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Anaerobics are for metal only – so why list plastic compatibility?

If anaerobic sealants are only for use on metal why is Permabond LH056 a CPVC Compatible Anaerobic Sealant?

The short answer is that Permabond LH056 is a designed for use as a metal pipe sealant only – if Permabond LH056 is used on metal pipe work in a fire protection system that also contains CPVC, the CPVC will not be adversely affected.

There are various ways of thread sealing. For metal pipe, the preferred method is anaerobic pipe sealants which only cure in the absence of oxygen and presence of metal.  Because metal is needed to make the anaerobic pipe sealant cure, they will not cure on plastic and therefore should not be used as a sealant for plastic. Anaerobic fire protection sealant should only be used on metal.

Permabond LH056 is an anaerobic sealant for metal.  Some fire protection systems contain metal in one area of a building and plastic in another. Permabond LH056 is used to seal the metal pipe connections only – but because there is the potential for excess, uncured LH056 to travel through the system and reach plastic, testing was done to prove that the LH056 will not stress crack the CPVC.

Again, Permabond LH056 should NOT be used to seal plastic pipe joints.  It will not cure on plastic, but LH056 was tested to ensure it will not harm CPVC if LH056 comes in to incidental contact with it.

Anaerobic metal pipe sealants are trusted to create a 100% leak-free seal, even when the pipe is not completely seated, eliminated “call back” repair costs.

For information on sealing metal pipe connections and weld sealing, see or contact Permabond.