... etc.many possesses,and presently substitute for the traditional castiron pipe of buildings,which is vastly applied in drainage system ... with the traditional castiron pipes1,The density of PVC pipe is the 1/5-1/6 of that of ... castiron pipe, light weight,convenient for transporting,stevedoring,and installing,which ... ,0.07mm/m.°c,little affected the defections; PVC pipe fittings