In which scenarios is a double-check valve suitable for backflow prevention?

A double-check valve is suitable for backflow prevention primarily in low hazard applications with minimal risk of contamination. This type of valve is designed to protect the potable water supply from backflow due to backpressure or backsiphonage, but it is not robust enough to handle the potential risks associated with high hazard applications.

In low hazard scenarios, the potential contaminants are less severe, meaning the likelihood of significant health risks from backflow is reduced. Since double-check valves provide adequate protection against these lower risks, they are widely accepted for use in residential and light commercial settings, where the water supply might mix with less critical contaminants, such as those found in lawn irrigation systems or garden hoses.

Contrastingly, high hazard applications, such as those involving toxic or hazardous materials, require more stringent backflow prevention devices, like reduced pressure zone (RPZ) assemblies, to provide the necessary level of protection. Domestic water supply systems may cover both low and high hazard scenarios, but without additional context, the statement that the double-check valve is suitable only pertains to lower hazards. Lastly, while double-check valves can be used in irrigation systems, they are not limited to this application; hence, framing it solely around irrigation is inaccurate. This solidifies why low hazard