Testing Procedures for Backflow Preventers

Prior to initiating a test of any backflow device, it is recommended that the following procedures be followed:

1. Permission be obtained from the owner, or his representative, to shut down the water supply. This is necessary to insure that since all testing is accomplished under no-flow conditions, the owner is aware that his water supply will be temporarily shut off while the testing is being performed. Some commercial and industrial operations require constant and uninterrupted water supplies for cooling, boiler feed, seal pump water, etc. and water service interruption cannot be tolerated. The water supply to hospitals and continuous process industries cannot be shut off without planned and coordinated shut downs. The request to shut down the water supply is therefore a necessary prerequisite to protect the customer as well as limit the liability of the tester.
   Concurrent with the request for permission to shut off the water, it is advisable to point out to the owner, or his representative, that while the water is shut off during the test period, any inadvertent use of water within the building will reduce the water pressure to zero. Backsiphonage could result if unprotected crossconnections existed which would contaminate the building water supply system. In order to address this situation, it is recommended that the owner caution the inhabitants of the building not to use the water until the backflow test is completed and the water pressure restored. Additional options available to the building owner would be the installation of two backflow devices in parallel that would enable a protected bypass flow  around the device to be tested. Also, if all water outlets are protected within the building with “fixture outlet protection” backflow devices, crossconnections would not create a problem in the event of potential backsiphonage conditions occurring while devices are tested, or for any other reason. 
2. Determine the type of device to be tested i.e., double check valve or reduced pressure principle device.
3. Determine the flow direction. (Reference directional flow arrows or wording provided by the manufacturer on the device.)
4. Number the test cocks, bleed them of potential debris, and assemble appropriate test cock adapters and bushings that may be required.
5. Shut off the downstream (number 2) shut-off valve. (Ref. Item (1) above.)
6. Wait several moments prior to hooking up the test kit hoses when testing a reduced pressure principle device. If water exits the relief valve, in all likelihood, the first check valve is fouled and it is impractical to proceed with the testing until the valve is serviced. This waiting period is not necessary when testing double check valves.
7. Hook up the test kit hoses in the manner appropriate to the device being tested and the specific test being performed.

Test personnel are cautioned to be aware and follow local municipal, county, and state testing requirements and guidelines as may be dictated by local authority. The following test procedures are guidelines for standard, generally acceptable test procedures but may be amended, superceded, or modified by local jurisdiction.