Steam Pipe Hanger Question

CKNJ

Need some advice. I have a 1909 Foursquare with one pipe steam system. In the basement, the mains run below the floor joists, but the branches to the radiators run inside the floor joist cavity. These pipes are 1 1/2" diameter. The floor joists are 7 1/2" high on 20" centers, with about 5 1/2" inches clearance from subfloor to top of pipe. There are no supports for any of the branches which run between 8' and 15' in length! I am in the process of insulating the pipes but I want to add hangers to take some of the load off the radiator and main. Since I cannot put a regular hinged hanger in there due to close clearance (I would have to put a 2x4 across to attach the hanger rod), can i use a "strap" nailed to the sides of the floor joist to provide a "cradle" for the steam pipe? If so, what material should the strap be?

Or if anyone has other suggestions?

Jamie Hall

I've had decent results with straps here and there. I use the 1 inch or so steel strapping with holes punched along it. I usually use screws and washers to pin it to the joists where it needs to go, having had nails pull out.

ChrisJ

None of my runouts have supports either and I didn't add any.

My opinion is that runout needs to be able to drop as it heats, otherwise it's going to push up on the radiator valve a little.

Personally, I have no problem with the runout hanging off of the radiator and some of mine are 12 feet long 1 1/4". As long as there's no sags it's fine, it's been around far longer than we have.

CKNJ

Thanks for the input.

ChrisJ: the other problem i have is the radiators have begun to "dig" into the floor on the shutoff valve side quite noticeably. Tonight i am going to measure the pitch on those runouts so we shall see. If pitch is good, i might just leave it otherwise will strap.

Background is I just bought the house in August. Gas fired steam and the things I have found so far are mind boggling. No insulation on any pipes; a main vent that was shot, the other main vent tapping had a plug in it. (Both mains now have Gorton Vent Valves on them.) Radiators on main with the plug had Gorton "D" vent valves on them! I will have to replace them once i start balancing the system. Obviously they never read Dan's Book.

Coolest thing so far? House still has a Honeywell Acratherm that still works!

BobC

My 98 year old house has settled some over the years and the 12-15ft runout slope was bit lacking. I levered the radiators up and put 5/8" 1" wide plywood strips under the shutoff valve end and a 3/4" thick strip under the vent end.

If you try this be gentle when you try to raise the radiators.

Bob

Fred

I too would leave it alone, unless there is a sag in the pipe. It's been that way for 100+ years. The radiator feet, digging into the floor isn't an indication if pipe weight on the radiators. Radiators will expand/contract each time they get hot and/or cool down. That is typical of just about every steam system. Put a thin pad under those feet, something that will allow the rads to slide a little bit as they expand/contract.
Also, the last thing you want to do is put a rigid brace on those run-outs in a way that will cause the pipe on either side of the bracing to bow when those pipes get hot. That will create an artificial "sag" on each side of the bracing.