Forgefix pipe clip with masonry nail forgefix pcmn22 these forgefix pipe clips are made from heat resistant polypropylene designed to withstand the temperature changes in most central heating systems they are effective with temperatures of up to 100c they each come complete with a hardened masonry nail which is easy to fix and durable used when fitting most types of pipe work ensure when fitting that goggles are used polypropylene also known as polypropene is a thermoplastic polymer