What are suggested guidelines for installing plastics valves and other flow control products in a pipeline? Can plastic valves be used in metal piping system?

Answer:

Valves should be installed 10 pipe diameters downstream of the pump discharge. For example, in an 8" diameter pipe, a valve should be installed 80" downstream from the pump. Failure to do so can prevent a valve from closing, or result in catastrophic failure of the system.

Plastic flow control products can be used in metal piping system, but care must be taken to ensure that product meets the chemical, pressure and temperature-operating condition require for the application. Information on the expected flow rate is also important since metal piping systems are designed for flow rates of 15 feet per second or higher, while plastic system are designed for a maximum flow velocity of 8 feet per second. The suggested installation guidelines are included in the Installation & Operations Manuals (IOM) shipped with every Hayward flow control product.