve failure, with back pressure exceeding supply pressure, the atmospheric port will discharge and visually indicate failure.

Under static (non-flowing) conditions, the check valves remain in the closed position. When a valve is opened downstream (i.e., a drink is delivered from the carbonator), the check valves open and permit water flow.

Under backflow conditions, the diaphragm seat on the primary check valve lifts and vents flow through the atmospheric port, thus protecting the potable water supply.

Under normal operation, the atmospheric port does not discharge.

Figure 13Typical DCAPC backflow preventer


Atmosphericport

Primarycheck valve

Inlet

Screen

Secondarycheck valve

Outlet

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4.3.8 RP and RPF backflow preventers

4.3.8.1 GeneralRP backflow preventers consist of two independently acting, internally loaded check valves separated by a reduced pressure zone (see Figure 14). During normal operation, the pressure between the two check valves is maintained at a lower pressure than the supply pressure. If either check valve leaks, a relief valve maintains a differential of not less than 14 kPa between the supply pressure and the reduced pressure zone by discharging water through the relief port. Such an occurrence indicates that maintenance is required. Test cocks are provided for periodic testing.

Figure 14Typical RP backflow preventer


4.3.8.2 UseRP backflow preventers(a) are intended to isolate severe hazards (see Clause 5);(b) provide reliable protection from both back siphonage and back pressure (see Figure 15); and(c) are generally used in locations where an air gap is impractical.Note: One advantage of RP backflow preventers is the visible leakage from the relief port in some instances of failure.

Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-off valve 1

Checkvalve 2

Shut-off valve 2

Differential pressurerelief valve

Checkvalve 1

Inlet Outlet

Relief port

Reduced pressurezone

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Figure 15Use of RP backflow preventers


4.3.8.3 RPF backflow preventersRPF backflow preventers are used to prevent backflow due to both back siphonage and back pressure from fire protection systems where a severe hazard exists (see Clause 5.5).

4.3.9 DCVA and DCVAF backflow preventers

4.3.9.1 GeneralDCVA backflow preventers consist of two internally loaded check valves, either force-loaded or internally weighted (see Figure 16). With the two check valves in series, the devices prevent backflow even if one check valve fails to close tight, but no visible warning is given of this failure. Test cocks are provided for periodic testing.

City watersupply

Domesticwater distributionsystem

Air gap

RP backflow preventer

Open tank or pressure vesselcontaining a toxic chemical

Irrigation system

Fertilizer

CV

Pump

City water supplyor domesticwater distributionsystem

Air gap

RP backflow preventer

(a) Back siphonage protection

(b) Back pressure protection

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Figure 16Typical DCVA backflow preventer


4.3.9.2 UseDCVA backflow preventers are used to prevent backflow due to both back siphonage and back pressure where a minor or moderate hazard exists (see Figure 17).

Figure 17Use of DCVA backflow preventers


Test cock 2

Test cock 1

Shut-off valve 1 Shut-off valve 2

Checkvalve 1

Test cock 3

Test cock 4

Checkvalve 2

SeatsDisc Disc Outlet

Inlet

Watersupply

DCVA backflow preventer

Open tank

Tanks determined to be a minor ormoderate hazard

Tank underpressure

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4.3.9.3 DCVAF backflow preventersDCVAF backflow preventers are used to prevent backflow due to both back siphonage and back pressure from fire protection systems where a minor or moderate hazard exists (see Clause 5.5).

4.3.10 DuC and DuCF backflow preventers

4.3.10.1 GeneralDuC backflow preventers consist of two independently acting, internally loaded check valves in series. The device prevents backflow if one check valve fails, but no visible warning is given of this failure. Test cocks are not provided (see Figure 18).

Figure 18Typical DuC backflow preventer


4.3.10.2 UseDuC backflow preventers are used to prevent backflow due to both back siphonage and back pressure, where a minor hazard exists, and are intended to be used on residential supply services or individual outlets.

4.3.10.3 DuCF backflow preventersDuCF backflow preventers are used to prevent backflow due to both back siphonage and back pressure from fire protection systems where a minor hazard exists (see Clause 5.5).

4.3.11 LFVB devices

4.3.11.1 GeneralLFVB devices consist of two independently acting force-loaded check valves. The space between the check valves is vented to atmosphere. The check valves are biased to the closed position and the atmospheric vent is biased to the open position. Test cocks are not provided (see Figure 19).

Primary check valve


Outlet

Inlet

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4.3.11.2 UseLFVB devices are(a) intended for use on laboratory faucets;(b) intended for use on the discharge side of the last control valve; and(c) used for minor hazards. If used for moderate or severe hazards, zone or area protection shall also be

used. (See Clause 5.4.)LFVB devices shall not be used under continuous pressure conditions (see Figure 19).

Figure 19LFVB devices


4.3.12 DuCV backflow preventers

4.3.12.1 GeneralDuCV backflow preventers consist of two independently acting, internally loaded check valves and an intermediate vent to atmosphere. The check valves are biased to the closed position and the atmospheric vent is biased to the open position. DuCV backflow preventers are intended for use under continuous pressure. No test cocks are provided (see Figure 20).

4.3.12.2 UseDuCV backflow preventers are(a) intended for use on individual outlets or appliances with flow rates of less than 0.25 L/s; and(b) used to prevent backflow due to both back pressure and back siphonage where a minor hazard exists.

If used for moderate hazards, zone or area protection shall also be used (see Clause 5.4).

Inlet

Outlet

Primary check valve


Faucet

Aspirator

LFVB device

Atmospheric vent

(a) Typical LFVB device (b) Use of LFVB devices

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Figure 20Typical DuCV backflow preventer


4.3.13 SCVAF backflow preventers

4.3.13.1 GeneralSCVAF backflow preventers consist of one independently acting, internally loaded check valve. No visible warning is given of failure of the check valve to close tight. Inlet and outlet shut-offs and test cocks are provided for periodic testing.

4.3.13.2 UseSCVAF backflow preventers are used to prevent backflow due to both back siphonage and back pressure from fire protection systems where a minor hazard exists (see Clause 5.5).

5 Selection of backflow preventers

5.1 General

5.1.1Plumbing codes mandate that the potable water system be protected from backflow. The principal method of protection adopted by plumbing codes is the mandatory provision of an air gap at the supply to the fixture. When an air gap is not provided, a backflow preventer shall be used.

Outlet

Primary check valve


Inlet

Atmospheric vent

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5.1.2In buildings, interconnections can easily be made between the potable water supply and any fixture, appliance, system, or non-potable water supply. Such connections are defined as cross-connections and backflow preventers shall be used.

5.1.3

5.1.3.1Connections to potable water systems shall be designed so that substances that may render the water non-potable, or change the quality of the water in other respects, cannot enter the potable water system. Where there is an identifiable risk of contamination of a potable water system, preventive measures shall be taken.

5.1.3.2Connections shall be divided into the following two categories:(a) atmospheric connections — connections that have a pressure that is at, or below, atmospheric

pressure; and(b) pressure connections — connections that have a pressure that is greater than atmospheric pressure.

5.1.4To determine whether protection is necessary, the following shall be identified:(a) the probability that back siphonage will cause backflow;(b) the probability that back pressure will cause backflow;(c) the severity of hazard; and(d) the type of building.

5.1.5A suitable backflow preventer shall be selected based on(a) a good knowledge of available devices;(b) an understanding of the protection that each device provides; and(c) maintenance requirements of the devices.

5.2 Categories of hazardsHazards shall be divided into three categories — minor hazard (MH), moderate hazard (MoH), and high or severe hazard (HH). (See the definition of “hazard” in Clause 3.1.)Note: This Clause addresses the assessment of the potential hazard and the probability that backflow could occur. There is no simple method to quantify the problem by assessing the relevant factors, nor can the backflow preventers be categorized numerically according to the degree of protection they provide.

5.3 Principal ways of providing protection

5.3.1 General

5.3.1.1To provide complete protection for the potable water supply and the consumer’s potable water system within the premises, backflow protection shall be provided based on a review of the drawings of the proposed piping layout or a survey of the premises. The type of backflow protection shall be selected in accordance with(a) Clause 5.2 (the degree of hazard);(b) Clauses 5.3.1.2 to 5.3.1.4;(c) Clauses 5.3.2 to 5.3.4;(d) Clause 5.4 and Table 2; and(e) Clause 5.5 and Table 3.

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5.3.1.2Premises isolation shall be provided by the installation of an RP backflow preventer on all water systems where a potentially severe hazard may be caused by backflow. The hazard shall be determined based on the type of occupancy or a survey of the premises. Examples of hazard classification are given in Clause 5.3.4.5 and Table B.2.

5.3.1.3Premises isolation for all other water services shall be provided when required by a cross-connection control program (CCCP).Note: The regulatory authority generally enforces a CCCP through the enactment of a bylaw. See the model bylaw in Annex E.

5.3.1.4Additional protection by one or all of the following means shall also be required as determined by the survey of the premises:(a) individual protection;(b) zone protection; and(c) area protection.Note: Determining the proper backflow preventer is a subjective matter. Annex B is based on experience and is intended for reference only. Consult your local cross-connection control authority for acceptable standards within your jurisdiction.

5.3.2 Individual protection

5.3.2.1Individual protection against back siphonage shall be provided by any of the following:(a) an air gap;(b) an AVB device;(c) an HCDVB device;(d) an HCVB device;(e) a PVB device;(f) an SRPVB device; or(g) any device listed in Clause 5.3.2.2.

5.3.2.2Protection from back pressure type backflow shall be provided by any of the following:(a) DuC backflow preventer;(b) DCAP backflow preventer;(c) DuCV backflow preventer;(d) DCVA backflow preventer;(e) RP backflow preventer; or(f) an air gap.

5.3.2.3An air gap does not guarantee continuous protection, as it can easily be bypassed. However, an air gap shall remain the first choice to eliminate backflow and shall be inspected, if used on a high hazard, in the yearly testing program for backflow preventers (see Clause 4.1 of CSA B64.10.1).

5.3.3 Zone protectionWhen zone protection is provided, isolated non-potable water systems shall be clearly identified as required by CAN/CGSB-24.3.

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5.3.4 Premises isolation

5.3.4.1When required by Clause 5.3.1.2 or 5.3.1.3, premises isolation for a building shall be provided even if the water distribution system in the building complies with current plumbing or building code requirements, because backflow into the potable water system can still occur if the individual protection fails.

5.3.4.2Three levels of protection shall be recognized for premises isolation, as follows:(a) Premises with a minor hazard classification shall be isolated with a DuC backflow preventer. This

requirement shall not apply to residential premises if no hazards are present. Examples of this hazard classification are given in Clause 5.3.4.3 and Table B.2.

(b) Premises with a moderate hazard classification shall be isolated with a DCVA backflow preventer. Examples of this hazard classification are given in Clause 5.3.4.4 and Table B.2.

(c) Premises with a severe hazard classification shall be isolated with an RP backflow preventer. Examples of this hazard classification are given in Clause 5.3.4.5 and Table B.2.

5.3.4.3Buildings or facilities that shall be isolated from the potable water supply by a DuC backflow preventer include the following:(a) residential premises with access to an auxiliary water supply (not directly connected);(b) residential premises serving fewer than four dwelling units with single water service; and(c) buildings with minor hazard classification.Note: This is not an all-inclusive list; see Table B.2 for additional examples.

5.3.4.4Buildings or facilities that shall be isolated from the potable water supply by a DCVA backflow preventer include the following:(a) buildings with moderate hazard classification;(b) pleasure-boat marinas;(c) apartment or office buildings;(d) multi-service interconnected facilities;(e) schools and colleges;(f) multi-tenant single-service facilities; and(g) shopping malls.Note: This is not an all-inclusive list; see Table B.2 for additional examples.

5.3.4.5Buildings or facilities that shall be isolated from the potable water supply by an RP backflow preventer include the following:(a) chemical or plating plants;(b) commercial laundries;(c) dockside facilities for ships;(d) food and beverage processing plants;(e) hospital, operating, laboratory, or mortuary facilities;(f) petroleum processing and storage facilities;(g) plants using radioactive material;(h) premises where access is restricted;(i) trackside facilities for trains;(j) sewage treatment plants; and(k) steam plants.Note: This is not an all-inclusive list; see Table B.2 for additional examples.

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5.4 Selection guide

5.4.1The type of backflow preventer to be used for individual protection shall be selected in accordance with Table 2, and the degree of hazard shall be assessed in accordance with Clause 5.2 and Table B.1. For fire protection systems, refer to Clause 5.5 and Table 3.

5.4.2Zone or area protection provided by a DCVA backflow preventer, an RP backflow preventer, or an air gap shall be required when any one of the following backflow preventers is used for individual protection of a moderate hazard (MoH):(a) HCVB or HCDVB devices;(b) DCAP backflow preventers;(c) LFVB devices; or(d) DuCV backflow preventers.

5.4.3Zone protection provided by an RP backflow preventer or an air gap shall be required when any one of the following backflow preventers is used for individual protection of a high or severe hazard (HH):(a) AVB devices;(b) HCVB or HCDVB devices; or(c) LFVB devices.

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Table 2Selection guide for backflow preventers

(See Clauses 5.3.1.1 and 5.4.1.)

5.5 Backflow from fire protection systems

5.5.1Residential “full flow through” fire protection systems in which pipe and fittings are made of materials acceptable for potable water systems shall not require a backflow preventer.

5.5.2Potable water connections to fire protection systems (standpipe and sprinkler systems) shall be protected against backflow caused by back siphonage or back pressure in accordance with the following (see Table 3):(a) Residential “partial flow through” fire protection systems in which the pipe and fittings are made of

materials acceptable for potable water systems shall be protected by(i) a DuC backflow preventer complying with CSA B64.6; or(ii) a DuCF backflow preventer complying with CSA B64.6.1.

(b) Class 1 fire protection systems that use no antifreeze or other additives of any kind and in which all pipes and fittings are made of materials acceptable for potable water systems shall be protected by(i) an SCVAF backflow preventer complying with CSA B64.9; or

Type of device

CSA Standard designation

Degree of hazard

Device under continuous pressureMinor Moderate Severe

Air gap — ✓ ✓ ✓ No

AVB B64.1.1 ✓ ✓ ✓* No

DCAP B64.3 ✓ ✓† — Yes

DCAPC B64.3.1 ✓ ✓ — Yes

DCVA B64.5 ✓ ✓ — Yes

DuC B64.6 ✓ — — Yes

DuCV B64.8 ✓ ✓† — Yes

HCDVB B64.2.1.1 ✓ ✓† ✓* No

HCVB B64.2 ✓ ✓† ✓* No

LFVB B64.7 ✓ ✓† ✓* No

PVB B64.1.2 ✓ ✓ ✓ Yes

RP B64.4 ✓ ✓ ✓ Yes

SRPVB B64.1.3 ✓ ✓ ✓ Yes

*When the recommended backflow preventer is used for this degree of hazard, zone protection with an RP backflow preventer or an air gap shall also be required.†When the recommended device is used for this degree of hazard, zone or area protection with a DCVA backflow preventer, RP backflow preventer, or an air gap shall also be required.

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(ii) a DCVA backflow preventer complying with CSA B64.5.(c) Class 1 systems not covered by Item (b), Class 2, and Class 3 fire protection systems that use no

antifreeze or other additives of any kind shall be protected by (i) a DCVA backflow preventer complying with CSA B64.5; or (ii) a DCVAF backflow preventer complying with CSA B64.5.1.

(d) Class 1, Class 2, or Class 3 fire protection systems in which antifreeze or other additives are used shall be protected(i) by an RP backflow preventer complying with CSA B64.4 or an RPF backflow preventer

complying with CSA B64.4.1, on the portion of the fire protection system with the additives; and(ii) in accordance with Item (b) or (c), on the balance of the fire protection system.

(e) Class 4 and Class 5 fire protection systems shall be protected by(i) an RP backflow preventer complying with CSA B64.4; or(ii) an RPF backflow preventer complying with CSA B64.4.1.

(f) Class 6 fire protection systems shall be protected by(i) a DCVA backflow preventer complying with CSA B64.5;(ii) a DCVAF backflow preventer complying with CSA B64.5.1;(iii) an RP backflow preventer complying with CSA B64.4; or(iv) an RPF backflow preventer complying with CSA B64.4.1.The type of protection shall be determined by a survey of the premises and an assessment of the hazard.

(g) Where premises isolation backflow protection with an RP backflow preventer is required on the water service pipe at an industrial, commercial, or domestic service connection that is located on the same premises as the fire service pipe in Class 3, Class 4, Class 5, and Class 6 fire protection systems, backflow protection with an RP backflow preventer complying with CSA B64.4 or an RPF backflow preventer complying with CSA B64.4.1 shall also be provided on the fire service connection.

Table 3Selection guide for backflow preventers for fire protection systems

(See Clauses 5.4.1 and 5.5.2.)

Type of device*

CSA Standard designation

Pipe and fittings made of materials acceptable for potable water systems

Pipe and fittings made of materials not acceptable for potable water systems

Residential “partial flow through” system

Class 1 system

Class 1, Class 2, or Class 3 system

With antifreezeor other additives;any class system

DCVA B64.5 ✓ ✓ ✓ —

DCVAF B64.5.1 ✓ ✓ ✓ —

DuC B64.6 ✓ — — —

DuCF B64.6.1 ✓ — — —

RP B64.4 ✓ ✓ ✓ ✓

RPF B64.4.1 ✓ ✓ ✓ ✓

SCVAF B64.9 ✓ ✓ — —

*The “F” at the end of the acronym indicates that the backflow preventer is only for use on fire protection systems.

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36 July 2007

5.5.3Backflow preventers specified in Clause 5.5.2 shall be installed upstream of the fire department pumper connection.

5.6 Backflow from water fill stations

5.6.1Any outlet used on a temporary or permanent basis to dispense potable water from the water distribution system to water-hauling equipment shall be protected against backflow caused by back siphonage or back pressure with an RP backflow preventer.

5.6.2The water fill station piping shall be installed to enable the water downstream of the final control valve to automatically drain to atmosphere when the connection to the water-hauling equipment is disconnected, at the end of each fill cycle.Note: See Annex C for additional information on water-hauling equipment.

5.7 Backflow from temporary water servicesAny outlet used to dispense potable water from the water distribution system to supply a temporary water service for construction or other purposes shall be protected against backflow caused by back siphonage or back pressure with(a) an RP backflow preventer, where there is no final connection to a plumbing system;(b) a DCVA backflow preventer, where the temporary service is connected to a plumbing system that

would be regarded as a low or moderate hazard; or(c) an RP backflow preventer, where the temporary service is connected to a plumbing system that

would be regarded as a high or severe hazard.

5.8 Backflow from irrigation systems

5.8.1 Above-ground irrigation systemsAny outlet used to dispense potable water from the water distribution system to supply a non-chemical-injected, above-ground irrigation system shall be protected against backflow caused by back siphonage with one of the following:(a) an HCVB device located at the hose bibb and installed downstream of the irrigation system shut-off,

solenoid, or other control valves;(b) an AVB device installed downstream of the irrigation system shut-off, solenoid, or other control

valves, provided that(i) the irrigation system is not in continuous use for more than 12 h at any one period of time; and(ii) the distance to the critical level of the AVB device is measured relative to the highest point of the

irrigation system (see Clause 4.3.3.4); or(c) a device specified in Clause 5.8.2.

5.8.2 In-ground irrigation systemsAny outlet used to dispense potable water from the water distribution system to supply an in-ground irrigation system shall be protected against backflow caused by back siphonage with the following:(a) for systems without injection of chemicals:

(i) a PVB device installed upstream of the irrigation system shut-off or other control valves and at least 300 mm above the highest point of the irrigation system; or

(ii) a DCVA backflow preventer installed upstream of the irrigation system shut-off or other control valves; or

(b) for systems with injection of chemicals, an RP backflow preventer installed upstream of the irrigation system shut-off valves.

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6 Installation of backflow preventers and vacuum breakers

6.1 General requirements

6.1.1 AccessibilityBackflow preventers and vacuum breakers shall be installed in readily accessible areas to facilitate inspection, field testing, and maintenance.Note: It is not recommended that backflow preventers or vacuum breakers be installed in confined spaces. See Clause 6.11.

6.1.2 ClearancesExcept when the device is installed within an enclosure that complies with ASSE 1060, the minimum clearances specified in Table 4, or the manufacturer’s recommendations, whichever are greater, shall be used when installing backflow preventers or vacuum breakers.

Table 4Clearances, mm

(See Clause 6.1.2.)

6.1.3 Support and restraintBackflow preventers and vacuum breakers shall be adequately supported and restrained to prevent lateral movement. Installation accessories, such as pipe hangers, braces, saddles, stanchions, and piers, shall be used to support backflow preventers and vacuum breakers and shall be placed in a manner that will not obstruct access to the device for testing and maintenance or interfere with the operation of the relief valve (on RP backflow preventers).

6.1.4 BypassesBypasses around backflow preventers or vacuum breakers shall be prohibited, except where an equivalent backflow preventer is installed on the bypass (see Clause 6.7).

Minimum clearance

Type of device

Centreline height above the floor

Between the bottom of the relief valve and the floor

Above the device

In front of the device†

Behind the device†Minimum Maximum*

DCVA 750 1500 — 300 750 20

DCVAF 750 1500 — 300 750 20

PVB — 1500 — 300 750 20

RP 750 1500 300 300 750 20

RPF 750 1500 300 300 750 20

SCVAF 750 1500 — 300 750 20

SRPVB — 1500 — 300 750 20

*Installations with a greater centreline height may be used if provided with a fixed platform.†To the nearest wall or obstruction.Notes: (1) An em-dash (—) indicates that there is no requirement specified in this Standard.(2) Clearances might have to be increased for backflow preventers with side-mounted test cocks or relief valves or

when the sight tube method of testing is used.

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6.1.5 Field testing at installationThe following backflow preventers and vacuum breakers shall be field tested in accordance with CSA B64.10.1 at the time of initial installation:(a) PVB devices;(b) SRPVB devices;(c) DCVA and DCVAF backflow preventers;(d) RP and RPF backflow preventers; and(e) SCVAF backflow preventers.

6.1.6 Installation of DCAPC backflow preventersWhen installing DCAPC backflow preventers the following shall apply:(a) The piping or fittings installed downstream of a DCAPC backflow preventer or attached to its

atmospheric port shall not be made of copper or copper alloy.(b) The atmospheric port of a DCAPC backflow preventer shall not be directly connected to the drain.

When a tube is attached to the atmospheric port to extend the vent, the tube shall have an air gap at the discharge or termination point.

(c) Appropriate measures shall be taken to accommodate the flow during backflow conditions, as water or carbon dioxide will be discharged from the atmospheric port. In addition, adequate ventilation and drainage, as recommended by the manufacturer, shall be provided for the discharge from the atmospheric port.

Note: See Clause 7 of CSA B64.3.1 and the manufacturer’s installation instructions.

6.1.7 FlushingBefore a backflow preventer or vacuum breaker is installed, the pipeline shall be thoroughly flushed to remove all foreign material that could foul the operation of the device.

6.2 SizingTo avoid excessive pressure loss, backflow preventers and vacuum breakers shall be sized according to the manufacturer’s recommendations.

6.3 Working pressures and temperaturesWorking pressures and temperatures for backflow preventers and vacuum breakers shall be in accordance with the applicable product Standard of the CSA B64 Series. The manufacturer’s literature should be consulted for the actual working pressures and temperatures.

6.4 Shut-off valves and test cocks

6.4.1Shut-off valves shall be provided as part of the following backflow preventers and vacuum breakers:(a) PVB devices;(b) SRPVB devices;(c) DCVA backflow preventers;(d) DCVAF backflow preventers;(e) RP backflow preventers;(f) RPF backflow preventers; and(g) SCVAF backflow preventers.

6.4.2Shut-off valves shall have resilient seats providing a drip-tight shut-off.Note: Shut-off valves intended for fire protection service should be of the indicating type.

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July 2007 39

6.4.3Test cocks shall (a) have resilient seats; (b) not be metal-to-metal; and(c) provide a drip-tight shut-off.

6.5 StrainersAn in-line strainer shall be installed where water contains foreign material that could lodge on or erode the seating surfaces.

6.6 Location

6.6.1Air gaps, backflow preventers, or vacuum breakers with vents to atmosphere shall not be installed in a corrosive or polluted atmosphere, because the contaminated air can enter the piping system through the air gap or open vent or cause the backflow preventer or vacuum breaker to malfunction.

6.6.2RP backflow preventers shall not be installed in a below-grade pit or vault.

6.6.3DCVA backflow preventers shall not be installed in a below-grade pit or vault unless the pit or vault can be maintained in a dry condition.Note: A permanently installed sump pump may be acceptable to the regulatory authority.

6.6.4When a DCVA backflow preventer is installed in a below-grade pit or vault, all test cocks on the device shall be plugged using a means that is watertight.

6.6.5The location of backflow preventers and vacuum breakers shall not hinder the operation of other system safety devices.

6.6.6PVB devices shall be installed only in areas where water discharge from the vent valve during initial pressurization will not be objectionable, or where the spillage can be safely directed to a drain to prevent property damage. This requirement shall not apply to SRPVB devices.

6.7 Parallel serviceFor installations where uninterrupted service is a necessity, backflow preventers or vacuum breakers of equal size shall be provided in parallel. Each device shall be in operation normally. See Clause 6.1.4.

6.8 Connections to drains

6.8.1Relief ports shall not be directly connected to a drain. Adequate drainage, as recommended by the manufacturer, shall be provided for discharge from relief ports.

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6.8.2A connection to the relief port of an RP backflow preventer shall be made using the manufacturer’s drain connection fitting, and the pipe from the outlet of the drain connection fitting shall(a) be at least equal in size to that of the drain connection fitting;(b) be rigid;(c) slope downward from the backflow preventer; and(d) terminate with an indirect connection (air break) above a floor drain, sump, or other safe location.

6.9 Thermal expansionWhen the installation of a backflow preventer creates a closed piping system (e.g., zone, area, or premises isolation), one of the following means shall be installed to protect against the increase of pressure due to thermal expansion:(a) a suitably sized diaphragm-type expansion tank appropriate for use within a potable water system;(b) an auxiliary thermal expansion relief (TER) valve set at a pressure of no more than 550 kPa. The TER

valve shall be designed for repeated use and shall comply with the requirements of CSA B125.3; or(c) other means acceptable to the regulatory authority.

6.10 Installation orientationBackflow preventers shall be installed in an orientation in which they have been tested and have shown compliance with the applicable Standard of the CSA B64 Series.

6.11 Enclosures and protection from freezing (see Figure 21)

6.11.1Backflow preventers and vacuum breakers installed in areas subject to freezing shall be protected in a manner acceptable to the regulatory authority.

6.11.2Insulation or any other protection of a backflow preventer or vacuum breaker shall not interfere with its operation, testing, or maintenance.

6.11.3Insulation applied directly to a backflow preventer or vacuum breaker shall be removable to allow access for testing and maintenance.

6.11.4Insulated enclosures (whether supplied with or without heat) shall comply with the requirements of ASSE 1060.

6.11.5An enclosure complying with ASSE 1060 is an alternative to any location that would be considered a confined space.

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Figure 21Typical enclosure

(See Clause 6.11.)

One-way drain (each side)

Optional heaterlocation

One-way drain

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42 July 2007

Annex A (informative)How backflow can occur

Note: This Annex is not a mandatory part of this Standard.

A.1 Back siphonage

A.1.1 For back siphonage to occur, at least four conditions must occur simultaneously:(a) pressure in the potable water system below atmospheric;(b) an open supply valve;(c) the outlet of a supply valve immersed in a fluid other than potable water; and(d) absence of protection from back siphonage (this includes the malfunctioning of an existing device or

method).If any one of the four conditions described in Items (a) to (d) does not exist, the potable water system will not be contaminated.

A.1.2 The main reasons for the water pressure to fall below atmospheric are(a) a break in the water main;(b) drainage of the potable water system for repairs; or(c) an abnormally high demand on another part of the potable water system.

Breaks in water mains do occur and are repaired by the municipality. It is standard practice to loop water mains so that a high demand at one point is fed from two directions, thus minimizing the pressure drop that occurs.

A.1.3 When a high demand is caused by a fire pumper truck, a negative pressure is likely to occur in the potable water system. The chance that a pressure below atmospheric will occur increases with the height of the building and the rate of water withdrawal. This situation is illustrated in Figure A.1 and explained as follows:(a) Under normal conditions, the pressure at A is always sufficient to provide the flow pressure required

at outlets B to E.(b) When the fire pumper starts drawing water from the water main or the potable water supply system

is drained for repairs, the pressure at A is reduced, and a corresponding pressure reduction occurs at B, C, D, and E.

(c) The pressure at A can fall to a pressure less than that corresponding to a column of water the same height as E. When this occurs, a suction pressure occurs at E that is equal to the difference between A and E.

(d) If the difference is greater than the height between D and E, both D and E will be subjected to the same suction pressure, as the effect of the column of air is insignificant.

(e) The pipes supplying E and D are, of course, still full of water, since the valves are normally closed. If one of those valves is opened under the conditions described in Item (d), air will be drawn into the potable water system, and the surface of the water in the riser will fall to some point F corresponding to the pressure at A, expressed as an equivalent column of water.

(f) If E or D is directly connected to a fluid and there is no air gap, and a backflow preventer has not been installed, the fluid will be drawn into the riser. Back siphonage is considered to have occurred and will continue to occur until the surface of the contaminating fluid falls below the outlet and air can be drawn into the potable water system.

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(g) When air is drawn into the potable water system, the height of fluid and water in the riser will level off at F. When the fire is over, the pressure at A will rise to normal. The water and fluid in the riser will then be forced back to where the fluid came from, as the valve is still open.

A.1.4 Another reason that the pressure in the riser (see Figure A.1) could fall below atmospheric is an accidental break in the water main, for example at A. The pressure at A will fall until it is equal to the resistance to flow from the break into the ground, and point F would probably be found at about ground level. Back siphonage could then occur as described in Clause A.1.3.

A.2 Back pressure backflow

A.2.1 When the pressure causing backflow is higher than atmospheric pressure, it is referred to as back pressure. Such back pressure is usually caused by mechanical means such as a pump or by thermal means such as a boiler. For backflow to occur, the following four conditions must exist:(a) the back pressure has risen above the supply pressure (or the supply pressure has fallen below the

back pressure);(b) a supply valve is open;(c) the potable water system is connected to a device or system that contains a fluid other than potable

water; and(d) no backflow preventer has been installed (or the device is not working).

A.2.2

A.2.2.1Of the four conditions listed in Clause A.2.1, it can generally be assumed that conditions (b) and (c) exist. Unfortunately, in many industrial plants, condition (d) seems to be more common than it should be. Since the pressure on the supply side can vary, it is necessary to consider how a pressure variation can result in the development of back pressure, as explained in Clauses A.2.2.2 and A.2.2.3.

A.2.2.2Probably the most common examples of piping systems in which pumps can cause back pressure are found in docked ships and in industrial plants where a secondary or alternative water system exists. In these cases, the municipal potable water and alternative water systems are interconnected. As long as a backflow preventer is installed and is in working order, no back pressure is exerted on the municipal potable water system, and backflow cannot occur. Generally, in industry, one system will be used as the principal supply, with the other being connected as an alternative supply in case of an emergency.

When ships are in harbour they are generally connected to the public water mains for improved fire protection and refilling of their potable water storage tanks. The ships no longer have to rely on their own mechanical pumping system, which can be temporarily shut down for servicing. It is common practice to flush a ship’s fire protection systems with dockside potable water. After the flushing operation, the ship’s fire pumps are tested to ensure that they are functioning properly. These pumps may generate a pressure of 1400 kPa, which is considerably higher than that of the municipal potable water supply system. If only a shut-off valve has been installed on the municipal potable water system and no backflow preventer is provided at the connection point of the ship’s water system, sea or lake water will be forced into the municipal potable water system whenever the shut-off valve is open and the ship’s pumps are operated.

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A.2.2.3Back pressure can also be caused by thermal means when a potable water system is directly connected to a boiler and the backflow preventer is either missing or defective. In such cases the pressure in the boiler is that provided by the potable water system, regardless of whether it is a hot water boiler or a steam boiler. Back siphonage can occur in the same manner as discussed in Clause A.1, but back pressure can only be developed if the boiler controls fail and overheating occurs. The overheating can cause steam to be formed whose volume is many times that of hot water, so that the water in the boiler is forced back into the potable water system. If steam is not formed, backflow due to back pressure will be relatively small and equal to the change in volume of water corresponding to its increase in temperature.

Figure A.1Example of potential back siphonage hazard

(See Clauses A.1.3 and A.1.4.)

To fire department pumpersuction connection

A

Public water supply

F

Drain valve

E

D

C

B

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Annex B (informative)Guide to the assessment of hazards


B.1To protect the municipal and private potable water supply systems from contamination, the authority administering the local cross-connection control program has several options available when determining the location of backflow preventers within industrial, commercial, and residential premises:(a) The first option is based on a containment theory according to which backflow protection is installed

on the incoming service, providing premises isolation that utilizes a minimum number of backflow preventers to isolate the municipal potable water system from the private system, but that does not protect the consumer from the source of contamination via internal cross-connections.

(b) The second option is based on internal protection: backflow preventers are either installed on individual water usages or zones of usage. This approach protects the private potable water system from internal contamination, but does not adequately protect the municipal potable water system, because of the complexity of the plumbing system (e.g., plumbing modifications and occupancy changes), that are inherent in industrial, commercial, or residential developments.

(c) The third option is based on combining premises, zone, and individual protection to ensure that both the public and private potable water supply systems are protected from contamination.

B.2Tables B.1 and B.2 are a guide to the degree of hazard, but do not provide a complete list of potential hazards.

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46 July 2007

Table B.1Guide to degree of hazard — Point of use cross-connections

(See Clauses 5.4.1 and B.2.)

Source of pollution or contamination Degree of hazard

Agricultural chemical (sprayer) Severe

Air compressor oil cooler Moderate

Animal watering Moderate

Aspirator (non-toxic) Moderate

Aspirator (toxic) Severe

Autoclave Severe

Autopsy and mortuary equipment Severe

Auxiliary water supply Severe

Baptistery Moderate

Basin Moderate

Bathtub (all) Moderate

Bedpan washer Severe

Beverage dispensing equipment (no carbonator) Minor

Beverage dispensing equipment (with carbonator) Moderate

Bidet Moderate to severe

Bottle washer Moderate to severe

Bread making equipment Minor to moderate

Canopy washers Severe

Carwash Severe

Chemical feed tank Severe

Chiller tank (closed, no chemicals) Moderate to severe

Chiller tank (open or with chemicals) Severe

Chlorinator Severe

Clothes washer (residential) Moderate

Condensate tank Severe

Condensate tank (top feed) Moderate

Cooking kettle (for food only) Minor

Cooling condenser, AC unit (solenoid downstream) Severe

Cooling condenser, AC unit (solenoid upstream) Minor

(Continued)

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July 2007 47

Table B.1 (Continued)


Cooling tower Severe

Cuspidor Severe

De-aerator (bottom feed) Severe

De-aerator (top feed) Moderate

Degreasing equipment Severe

Dental delivery system (water supply) Minor

Dental vacuum pump Severe

Detergent dispenser Severe

Dipper well in ice cream parlour or restaurant Moderate

Dish rinse unit with flex hose Moderate

Dishwasher (commercial) Moderate

Dishwasher (residential) Moderate

Distiller Minor

Dockside marine facility Severe

Emergency eyewash/shower Eyewash/shower to be installed upstream of the zone isolation

Flexible shower head with hose Minor to severe

Floor drain with flushing rim Severe

Flush tank Moderate

Flushing equipment device Severe

Flushometer Severe

Fountain, ornamental Moderate to severe

Fountain, ornamental (chemicals added) Severe

Fume hood Severe

Garbage can washer Severe

Garbage disposal unit Severe

Heat exchanger Moderate to severe

Heating system (chemicals added) Severe

Heating system (no chemicals added) Moderate

Heating system (residential; boiler with copper or plastic piping; no chemicals added)

Minor to moderate

Hose connection (other than residential) Moderate to severe

(Continued)

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48 July 2007



Hose connection (residential) Minor to moderate

Hospital (active treatment area) Severe

Hospital (non-treatment area) Moderate

Hot tub or spa Moderate

Humidifier Moderate

Humidifier with sump (chemicals added) Severe

Hydrotherapy bath Moderate

Ice machine for commercial restaurant Moderate to severe

Ice making equipment for sports arena Severe

Industrial fluid system Severe

Irrigation system (chemicals injected) Severe

Irrigation system (no chemicals injected) Moderate

Lab bench equipment (non-toxic) Minor

Lab bench equipment (toxic) Severe

Lab faucet Moderate to severe

Laboratory Severe

Laundry machine Moderate

Lavatory Moderate

Lethal substance Severe

Livestock equipment Severe

Mixing tee with steam and water Moderate

Mortuary or morgue Severe

Non-potable water Severe

Optician or ophthalmology equipment Minor to moderate

Photo lab sink Severe

Pipette washer Severe

Piping to chemical dispensers Minor to severe

Plating tank Severe

Potato peeler Moderate

Poultry barn Severe

Pressure washer (no aspirator) Minor

(Continued)

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July 2007 49



Pressure washer (with aspirator) Severe

Private fire hydrants Moderate

Private water source Severe

Pump primer line (non-toxic) Moderate

Pump primer line (toxic) Severe

Radiator flushing equipment Severe

Restricted area Severe

Reverse osmosis equipment Minor

Reverse osmosis equipment with backwashing Moderate

Reverse osmosis equipment with chemical cleaning Severe

Serrated faucets Severe

Sewage ejectors Severe

Sewage pump Severe

Shampoo sinks Moderate

Sizing vats Severe

Solar energy units Severe

Solution tanks Severe

Spa or hot tub Moderate

Specimen tank Severe

Steam boiler Severe

Steam cleaner Moderate

Steam generator Moderate

Steam table Minor to moderate

Sterilizer (condensate cooling only) Moderate

Sterilizer (connection into chamber) Severe

Still Minor

Swimming pool (direct connection) Moderate

Swimming pool (other than residential) Moderate

Swimming pool (residential) Minor

Swimming pool makeup tank Moderate

Teeth cleaning equipment (veterinary type) Moderate

(Continued)

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50 July 2007

Table B.1 (Concluded)


Trap primer Severe

Vending machine with no carbonators Minor

Wash rack Severe

Wash tank Moderate

Wash tanks (toxic) Severe

Water closet (flushometer type) Moderate

Water closet (tank type) Moderate

Water hauling equipment (see Annex C) Severe

Water softener Minor

Water softener drain Severe

Wok table (for Oriental cooking) with submerged inlet Moderate

X-ray equipment Severe

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July 2007 51

Table B.2Guide to degree of hazard — Premises

(See Clauses 5.3.1.2, 5.3.4, and B.2.)

Type of building or facility Degree of hazard

Airport Moderate

Animal feed lot Moderate to severe

Animal stock yard Moderate to severe

Apartment building Moderate

Aquaculture farm Severe

Aquarium (public) Severe

Arena Moderate

Asphalt plant Severe

Auto body shop Severe

Auto dealership Moderate

Automotive repair Severe

Automotive repair shop Severe

Beverage processing plant (includes distillery and brewery) Severe

Blood clinic Severe

Campsite Moderate

Campsite with RV hook-ups or dump-stations Severe

Carwash Severe

Chemical plant Severe

Church Minor to moderate

Commercial premises Moderate to severe

Concrete plant Severe

Dental office Moderate

Dental surgery facility Severe

Dock and marine facility Severe

Dry cleaning plant Severe

Duplex housing with shared service Minor

Dye plant Severe

Exhibition ground Severe

Farm Moderate to severe

(Continued)

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52 July 2007



Film processing facility Severe

Fire station Moderate to severe

Fish farms or hatchery Severe

Food processing plant Severe

Fuel dispensing facility Moderate

Funeral home Moderate to severe

Garbage transfer facility Severe

Golf course Moderate to severe

Grocer Moderate

Hair salon Moderate

Hospital Severe

Hotel Moderate

Industrial and institutional premises Moderate to severe

Kennel Moderate

Laboratory Severe

Laundry (commercial) Severe

Laundry (commercial, coin-operated) Moderate

Manufacturing plant (not specified) Moderate

Marina (pleasure-boat) Moderate to severe

Meat packing plant Severe

Medical clinic (non surgical) Moderate

Medical clinic (surgical) Severe

Milk processing plant Severe

Mining facility Severe

Mobile home park Moderate

Mortuary or morgue Severe

Motel Moderate

Motorcycle repair facility Severe

Nursing home Moderate

Oil refinery Severe

Paint manufacturing plant Severe

(Continued)

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July 2007 53



Penitentiary Moderate

Petroleum processing or storage facility Severe

Pharmaceutical manufacturing facility Severe

Photo processing facility Severe

Plants using radioactive material Severe

Plastic manufacturing plant Severe

Plating shop Severe

Poultry farm Severe

Power generating facility Severe

Premises where access is prohibited Severe

Printing plant Severe

Pulp and/or paper plant Severe

Radiator shop Severe

Recycling facility Severe

Refinery, petroleum processing Severe

Rendering facility Severe

Research building Severe

Residential premises Minor

Restaurant Moderate

School (elementary, junior high, and senior high) Moderate

Sewage dump station Severe

Sewage treatment plant Severe

Steel manufacturing plant Severe

Swimming pool facility Moderate

Townhouse (shared services) Minor

University Moderate to severe

Veterinary clinic Moderate to severe

Waste disposal plant Moderate to severe

Wastewater facility Severe

Wastewater pump station Severe

Wastewater treatment plant Severe

(Continued)

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54 July 2007

Table B.2 (Concluded)


Water filling station Severe

Water park Moderate

Water treatment plant Severe

Water treatment pump station Severe

Zoo Severe

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July 2007 55

Annex C (informative)Water-hauling equipment and backflow devices

Note: This informative (non-mandatory) Annex has been written in normative (mandatory) language to facilitate adoption where users of the Standard or regulatory authorities wish to adopt it formally as additional to requirements to this Standard.

C.1An RP backflow preventer or an air gap shall be installed on all water-hauling equipment. See Figures C.1 and C.2.Note: For air gaps, see Clauses 3.1 and 4.1.

Figure C.1(See Clause C.1.)

Figure C.2(See Clause C.1.)

Air gapPermanentlyattached pipe

Hose connection

RP backflowpreventer

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56 July 2007

Annex D (informative)Conversion tables


Table D.1Conversion factors

Table D.2Flow rate equivalencies

To convert To Multiply by

°C °F 1.8 and add 32

kPa lbf/in2 (psi) 0.145

kPa lbf/ft2 20.885

L imperial gallon 0.220

L/s imperial gal/min (imperial gpm) 13.198

L US gallon 0.264

L/s US gal/min (US gpm) 15.850

m ft 3.281

m2 ft2 10.764

mm in 0.0394

N lbf 0.225

N•m lbf•in 8.851

L/s US gpm

0.19 3.0

0.32 5.0

0.63 10.0

1.00 15.9

1.26 20.0

1.89 30.0

2.52 40.0

3.78 60.0

4.73 75.0

5.67 90.0

6.30 100.0

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July 2007 57

Annex E (informative)Model backflow prevention bylaw

Notes: (1) This informative (non-mandatory) Annex has been written in normative (mandatory) language to facilitate adoption

where users of the Standard or regulatory authorities wish to adopt it formally as additional to the requirements in this Standard.

(2) If a regulatory authority adopts this bylaw, consideration should be given to exceptions or changes that may be required due to local or provincial regulations.

E.1Figure E.1 comprises a model bylaw for enforcement of a cross-connection control program (CCCP) by the regulatory authority.

Figure E.1Model backflow prevention bylaw

(Continued)

Backflow Prevention Bylaw

1 DefinitionsFor the purposes of this Bylaw, the following definitions shall apply:

Authorized functions list — the list of functions and the persons authorized to carry out such functions, as outlined in Table 1.

Backflow — the reversal of the normal direction of the flow of water.

Backflow preventer — a device that prevents backflow.

Building — refer to the definition of “building” in [insert reference to provincial building code here].

Cross-connection — any actual or potential connection between a potable water system and any source of pollution or contamination. Note: Bypass arrangements, jumper connections, removable sections, swivel or changeover devices, or any other temporary or permanent connecting arrangements through which backflow can occur are considered cross-connections.

Owner — any person, firm, or corporation having control over property to which this Bylaw applies.

Potable water — water safe for human consumption.

Premises isolation — isolation of the water located within a building or structure from the municipal water supply.

Regulatory authority (municipality) — the Corporation of [insert name of city, town, or regulatory authority here], including its employees, servants, and agents.

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58 July 2007

Figure E.1 (Continued)(Continued)

2 Contamination and backflow preventionNo person shall connect, cause to be connected, or allow to remain connected to the plumbing system or water distribution system any piping, fixture, fitting, container, or appliance that, under any circumstances, might allow any untreated water, waste water, pollutant, or any other liquid, chemical, or substance to enter the plumbing system or potable water distribution system.

3 Inspection for cross-connections — Access

3.1The regulatory authority shall be allowed access, with reasonable notice, to any premises connected to the water distribution system for the purpose of performing inspections to locate possible cross-connections. The regulatory authority may request a routine cross-connection inspection of the premises (at the owner’s expense), to be performed by an approved company or person as described in the Authorized Functions List (Table 1).

3.2The regulatory authority shall be allowed access, with reasonable notice, to any premises connected to the water distribution system for the purpose of performing inspections to verify compliance with Section 8.

3.3Where the access requirements of Sections 3.1 and 3.2 are not fulfilled, a written notice may be issued by the regulatory authority outlining a revised deadline for access to the premises in question. If access is not provided by this deadline, the regulatory authority may, at its discretion, shut off the supply of water to the premises until the access is provided.

3.4If a condition is found to violate Section 2, the regulatory authority may immediately carry out an inspection and may issue any notice required to obtain compliance with Section 2.

4 Notices and orders to correct cross-connectionsIf the person(s) to whom the regulatory authority has issued notice fails to comply with that notice, the regulatory authority may(a) give further notice to the person(s) to correct the fault (at his or her expense) within a specified

time period; if the notice is not complied with, the regulatory authority may then shut off the water service;

(b) issue an order, citing unsafe conditions, in accordance with [insert reference to provincial building code here] to correct the condition that could be hazardous to the health or safety of persons in the normal use of the building, persons outside the building, or persons whose access to the building has not been reasonably prevented; and

(c) without notice to the consumer, shut off the water service where the commissioner of works has determined, in his or her sole discretion, that an immediate threat of contamination to the water system exists that can endanger public health or safety.

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July 2007 59


5 Premises isolation

5.1Where, in the opinion of the regulatory authority, a risk of possible contamination of the potable water distribution system exists, the owner, on notice from the regulatory authority, shall install premises isolation in addition to any other backflow protection devices on the premises.

5.2Premises isolation shall be installed(a) in buildings of high or severe hazard in accordance with the premises isolation requirements

outlined in [insert reference to provincial building code here]; or(b) as required by the regulatory authority.

6 Required surveys

6.1A cross-connection survey of the plumbing system of all existing industrial, commercial, institutional, and multi-residential buildings and structures, except buildings of residential occupancies within the scope of [insert reference to provincial building code here], shall be completed (at the owner’s expense) by the approved personnel specified in the Authorized Functions List (Table 1).

6.2The cross-connection survey shall be completed along with a report and sent to the regulatory authority within 30 days of the date of the request by the municipality. The cross-connection survey report shall include existing backflow preventers and cross-connections, corrective measures, recommendations, and a schedule of work to be completed.

6.3A cross-connection survey shall be completed every 5 years from the date of the first requested survey or as required by the regulatory authority.

7 Selection and installation of backflow preventersThe selection and installation of backflow preventers shall be in accordance with [insert reference to provincial building code here].

8 Maintenance and field-testing of backflow preventers

8.1Where required by [insert reference to provincial building code here] and CSA B64.10.1, all backflow preventers shall be inspected and tested (at the owner’s expense) to demonstrate that the devices are in proper working condition.

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60 July 2007


8.2When the results of the test in Section 8.1 demonstrate that a backflow preventer is not in proper working condition, the owner shall make all necessary repairs or replace the device within 5 days.

8.3If the owner does not make the appropriate repairs or replace the defective device within 5 days, the regulatory authority may issue a notice (see Section 3.4) or may shut off the water service(s).

8.4If the owner fails to have a backflow preventer tested, the regulatory authority may notify the owner that the backflow preventer must be tested within a specified time.

8.5If the owner fails to have a backflow preventer tested within the specified time of the notice described in Section 8.4, the regulatory authority may shut off the water service(s) until the backflow preventer has been tested and approved as required by Section 8.1.

8.6Failure to comply with Sections 8.1 to 8.5 can result in penalties as described in Section 4.

9 Removal of backflow preventersNo person shall remove a backflow preventer or any part thereof after it has been installed, and no owner of a building or structure in which a backflow preventer is installed shall cause or permit the removal of such a device, unless the purpose of such removal is to(a) facilitate the repair of the device, with the device replaced immediately after the repair is carried

out; (b) replace the device with another device that meets or exceeds the provisions of this Bylaw; or(c) remove a device when the fixture or equipment has been taken out of service and removed.

10 Backflow test equipment maintenanceWhere required by [insert reference to provincial building code here] and CSA B64.10.1, all equipment used to test backflow preventers shall be verified or calibrated for accuracy.

11 Authorized functionsOnly those persons listed in the Authorized Functions List (see Table 1) shall carry out the corresponding functions set out in such list.

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July 20076

1

© C

anadian Standards AssociationSelection and installation of backflow

preventers

Figure E.1 (Concluded)

Table 1Authorized functions listMunicipality of _________________Bylaw number __________________

Item Authorized function

Professional engineer with tester’s licence

Certified engineering technologist with tester’s licence*

Licensed master plumber with contractor’s and tester’s licence

Journeyman plumber with tester’s licence†

Apprentice plumberwith tester’s licence‡

Fire system sprinklerfitter with a tester’s licence

Lawn irrigation system installer with tester’s licence

1 Carry out cross- connection survey

✓ ✓ ✓ ✓ — — —

2 Install, relocate, or replace backflow preventer

— — ✓ ✓ ✓ — —

3 Repair backflow preventer

✓ ✓ ✓ ✓ ✓ — —

4 Test backflow preventer ✓ ✓ ✓ ✓ ✓ — ✓

5 Complete Items 1, 2, 3, and 4 in relation to fire protection systems

✓ ✓ ✓ ✓ ✓ ✓ —

6 Complete Items 3 and 4 in relation to lawn sprinkler systems

✓ ✓ ✓ ✓ ✓ — —

*Required to be under the direction of a professional engineer.†Required to be employed by a licensed plumbing contractor or licensed fire sprinkler contractor.‡Required to be employed by a licensed plumbing contractor and under the direct supervision of a journeyman plumber or master plumber.

Licensed for/Autorisé à Jeff Whitaker, Utilities Kingston, Sold by/vendu par CSA on/le 4/8/2009. Single user license only. Storage, distribution or use on network prohibited./Permis d'utilisateur simple seulement. Le stockage, la distribution ou l'utilisation sur le réseau est interdit.

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CSA Standard

B64.10.1-07Maintenance and field testing of

backflow preventers

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© Canadian Standards Association Maintenance and field testing of backflow preventers

July 2007 65

B64.10.1-07Maintenance and field testing of backflow preventers

1 Scope

1.1This Standard specifies requirements for the maintenance and field testing of backflow preventers.

1.2This Standard does not specify requirements for the selection and installation of backflow preventers. Such requirements are specified in CSA B64.10.

1.3In CSA Standards, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; “should” is used to express a recommendation or that which is advised but not required; “may” is used to express an option or that which is permissible within the limits of the standard; and “can” is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.4This Standard is written in SI (metric) units. For conversion tables, see Annex D of CSA B64.10. Vacuum is expressed in pressure below ambient.

2 Reference publicationsThis publications referenced in this Standard are listed in Clause 2 of CSA B64.10.

3 Definitions, abbreviations, and symbolsThe definitions, abbreviations, and symbols given in Clause 3 of CSA B64.10 apply in this Standard.

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B64.10.1-07 © Canadian Standards Association

66 July 2007

4 Devices to be field tested, frequency, and reporting

4.1 Devices to be field tested

4.1.1To ensure that continuing backflow protection is available, the following backflow preventers shall be checked and field tested in accordance with Clauses 4.2 and 4.3 by a backflow preventer tester (see Clause 5.2.1):(a) DCVA and DCVAF backflow preventers;(b) RP and RPF backflow preventers;(c) PVB and SRPVB devices; and(d) SCVAF backflow preventers.

4.1.2Air gaps on severe hazard applications shall be inspected in accordance with Clause 4.2. Other backflow preventers shall be visually checked periodically.

4.2 Frequency of field testingThe backflow preventers specified in Clause 4.1 shall be field tested in accordance with the applicable requirements specified for each device in Clauses 8.1, 8.2, and 8.3 at the following times:(a) upon installation;(b) when cleaned, repaired, or overhauled;(c) when relocated;(d) annually; and(e) as required by the regulatory authority.Note: Recommended field testing procedures are provided in Annex A.

4.3 Reporting

4.3.1Test results shall be reported on the form appropriate for the type of backflow preventer and procedure. Sample reporting forms are shown in Figures 1(a), 1(b), and 1(c).

4.3.2Fire departments and fire alarm companies shall be notified when a fire protection service is to be shut down for field testing.

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July 2007 67

Figure 1(a)Sample testing and inspection report

for DCVA backflow preventers and PVB devices(See Clause 4.3.1.)

35

3637383940414243

Cleaned ReplacedDisc SpringGuidePin RetainerHinged PinSeatDiaphragmOther, describe above

Distribution

White – Cross-connection control officer

Canary – Certified tester

Pink – Occupant or owner

OccupantLocation address

Mailing address

Owner address

Owner of device

Owner contact

Location of device in building

Make of test kit

Reason for failure (if apparent)

Type of test

For office use only

Signature registered tester

Remarks

MMYY DD Line pressureat time of test

kPapsi

Date of test

Type of device SizeSerial numberModel numberMake of device

Serial numberModel number Calibration due date

Name of certified tester Tester certification number Telephone

Telephone

Business name Business address Postal code

Postal code

Testing and inspection reportDouble check valve backflow preventer

and pressure vacuum breaker

Double check valve backflow preventer/Pressure vacuum breaker

If the device fails the test for any reason, complete this section and note repair below

InitialAnnual

Check valve 2Check valve 1Double check valve backflow preventer


Pressure dropacross check valve

kPapsi

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

PassedFailed

Re-test results

MMYY DDDate of re-test

I certify that I have tested the above device in accordance with the City of Bylaw

MMYY DD

MMYY DD

DCVA, PVB

Rep

air

sTe

stR

e-te

st

DCVA PVB

Pressure vacuumbreaker

With flow Against flow With flow Against flow

Failed to openOpened at

Air inlet valveLeakedClosed tight

Check valve


kPapsi

Pressure dropacross check

kPapsi

kPapsi

PassedFailed

Test results


kPapsi

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

With flow Against flow With flow Against flow


kPapsi

PassedFailed

Re-test results

Pressure vacuumbreaker

44

4546474849505152

Cleaned ReplacedDisc SpringGuidePin RetainerHinged PinSeatDiaphragmOther, describe above

53

5455565758596061

Cleaned ReplacedVent Disc Vent SpringPoppetRetainerSpringDiscGuideOther, describe above


Air inlet valveLeakedClosed tight

Check valve


kPapsi

kPapsi

PassedFailed

Test results

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68 July 2007

Figure 1(b)Sample testing and inspection report for RP backflow preventers

(See Clause 4.3.1.)

1

234567

Diaphragm smallUpperSpacerSeatOther (describe above)

89101112

CleanedReplacedDisc upperDisc lowerSpringDiaphragm lg.UpperLower

13

141516171819

DiaphragmOther (describe above)

2021

CleanedReplacedDiscSpringGuidePin retainerHinged pinSeat

22

232425262728

DiaphragmOther (describe above)

2930

CleanedReplacedDiscSpringGuidePin retainerHinged pinSeat

31

323334

CleanedReplacedDiscSeatOther (describe above)

Distribution

White – Cross-connection control officer

Canary – Certified tester

Pink – Occupant or owner

OccupantLocation address

Mailing address

Owner address

Owner of device

Owner contact

Location of device in building

Make of test kit

Reason for failure (if apparent)

Type of test

For office use only

Signature registered tester

Remarks

MMYY DD Shut-offvalve no. 2

LeakedClosed tight

Line pressureat time of test

kPapsi

Date of test

Make of device SizeSerial numberModel number

Serial numberModel number Calibration due date

Name of certified tester Tester certification number Telephone

Telephone

Business name Business address Postal code

Postal code

Testing and inspection reportReduced pressure principle backflow preventer

Reduced pressure principle backflow preventer

If the device fails the test for any reason, complete this section and note repair below

InitialAnnual

Check valve 2Check valve 1Differential pressure

relief valve

Check valve 2Check valve 1Differential pressure

relief valveShut-offvalve 2

Pressure differential acrossfirst check valve (no flow)

Pressure differential acrosssecond check valve (no flow)

kPapsi

kPapsi

PassedFailed

LeakedClosed tight

Failed to openOpened at kPa psi

LeakedClosed tight

Test results

Pressure differential acrossfirst check valve (no flow)

Pressure differential acrosssecond check valve (no flow)

kPapsi

kPapsi

PassedFailed

LeakedClosed tight

Failed to openOpened at kPa psi

LeakedClosed tight

Re-test results

MMYY DDDate of re-test


MMYY DD

MMYY DD

RPR

epai

rsTe

stR

e-te

st

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July 2007 69

Figure 1(c)Sample testing and inspection report for RP and

DCVA backflow preventers and PVB and SRPVB devices(See Clause 4.3.1.)

5 School accreditation and tester certification and licensing

5.1 School accreditationA school or college conducting certification or re-certification courses shall be accredited by an organization or association. The accrediting organization or association shall have minimum requirements established for the following:(a) instructor and backflow prevention device tester qualifications;(b) instructor and backflow prevention device tester re-certification qualifications;(c) course content and duration for device tester qualifications;(d) course content and duration for device tester re-certification courses;(e) examinations and minimum passing criteria for Items (c) and (d);

CleanedReplacedDiscSeat Other (describe)

CleanedReplacedDiscSpringGuidePin retainerHinge pinSeatDiaphragmOther (describe)

CleanedReplacedDisc, upperDisc, lowerSpringDiaphragm, large UpperLowerDiaphragm, smallUpperLowerSpacer, lowerOther (describe)

CleanedReplacedVent discVent springPoppetRetainerSpringDiscGuideOther (describe)

70

7172737475767778

50

5152535455565758596061

30

3132333435363738

20

212223

1

23456789

CleanedReplacedDiscSpring GuidePin retainerHinge pinSeatDiaphragmOther (describe)

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

Failed to open kPaOpened at psi

LeakedClosed tight

PassedFailed


LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight

LeakedClosed tight


LeakedClosed tight

PassedFailed


Pressure differential across kPaFirst check valve (no flow) re-test psi

Remarks – reason for failure (if apparent)


Signature of certified tester Date

For office use only

Distribution: White – Cross-connection control officer Canary – Certified tester Pink – Occupant or owner

YY MM DD

Re-test

Air inlet valve Check valveWith flow Against flowWith flow Against flowDifferential pressure

relief valveShut-off valve 2

If the device fails the initial test for any reason, complete this section and note repair below

OccupantLocation address Party contacted Telephone number

Mailing address

Telephone numberAddress of owner Postal codeOwner

Type of device Make of device Serial number Size Install dateModel number

Location of device (i.e., building, room number)

Tester’s certification number Tester’s equipment number Name of certified tester Business name Telephone number

Location address

Line pressure kPaat time of test psi

kPaPressure differential across first check valve (no flow) psi kPa kPaMinus the opening point of relief valve psi = Buffer psi

Type of test (please check one)

Postal code

Repairs Results


YY MM DDRP DCVA PVB

Test dateYY MM DD

Re-test dateYY MM DD

Test

Pressure vacuum breaker or spill-resistant pressure

vacuum breaker

InitialAnnualReplacement

SRPVB

Reduced pressure principle backflow preventer

Testresults

Re-testresults

Testing and inspection reportReduced pressure principle backflow preventer,

double check valve backflow preventer,pressure vacuum breaker, and

spill-resistant pressure vacuum breaker

RP, DCVA, PVB, SRPVB

Installed on what system

– –

– –

– –

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70 July 2007

(f) laboratory facilities;(g) issuance of certificates for certified or re-certified testers; and(h) current liability insurance coverage (with an expiry date no less than 6 months after the date of

application for licensing or registration).

5.2 Tester certification and re-certification

5.2.1To be recognized as such, a backflow prevention device tester shall have completed and passed a cross-connection control course in backflow preventer testing at an accredited school or college and shall have a certificate issued by an accrediting organization.

5.2.2To maintain active status, the tester shall provide proof to the appropriate authority that he or she complies with the active status requirements of the accrediting organization.Note: The appropriate authority may be the regulator or its designated representative.

5.2.3If a tester does not maintain active status, or every 5 years, the tester shall attend and pass a re-certification course before his or her licence is accepted.

5.2.4If a tester repeatedly submits test reports that are unacceptable because(a) information that is required to be submitted by Clause 8.1, 8.2, or 8.3 is missing or falsified on the

report form; or(b) a device is reported as “passed” when the data obtained in the test indicate that the device has failed,the tester shall be required to attend and pass a re-certification course at an accredited school or college before submitting any further test reports.

5.2.5To be re-certified, a backflow prevention device tester shall complete and pass a backflow prevention device tester re-certification course at an accredited school or college.

5.3 Tester licensing and registrationWhen applying to the regulatory authority for licensing or registration as a backflow prevention device tester, the individual shall have the following qualifications:(a) a certificate from an accredited organization or association as a backflow prevention device tester that

has been issued, or renewed through completion of a re-certification course, within the 5 years before the date of application;

(b) a current calibration certificate for test equipment (dated within the 12 months before the date of application for licensing or registration);

(c) another trade or professional qualification (e.g., plumbing certificate, sprinkler fitter certificate, etc.); and

(d) current liability insurance coverage (with an expiry date no less than 6 months after the date of application for licensing or registration).

Note: The regulatory authority administering the cross-connection control program should license or register backflow prevention device testers who have the above-noted qualifications.

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July 2007 71

6 Maintenance

6.1 General

6.1.1If a backflow preventer has to be removed from a water line and the line is used as the electrical ground, a jumper wire shall be installed.

6.1.2When entering a confined space, entry procedures established by the regulatory authority shall be followed.

6.1.3Backflow preventers designed for in-line servicing and repair shall not be replaced with a spool or pipe and shall not be reassembled while awaiting delivery of replacement parts if any parts have been removed.Note: To eliminate the necessity of removal for servicing, many backflow preventers are designed for in-line repairs. Once a backflow preventer has been removed, no protection is provided. A false sense of protection can be given when a backflow preventer appears to be still operational.

6.1.4Valve springs on large backflow preventers shall be removed with caution. The manufacturer’s instructions shall be consulted.

6.1.5After repairs are completed, entrapped air shall be bled off.

6.2 RP backflow preventers

6.2.1On RP backflow preventers, parts in the upstream check valve need not be interchangeable with the parts in the downstream check valve.

6.2.2If an RP backflow preventer is continuously leaking from the relief port, the upstream check valve, the downstream check valve, or the relief valve has failed. The check valves shall be cleaned and the valve seats checked for damage.

6.2.3If the downstream shut-off valve of an RP backflow preventer is closed and water begins to be discharged from the relief port, the upstream check valve shall be checked for possible leakage.

6.3 DCAPC backflow preventers

6.3.1If the atmospheric port of a DCAPC backflow preventer discharges, the device shall be disassembled, thoroughly inspected, cleaned, and reassembled with new parts as necessary, following the manufacturer’s instructions.

6.3.2DCAPC backflow preventers shall be checked for water and carbon dioxide (CO2) leaks before they are returned to service.

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72 July 2007

7 Test gauges and kits

7.1 AccuracyThe accuracy of test equipment used by backflow prevention device testers shall be monitored by the regulatory authority or its designated agent.

7.2 Verification and calibrationMechanical test kits shall be verified or calibrated for accuracy at least annually or as required by the regulatory authority. Compliance with this requirement shall be a condition for the issuing or reissuing of a tester’s licence or registration. All verification or calibration equipment shall be traceable to a national standard.

7.3 UnitsTest equipment calibrated in yard/pound units equivalent to the SI (metric) units specified in this Standard shall be acceptable.

8 Field test requirements and pass/fail criteriaNote: Recommended field test procedures are provided in Annex A.

8.1 PVB devices

8.1.1 GeneralTo be recorded as “passed”, a PVB device shall comply with the requirements of Clauses 8.1.2, 8.1.3, and 8.1.4. If “failed” is recorded in one or more of these tests, the PVB device shall be recorded as “failed”. The test results shall be recorded as specified in Clause 4.3.1 (see Table 1).

8.1.2 Air inlet valve

8.1.2.1 RequirementsThe air inlet valve shall begin to open when the internal pressure in the PVB device is at least 6.9 kPa higher than atmospheric pressure and shall be fully open when the water drains from the PVB device.

8.1.2.2 Pass/fail criteriaIf the air inlet valve begins to open when the internal pressure in the PVB device is at least 6.9 kPa higher than atmospheric pressure and is fully open when the water drains from the PVB device, the test shall be recorded as “opened/passed”.

If one or both requirements are not met, the test shall be recorded as “failed to open/failed”.

8.1.3 Check valve

8.1.3.1 RequirementsThe check valve shall close tight for a minimum period of 2 min or until the gauge reading stabilizes, in the direction of flow, when the inlet pressure is at least 6.9 kPa higher than the outlet pressure.

8.1.3.2 Pass/fail criteriaIf the check valve closes tight for a minimum period of 2 min or until the gauge reading stabilizes, in the direction of flow, when the inlet pressure is at least 6.9 kPa higher than the outlet pressure, the test shall be recorded as “closed tight/passed”.

If the check valve does not close tight for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as “leaked/failed”.

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July 2007 73

8.1.4 Static line pressure

8.1.4.1 RequirementsThe static inlet line pressure shall be measured at the time of the test and recorded on the test report form.

8.1.4.2 Pass/fail criteriaIf the static inlet line pressure at the time of testing is(a) recorded on the test report form, the test shall be recorded as “passed”; and(b) not recorded on the test report form, the test shall be recorded as “failed”.

8.2 RP and RPF backflow preventers

8.2.1 GeneralTo be recorded as “passed”, RP and RPF backflow preventers shall comply with the test requirements of Clauses 8.2.2 to 8.2.5. If “failed” is recorded in one or more of the tests, the backflow preventer shall be recorded as “failed”. The test results shall be recorded as specified in Clause 4.3.1 (see Table 1).

8.2.2 Relief valve

8.2.2.1 RequirementsThe relief valve shall open at a minimum pressure differential of 13.8 kPa for an RP backflow preventer or 6.9 kPa for an RPF backflow preventer, as measured across check valve 1.

8.2.2.2 Pass/fail criteriaIf the relief valve opens at a pressure differential of 13.8 kPa or greater for an RP backflow preventer or 6.9 kPa for an RPF backflow preventer across check valve 1, the test shall be recorded as a “pass”, and the relief valve opening pressure shall be recorded (“Opened at ___ kPa”).

If the relief valve does not open or opens below a pressure differential of 13.8 kPa for an RP backflow preventer or 6.9 kPa for an RPF backflow preventer, as measured across check valve 1, the test shall be recorded as “failed”, and the relief valve opening pressure shall be recorded (“Opened at ___ kPa”).

8.2.3 Check valve 1

8.2.3.1 Requirements

8.2.3.1.1Check valve 1 (upstream) shall close tight in the direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes.

8.2.3.1.2The differential pressure across check valve 1 shall be a minimum of 20.7 kPa higher than the opening pressure of the relief valve. This requirement shall not apply to RPF backflow preventers.

8.2.3.2 Pass/fail criteria

8.2.3.2.1If check valve 1 closes tight in the direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as “passed/closed tight”.

If check valve 1 does not close tight in the direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as “leaked/failed”.

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74 July 2007

8.2.3.2.2For RP backflow preventers only, if the differential pressure across check valve 1 is at least 20.7 kPa higher than the opening pressure of the relief valve, the test shall be recorded as “passed”.

If the differential pressure across check valve 1 is less than 20.7 kPa higher than the opening pressure of the relief valve, the test shall be recorded as “failed”.

8.2.4 Check valve 2

8.2.4.1 RequirementsCheck valve 2 (downstream) shall close tight in the reverse direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes.

8.2.4.2 Pass/fail criteriaIf check valve 2 closes tight in the reverse direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as “closed tight/passed”.

If check valve 2 does not close tight in the reverse direction of flow, holding a differential pressure for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as “leaked/failed”.


8.2.5.1 RequirementsThe static inlet line pressure shall be measured at the time of the test and recorded on the test report form.

8.2.5.2 Pass/fail criteriaIf the static inlet line pressure at the time of the test is recorded on the test report form, the test shall be recorded as “passed”.

If the static inlet line pressure at the time of the test is not recorded on the test report form, the test shall be recorded as “failed”.

8.3 DCVA, DCVAF, and SCVAF backflow preventers

8.3.1 GeneralTo be recorded as “passed”, DCVA, DCVAF, and SCVAF backflow preventers shall comply with the test requirements of Clauses 8.3.2 to 8.3.4. If “failed” is recorded in one or more of the tests, the backflow preventer shall be recorded as “failed”. The test results shall be recorded as specified in Clause 4.3.1 (see Table 1).

8.3.2 Check valve 1

8.3.2.1 RequirementsCheck valve 1 shall close tight in the direction of flow for a minimum period of 2 min or until the gauge reading stabilizes, when there is a differential pressure across the check valve with the(a) inlet pressure 6.9 kPa higher than the outlet pressure for DCVA and SCVAF backflow preventers; or(b) inlet pressure 3.45 kPa higher than the outlet pressure for DCVAF backflow preventers.

8.3.2.2 Pass/fail criteriaIf check valve 1 complies with the requirements of Clause 8.3.2.1, the test shall be recorded as “closed tight/passed”.

If check valve 1 does not comply with the requirements of Clause 8.3.2.1, the test shall be recorded as “leaked/failed”.

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8.3.3 Check valve 2

8.3.3.1 RequirementsCheck valve 2 shall close tight in the direction of flow for a period of 2 min or until the gauge reading stabilizes, when there is a differential pressure across the check valve with the(a) inlet pressure 6.9 kPa higher than the outlet pressure for DCVA backflow preventers; or(b) inlet pressure 3.45 kPa higher than the outlet pressure for DCVAF backflow preventers.

8.3.3.2 Pass/fail criteriaIf check valve 2 satisfies the requirements of Clause 8.3.3.1, the test shall be recorded as “closed tight/passed”.

If check valve 2 does not satisfy the requirements of Clause 8.3.3.1, the test shall be recorded as “leaked/failed”.


8.3.4.1 RequirementsThe static inlet line pressure shall be taken at the time of the test and recorded on the test report form.

8.3.4.2 Pass/fail criteriaIf the static inlet line pressure at the time of the test is recorded on the test report form, the test shall be recorded as “passed”.

If the static inlet line pressure at the time of the test is not recorded on the test report form, the test shall be recorded as “failed”.

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76 July 2007

Table 1Field test requirements for backflow preventers

(See Clauses 8.1.1, 8.2.1, 8.3.1, and 8.5.1.)

8.4 HCDVB devices — Manual field test of downstream check valve

8.4.1 Test requirementWhen a back pressure equivalent to 3 m of head pressure is applied to the downstream check valve of an HCDVB device, it shall not allow leakage from the atmospheric vent exceeding 6 s in duration (this is normal and indicates proper operation). Continuous leakage exceeding 6 s at the atmospheric vent indicates that the downstream check valve is faulty and that the HCDVB device should be repaired or replaced.

8.4.2 Test set-upWith the HCDVB device in its normal operating position, as specified by the manufacturer, a hose shall be attached to its outlet.

Type of backflow preventer

Tests required

Check valve 1 Check valve 2

Check valve 1 buffer

Relief or air inlet required opening pressure

Record line pressure

DCVA Hold a 6.9 kPa differential in direction of flow

Hold a 6.9 kPa differential in direction of flow

N/A N/A Yes

DCVAF Hold a 3.4 kPa differential in direction of flow

Hold a 3.4 kPa differential in direction of flow

N/A N/A Yes

PVB/SRPVB Hold a 6.9 kPa differential in direction of flow

N/A N/A Before a 6.9 kPa differential

Yes

RP Hold tight with a differential in direction of flow

Hold tight with a differential in reverse direction of flow

20.7 kPa Before a 13.8 kPa differential

Yes

RPF Hold tight with a differential in direction of flow

Hold tight with a differential in reverse direction of flow

N/A Before a 6.9 kPa differential

Yes

SCVAF Hold a 6.9 kPa differential in direction of flow

N/A N/A N/A Yes

Notes: (1) This Table provides a condensed version of the tests required. For the complete requirements, see Clauses 8.1, 8.2,

and 8.3.(2) N/A means not applicable.

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8.4.3 Test procedureThe manual field test of the downstream check valve of an HCDVB device shall be conducted as follows:(a) Raise the hose until the end of the hose is at a height of 3 m.(b) Turn on the faucet or shut-off valve upstream of the specimen and let water run to fill the hose and

purge any trapped air.(c) Turn off the faucet or shut-off valve and follow the manufacturer’s instructions to operate or open the

atmospheric vent and reduce the pressure between the check valves to atmospheric, and then return the check valves to their normal operating position.

(d) Maintain the hose at a height of 3 m for 5 min while observing the atmospheric vent for leakage.

8.5 SRPVB devices

8.5.1 GeneralTo be recorded as “passed”, an SRPVB device shall comply with the test requirements of Clauses 8.5.2 to 8.5.4. If “failed” is recorded in one or more of these tests, the SRPVB device shall be recorded as “failed”. The test results shall be recorded as specified in Clause 4.3.1 (see Table 1).

8.5.2 Air inlet valve

8.5.2.1 RequirementsThe air inlet valve shall begin to open when the internal pressure in the valve is 6.9 kPa or more above atmospheric pressure and shall be fully open when the water drains from the body of the SRPVB device.

8.5.2.2 Pass/fail criteriaIf the air inlet valve begins to open when the internal pressure in the valve is 6.9 kPa or more above atmospheric pressure and is fully open when the water drains from the body, the test shall be recorded as ”opened/passed”.

If one or both of the requirements are not met, the test shall be recorded as “failed to open/failed”.

8.5.3 Check valve

8.5.3.1 RequirementsThe check valve shall close tight in the direction of flow for a minimum period of 2 min or until the gauge reading stabilizes, when the inlet pressure is a minimum of 6.9 kPa.

8.5.3.2 Pass/fail criteriaIf the check valve closes tight in the direction of flow for a minimum period of 2 min or until the gauge reading stabilizes, when the inlet pressure is a minimum of 6.9 kPa, the test shall be recorded as “closed tight/passed”.

If the check valve does not close tight for a minimum period of 2 min or until the gauge reading stabilizes, the test shall be recorded as ”leaked/failed”.


8.5.4.1 RequirementsThe static inlet line pressure test shall be measured at the time of the test and recorded on the test report form.

8.5.4.2 Pass/fail criteriaIf the static inlet line pressure at the time of testing is(a) recorded on the test report form, the test shall be recorded as “passed”; and(b) not recorded on the test report form, the test shall be recorded as “failed”.

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Annex A (informative)Field testing procedures

Note: This informative (non-mandatory) Annex has been written in normative (mandatory) language to facilitate adoption where users of the Standard or regulatory authorities wish to adopt it formally as additional to the requirements in this Standard.

A.1 PVB devices — Field testing using a differential pressure gauge

A.1.1 PVB devices — Testing procedures using a 3-valve differential pressure gauge

A.1.1.1 Equipment required

The tests specified in Clauses A.1.1.2 to A.1.1.5 shall be conducted using a 3-valve differential pressure gauge. To avoid damage to the gauge, it shall be gradually pressurized when using only one side of the gauge. The gauge and hoses (including hoses not used) shall be held at the same level as the PVB device being tested.

A.1.1.2 PVB devices — Test No. 1: Air inlet valve test

A.1.1.2.1 PurposeThe purpose of the air inlet valve test is to test the operation of the air inlet valve of PVB devices.

A.1.1.2.2 RequirementsThe requirements for the air inlet valve test for PVB devices are specified in Clause 8.1.2.

A.1.1.2.3 Procedure (see Figure A.1)The air inlet valve test for PVB devices shall be conducted as follows:(a) Remove the atmospheric vent shield and conduct a physical examination of the PVB device to

determine the condition of the air inlet valve and atmospheric vent.(b) Blow out the test cocks to remove any foreign material.

Notes: (1) Do not stand directly in front of the test cocks when turning them on or off; foreign material may be discharged

or the test cocks may blow off, inflicting injury.(2) It is strongly recommended that safety glasses be worn to protect the eyes.

(c) Connect the hose to test cock 2, and gradually open test cock 2.(d) Open the high-pressure valve; then open the low-pressure valve and bleed the gauge and hoses.

Close the low-pressure valve.(e) Close shut-off valve 2, then shut-off valve 1.

Quantity Description

1 3-valve differential pressure gauge

1 Pressure gauge with a range of either 0 to 420 kPa, 0 to 700 kPa, or 0 to 1120 kPa, depending on the maximum line pressure

1 Bleed valve with NPS-1/4 tee, 1/4 needle valve, 1/4 nipple, and IPS-1/4 flare adapter end

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(f) Gradually open the low-pressure valve, relieving pressure from the specimen and being careful not to drop the reading on the gauge too quickly.

(g) Observe and note the gauge reading when the air inlet valve begins to open.(h) Completely open the low-pressure valve to drain the water from the specimen.

(i) If the air inlet valve begins to open before the gauge reading drops below 6.9 kPa and is opened fully when the water is completely drained from the specimen, the test shall be recorded as “opened”.

(ii) If the air inlet valve does not open or opens with a reading less than 6.9 kPa, the test shall be recorded as “failed to open/failed”.

(i) Close the high-pressure valve, close the low-pressure valve, close test cock 2, and remove the gauge.(j) If the air inlet valve does not open, the gauge reading does not drop, and water continues to be

discharged from the low-pressure valve, see Clause A.1.1.2.4.

Figure A.1PVB devices — Test No. 1: Air inlet valve test

(See Clause A.1.1.2.3.)

0

5 10

15HI LO

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Atmosphericvent

Air inletvalve

Check valve

Differential pressuregauge

High-pressure valve

Low-pressure valve Shield

Hose

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A.1.1.2.4 Leaking shut-off valves (see Figure A.2)If the low-pressure valve has to be opened more than one-quarter of the fully open position, it is likely that shut-off valve 1 is leaking and the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 1.(b) If the leak persists, divert the leak so that the air inlet valve can be tested.(c) To redirect the leakage from shut-off valve 1, gradually open test cock 1, monitoring the gauge until

its reading stabilizes.(d) Once the leakage has been diverted through test cock 1, resume testing at Item (f) of

Clause A.1.1.2.3.(e) If the air inlet valve does not open and the leak through shut-off valve 1 exceeds the limit of test

cock 1, repair or replace shut-off valve 1 before continuing with the test.

Figure A.2PVB devices — Leaking shut-off valve 1: Air inlet valve test


0

5 10

15HI LO

Test cock 2

Test cock 1 Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent


Shut-off valve 1

High-pressure valve

Low-pressure valve

Hose

Shield

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A.1.1.3 PVB devices — Test No. 2: Check valve test

A.1.1.3.1 PurposeThe purpose of the check valve test is to determine whether the check valve of PVB devices will close tight in the direction of flow.

A.1.1.3.2 RequirementsThe requirements for the check valve test for PVB devices are specified in Clause 8.1.3.

A.1.1.3.3 Procedure (see Figure A.3)The check valve test for PVB devices shall be conducted as follows:(a) Open shut-off valve 1 to re-establish pressure in the PVB device.(b) Connect the hose to test cock 1 and gradually open test cock 1.(c) Open the high-pressure valve; then open the low-pressure valve and bleed the gauge and hoses.

Close the gauge low valve.(d) Close shut-off valve 1 (shut-off valve 2 should still be closed from the air inlet valve test).(e) Open test cock 2, reducing the downstream side of the check valve to atmospheric pressure.(f) When the water stops flowing from test cock 2,

(i) if the gauge reading has stabilized at 6.9 kPa or greater, record that the check valve “closed tight”;

(ii) if the gauge reading drops to 0 kPa, or stabilizes at less than 6.9 kPa, record that the check valve “leaked/failed”; or

(iii) if water continues to flow from test cock 2, see Clause A.1.1.3.4.(g) Close test cocks 1 and 2 and remove the pressure gauge.(h) Open shut-off valve 1, then open shut-off valve 2.(i) Reinstall the atmospheric vent shield.

Figure A.3PVB devices — Test No. 2: Check valve test


0

5 10

15HI LO

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent


High-pressure valve

Low-pressure valve

Hose

Shield

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A.1.1.3.4 Leaking shut-off valves (see Figure A.4)If water continues to flow from test cock 2 during Item (e) of Clause A.1.1.3.3, shut-off valve 1 is leaking and the following procedure shall be used:(a) Close test cock 1 and remove the hose.(b) Connect the bleed valve to test cock 1 and reconnect the hose.(c) Open test cock 1 (test cock 2 should still be open from the check valve test).(d) Gradually open the bleed valve until the water flow from test cock 2 is reduced to a slight drip.(e) Observe the reading on the gauge as the static pressure drop across the check valve decreases.

(i) If the water flow ceases through test cock 2 and if the gauge reading has stabilized at 6.9 kPa or greater, record that the check valve “closed tight”.

(ii) If the water flow from test cock 2 cannot be eliminated by opening the bleed valve, do not attempt to determine the tightness of the check valve until shut-off valve 1 is repaired or replaced.

Figure A.4PVB devices — Leaking shut-off valve 1: Check valve test


0

5 10

15HI LO

Test cock 2

Test cock 1

Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent


Shut-off valve 1

High-pressure valve Low-pressure

valve

Hose

Bleed valve

Shield

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A.1.1.4 PVB devices — Test No. 3: Static line pressure test

A.1.1.4.1 PurposeThe purpose of the static line pressure test is to determine the static inlet line pressure upstream of the check valve of a PVB device.

A.1.1.4.2 RequirementsThe requirements for the static line pressure test for PVB devices are specified in Clause 8.1.4.

A.1.1.4.3 Procedure (see Figure A.5)The static line pressure test for PVB devices shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge to remove the air.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at the time of the test is not recorded on the test report form, record

the test result as “failed”.(e) Close test cock 1 and remove the gauge.

Figure A.5PVB devices — Test No. 3: Static line pressure test


010

20

3040

5060

7080

90100

Test cock 2

Test cock 1Shut-off valve 2

Atmosphericvent

Air inletvalve

Check valve

Pressure gauge

Shut-off valve 1

Hose

Shield

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A.1.1.5 Returning PVB devices to serviceAfter completing the tests specified in Clauses A.1.1.2 to A.1.1.4, PVB devices shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the PVB device for leaks.(e) Inform the regulatory authority that the water supply is ready to be turned on.(f) Open shut-off valve 2, putting the PVB device back into service.

A.1.2 PVB devices — Testing procedures using a 5-valve differential pressure gauge


The tests specified in Clauses A.1.2.2 to A.1.2.5 shall be conducted using a 5-valve differential pressure gauge. To avoid damage to the gauge, it shall be gradually pressurized when using only one side of the gauge. The gauge and hoses (including hoses not used) shall be removed or held at the same level as the PVB device being tested.

A.1.2.2 PVB devices — Test No. 1: Air inlet valve test

A.1.2.2.1 PurposeThe purpose of the air inlet valve test is to test the operation of the air inlet valve of PVB devices.

A.1.2.2.2 RequirementsThe requirements for the air inlet valve test for PVB devices are specified in Clause 8.1.2.

A.1.2.2.3 Procedure (see Figure A.6)The air inlet valve test for PVB devices shall be conducted as follows:(a) Remove the atmospheric vent shield and conduct a physical examination of the PVB device to




(c) Connect the hose to test cock 2 and gradually open test cock 2.(d) Bleed the gauge and hoses as follows:

(i) open the high-pressure valve;(ii) bleed the gauge and hoses; and(iii) close the high-pressure valve.

(e) Close shut-off valve 2 and then close shut-off valve 1.(f) Gradually open the high-pressure valve, relieving pressure from the PVB device and being careful not

to drop the reading on the gauge too quickly.





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July 2007 85

(g) Observe and note the gauge reading when the air inlet valve begins to open.(h) Completely open the high-pressure valve to drain the water from the body of the PVB.

(i) If the air inlet valve begins to open before the gauge reading drops below 6.9 kPa and is fully open when the water is completely drained from the body, the test shall be recorded as “opened/passed”.


(i) Close the high-pressure valve, then close test cock 2 and remove the gauge.(j) If the air inlet valve does not open, the gauge reading does not drop, and water continues to

discharge from the low-pressure valve, see Clause A.1.2.2.4.



Test cock 2


Atmosphericvent

Air inletvalve

Check valve

0

1

2

3

4

56 7 8 9

10

11

12

13

14

15

High-pressureinlet

Bypass

Low-pressure inlet

Low-pressurevalve

High-pressurevalve

Differential pressure gauge

Shut-off valve 1

Shield

Hose

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86 July 2007

A.1.2.2.4 Leaking shut-off valves (see Figure A.7)If the high-pressure valve has to be opened more than one-quarter of the fully open position, it is likely that shut-off valve 1 is leaking and the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 1.(b) If the leak persists, divert the leak so that the air inlet valve can be tested.(c) To redirect the leakage from shut-off valve 1, gradually open test cock 1, monitoring the gauge until

its reading stabilizes.(d) Once the leakage has been diverted through test cock 1, testing may be resumed at Item (f) of

Clause A.1.2.2.3.(e) If the air inlet valve does not open and the leak through shut-off valve 1 exceeds the limit of

test cock 1, repair or replace shut-off valve 1 before continuing with the test.



Test cock 2

Test cock 1 Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent

Shut-off valve 1

Shield

0

1

2

3

4

56 7 8 9

10

11

12

13

1415

High-pressureinlet

Bypass

Low-pressure inlet

Low-pressurevalve

High-pressurevalve


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July 2007 87

A.1.2.3 PVB devices — Test No. 2: Check valve test

A.1.2.3.1 PurposeThe purpose of the check valve test is to determine whether the check valve of a PVB device will close tight in the direction of flow.

A.1.2.3.2 RequirementsThe requirements for the check valve test for PVB devices are specified in Clause 8.1.3.

A.1.2.3.3 Procedure (see Figure A.8)The check valve test for PVB devices shall be conducted as follows:(a) Open shut-off valve 1 to re-establish pressure in the PVB device.(b) Connect the hose to test cock 1 and gradually open test cock 1.(c) Open the high-pressure valve and bleed the gauge and hose. Close the high-pressure valve.(d) Close shut-off valve 1 (shut-off valve 2 should still be closed from the air inlet valve test).(e) Open test cock 2, reducing the downstream side of the check valve to atmospheric pressure.(f) When the water stops flowing from test cock 2,

(i) if the gauge reading has stabilized at 6.9 kPa or greater, record that the check valve “closed tight/passed”;

(ii) if the gauge reading drops to 0 kPa or stabilizes at less than 6.9 kPa, record that the check valve “leaked/failed”; or

(iii) if water continues to flow from test cock 2, see Clause A.1.2.3.4.(g) Close test cocks 1 and 2 and remove the gauge.(h) Open shut-off valve 1, then open shut-off valve 2.(i) Reinstall the atmospheric vent shield.



Test cock 2


Air inletvalve

Check valve

0

1

2

3

4

56 7 8 9

10

11

12

13

14

15

High-pressureinlet

Bypass

Low-pressure inlet

Low-pressurevalve

High-pressurevalve

Atmosphericvent


Shut-off valve 1

Hose

Shield

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88 July 2007

A.1.2.3.4 Leaking shut-off valves (see Figure A.9)If water continues to flow from test cock 2 during Item (e) of Clause A.1.2.3.3, shut-off valve 1 is leaking and the following procedure shall be used:(a) Close test cock 1 and remove the hose from the gauge.(b) Connect the bleed valve to test cock 1 and reconnect the hose.(c) Open test cock 1 (test cock 2 should still be open from the check valve test).(d) Gradually open the bleed valve until the water flow from test cock 2 is reduced to a slight drip.(e) Observe the reading on the gauge as the static pressure drop across the check valve decreases.(f) If the water flow ceases through test cock 2, and if the gauge reading has stabilized at 6.9 kPa or

greater, record that the check valve “closed tight”.(g) If the water flow from test cock 2 cannot be eliminated by opening the bleed valve, do not attempt to

determine the tightness of the check valve until shut-off valve 1 is repaired or replaced.



Test cock 2

Test cock 1

Shut-off valve 2

Air inletvalve

Check valve

0

1

2

3

4

56 7 8 9

10

11

12

13

14

15

High-pressureinlet

Bypass

Low-pressure inlet

Low-pressurevalve

High-pressurevalve

Bleedvalve

Atmosphericvent


Shut-off valve 1Hose

Shield

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July 2007 89

A.1.2.4 PVB devices — Test No. 3: Static line pressure

A.1.2.4.1 PurposeThe purpose of the static line pressure test is to determine the static inlet line pressure upstream of the check valve of a PVB device.

A.1.2.4.2 RequirementsThe requirements for the static line pressure test for PVB devices are specified in Clause 8.1.4.

A.1.2.4.3 Procedure (see Figure A.10)The static line pressure test for PVB devices shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge to remove the air.(c) Observe the pressure reading and record it on the test report form. If the static inlet line pressure at

the time of test is not recorded on the test report form, record the test result as “failed”.(d) Close test cock 1 and remove the gauge.



010

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Test cock 2


Atmosphericvent

Check valve

Air inletvalve

Pressure gauge

Shut-off valve 1

Shield

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90 July 2007

A.1.2.5 Returning PVB devices to serviceAfter completing the tests specified in Clauses A.1.2.2 to A.1.2.4, PVB devices shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the PVB device for leaks.(e) Inform the regulatory authority in charge that the water supply is ready to be turned on.(f) Open shut-off valve 2, putting the PVB device back into service.

A.2 PVB devices — Field testing using the sight tube method

A.2.1 Equipment required

A.2.2 PVB devices — Test No. 1: Air inlet valve test

A.2.2.1 PurposeThe purpose of the air inlet valve test is to test the operation of the air inlet valve of a PVB device.

A.2.2.2 RequirementsThe requirements for the air inlet valve test for PVB devices are specified in Clause 8.1.2.

A.2.2.3 Procedure (see Figure A.11)The air inlet valve test for PVB devices shall be conducted as follows:(a) Remove the atmospheric vent shield and conduct a physical examination of the PVB device to




(c) Install the sight tube on test cock 2.(d) Open test cock 2, fill the sight tube to within 50 mm of the top (865 mm above the centreline of the

air inlet valve seat), and then close test cock 2.(e) Mark the sight tube at 711 mm (equivalent to 6.9 kPa) above the centreline of the air inlet valve seat.(f) Close shut-off valve 2, then shut-off valve 1, and wait for 2 min.(g) If the air inlet valve opens at this time, it is an indication that shut-off valve 2 is leaking and should be

repaired if the test cannot be continued.


1 Clear plastic tube (NPS-3/4 ID recommended) 900 mm long, complete with the necessary brass fittings and drain valve to allow it to be attached to a NPS-1/8 or NPS-1/4 female fitting

2 NPS-1/4 IP to NPS-1/4 flare adapters


2 Adapter fittings for each test cock, NPS-1/8 or NPS-1/4 female fitting


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July 2007 91

(h) Open test cock 2, and if the air inlet valve does not open at this time, gradually open the drain valve to drain the water from the sight tube.

(i) Watch the changing water level in the sight tube and observe when the air inlet valve opens.(j) If the air inlet valve

(i) begins to open at or above the 711 mm mark and is fully open when the water drains from the body, record the test as “opened”; or

(ii) opens below the 711 mm mark, record the test as “failed to open/failed”.(k) Close test cock 2 and remove the sight tube.(l) If the air inlet valve does not open when test cock 2 and the drain valve are open and water continues

to be discharged through the drain valve, or water continues to rise in the sight tube, shut-off valve 1 could be leaking. See Figure A.12 and Clause A.2.2.4.


(See Clause A.2.2.3.)

711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Atmosphericport

Air inletvalve

Check valve

Drain valve

Sight tube

Shield

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92 July 2007

A.2.2.4 Leaking shut-off valves (see Figure A.12)If the conditions described in Item (l) of Clause A.2.2.3 occur, the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 1.(b) If the leak persists, divert the leak so that the air inlet valve can be tested.(c) To redirect the leakage from shut-off valve 1, gradually open test cock 1, monitoring and maintaining

the water level in the sight tube.(d) Once the leakage has been diverted through test cock 1, resume testing at Item (e) of Clause A.2.2.3.(e) If the leak through shut-off valve 1 exceeds the limit of the test cock 1, repair or replace shut-off

valve 1 before continuing with the test.



711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Atmosphericvent

Air intakevalve

Check valve

Sight tube

Shield

Drain valve

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July 2007 93

A.2.3 PVB devices — Test No. 2: Check valve test

A.2.3.1 PurposeThe purpose of the check valve test is to determine whether the check valve of a PVB device will close tight in the direction of flow.

A.2.3.2 RequirementsThe requirements for the check valve test for PVB devices are specified in Clause 8.1.3.

A.2.3.3 Procedure (see Figure A.13)The check valve test for PVB devices shall be conducted as follows:(a) Open shut-off valve 1 to re-establish pressure in the PVB device.(b) Connect the sight tube to test cock 1.(c) Open test cock 1 and fill the sight tube to a minimum height of 711 mm above test cock 2, then

close test cock 1.(d) Close shut-off valve 1.(e) Open test cock 2, reducing the downstream side of the check valve to atmospheric pressure.(f) If water continues to flow from test cock 2, see Clause A.2.3.4.(g) Open test cock 1.(h) Observe the water level in the sight tube.

(i) If the water level in the sight tube holds steady at or higher than the 711 mm mark for a period of 2 min, record that the check valve “closed tight” in the direction of flow.

(ii) If the water level is not maintained at 711 mm, record that the check valve “leaked/failed” in the direction of flow.

(iii) If the sight tube is filled to a height greater than 711 mm above test cock 2 and the water level in the sight tube drops, do not record that the check valve failed in the direction of flow until the water level drops below 711 mm. The water level should first be lowered to the 711 mm mark. If it continues to drop, record that the check valve “leaked/failed”.

(iv) If the water level in the sight tube holds at 711 mm, record that the check valve “closed tight”.(i) Record the test results on the test report form.(j) Close test cocks 1 and 2, remove the sight tube, and reinstall the atmospheric vent shield.

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94 July 2007



711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent

Sight tube

Shield

Drain valve

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July 2007 95

A.2.3.4 Leaking shut-off valves (see Figure A.14)If water continues to flow from test cock 2 during Item (e) of Clause A.2.3.3, shut-off valve 1 is leaking and the procedure below shall be followed:(a) Open test cock 1 (test cock 2 should still be open from the check valve test).(b) Gradually open the drain valve until the water flow from test cock 2 is reduced to a slight drip.(c) Observe and maintain the water level in the sight tube (a minimum height of 711 mm above test

cock 2).(d) Once the leakage has been diverted through test cock 1, resume testing at Item (e) of Clause A.2.3.3.(e) If the leak through shut-off valve 1 exceeds the limit of test cock 1, then repair or replace shut-off

valve 1 before continuing with the test.



711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Air inletvalve

Check valve

Atmosphericvent

Sight tube

Shield

Drainvalve

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96 July 2007

A.2.4 PVB devices — Test No. 3: Static line pressure test

A.2.4.1 PurposeThe purpose of the static line pressure test is to determine the static inlet line pressure upstream of the check valve of a PVB device.

A.2.4.2 RequirementsThe requirements for the static line pressure test for PVB devices are specified in Clause 8.1.4.

A.2.4.3 Procedure (see Figure A.15)The static line pressure test for PVB devices shall be conducted as follows:(a) Open shut-off valve 1 to re-establish pressure in the valve.(b) Connect the pressure gauge to test cock 1.(c) Open test cock 1 and bleed the pressure gauge to remove the air.(d) Observe and record the pressure reading on the test report form.(e) If the static inlet line pressure at time of test is not recorded on the test report form, record this test as

“failed”.(f) Close test cock 1 and remove the pressure gauge.



010

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5060

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90100

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Atmosphericvent

Check valve

Pressure gauge

Air inletvalve

Hose

Shield

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July 2007 97

A.2.5 Returning PVB devices to serviceAfter completing the tests specified in Clauses A.2.2 to A.2.4, PVB devices shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the PVB device for leaks.(e) Inform the regulatory authority that the water supply is ready to be turned on.(f) Open shut-off valve 2, putting the PVB device back into service.

A.3 RP backflow preventers — Field testing using a differential pressure gauge

A.3.1 RP backflow preventers — Testing procedures using a 3-valve differential pressure gauge


The procedures specified in Clauses A.3.1.2 to A.3.1.4 shall be conducted using a 3-valve differential pressure gauge.

A.3.1.2 RP backflow preventers — Test No. 1: Relief valve test

A.3.1.2.1 PurposeThe purpose of the relief valve test for RP backflow preventers is to test the operation of the relief valve and determine the pressure at which it will open.

A.3.1.2.2 RequirementsThe requirements for the relief valve test for RP backflow preventers are specified in Clause 8.2.2.

A.3.1.2.3 Procedure (see Figure A.16)The relief valve test for RP backflow preventers shall be conducted as follows:(a) Open test cock 4 to ensure flow through the RP backflow preventer. Next,

(i) gradually open, flush, and gradually close each test cock, starting with test cock 1, then 2, and then 3, to remove any foreign material; and

(ii) gradually close test cock 4.Notes: (1) Do not stand directly in front of the test cocks when turning them on or off; foreign material may be discharged


(b) Connect the high-pressure hose to test cock 2.(c) Connect the low-pressure hose to test cock 3.(d) Open the bypass valve, gradually open test cock 3, then open the low-pressure valve and bleed the

low-pressure side of the gauge (leave it discharging while proceeding to Item (e)).




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98 July 2007

(e) Bleed the high-pressure side of the gauge as follows:(i) gradually open test cock 2;(ii) open the high-pressure valve;(iii) bleed the high-pressure side of the gauge;(iv) close the high-pressure valve;(v) close the low-pressure valve; and(vi) close the bypass valve.Note: When performing these procedures, it is important that the tester does not cause the relief valve to discharge before Item (e)(vi).

(f) Close shut-off valve 2 and observe the gauge reading. If the reading drops very low and the relief valve begins to discharge continuously, check whether valve 1 is leaking. Repair the valve before proceeding.Note: This reading will be referenced as the “apparent reading”.

(g) Open the high-pressure valve; then slightly open (one-quarter of the fully open position or less) the low-pressure valve, bypassing water from the high-pressure side of the gauge through test cock 3 into the reduced pressure zone until the gauge reading begins to drop (it is important that the rate of drop be gradual).

(h) Hold one hand below the relief port and observe the gauge reading drop. Record the pressure at which water starts to be discharged from the relief port.(i) If the gauge reading is 13.8 kPa or higher, record that the relief valve “opened” and record the

gauge reading at the opening point.(ii) If the gauge reading is lower than 13.8 kPa, record that the relief valve “failed to open” at the

required pressure.(iii) If the relief valve does not open after bypassing water from the high-pressure to the low-pressure

side, it could indicate that either the relief valve is faulty or shut-off valve 2 is leaking.(1) If the relief valve is faulty, the differential pressure will drop to 0 kPa.(2) If shut-off valve 2 is leaking, the low-pressure valve will have to be opened more than

one-quarter of the fully open position to decrease the gauge reading to the opening pressure of the relief valve. In this case, see Clause A.3.1.2.4.

(i) Close the high- and low-pressure valves.Note: If wide line pressure fluctuations are observed during this test, shut-off valve 1 may have to be closed before proceeding with the test. Open shut-off valve 1 upon completion of the test.

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July 2007 99

Figure A.16RP backflow preventers — Test No. 1: Relief valve test


A.3.1.2.4 Leaking shut-off valvesIf the low-pressure valve needs to be opened more than one-quarter of the fully open position to decrease the gauge reading to the opening pressure of the relief valve, shut-off valve 2 could be leaking and the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 2.(b) If the gauge reading does not drop to the opening pressure of the relief valve, repair or replace

shut-off valve 2.

Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-off valve 1

Checkvalve 2

Shut-off valve 2

Relief valve

0

5 10

15HI LO

Checkvalve 1


Relief port

Bypass valve

Low-pressure valve

Hoses

High-pressure valve

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100 July 2007

A.3.1.3 RP backflow preventers — Test No. 2: Check valve 2 test

A.3.1.3.1 PurposeThe purpose of the check valve 2 test for RP backflow preventers is to determine whether check valve 2 will close tight.

A.3.1.3.2 RequirementsThe requirements for the check valve 2 test for RP backflow preventers are specified in Clause 8.2.4.

A.3.1.3.3 Procedure (see Figure A.17)The check valve 2 test for RP backflow preventers shall be conducted as follows:(a) Open the high-pressure valve and then slightly open the bypass valve to bleed air from the bypass

hose.(b) Connect the bypass hose to test cock 4, close the bypass valve, and then open test cock 4.(c) Slightly unthread the low-pressure hose from test cock 3 and bleed water from the gauge until the

reading is equal to or above the apparent reading (see Item (f) of Clause A.3.1.2.3). Retighten the hose.

(d) Open the bypass valve to allow water to flow from test cock 2 through the bypass and test cock 4 into the RP backflow preventer.

(e) The gauge reading across check valve 1 should remain the same or decrease slightly from the previous reading in test No. 1. Maintain the gauge reading for a period of 2 min.(i) If the pressure differential remains the same, record that check valve 2 “closed tight” in the

reverse direction of flow.(ii) If the pressure differential is not maintained and drops to the relief valve opening pressure, either

check valve 2 is fouled or disc compression has led to the discharge. To determine the cause, use the following procedure:(1) Slightly loosen the low-pressure hose from test cock 3, allowing water to bleed out.(2) Tighten the low-pressure hose to test cock 3.(3) If the relief valve discharges again, record on the test report that check valve 2 “leaked” in

the reverse direction of flow.(4) If, after tightening the low-pressure hose to test cock 3, the gauge reading settles above the

relief valve opening pressure, record that check valve 2 “closed tight” in the reverse direction of flow. It was disc compression that originally caused the relief valve to discharge.

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July 2007 101

Figure A.17RP backflow preventers — Test No. 2: Check valve 2 test


Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-off valve 1

Checkvalve 2

Shut-off valve 2

Relief valve

0

5 10

15HI LO

Checkvalve 1


Relief port

High-pressurevalve Bypass valve

Low-pressure valve

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102 July 2007


A.3.1.4.1 PurposeThe purpose of the check valve 1 test for RP backflow preventers is to determine whether check valve 1 will close tight in the direction of flow, and to record the static pressure drop across check valve 1.

A.3.1.4.2 RequirementsThe requirements for the check valve 1 test for an RP backflow preventer are specified in Clause 8.2.3.

A.3.1.4.3 Procedure (see Figure A.18)The check valve 1 test for an RP backflow preventer shall be conducted as follows:(a) To re-establish the pressure across check valve 1, slightly unthread the low-pressure hose connection

at test cock 3, allowing a small amount of water to bleed, until the gauge reading is equal to or above the apparent check valve 1 reading (see Item (f) of Clause A.3.1.2.3 and Figure A.18). Then retighten the hose connection.

(b) Observe the gauge reading for 2 min or until the reading stabilizes.(c) Record the gauge reading (this reading is the actual static pressure drop across check valve 1).

(i) If the gauge reading remains constant, record that check valve 1 “closed tight” in the direction of flow.

(ii) If the pressure differential reading falls until the relief valve opens, record that check valve 1 “leaked” in the direction of flow.

(d) Calculate the buffer between the static pressure drop across check valve 1 and the opening pressure of the relief valve. The buffer is the static pressure drop across check valve 1, minus the opening pressure of the relief valve.

(e) Record the buffer on the test report form.(i) If the buffer is 20.7 kPa or greater, record the test as “passed”.(ii) If the buffer is less than 20.7 kPa, record the test as “failed”.

(f) Close all test cocks and remove the gauge.

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July 2007 103



Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-off valve 1

Check valve 2

Shut-off valve 2

Relief valve

0

5 10

15HI LO

Check valve 1


Relief port

Bypass valve

Low-pressure valveHigh-pressurevalve

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104 July 2007

A.3.1.5 RP backflow preventers — Test No. 4: Static line pressure test

A.3.1.5.1 PurposeThe purpose of the static line pressure test for RP backflow preventers is to determine the static inlet pressure at the time of the test.

A.3.1.5.2 RequirementsThe requirements for the static line pressure test for RP backflow preventers are specified in Clause 8.2.5.

A.3.1.5.3 Procedure (see Figure A.19)The static line pressure test for RP backflow preventers shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at time of test is not recorded on the test report form, record this test as

“failed”.(e) Close test cock 1, and remove the gauge.

Figure A.19RP backflow preventers — Test No. 4: Static line pressure test


Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-offvalve 1

Check valve 2

Shut-offvalve 2

Relief valve

010

20

3040

5060

7080

90100

Check valve 1

Pressuregauge

Relief port

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July 2007 105

A.3.1.6 Returning RP backflow preventers to serviceAfter completing the tests specified in Clauses A.3.1.2 to A.3.1.5, RP backflow preventers shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the RP backflow preventer for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the RP backflow preventer back into service.

A.3.2 RP backflow preventers — Testing procedures using a 5-valve differential pressure gauge


The test procedures specified in Clauses A.3.2.2 to A.3.2.5 shall be conducted using a 5-valve differential pressure gauge.

A.3.2.2 RP backflow preventers — Test No. 1: Relief valve test

A.3.2.2.1 PurposeThe purpose of the relief valve test for RP backflow preventers is to test the operation of the relief valve and determine the pressure at which it will open.

A.3.2.2.2 RequirementsThe requirements for the relief valve test for RP backflow preventers are specified in Clause 8.2.2.

A.3.2.2.3 Procedure (see Figure A.20)The relief valve test for RP backflow preventers shall be conducted as follows:(a) Open test cock 4 to ensure flow through the RP backflow preventer.

(i) Gradually open, flush, and close each test cock, starting with test cock 1 and finishing with 3, to remove any foreign material.

(ii) Gradually close test cock 4.Notes: (1) Do not stand directly in front of the test cocks when turning them on or off; foreign material may be discharged


(b) Connect the high-pressure hose of the gauge to test cock 2.(c) Connect the low-pressure hose of the gauge to test cock 3.(d) Gradually open test cock 3, then open the low-pressure valve and bleed the low-pressure side of the

gauge (leave it discharging while proceeding to Item (e)).(e) Bleed the high-pressure side of the gauge as follows:

(i) gradually open test cock 2;(ii) open the high-pressure valve;(iii) bleed the high-pressure side of the gauge;(iv) close the high-pressure valve; and




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106 July 2007

(v) close the low-pressure valve.Note: When performing these procedures it is important that the tester does not cause the relief valve to discharge before Item (f).

(f) Close shut-off valve 2 and observe the gauge reading. If the reading drops very low and the relief valve begins to discharge continuously, check whether valve 1 is leaking. Repair the valve before proceeding.Note: This reading will be referenced as the “apparent reading”.

(g) Open the high-pressure valve, then slightly open (one-quarter of the fully open position or less) the low-pressure valve, bypassing water from the high-pressure side of the gauge through test cock 3 into the zone of reduced pressure until the gauge reading begins to drop (it is important that the rate of drop be gradual).

(h) Hold one hand below the relief port and observe the gauge reading drop. Record the gauge reading at the pressure at which water starts to be discharged from the relief port.(i) If the gauge reading is 13.8 kPa or higher, record that the relief valve “opened” and the gauge

reading at the opening point.(ii) If the gauge reading is lower than 13.8 kPa, record that the relief valve “failed to open” at the

required pressure.(iii) If the relief valve does not open after bypassing water from the high-pressure side to the

low-pressure side, it could indicate that either the relief valve is faulty or that shut-off valve 2 is leaking.(1) If the relief valve is faulty, the differential pressure will drop to 0 kPa.(2) If shut-off valve 2 is leaking, the low-pressure valve will have to be more than one-quarter of

the fully open position to lower the gauge reading to the relief valve opening pressure. In this case, see Clause A.3.2.2.4.

(i) Close the high- and low-pressure valves.Note: If wide fluctuations of line pressure are observed during this test, shut-off valve 1 may have to be closed before proceeding with the test. Open shut-off valve 1 upon completion of the test.

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July 2007 107

Figure A.20RP backflow preventers — Test No. 1: Relief valve test


0

1

2

3

4

56 7 8 9

10

11

12

13

1415

High-pressure inlet

Bypassvalve

Low-pressureinlet

Low-pressurevalve

High-pressurevalve

Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-offvalve 1

Checkvalve 2

Shut-offvalve 2

Relief valve

Checkvalve 1

Relief port


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108 July 2007

A.3.2.2.4 Leaking shut-off valvesIf the low-pressure valve needs to be opened more than one-quarter of the fully open position to decrease the gauge reading to the relief valve opening pressure, shut-off valve 2 could be leaking and the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 2.(b) If the gauge reading does not drop to the relief valve opening pressure, repair or replace shut-off

valve 2.


A.3.2.3.1 PurposeThe purpose of the check valve 2 test for RP backflow preventers is to determine whether check valve 2 will close tight.


A.3.2.3.3 Procedure (see Figure A.21)The check valve test No. 2 for RP backflow preventers shall be conducted as follows:(a) Slightly open the bypass valve to bleed air from the bypass hose, then close the bypass valve.(b) Connect the bypass hose to test cock 4 and open test cock 4.(c) Open the low-pressure valve and relieve the excess pressure to re-establish the apparent pressure

drop reading across check valve 1. Close the low-pressure valve.(d) Open the bypass valve to allow water to flow from test cock 2 through the bypass and from

test cock 4 into the valve.(e) The gauge reading across check valve 1 should remain the same or decrease slightly from the

previous reading in test No. 1. Maintain the gauge reading for a period of 2 min.(i) If the pressure differential remains the same, record that check valve 2 “closed tight” in the

reverse direction of flow.(ii) If the pressure differential is not maintained and drops to the relief valve opening pressure, either

check valve 2 is fouled or disc compression has led to the discharge. To determine the cause, use the following procedure:(1) Open the low-pressure valve to allow water to bleed.(2) Close the low-pressure valve.(3) If the relief valve discharges again, record on the test report that check valve 2 “leaked” in

the reverse direction of flow.(4) If, after closing the low-pressure valve, the gauge reading settles above the relief valve

opening pressure, record that check valve 2 “closed tight” in the reverse direction of flow. This indicates that disc compression originally caused the relief valve to discharge.

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July 2007 109




A.3.2.4.1 PurposeThe purpose of the check valve 1 test for RP backflow preventers is to determine whether check valve 1 will close tight in the direction of flow, and to record the static pressure drop across check valve 1.


0

1

2

3

4

56 7 8 9

10

11

12

13

1415

High-pressure inlet

Bypassvalve

Low-pressureinlet

Low-pressurevalveHigh-pressure

valve

Test cock 3 Test cock 4

Test cock 2

Testcock 1

Shut-offvalve 1

Checkvalve 2

Shut-offvalve 2

Relief valveCheckvalve 1

Relief port


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110 July 2007

A.3.2.4.3 Procedure (see Figure A.22)The check valve 1 test for RP backflow preventers shall be conducted as follows:(a) To re-establish the pressure across check valve 1, open the low-pressure valve, allowing a small

amount of water to bleed, until the gauge reading is equal to or above the apparent check valve 1 reading (see Item (g) of Clause A.3.2.2.3). Close the low-pressure valve.

(b) Observe the gauge reading for 2 min or until the reading stabilizes.(c) Record the gauge reading (this reading is the actual static pressure drop across check valve 1).

(i) If the gauge reading remains constant, record that check valve 1 “closed tight” in the direction of flow.

(ii) If the pressure differential reading falls until the relief valve opens, record that check valve 1 “leaked” in the direction of flow.

(d) Calculate the buffer between the static pressure drop across check valve 1 and the opening pressure of the relief valve. The buffer is the static pressure drop across check valve 1 minus the opening pressure of the relief valve.

(e) Record the buffer on the test report form.(i) If the buffer is 20.7 kPa or greater, record the test as “passed”.(ii) If the buffer is less than 20.7 kPa, record the test as “failed”.

(f) Close all test cocks and remove the gauge.

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July 2007 111



0

1

2

3

4

56 7 8 9

10

11

12

13

1415

High-pressure inlet

Bypassvalve

Low-pressureinlet

Low-pressurevalve

High-pressurevalve


Test cock 2

Testcock 1

Shut-offvalve 1

Checkvalve 2

Shut-offvalve 2

Relief valveCheckvalve 1

Relief port


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112 July 2007

A.3.2.5 RP backflow preventers — Test No. 4: Static line pressure

A.3.2.5.1 PurposeThe purpose of the static line pressure test for RP backflow preventers is to determine the static inlet pressure at the time of the test.

A.3.2.5.2 RequirementsThe requirements for the static line pressure test for RP backflow preventers are specified in Clause 8.2.5.

A.3.2.5.3 Procedure (see Figure A.23)The static line pressure test for RP backflow preventers shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at the time of the test is not recorded on the test report form, record

the test as “failed”.(e) Close test cock 1 and remove the gauge.

Figure A.23RP backflow preventers — Test No. 4: Static line pressure test


Test cock 3

Test cock 4

Test cock 2

Testcock 1

Shut-offvalve 1

Check valve 2

Shut-offvalve 2

Relief valve

010

20

3040

5060

7080

90100

Check valve 1

Pressuregauge

Relief port

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July 2007 113

A.3.2.6 Returning the RP backflow preventer to serviceAfter completing the tests specified in Clauses A.3.2.2 to A.3.2.5, RP backflow preventers shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the RP backflow preventer for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the RP backflow preventer back into service.

A.4 DCVA backflow preventers — Testing procedures using the sight tube method

A.4.1 Equipment required

A.4.2 DCVA backflow preventers — Test No. 1: Check valve 1

A.4.2.1 PurposeThe purpose of the check valve 1 test for DCVA backflow preventers is to determine if check valve 1 will close tight in the direction of flow and to measure the static pressure drop across check valve 1.

A.4.2.2 RequirementsThe requirements for the check valve 1 test for DCVA backflow preventers are specified in Clause 8.3.2.

A.4.2.3 Procedure (see Figure A.24)The check valve 1 test for DCVA backflow preventers shall be conducted as follows:(a) Blow out the test cocks to remove any foreign material.



(b) Install the sight tube on test cock 2.(c) Mark the sight tube at 711 mm above the centreline of test cock 3. If test cock 3 is below the

centreline of the DCVA backflow preventer, take the 711 mm measurement from the centreline of the DCVA backflow preventer [see Figure A.24(a)].

(d) Open test cock 2 and fill the sight tube with water to the predetermined mark. Close test cock 2.(e) Close shut-off valve 2, then close shut-off valve 1.


1 Clear plastic tube (NPS-3/4 ID recommended) 900 mm long, complete with the necessary brass fittings and drain valve to allow it to be attached to an NPS-1/8 or NPS-1/4 female fitting

1 NPS-1/2 × 1/4 brass bushing (used for testing NPS-2-1/2 to NPS-4 valves inclusive)

1 NPS-3/4 × 1/4 brass bushing (used for testing NPS-6 and larger valves)

2 NPS-1/4 IP to NPS-1/4 flare adapters

1 Hose with flare adapter ends


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114 July 2007

(f) Open test cock 2, then open test cock 3.(g) Observe the water level in the sight tube.

(i) If the water level in the sight tube holds steady at a height of 711 mm for a period of 2 min, record that check valve 1 “closed tight” in the direction of flow.

(ii) If the water level is not maintained at 711 mm, record that check valve 1 “leaked/failed” in the direction of flow.

(iii) If the sight tube is filled to a level higher than 711 mm and the water level drops, do not record that check valve 1 “leaked/failed” in the direction of flow until the water level in the sight tube drops below the 711 mm mark.

(iv) If the water level drops below the 711 mm mark, record that check valve 1 “leaked/failed” in the direction of flow.

(v) If the water level in the sight tube rises, it indicates that shutoff valve 1 is leaking. Repair the shut-off valve before proceeding with the test.

(h) Close test cock 3, close test cock 2, and then remove the sight tube.Note: Figures A.24(a) and (b) illustrate alternative methods of measurement depending on the test cock location.

(a) Test cocks located on the centreline

Figure A.24DCVA backflow preventers — Test No. 1: Check valve 1 test

(See Clause A.4.2.3.)(Continued)

711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2

Check valve 1


Check valve 2

Sight tube

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July 2007 115

Figure A.24 (Concluded)

A.4.3 DCVA backflow preventers — Test No. 2: Check valve 2 test

A.4.3.1 PurposeThe purpose of the check valve 2 test for DCVA backflow preventers is to determine if check valve 2 will close tight in the direction of flow and to measure the static pressure drop across check valve 2.

A.4.3.2 RequirementsThe requirements for the check valve 2 test for DCVA backflow preventers are specified in Clause 8.3.3.

A.4.3.3 Procedure (see Figure A.25)The check valve 2 test for DCVA backflow preventers shall be conducted as follows:(a) Install the sight tube on test cock 3.(b) Mark the sight tube at 711 mm above the opening of test cock 4. If the downstream test cock is

below the centreline of the DCVA backflow preventer, the 711 mm measurement shall be taken from the centreline of the DCVA backflow preventer [see Figure A.25(a)].

(c) Open shut-off valve 1, then open test cock 3 and fill the sight tube with water to the 711 mm mark. Close test cock 3.

(d) Close shut-off valve 1.(e) Open test cock 3, then open test cock 4.

711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2Check valve 1

Test cock 3Test cock 4

Check valve 2

Sight tube

(b) Test cocks located above the centreline

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116 July 2007

(f) Observe the water level in the sight tube.(i) If the water level in the sight tube holds steady at a height of 711 mm for a period of 2 min,

record that check valve 2 “closed tight” in the direction of flow.(ii) If the water level is not maintained at a height of 711 mm, record that check valve 2

“leaked/failed” in the direction of flow.(iii) If the sight tube is filled to a level higher than 711 mm and the water level drops, do not record

that check valve 2 “leaked/failed” in the direction of flow until the water level in the sight tube drops below the 711 mm mark.

(iv) If the water level does drop below the 711 mm mark, record that check valve 2 “leaked/failed” in the direction of flow.

(v) A continuous discharge of water from test cock 4, while the water level in the sight tube remains constant, indicates that shut-off valve 2 is leaking. This will only occur if there is back pressure in the piping system. Repair shut-off valve 2 before proceeding with the test.

(g) Close test cock 4, close test cock 3, then remove the sight tube.Note: Figures A.25(a) and (b) illustrate alternative methods of measurement depending on the test cock location.


(See Clause A.4.3.3.)(Continued)

711 mm

Test cock 2

Test cock 1

Shut-off valve 1

Shut-off valve 2Check valve 1 Test cock 3 Test cock 4

Check valve 2

Sight tube

(a) Test cocks located on the centreline

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July 2007 117

Figure A.25 (Concluded)

A.4.4 DCVA backflow preventers — Test No. 3: Static line pressure test

A.4.4.1 PurposeThe purpose of the static line pressure test for DCVA backflow preventers is to determine the static inlet pressure at the time of the test.

A.4.4.2 RequirementsThe requirements for the static line pressure test for DCVA backflow preventers are specified in Clause 8.3.4.

A.4.4.3 Procedure (see Figure A.26)The static line pressure test for DCVA backflow preventers shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at the time of test is not recorded on the test report form, record the

test as “failed”.(e) Close test cock 1 and remove the gauge.

711 mm

Test cock 2


Shut-off valve 2Check valve 1


Check valve 2

Sight tube

(b) Test cocks located above the centreline

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118 July 2007

Figure A.26DCVA backflow preventers — Test No. 3: Static line pressure test


A.4.5 Returning DCVA backflow preventers to serviceAfter completing the tests specified in Clauses A.4.2 to A.4.4, DCVA backflow preventers shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the DCVA backflow preventer for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the DCVA backflow preventer back into service.

010

20

3040

5060

7080

90100 Test cock 2

Test cock 1Shut-offvalve 1

Shut-offvalve 2

Check valve 1


Check valve 2

Pressuregauge

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July 2007 119

A.5 DCVA backflow preventers — Field testing of DCVA backflow preventers using a differential pressure gauge

A.5.1 DCVA backflow preventers — Testing procedures using a 3-valve differential pressure gauge


The tests specified in Clauses A.5.1.2 to A.5.1.4 shall be conducted using a 3-valve differential pressure gauge. To avoid damage to the gauge, it shall be gradually pressurized when using only one side of the gauge. To obtain accurate readings, the gauge and hoses (including hoses not used) shall be held at the same level as the DCVA backflow preventer being tested.

A.5.1.2 DCVA backflow preventers — Test No. 1: Check valve 1 test for DCVA backflow preventers

A.5.1.2.1 PurposeThe purpose of the check valve 1 test for DCVA backflow preventers is to determine whether check valve 1 will close tight in the direction of flow and to measure the static pressure drop across check valve 1.

A.5.1.2.2 RequirementsThe requirements for the check valve 1 test for DCVA backflow preventers are specified in Clause 8.3.2.

A.5.1.2.3 Procedure (see Figure A.27)The check valve 1 test for DCVA backflow preventers shall be conducted as follows:(a) Blow out the test cocks to remove any foreign material.



(b) To obtain proper readings from the pressure gauge, locate it at the same elevation or level as the test cock downstream of check valve 1 (test cock 3).(i) If test cock 3 is the highest point of check valve 1, the top of test cock 3 can be used as a

reference point; advance to Item (c).(ii) If test cock 3 is not the highest point of check valve 1, install a vertical tube on test cock 3 so that

it rises above the DCVA backflow preventer.(c) Install the bleed valve on test cock 2. Then

(i) connect the high-pressure hose to the bleed valve;(ii) gradually open test cock 2;(iii) open the high-pressure valve;(iv) open the low-pressure valve;



1 Clear plastic tube (NPS-3/4 ID is recommended) 900 mm long, complete with the necessary brass fittings and drain valve to allow it to be attached to an NPS-1/8 or NPS-1/4 female fitting

1 Pressure gauge with range of either 0 to 420 kPa, 0 to 700 kPa, or 0 to 1120 kPa, depending on the maximum line pressure


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120 July 2007

(v) bleed the high-pressure side of the gauge;(vi) close the low-pressure valve; and(vii) close the high-pressure valve.

(d) If the vertical tube is attached, open test cock 3 and fill the tube to the elevation that is level with the centreline of the gauge, then close test cock 3.

(e) Close shut-off valve 2, then close shut-off valve 1.(f) Gradually open test cock 3; after water stops discharging from test cock 3 and the gauge stabilizes,

observe the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record the value and that check valve 1 “closed tight”.(ii) If the gauge reading stabilizes at less than 6.9 kPa, record that check valve 1 “leaked/failed”.

(g) Close all test cocks, open shut-off valve 1, and remove the gauge.


(See Clauses A.5.1.2.3 and A.5.1.2.4.)

A.5.1.2.4 Leaking shut-off valves (see Figure A.27)

A.5.1.2.4.1 Leaking shut-off valve 2 (with no pressure downstream)If the water recedes (in the vertical tube) through test cock 3, lower the centreline of the gauge to the centreline of the DCVA backflow preventer and observe and record the gauge reading as follows:(a) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(b) If the reading stabilizes at less than 6.9 kPa, record that

(i) check valve 1 “leaked”;(ii) shut-off valve 2 “leaked”; and(iii) check valve 2 “leaked”.

0

5 10

15HI LO

Test cock 2

Test cock 1

Shut-off valve 1 Shut-off valve 2Check valve 1

Test cock 3

Test cock 4

Check valve 2Bleed valve

Water levelto centrelineof gauge


Vertical tube

High-pressure valve

Low-pressurevalve

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July 2007 121

(c) Advance to Item (f) of Clause A.5.1.2.3.

A.5.1.2.4.2 Leaking shut-off valves 1 and 2 (with pressure downstream)If the water rises (in the vertical tube) through test cock 3, one of the shut-off valves could be leaking. Observe and note the gauge reading and use the following procedure:(a) Gradually open the bleed valve.(b) If water continues to flow through the bleed valve, and the bleed valve can be adjusted so there is

only a slight rise (in the vertical tube) or a drip through test cock 3, observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(ii) If the reading stabilizes at less than 6.9 kPa, record that

(1) check valve 1 “leaked/failed”; and (2) shut-off valve 1 “leaked”.

(c) If the water flow cannot be reduced sufficiently, repair or replace shut-off valve 1 before proceeding.(d) If water does not continue to flow through the bleed valve, yet continues to flow through test cock 3,

observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(ii) If the reading stabilizes at less than 6.9 kPa, record that

(1) check valve 1 “leaked/failed”;(2) shut-off valve 2 “leaked”; and(3) check valve 2 “leaked”.

(e) Advance to Item (f) of Clause A.5.1.2.3.

A.5.1.3 DCVA backflow preventers — Test No. 2: Check valve 2 test



A.5.1.3.3 Procedure (see Figure A.28)The check valve 2 test for DCVA backflow preventers shall be conducted as follows:(a) To obtain proper readings from the gauge, locate it at the same elevation or level as the test cock

downstream of check valve 2 (test cock 4).(i) If test cock 4 is the highest point of check valve 2, use the top of test cock 4 as a reference point,

and advance to Item (b).(ii) If test cock 4 is not the highest point of check valve 2, install a vertical tube on test cock 4 so that

it rises above the body of the DCVA backflow preventer.(b) Install the bleed valve on test cock 3. Then

(i) connect the high-pressure hose to the bleed valve;(ii) gradually open test cock 3;(iii) open the high-pressure valve;(iv) open the low-pressure valve;(v) bleed the high-pressure side of the gauge;(vi) close the low-pressure valve; and(vii) close the high-pressure valve.

(c) If the tube is attached, open test cock 4 and fill the tube to an elevation that is level with the centreline of the gauge; then close test cock 4.

(d) With shut-off valve 2 still closed, close shut-off valve 1.

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122 July 2007

(e) Gradually open test cock 4; after water stops discharging from test cock 4 and the gauge stabilizes, observe the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record the value of the reading and that check valve 2 “closed

tight”.(ii) If the gauge reading stabilizes at less than 6.9 kPa, record that check valve 2 “leaked/failed”.

(f) Close all test cocks, open shut-off valve 1, and remove the gauge.




A.5.1.3.4.1 Leaking shut-off valve 2 (with no pressure downstream)If the water recedes (in the vertical tube) or flows through test cock 4, lower the centreline of the gauge to the centreline of the DCVA backflow preventer and observe and record the gauge reading as follows:(a) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(b) If the gauge reading stabilizes at less than 6.9 kPa, record that check valve 1 “leaked/failed” and

shut-off valve 2 “leaked”.


0

5 10

15HI LO

Test cock 2

Test cock 1


Test cock 3

Test cock 4

Check valve 2

Bleed valve


Vertical tube

Low-pressurevalve

High-pressure valve

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A.5.1.3.4.2 Leaking shut-off valves 1 and 2 (with pressure downstream)If the water rises (in the vertical tube) or flows through test cock 4, one of the shut-off valves could be leaking. Observe and note the gauge reading and use the following procedure:(a) Gradually open the bleed valve.(b) If water continues to flow through the bleed valve, and the bleed valve can be adjusted so that there

is only a slight rise (in the vertical tube) or a drip through test cock 4, observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 2 “closed tight”.(ii) If the reading stabilizes at less than 6.9 kPa, record that check valve 2 “leaked/failed” and

shut-off valve 1 “leaked”.(c) If water does not continue to flow through the bleed valve, yet continues to flow through test cock 4,

observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 2 “closed tight”.(ii) If the reading is less than 6.9 kPa, record that check valve 2 “leaked/failed” and shut-off valve 2

“leaked”.

A.5.1.4 DCVA backflow preventers — Test No. 3: Static line pressure test

A.5.1.4.1 PurposeThe purpose of the static line pressure test for DCVA backflow preventers is to determine the static inlet pressure at the time of the test.

A.5.1.4.2 RequirementsThe requirements for the static line pressure test for DCVA backflow preventers are specified in Clause 8.3.4.

A.5.1.4.3 Procedure (see Figure A.29)The static line pressure test for DCVA backflow preventers shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at time of test is not recorded on the test report form, record the test as

“failed”.(e) Close test cock 1 and remove the gauge.

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124 July 2007

Figure A.29DCVA backflow preventers — Test No. 3: Static line pressure test


A.5.1.5 Returning DCVA backflow preventers to serviceAfter completing the tests specified in Clauses A.5.1.2 to A.5.1.4, DCVA backflow preventers shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the DCVA backflow preventer for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the DCVA backflow preventer back into service.

A.5.2 DCVA backflow preventers — Testing procedures using a 5-valve differential pressure gauge


The tests specified in Clauses A.5.2.2 to A.5.2.5 shall be conducted using a 5-valve differential pressure gauge. To avoid damage to the gauge, it shall be gradually pressurized when using only one side of the gauge. To obtain accurate readings, the gauge and hoses (including hoses not used) shall be removed or held at the same level as the DCVA backflow preventer being tested.


1 Clear plastic tube (NPS-3/4 ID is recommended) 900 mm long, complete with the necessary brass fittings and drain valve to allow it to be attached to an NPS-1/8 or NPS-1/4 female fitting




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Check valve 1


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A.5.2.2.3 Procedure (see Figure A.30)The check valve 1 test for DCVA backflow preventers shall be conducted as follows:(a) Blow out the test cocks to remove any foreign material.



(b) To obtain proper readings from the pressure gauge, locate it at the same elevation or level as the test cock downstream of check valve 1 (test cock 3).(i) If test cock 3 is the highest point of check valve 1, the top of test cock 3 can be used as a

reference point; advance to Item (c).(ii) If test cock 3 is not the highest point of check valve 1, install a vertical tube on test cock 3 so that

it rises above the DCVA backflow preventer.(c) Install the bleed valve on test cock 2 as follows:

(i) connect the high-pressure hose to the bleed valve;(ii) gradually open test cock 2;(iii) open the high-pressure valve;(iv) bleed the high-pressure side of the gauge; and(v) close the high-pressure valve.

(d) If the tube is attached, open test cock 3 and fill the tube to an elevation that is level with the centreline of the gauge; then close test cock 3.

(e) Close shut-off valve 2, then close shut-off valve 1.(f) Gradually open test cock 3; after water stops discharging from test cock 3 and the gauge stabilizes,

observe the reading as follows:(i) If the reading is 6.9 kPa or greater, record the value and record that check valve 1 “closed tight”.(ii) If the gauge reading stabilizes at less than 6.9 kPa, record that check valve 1 “leaked/failed”.

(g) Close all test cocks, open shut-off valve 1, and remove the gauge.

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A.5.2.2.4.1 Leaking shut-off valve 2 (with no pressure downstream)If the water recedes (in the vertical tube) through test cock 3, lower the centreline of the gauge to the centreline of the DCVA backflow preventer and observe and record the gauge reading as follows:(a) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(b) If the reading stabilizes at less than 6.9 kPa, record that

(i) check valve 1 “leaked”;(ii) shut-off valve 2 “leaked”; and(iii) check valve 2 “leaked”.

(c) Advance to Item (f) of Clause A.5.2.2.3.

A.5.2.2.4.2 Leaking shut-off valves 1 and 2 (with pressure downstream)If the water rises (in the vertical tube) through test cock 3, one of the shut-off valves could be leaking. Observe and note the gauge reading and use the following procedure:(a) Gradually open the bleed valve.(b) If water continues to flow through the bleed valve and it can be adjusted so there is only a slight rise

(in the vertical tube) or a drip through test cock 3, observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.

Test cock 2

Test cock 1


Test cock 3

Test cock 4

Check valve 2Bleed valve


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(ii) If the reading stabilizes at less than 6.9 kPa, record that check valve 1 “leaked/failed” and shut-off valve 1 “leaked”.

(c) If the water flow cannot be sufficiently reduced, repair or replace shut-off valve 1 before proceeding.(d) If water does not continue to flow through the bleed valve, yet continues to flow through test cock 3,

observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(ii) If the reading stabilizes at less than 6.9 kPa, record that

(1) check valve 1 “leaked/failed”;(2) shut-off valve 2 “leaked”; and(3) check valve 2 “leaked”.

(e) Advance to Item (f) of Clause A.5.2.2.3.




A.5.2.3.3 Procedure (see Figure A.31)The check valve 1 test for DCVA backflow preventers shall be conducted as follows:(a) To obtain proper readings from the pressure gauge, locate it at the same elevation or level as the test

cock downstream of check valve 2 (test cock 4).(i) If test cock 4 is the highest point of check valve 2, use the top of test cock 4 as a reference point;

advance to Item (b).(ii) If test cock 4 is not the highest point of check valve 2, install a vertical tube on test cock 4 so that

it rises above the DCVA backflow preventer.(b) Install the bleed valve on test cock 3, then

(i) connect the high-pressure hose to the bleed valve;(ii) gradually open test cock 3;(iii) open the high-pressure valve;(iv) bleed the high-pressure side of the gauge; and(v) close the high-pressure valve.

(c) If the vertical tube is attached, open test cock 4 and fill the tube to an elevation that is level with the centreline of the gauge; then close test cock 4.

(d) With shut-off valve 2 still closed, close shut-off valve 1.(e) Gradually open test cock 4; after water stops discharging from test cock 4 and the gauge stabilizes,

observe the reading as follows:(i) If the reading is 6.9 kPa or greater, record the value of the reading and that check valve 2 “closed

tight”.(ii) If the gauge reading stabilizes at less than 6.9 kPa, record that check valve 2 “leaked/failed”.

(f) Close all test cocks, open shut-off valve 1, and remove the gauge.

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128 July 2007




A.5.2.3.4.1 Leaking shut-off valve 2 (with no pressure downstream)If the water recedes (in the vertical tube) or flows through test cock 4, lower the centreline of the gauge to the centreline of the DCVA backflow preventer and observe and record the gauge reading as follows:(a) If the reading is 6.9 kPa or greater, record that check valve 1 “closed tight”.(b) If the reading stabilizes at less than 6.9 kPa, record that check valve 1 “leaked/failed” and shut-off

valve 2 “leaked”.

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Low-pressurevalve

High-pressurevalve


Test cock 2

Test cock 1Shut-offvalve 1

Shut-offvalve 2

Check valve 1


Check valve 2

Bleed valve Bypass valve

Low-pressureinlet


Vertical tube

Hoses

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A.5.2.3.4.2 Leaking shut-off valves 1 and 2 (with pressure downstream)If the water rises (in the vertical tube) or flows through test cock 4, one of the shut-off valves could be leaking. Observe and note the gauge reading, and use the following procedure:(a) Gradually open the bleed valve.(b) If water continues to flow through the bleed valve and it can be adjusted so there is only a slight rise

(in the vertical tube) or a drip through test cock 4, observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 2 “closed tight”.(ii) If the reading stabilizes at less than 6.9 kPa, record that check valve 2 “leaked/failed” and

shut-off valve 1 “leaked”.(c) If water does not continue to flow through the bleed valve and yet continues to flow through test

cock 4, observe and record the gauge reading as follows:(i) If the reading is 6.9 kPa or greater, record that check valve 2 “closed tight”.(ii) If the reading is less than 6.9 kPa, record that check valve 2 “leaked/failed” and shut-off valve 2

“leaked”.

A.5.2.4 DCVA backflow preventers — Test No. 3: Static line pressure test

A.5.2.4.1 PurposeThe purpose of the static line pressure test for DCVA backflow preventers is to determine the static inlet pressure at the time of the test.

A.5.2.4.2 RequirementsThe requirements for the static line pressure test for DCVA backflow preventers are specified in Clause 8.3.4.

A.5.2.4.3 Procedure (see Figure A.32)The static line pressure test for DCVA backflow preventers shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge.(c) Observe and record the pressure reading on the test report form.(d) If the static inlet line pressure at the time of test is not recorded on the test report form, record the

test as “failed”.(e) Close test cock 1 and remove the gauge.

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Figure A.32DCVA backflow preventers — Test No. 3 — Static line pressure test


A.5.2.5 Returning DCVA backflow preventers to serviceAfter completing the tests specified in Clauses A.5.2.2 to A.5.2.4, DCVA backflow preventers shall be returned to service as follows:(a) Close all test cocks.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the DCVA backflow preventer for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the DCVA backflow preventer back into service.

A.6 SRPVB devices — Field testing using a 3-valve differential pressure gauge

A.6.1 Equipment required — 3-valve differential pressure gauge

The tests specified in Clauses A.6.2 and A.6.3 shall be conducted using a 3-valve differential pressure gauge. During the tests, the gauge shall be held at the same level as the SRPVB device being tested, as illustrated in Figure A.33. To avoid damage to the gauge, it shall be gradually pressurized when using only one side of the gauge. The gauge and hoses (including hoses not used) shall be held at the same level as the SRPVB being tested.





Test cock 2

Test cock 1

Shut-off valve 1

Shut-offvalve 2Check valve 1


Check valve 2

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A.6.2 SRPVB devices — Test No. 1: Air inlet valve test

A.6.2.1 PurposeThe purpose of the air inlet valve test is to test the operation of the air inlet valve of SRPVB devices.

A.6.2.2 RequirementsThe requirements for the air inlet valve test for SRPVB devices are specified in Clause 8.5.2.

A.6.2.3 Procedure (see Figure A.33)The air inlet valve test for SRPVB devices shall be conducted as follows:(a) Remove the air atmospheric vent shield and conduct a physical examination of the SRPVB device to

determine the condition of the air inlet valve and atmospheric vent.(b) Blow out the test cock and the bleeder to remove any foreign material.

Notes: (1) Do not stand directly in front of the test cock when turning it on or off; foreign material may be discharged or the

test cock may blow off, inflicting injury.(2) It is strongly recommended that safety glasses be worn to protect the eyes.

(c) Connect the high-pressure hose to the test cock and gradually open the bleeder.(d) Bleed the gauge and hoses as follows:

(i) open the high-pressure valve;(ii) open the low-pressure valve;(iii) bleed the gauge and hoses; and(iv) close the low-pressure valve.

(e) Close shut-off valve 2, then close shut-off valve 1.(f) Gradually open the bleeder and relieve pressure from the SRPVB device, being careful not to drop the

reading on the gauge too quickly.(g) Observe and note the gauge reading when the air inlet valve begins to open.

(i) If the air inlet valve begins to open before the gauge reading drops below 6.9 kPa and is opened fully when the water is completely drained from the SRPVB device, the test shall be recorded as ‘’opened/passed’’.


(h) Close the high-pressure valve, the low-pressure valve, the bleeder, and the test cock, and remove the gauge.

(i) If the air inlet valve does not open, the gauge reading does not drop, and water continues to be discharged from the low-pressure valve, see Clause A.6.2.4.

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Figure A.33SRPVB devices — Test No. 1: Air inlet valve test


A.6.2.4 Leaking shut-off valves (see Figure A.34)If the low-pressure valve has to be opened more than one-quarter of its fully open position, it is likely that shut-off valve 1 is leaking and the following procedure shall be used:(a) To get a better seal, reopen and close shut-off valve 1.(b) If the leak persists, divert the leak so that the air inlet valve can be tested.(c) To redirect the leakage from shut-off valve 1, attach a bleed valve to the test cock and reconnect the

high-pressure hose.(d) Gradually open the test cock and divert some water, monitoring the gauge until its reading stabilizes.(e) Once the leakage has been diverted through the test cock, resume testing at Item (f) of

Clause A.6.2.3.(f) If the air inlet valve does not open and the leak through shut-off valve 1 exceeds the limit of test

cock 1, repair or replace shut-off valve 1 before continuing the test.

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Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve

Shut-off valve 2(closed position)

Check valve



High-pressure valve

Low-pressure valve

Shield

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Figure A.34SRPVB devices — Leaking shut-off valve 1: Air inlet valve test


A.6.3 SRPVB devices — Test No. 2: Check valve test

A.6.3.1 PurposeThe purpose of the check valve test is to determine if the check valve of SRPVB devices will close tight in the direction of flow.

A.6.3.2 RequirementsThe requirements for the check valve test for SRPVB devices are specified in Clause 8.5.3.

A.6.3.3 Procedure (see Figure A.35)The check valve test for SRPVB devices shall be conducted as follows:(a) Open shut-off valve 1 to re-establish pressure in the SRPVB device.(b) Connect the high-pressure hose to the test cock and gradually open the test cock.(c) Bleed the gauge and hoses as follows:

(i) open the high-pressure valve;(ii) open the low-pressure valve;(iii) bleed the gauge and hoses; and(iv) close the low-pressure valve.

(d) Close shut-off valve 1 (shut-off valve 2 should still be closed from the air inlet valve test).(e) Open the bleeder, reducing the pressure on the downstream side of the check valve to atmospheric.

When the water stops flowing from the bleeder,(i) if the gauge reading has stabilized at 6.9 kPa or greater, record that the check valve “closed

tight/passed”;(ii) if the gauge reading drops to 0 kPa, or stabilizes at less than 6.9 kPa, record that the check valve

“leaked/failed”; or(iii) if water continues to flow from the bleeder, see Clause A.6.3.4.

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Test cock

Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve


Check valve


Bleedvalve


High-pressure valve

Low-pressure valve

Shield

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(f) Close the test cocks and bleeder and remove the gauge.(g) Open shut-off valve 1, then open shut-off valve 2.(h) Reinstall the atmospheric vent shield.

Figure A.35SRPVB devices — Test No. 2: Check valve test


A.6.3.4 Leaking shut-off valves (see Figure A.36)If water continues to flow from the bleeder (see Item (e) of Clause A.6.3.3), shut-off valve 1 is leaking and the following procedure shall be used:(a) Close the test cock and remove the hose from the gauge.(b) Attach a bleed valve to the test cock and reconnect the high-pressure hose.(c) Open the test cock (the bleeder should still be open from the check valve test).(d) Gradually open the bleed valve until the water flow from the bleeder is reduced to a slight drip.(e) Observe the reading on the gauge as the static pressure drop across the check valve decreases.

(i) If the water flow ceases through the bleeder and if the gauge reading has stabilized at 6.9 kPa or greater, record that the check valve “closed tight/passed”.

(ii) lf the water flow from the bleeder cannot be eliminated by opening the bleed valve, do not attempt to determine the tightness of the check valve until shut-off valve 1 is repaired or replaced.

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Test cock

Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve


Check valve



Hose

High-pressure valve

Low-pressure valve

Shield

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July 2007 135

Figure A.36SRPVB devices — Leaking shut-off valve 1: Check valve test


A.6.4 SRPVB devices — Test No. 3: Static line pressure

A.6.4.1 PurposeThe purpose of the static line pressure test is to determine the static inlet line pressure upstream of the check valve of a SRPVB device.

A.6.4.2 RequirementsThe requirements for the static line pressure test for SRPVB devices are specified in Clause 8.5.4.

A.6.4.3 Procedure (see Figure A.37)The static line pressure test for SRPVB devices shall be conducted as follows:(a) Connect the pressure gauge to test cock 1.(b) Open test cock 1 and bleed the gauge to remove the air.(c) Observe the pressure reading and record it on the test report form. If the static inlet line pressure at

the time of test is not recorded on the test report form, record the test result as “failed”.(d) Close test cock 1 and remove the gauge.

0

5 10

15HI


LO

Test cock

Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve


Check valve


Bleed valve

Shield

Low-pressure valve

High-pressure valve

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136 July 2007

Figure A.37SRPVB devices — Test No. 3: Static line pressure


A.6.5 Returning SRPVB devices to serviceAfter completing the tests specified in Clauses A.6.2 and A.6.3, SRPVB devices shall be returned to service as follows:(a) Close the test cock and the bleeder.(b) Remove the test equipment.(c) Ensure that shut-off valve 1 is fully open.(d) Check the SRPVB device for leaks.(e) Inform the regulatory authority that the water is ready to be turned on.(f) Open shut-off valve 2, putting the SRPVB device back into service.

Test cock

Bleeder

Membrane(not shown)

Atmospheric vent

Air inlet valve


Check valve


Shield

010

20

3040

5060

7080

90100

Pressure gauge

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