Forgefix pipe clip reducer forgefix pcr these forgefix pipe clip reducers are made from heat resistant polypropylenedesigned to withstand the temperature changes in central heating systems and is effective with temperatures up to 100 degrees celsius most pipes in domestic central heating systems operate at around 70 c reduce a 22mm pipe clip to 15mm and are mainly used in a double 22mm pipe clip to reduce one side to 15mm when used in a run of 2 pipes polypropylene also known as polypro