What type of backflow prevention assembly is required for potable water connections to steam or hot water boilers?

The requirement for a backflow prevention assembly for potable water connections to steam or hot water boilers is based on the potential risks associated with contamination of drinking water. A double check valve backflow prevention assembly is designed to prevent backflow, which is the undesirable reverse flow of water from a potentially contaminated source back into the potable water supply.

This type of assembly consists of two check valves arranged in series. If one of the valves fails, the second valve serves as a backup to prevent any possible backflow, thereby providing a higher level of reliability than a single check valve. This is particularly important for connections to boilers, where variations in pressure could lead to contamination if there’s a backflow incident.

In contrast, a reduced pressure principle backflow prevention assembly, while effective, is typically required for situations with higher risk of contamination, such as connections to chemical feed systems or irrigation systems where there is a potential for severe backflow incidents. A vacuum breaker is suited for preventing back siphonage, primarily in hose connections and certain fixtures, but does not adequately protect against backpressure situations often encountered in boiler systems.

Thus, for the specific scenario of protecting potable water connections to steam or hot water boilers, the double check valve backflow prevention assembly is the