Find all types of backflow preventer devices in one place!

Certain types of backflow preventer devices must undergo field testing to ensure proper operation. They are said to be “verifiable”. The law obliges to certify these devices after installation and annually thereafter, after a relocation or after a repair. For Canada, the requirements for testing are described in B64.10.1-11 – Maintenance and Field Testing of Backflow Preventers.

Other types of so-called “unverifiable” devices are installed on specific applications and are designed to protect a particular type of risk.

Here is a list of the most frequently requested backflow preventers.

Dual check valve backflow preventer (DCAPC)

  • CSA: B64.6
  • ASSE: 1024
  • Highest hazard protection: minor
  • Back pressure resistant: yes
  • Continuous pressure resistant: yes
  • Field testing required: no

Overview/Benefits

  • Provide reliable protection from both back siphonage and back pressure if  minor hazards exist.
  • Can be placed in a vault.

Application examples

  • Domestic water supply
  • Coffee machine

Models

 WILKINS

  • 700 & 700XL
  • 705

CONBRACO

  • DUC40 & DUCLF40
  • DUC4FP
  • DUC4N & DUCLF4N

WATTS

  • 7 & LF7
  • LF7R
  • 07S & LF07S
  • 7C & LF7C
  • 7B

Dual check valve backflow preventer with atmospheric port (DCAP)

  • CSA: B64.3
  • ASSE: 1012
  • Highest hazard protection: minor
  • Back pressure resistant: yes
  • Continuous pressure resistant: yes
  • Field testing required: no

Overview/Benefits

  • Provide reliable protection from both back siphonage and back pressure if  minor hazards risk exist.
  • Do not use in place of Reduced pressure principle backflow preventer (RP).
  • Leaks are easily detected in case of failure.
  • Should not be installed below ground level, in a pit or a vault.

Application examples

  • Terminal
  • Chemical plant
  • Petroleum product storage
  • Sprinkler line where there is a risk of freezing with glycol gel

Models

 WILKINS

  • 760

CONBRACO

  • DCAP  & DCAPLF

WATTS

  • 9D

Dual check valve backflow preventer with atmospheric port for carbonators (DCAPC)

  • CSA: B64.3.1
  • ASSE: 1022
  • Highest hazard protection: moderate
  • Back pressure resistant: yes
  • Continuous pressure resistant: yes
  • Field testing required: no

Overview/Benefits

  • If a backflow occurs, the diaphragm seat of the first check valve rises and allows atmospheric pressure to flow through the relief port.
  • Leaks are easily detected in case of failure.

Application examples

  • Soft drink dispenser water supply connections

Models

 WILKINS

  • 740 (ASSE only)

CONBRACO

  • CBBP

WATTS

  • SD-2 (ASSE 1032)
  • SD-3 (with strainer)
  • 9BD (New York)

Atmospheric vacuum breaker (AVB)

  • CSA: B64.1.1
  • ASSE: 1001
  • Highest hazard protection: moderate
  • Back pressure resistant: no
  • Continuous pressure resistant: no (12 hours maximum)
  • Field testing required: no

Overview/Benefits

  • Provide reliable protection from back siphonage only if minor or moderate hazards exist.
  • AVB devices do not provide adequate backflow protection when
    • back pressure can be developed on the downstream side of the device;
    •  the device is located in an area subject to flooding;
    • The device is under constant pressure for more than 12 hours, because the float disc can get stuck in the open position, rendering it inoperative in the event of back siphoning.
  • The critical level must be located at least 150 mm above the overflow level of the fixture, container or accessory.

Application examples

  • Washing tank
  • Outdoor faucet hose
  • Potato-peeling machines

Models

 WILKINS

  • 35XL
  • 35XLVCH

CONBRACO

  • AVB1
  • AVB1LF
  • AVB2

WATTS

  • 188A
  • 288A & LF288A
  • LF288A-DM
  • N388 & LFN388

Hose connection vacuum breaker (HCVB)

  • CSA: B64.2
  • ASSE: 1011
  • Highest hazard protection: minor
  • Back pressure resistant: yes
  • Continuous pressure resistant: no (12 hours maximum)
  • Field testing required: no

Overview/Benefits

  • HCVB  devices are subgroups of AVB devices;
  • Intended for low risk installations such as faucets to which a garden hose can be attached.
  • Must be installed on the outlet side of the shut-off valve.
  • If the shut-off valve is closed, the check valve closes and the breather vent opens, allowing air to enter downstream.
  • Incorporate a check valve that is force-loaded to the closed position;
  • Install so that air vents cannot be submerged.
  • Withstand low back pressure that can occur if the end of the hose is higher than the hose valve when closed.

Application examples

  • Faucets to which a garden hose can be attached

Models

 WILKINS

  • 420XL
  • 720A

CONBRACO

  • PVB4A
  • PVBLF4A

WATTS

  • 800M4FR & LF800M4FR
  • 800M4QT & LF800M4QT

Laboratory faucet vacuum breaker (LFVB)

  • CSA: B64.7
  • ASSE: 1035
  • Highest hazard protection: minor
  • Back pressure resistant: no
  • Continuous pressure resistant: no (12 hours maximum)
  • Field testing required: no

Overview/Benefits

  • Intended for use on laboratory faucets;
  • Installed at the outlet of the faucet
  • Used for minor hazards.
  • Shall not be used under continuous pressure conditions

Application examples

  • Laboratory faucet

Models

 WILKINS

  • 730

CONBRACO

  • LFDUC

WATTS

  • NLF-9 & LFNLF9

Contact us to purchase the right backflow prevention device according to the application to protect.

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Discover backflow preventers requiring periodic field testing.

Source: CSA Standard B64.10 – 11, section 4.3 – Mechanical backflow preventers.