My colleague, Terry Burger, has written about the confusion over hydrant backflow protection, as well as the differences in the various devices, in his article “Understanding Hydrants and Backflow Protection.” In this article, we’ll attempt to highlight the commonalities between the five ASSE hydrant standards (see table to the right), as well as point out some areas where they differ. Understanding these unique characteristics is essential to certifying hydrant backflow protection products appropriately.
All ASSE certified hydrants are tested for leakage from vent ports, as well as backsiphonage of water from downstream piping into the water supply when a vacuum is created. Unique to ASSE 1052, 1053 and 1057 devices is the utilization of multiple check valves in their designs. As a result, the standards covering these devices share the following testing requirements:
- Backflow through inlet check valve test
- Backflow through outlet check valve test
- Backsiphonage and backpressure test when one of the check valves becomes fouled
- A test to measure the relief of an intermediate chamber pressure
In addition to the above, ASSE 1052 and 1053 also check the hydrant’s inlet and outlet check valves for tightness.
Most hydrants are required to be tested at 140°F. However, an ASSE 1011 device must show its ability to function at 180°F. The higher temperature requirement stems from an ASSE 1011 device’s ability to be used on a boiler feed system, while the other devices should not be employed for such use.
With the exception of yard hydrants, all hydrants need to demonstrate a minimum working pressure of 125 psi — yard hydrants need a minimum working pressure of 100 psi. This is largely due the fact that these devices are often found some distance from the main water supply, which results in a modest pressure drop.
Hose connection vacuum breakers and backflow preventers (ASSE 1011 and ASSE 1052) must demonstrate the ability to function without leakage after being subjected to a load of 25 lbs. While wall and yard hydrants (ASSE 1019, ASSE 1053 and ASSE 1057) must demonstrate such an ability after being subjected to a higher load of 100 lbs. This higher load requirement is imposed to account for the added weight of devices that are often hung from a wall or yard hydrants.
ASSE 1019 devices are classified as Type A, B and C. All these devices protect against backsiphonage and backpressure. The differences between each type comes from how the devices protect against backflow and/or their usage of a removable hose to prevent damage to the device from freezing. As a result, the different types of ASSE 1019 devices must pass testing requirements unique to their classification. For Type A and B devices, this includes testing the outlet pressure release mechanism. Type C devices must pass a unique criterion that determines if any contaminated water is transmitted back to the potable water system. A mixing hydrant must also pass a cross-flow test to determine if leakage occurs when the outlet(s) is blocked.
ASSE 1019 and ASSE 1053 devices are tested to ensure they are capable of discharging water in subfreezing climates. This is not required for ASSE 1057 devices, as the shut off valve is located below the frost line.
While details of the differences in these devices can be overwhelming, a commitment to providing protection against backflow into the potable water system is common among all ASSE certified hydrant devices.
To have your product certified to any of the ASSE hydrant standards, please contact ASSE International at listingcoordinator@asse-plumbing.org. To purchase a copy of ASSE 1011, 1019, 1052, 1053, or 1057, please visit the ASSE International Webstore at www.assewebstore.com.
