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Header Insulation and PVC Sleeves

klal Member Posts: 26
I'm looking to insulate the bare iron steam mains/headers in my basement with hinged 1" fiberglass insulation and then putting on PVC sleeves/jacketing. My mains are 2", with the risers heading upstairs being either 1" or 1-1/4".

So my main question is, with the 2" mains, which I believe are actually 2-3/8" in diameter (7.5" circumference), what is the size needed for the hinged fiberglass insulation and then the PVC jacketing? I'm looking at Johns Manville at Grainger.com, and I'm wondering if I'm ordering a 2" or a 2-1/2" inch size for the fiberglass. In other words are they referring to them like you would a 2 x 4, which really isn't that size. Don't want to order them and then have to return them for the correct size.

Thanks in advance for your help and knowledge.


  • KC_Jones
    KC_Jones Member Posts: 5,736
    For steel pipe it is usually sized nominally, so 2" pipe insulation fits nominal 2" pipe that has a 2 3/8" OD.


    I'd recommend the above website, the shipping is a bit high, but most of us have found they are more reasonable than some of the alternative suppliers, even with the shipping included. Might be worth a comparison to Grainger.
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  • klal
    klal Member Posts: 26
    KC, thanks for the quick response. Glad to confirm that the nominal size is what I'm ordering. I just checked out buyinsulationproducts.com, they are more than less what Grainger is charging. Thanks, I really appreciate it!
    EBEBRATT-Ed Member Posts: 15,513
    See the attached and there is more information on the Johns Mansfield web site. There are probably may places less expensive than Grainger