Question

Now, mainly flap valves are ended of HDPE. What is the major compensation of using HDPE as compared with cast iron?

Answer
(i) It has no response with sewage and seawater and does not undergo from corrosion trouble connected with cast iron.
(ii) No defensive coating is necessary and it is about protection free.
(iii) HDPE flap valves need low opening pressure in operation like 5mm water level difference. Fore cast iron flap valves, due to its own heavy self-weight, required opening pressure of cast iron flap valves is upper than that of HDPE flap valves. This criterion is necessary for dry climate flow conditions.
Though, pressure confrontation of HDPE flap valves is not as high-quality as cast iron flap valves. For example, a typical 450mm wide HDPE flap valve can only withstand about 5m water column.