If anaerobic sealants are only for use on metal, why is Permabond LH056 fire protection sealant a CPVC Compatible Anaerobic Sealant? The short answer is that Permabond LH056 is a fire protection sealant for use as a metal pipe sealant only. If Permabond LH056 is used on metal pipe work in a fire protection system … Continue reading Anaerobics are for metal only – so why list plastic compatibility?