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Too hot!!! Insulating steam pipes with fiberglass / PVC jacket

I've found some great info on this forum already. I'm hoping someone can help me with a few more details.

My wife is leasing a small space in an old building with steam radiators. Even with the radiator turned off and the windows open, the heat from the pipes (which run from ceiling to floor) makes the room so hot. So the plan is to insulate them with 1" fiberglass and a PVC jacket. My wife has some respiratory problems, so we want to install the insulation correctly, safely, and neatly.

My questions -

- do you think this would help reduce the amount of heat in the room?

- I'm curious as to how to deal with the bottom of the pipes as they don't run straight into the ground. (pic 2 and 3) If I need to stop the insulation before the floor, that's fine, but how would I cap off the end? Not sure how to deal with the bottom area...

- Is there anything I should know about putting the PVC jacket over a vertical pipe? To keep the pieces in place, would you recommend tacks or tape?

Thanks in advance for your help!!


    JUGHNE Member Posts: 11,021
    If that rad has both valves off and is cold, I can't imagine the piping alone overheating the room.
    Is this room above the boiler room?

    And are you sure this is steam and not hot water?
    That is a rather unique radiator connection, could you get a picture of the other end of it to see if it has an air vent?
  • choiahoy
    choiahoy Member Posts: 3
    The room is on the 10th floor of an old NYC office building. Here's a picture of the other end. And on a different note, any ideas of what I can do to the area behind the radiator?

    JUGHNE Member Posts: 11,021
    That looks to be a steam radiator vent on the other end.

    But the radiator stays cool when both valves are off?

    Hopefully someone else here is familiar with the piping connections.
    2 pipe vented radiator steam system?
  • choiahoy
    choiahoy Member Posts: 3
    Yes, the radiator stays cool with the valves off.
  • Fred
    Fred Member Posts: 8,542
    That's quite the pipe configuration on that radiator. Insulation will reduce the room temps. It's hard to believe the rooms are too hot from just the pipes but, if they are small rooms and if the steam supply and returns also run under and across the floor, I suppose it is possible. I would be inclined to not put the PVC cover over the insulation until you determine if all or only a portion of the pipe needs to be insulated for the room to be comfortable.
    JUGHNE Member Posts: 11,021
    You have 2 different sizes of pipe there. Pipe sizes are based on the internal diameter....not the outside.

    Fiberglass comes with a fairly tight outer cover, you may not need the PVC jacket.
    There may be a little outgas as you work it, but it fades quickly IMO.
    Just doing the vertical pipes should cut a lot of heat down.