Which type of valve should be installed at a dead-end water main?

In water distribution systems, a blowoff valve is specifically designed for installation at dead-end water mains. The primary function of a blowoff valve is to allow for the draining of water from the system to facilitate maintenance, inspection, or repairs. This is particularly important at dead ends where water can stagnate, leading to potential water quality issues.

Blowoff valves provide a means to remove sediment and debris that might accumulate in stagnant water, thereby maintaining overall system health. By allowing for periodic flushing of the dead-end section of the main, these valves help ensure that water quality remains acceptable and that the pipes are kept clean.

In contrast, while check valves, isolation valves, and pressure relief valves serve critical roles in the water distribution system, they do not fulfill the specific purpose of managing stagnant water in dead-end mains. Check valves help prevent backflow, isolation valves are used to control flow or isolate sections of the system for maintenance, and pressure relief valves are designed to protect the system from overpressure conditions. However, none of these are suited for the specific task of draining and maintaining water quality at dead ends in the distribution system.