Water Treatment

In the world of water distribution, the pressures are almost always relatively low and the temperatures ambient. Those two application facts allow a number of valve design elements that would not be found on more challenged equipment such as high- temperature steam valves. The ambient temperature of water service allows use of elastomers and rubber seals not suitable elsewhere. These soft materials allow water valves to be equipped to tightly seal off drips.

Another consideration in water service valves is choice in materials of construction. Cast and ductile irons are used extensively in water systems, especially large outside diameter lines. Very small lines can be handled quite well with bronze valve materials.

The pressures that most waterworks valves see are usually well below 200 psi. This means thicker- walled higher-pressure designs are not needed. That having been said, there are cases where water valves are built to handle higher pressures, up to around 300 psi. These applications are usually on long aqueducts close to the pressure source. Sometimes higher-pressure water valves also are found at the highest-pressure points in a tall dam.

The American Water Works Association (AWWA) has issued specifications covering many different types of valves and actuators used in waterworks applications.