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Exterior Rated Hot Water Boiler Piping Insulation

I ran into a weird setup where a business that tests explosives has a residential hot water boiler installed in an outbuilding and then has about 15' of above ground 1.25" and 1.5" steel piping running into the building it heats. They run a glychol mix through the system and the existing piping insulation is shot. They want me to replace the insulation but I can't find any insulation approved for this through my local suppliers. All they have is indoor rated. So trying to find something rated to outdoor use. Under the gun a bit since we gotta change out the boiler soon. Please advise.....


  • pecmsg
    pecmsg Member Posts: 4,967
    Fiborglass with plastic covers. A sealer will he needed to make it water proof
    EBEBRATT-Ed Member Posts: 15,847
    Yes, @pecmsg is correct. Fiberglass covering with PVC jacket which needs to be sealed and caulked.

    If it was me I would hire a professional insulator. I believe you insulation supplier can cut and supply the pvc jacket
  • GroundUp
    GroundUp Member Posts: 1,959
    Armaflex rubberized insulation is often used for this with a PVC or galvalume jacket. The Armaflex will combat moisture on its own unlike fiberglass