What components are included in a double-check valve assembly?

A double-check valve assembly is specifically designed to prevent backflow in water systems, which is essential for protecting the potable water supply. The correct choice mentions two independently acting check valves, which is a defining feature of this assembly.

Each check valve within the assembly operates independently to allow water to flow in one direction while blocking flow in the reverse direction. This provides an additional layer of safety and redundancy—if one check valve fails to close properly, the other acts as a backup to help prevent contamination from entering the drinking water supply.

The design will typically incorporate ball or disc mechanisms within each check valve to ensure they perform their functions effectively. The use of two separate valves not only enhances reliability but also conforms to standards and regulations for backflow prevention systems, which often mandate this type of equipment in specific applications or when certain risks are present.

In contrast, the other options suggest fewer or identical check valves, which do not align with the purpose or design of a double-check valve assembly. Having only one check valve would not meet the requirements for backflow prevention, while claiming three would misrepresent the standard configuration. Identical check valves would not emphasize the importance of independent operation which is crucial for safety and functionality in backflow prevention.