What type of protection is required for a closed loop heating system containing chemicals?

In a closed loop heating system that contains chemicals, a reduced pressure zone (RPZ) assembly is required for backflow protection. This type of protection is designed to prevent the backflow of potentially hazardous fluids into the potable water supply.

RPZ devices are particularly effective because they contain two check valves and a relief valve that maintains a specific pressure level. If the pressure in the system drops below a threshold, the relief valve opens to ensure that any contaminated water is expelled rather than entering the clean water supply. This is crucial for systems that include chemicals, as these substances can pose serious health risks if they contaminate drinking water.

In comparison, other options such as a single check valve, double check valve, or air gap do not provide the same level of protection against backflow from potentially hazardous materials that an RPZ does. A single check valve might be sufficient for non-hazardous applications, but it does not adequately account for pressure fluctuations or siphoning situations that could compromise safe operation. A double check valve can provide better protection than a single check but still lacks the fail-safe mechanism present in an RPZ. An air gap, although effective in certain scenarios, may not be feasible for all installations and typically applies to drainage systems.

Therefore,