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PVC elbows for pipe insulation necessary?

Hello all:

I now have bare piping after the removal of the asbestos pipe insulation. I am in the process of measuring and ordering the 1" fiberglass pipe insulation. I have a number of elbows throughout the basement, and in lieu of purchasing the PVC connectors for elbows and such, I thought that I could purchase regular insulation, wrap theses connections with it, and duct tape over the top of it (I found white duct tape so it least will look a bit more neat and clean). I had done this prior with roll 1" insulation where the asbestos covering had fallen or had been removed.

Anyway, I called the supplier to find out what lengths the pipe insulation were so I could plan accordingly. I flew the idea of how I was going to do the elbows and joints, and he was a bit skeptical.

I will likely save a boatload doing it how I originally planned, and I am quite meticulous when it comes to things like this. Add in the fact that the majority of my basement has a dropped ceiling, and aesthetics are pretty much immaterial.

I am sure I will get opinions both ways, and I sure the PVC fittings are much nicer looking, but it is totally necessary to do it as such?

Last question - Any thoughts on going over pipe unions? There was solid asbestos covering on them prior to its removal.

Thanks for any help.


  • JeffMJeffM Posts: 157
    not necessary, but...

    Are the PVC fitting covers necessary? No, but I would recommend using them anyway. They aren't free, but in my opinion using them really makes a big difference in how good the insulation job looks. Is there going to be a performance difference? No, but you'll be happier with your work.

    If it were me, I'd either use the covers or just leave elbows uninsulated. I wouldn't recommend white duct tape - I ran out of PVC tape at the last joint on my system and used white duct tape, and it looked lousy and didn't stick well and I just ended up removing it and using white PVC like I should have in the first place. The PVC tape is available from your insulation supplier, and I prefer it for holding the PVC fitting covers together compared to using tacks.
  • gcp13gcp13 Posts: 117
    pronto covers

    i just finished my steam mains that are exposed and used the knauf 1" insulation with pronto pvc covers.for 1.50-2.50 each one the job look much better and a lot easier,

    using mastic to cover any exposed insulation
  • Hidden pipes?

    You mentioned a drop ceiling- does this mean the steam pipes are hidden from view? Let me throw this out.

    The formed fiberglass insulation is indeed nice and gives a tidy appearance. But if the pipes are hidden, you really don't benefit there. And the PVC covers also look sharp and offer a degree of protection for the somewhat delicate insulation. Again, this shouldn't be an issue above your drop ceiling. Finally, 1" is really a minimum here- 1 1/2" would be better and 2" would be great, but the price jump is pretty outrageous. Plain ol' fiberglass stud bay insulation however works great and is dirt cheap. I used it on my 4" drop header (aside from a few gallons of mastic and a mop it seemed like the most practical solution!) and it's a wonder. Stays cool through firing, but if you peal away the insulation you'll find the iron is still rocket hot an hour after. When I re-piped my mains I went with all Ward fittings and couldn't convince the boss to spend several hundred more on snazzy form fitting insulation to suit. I swallowed my pride and used more cheap insulation. I daresay it works better than the 1" stuff (I had a bit left over from the old mains and compared).

    With that diatribe out of the way- YES, you should definitely insulate your fittings as well. But the even more pricey PVC fitting covers were the last nail in the coffin for me. While I'm sure no one is getting rich manufacturing the darn things, the price just seemed far too high for what you are getting. But there's the rub- If I was going to buy the form fitted fiberglass because I had exposed pipes in a finished location I'd surely want to spring for the protective wrap, and of course I wouldn't want to spoil the look with "homemade" covers on the fittings. Kind of an all or nothing deal.

    If your pipes are hidden, I'd suggest using the cheap insulation, and wrap all your fittings. Then replace the drop ceiling, take yourself out to several steak dinners with the savings, and never think about it again!

    Good luck,

  • H3809H3809 Posts: 19

    Any pictures of using the wall insulation with mastic?
  • Nope-

    That came out awkwardly. I didn't use the wall insulation with mastic but instead of it. Given that the header is one crazy mass of enormous 4" fittings I thought it would take quite a lot of mastic (applied with a mop? ;) )and as I said, the pocketbook was pretty light at the time. With the aid of a utility knife and some "duck" tape the wall insulation easily conformed to all the twists and turns and seems to do a great job of keeping in the heat.

    It is, I'll admit, ugly as sin. Handsome and respectable as a nice mastic job looks (I'm thinking of Gerry Gill's photos) I've got a long list of projects that are taking priority over my quick and dirty (and cheap) insulation job.

    Good luck,

  • H3809H3809 Posts: 19

    Patrick, Ohhh i got ya I too am going with the wall insulation. At this point i want cheap results, and im ok with cheap looks, it isnt in the livingroom and since im the only one who sees it, it will be beautiful to me.

  • BobCBobC Posts: 4,333
    don't forget the boiler

    When i had the Smith G8 installed last fall i didn't insulate the header till the inspector blessed it. I used fitting covers only because i had them on hand. There are a few fittings and short runs where i  used 3-1/2 kraft insulation on just because there was no easy way to use standard pipe insulation - it's a cellar, only the cat and I ever go down there.

    While i was doing the header i also peeled the top of the boiler cabinet off and insulated to top and as far down the sides as i could easily get. That boiler stays hot for 5-6 hours now, I know that saves me some gas and it was dirt cheap to do.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Pics of boiler insulation?

    Hi Bob:

    Can you provide any pics of what you mean with insulating the boiler itself? That one is news to me.

  • BobCBobC Posts: 4,333
    edited August 2013
    Sorry no pics


    Almost all steam boilers have an outer cabinet that surrounds the actual boiler and they usually put about an inch on fluff against the shell so it's not too hot. If I'm paying for the fuel that runs a boiler I want it to stay as hot as possible.

    I just removed a half dozen screws that holds on the top lid and place insulation between the actual boiler and the outer cabinet. I also put insulation as far down as I can reach, the result is the boiler looses a lot less heat to the cold cellar and I save a few bucks to boot. I did the same thing with my old Burham v75 and it made a big difference in the boilers ability to retain the heat.

    I think the only boiler that does a decent job of insulating the boiler is the Megasteam and they absolutely refuse to allow gas to be used on it. I contacted Burnham when I was replacing my boiler and told them I wanted to install the Megasteam with a gas gun and they said no way. I went with the Smith G8 because they approved it for use with the Carlin EZ-Gas at that time and I was afraid of getting into a pissing contest with the damn inspector.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • JStarJStar Posts: 2,668

    This is a great idea!! I am definietly going to start doing this on our installations.
    - Joe Starosielec
    [email protected]
  • SWEISWEI Posts: 7,356
    If it will fit

    Owens Corning 700 series (rigid fiberglass) works great for this.
  • BobCBobC Posts: 4,333
    Better but doable?

    I've used the 700 series to control room resonances in my living room and it works great, in the boiler I've just used insulation bats because it's easy and it seems to work well.

    The rigid insulation would probably be better but if it does not conform to the shape of the boiler it means you would really have to surround the entire boiler so you don't just "push" the heat to other areas of the envelope. That is not a known fact it's just the way I see it.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • SWEISWEI Posts: 7,356
    edited August 2013
    Good point

    I've glued it to the sheetmetal as a replacement for the half inch or so that the factory installed.  Corners would benefit from some additional material for sure.

    My first experience with it was building acoustic traps for postproduction studios.
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