1 pipe steam pipe through uninsulated joist

Kjmass1

I’d like to add a small radiator to my 1 pipe steam system on an elevated porch that has exposed floor joists. Would having ~1’ (quick 90 degree fitting) of runout exposed to the elements be an issue assuming it is pitched correctly? I’ll eventually get it insulated but wondering if I could get through the winter as is (Boston). My thinking is the pipes are hot enough for the condensate to return without freezing, and at below freezing the boiler is running once an hour anyways.
Kevin

gfrbrookline

I live in Brookline and wouldn't risk it even with insulation.

Kjmass1

> @gfrbrookline said:
> I live in Brookline and wouldn't risk it even with insulation.

I’m in Brookline as well. Thanks good to know.

STEAM DOCTOR

It probably won't freeze but I don't know how much steam will actually make it to the radiator. The steam will probably condense before it gets the radiator

ethicalpaul

After my experience in my bedroom fed by a 1" supply in a cold exterior wall space that was basically exposed in a small area to the outside, I would say this:

Make it 1-1/4" pipe. Insulate it with nice thick fiberglass. The good stuff from https://www.buyinsulationproductstore.com/Fiberglass-Pipe-Insulation-SSL-ASJ/ or similar from local supply.

They have 2" insulation for 1-1/4 pipe.

If you set up the slope correctly you won't ever have to worry about freezing because there will be almost nothing to freeze, and if a small amount of condensate were to freeze, no problem. It's not like the whole pipe is going to be full of water. We're talking tiny pools at the threads.

My problem was all with the slope. I had an uphill section that collected water and it just flat out killed the steam.

I have two other radiators that are also in cold exterior walls, and they are fine. It still drives me crazy that I'm heating the exterior wall and I may re-run those to be inside the living space as well, but they heat fine.

Jamie Hall

I think I'm with @ethicalpaul on this one. With a heavy emphasis on insulate the dickens out of it. It's really hard to freeze a steam system (I've had a few frozen traps on outside walls over the years), but without insulation he's right -- steam will have a hard time getting by.

Kjmass1

Thanks- appreciate it. I can alternatively come up in the room next to it and then go through the baseboards/wall which would be all conditioned space. Unfortunately the 90 from the basement would be 5" from the baseboard in the floor so a little bit of a trip hazard.

Jamie Hall

Paint it orange. Or put a plant stand over it...

EBEBRATT-Ed

If you pitch it right it will be impossible to freeze it.....Maybe I shouldn't have said impossible. extreamely unlikely