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Silicone steam pipe through floor?

ChrisJ
ChrisJ Member Posts: 16,231
in Strictly Steam
I have quite a few radiator's who's pipes come up from a crawl space.  I've been pondering for a few years if there is anyway I could seal the gap around the pipe.



Has anyone ever used 100% clear silicone for this?  I don't see why it would have a problem, certainly not from the heat and I doubt the short amount of pipe connected between the floor and radiator expands much.





I welcome any and all thoughts as always.
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Comments

  • RobG
    RobG Member Posts: 1,850
    RTV

    I would use clear RTV, it's good up to 400 degrees. If you want to use regular silicone caulk just look at the label for its temp rating.



    Rob
  • Gordo
    Gordo Member Posts: 857
    edited July 2014
    Seal Around Steam Pipes

    Silicone may break down quickly around the steam pipes unless it is rated for high temperature (450*F or greater sustained temp.  500*F+ intermittent).



    Even then, I suspect it will turn brown and break down after a few years.
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  • ChrisJ
    ChrisJ Member Posts: 16,231
    temp rating

    RTV-108, a clear RTV we use at work has a continuous operating temp of 400F.

    Gordo, I'm not talking about caulk for around tubs and sinks, maybe I should've said RTV instead of silicone. 
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • RobG
    RobG Member Posts: 1,850
    edited July 2014
    Sealing

    If you have escutcheons around the pipes you can use any type of RTV. You could always do one rad and use rock wool around the others as a temporary air seal, see how it holds up and decide from there. Or just use rock wool and escutcheons period. That way if you ever need to disconnect anything you will not have to clean up silicone caulk.



    Rob
  • icesailor
    icesailor Member Posts: 7,265
    RTV:

    High Temp. RTV is used regularly on automobile engines. They run really hot. Hotter than your average residential low pressure steam system.
  • RobG
    RobG Member Posts: 1,850
    RTV

    That was my point. If escutcheons are used, high temp (orange or black) can be used. The clear only goes up to 400 degrees (which would probably be fine). If it were me, I would just pack it with rock wool.



    Rob
  • ChrisJ
    ChrisJ Member Posts: 16,231
    Rock whool?

    Is rockwhool what is commonly called rotten cotton?  If so, no way.



    I hate that stuff, we stuffed it around my B-vent's firestops after it was installed to make sure it was all sealed good.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • RobG
    RobG Member Posts: 1,850
    Rockwool

    What's wrong with rock wool? I've never had a problem with it. If you're against rock wool you can use fiberglass, it's good up to 1000 degrees. Rock wool is 2200 degrees and is much more user friendly in my opinion.



    Rob
  • ChrisJ
    ChrisJ Member Posts: 16,231
    Itchy

    Itchy, nasty stuff. 

    Fiberglass isn't much better.  I hated every second of insulating my piping, but I did it because I had to.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

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