What does a double check valve assembly mainly prevent?

A double check valve assembly is specifically designed to prevent backflow caused by both back pressure and back siphonage. Backflow can occur in a plumbing system for various reasons, and this assembly provides a reliable method of eliminating those potential hazards.

Back pressure occurs when the upstream pressure in a system exceeds the downstream pressure, which can happen due to conditions such as a nearby fire hydrant being opened or a pump being activated. On the other hand, back siphonage occurs when there is a drop in the supply line pressure (for example, due to a water main break), causing fluid to be pulled back into the system.

The double check valve assembly consists of two check valves arranged in a series which creates a barrier against these two forms of backflow. Because of this dual valve arrangement, the assembly is capable of responding to changes in pressure differentials, effectively preventing contamination of potable water supplies by ensuring that unwanted water does not flow back into the main supply. In accordance with various plumbing codes and standards, this assembly is commonly used in situations where a potential contamination risk exists, thus safeguarding public health and ensuring the integrity of the potable water system.