Insulate the riser's?

4Ever_Steamed

I have a mass brick three flat in Chicago with a one pipe, parallel flow, up feed, dry return system. For the most part it runs pretty well, especially compared to some of the horror stories I've heard. My goal of course is to make it perfect, my wife and I love steam heat.



At the moment I have the second floor gutted wall to wall, floor joists to ceiling rafters. So I want to do everything for the system that I can while I have it open. I've already replaced all of the radiator shut off valves and the brass inserts on the radiators (not easy).



Now I'm looking at these Schedule 80 riser pipes and have some ideas about optimizing them before I close up the walls. Bright ideas often lead to trouble so I thought I'd ask questions first.



I know that insulating the horizontal basement runs is important to keep the steam from condensing early which causes all kinds of trouble. But I don't think I've seen anything about insulating the vertical pipes, and these don't look like they ever were... I would think the same principals apply, but I also know that these systems don't like to be messed with.



Has anyone seen this, or done it? Are there any pitfalls I might encounter?



I'm also considering taking some wire wool to them and giving them a coat of rust reformer and/or high temp paint. But the pipes I've worked with haven't shown any real sign of corroding through, its schedule 80 so dang thick. I just don't want to miss an opportunity to put problems off until they're my grandkids problem!



I made one mistake already and thought it would be a good idea to tightly attach the pipes under the floor feeding the radiators to the framing with steel plumbers tape with leather between the tape & the pipe. I thought it would make doing any work on the radiators and shut-off valves less likely to crack the pipes after the sub-floor went back in. Of course the expanding pipes made a hell of a racket creaking & squeaking the framing, so I'm undoing that dumb idea. The old timers left them float free for a reason...



Any advice would be appreciated, thanks!



Rob



By the way- Dan's book The Lost Art of Steam Heating is excellent reading.

Jamie Hall

Usually aren't

but that, I think, is usually because they are either in a wall with not enough room to put the insulation on, or in a lived in space, where the insulation is not exactly designer decor.  Wouldn't do any harm to insulate them, though, and might help the efficiency a little bit (but I wouldn't try to quantify that!).



The building I care for has all the exposed risers (it's a vapour system in an early 1800s building -- all the pipes are exposed) painted.  Some with Rustoleum, but most with a high quality acrylic matching the room or ceiling paint.  Seems to be working fine, provided the surface prep (scrape, steel wool, etc.) was adequate.



I love your story of the pipe supports!  The best laid plans...

Mark N

Pipe Insulation

The risers in my home are in the walls.  The riser are insulated.  I've seen the insulation when I've had the some walls open for renovations.



Mark

4Ever_Steamed

Good info...

Great feedback, and some good points.



I do have the space in the walls for 2" insulation, so I'm inclined to do it... I think my worry is that by upsetting the condensing behavior I might create some kind of pressure change that'll bite me. I think that slowing the condensation action would only help, but not sure about that. Typically the reverse is what messes things up, removing insulation which speeds the cooling/condensation of the steam.



Maybe what I'll do is throw it on, then run the boiler for a few days and see what happens before I finish the walls. Worst case, I have to pull it off and I'm down the time & cost of the materials.



I'll probably prep & paint them too, I'm crazy like that.



Just no more pipe supports...

JStar

Conditioned space.

Uninsulated pipes in the wall = wall radiation?



I can't see it being a huge energy loss if you don't insulate the risers in the wall, unless they are on an outside wall.

4Ever_Steamed

Outside walls

Yeah, they're on the outside walls, and will be behind the new drywall... You make a good point, some of the heat I'd be "losing" is radiated into the room anyway by the hot pipes behind the wall.

Steamhead

And some of it

would radiate to the outside. Insulate those pipes! 

haaljo

Insulating steam riser inside an outside wall.....

.....is something you won't regret. You have to keep the riser from losing heat to the outside and you only have a one chance so do it now. No use heating the outside. I built a two story addition with steam radiators and put the risers inside the (exterisor)  walls. Insulated but didn't insulate enough. Looking back, I probably should have put the risers in a chase and not in the wall. 

Steamhead

So you are a member

of the Steam Installers Club?



Excellent!



How about some pics?

Therm_lag

Retrofit Riser Insulation

I do energy audits (also in Chicago) & specialize in steam heated buildings though have never talked a customer into selective insulation at risers run up exterior walls.  There are a couple of expand-in-place and a couple of pump-in-place insulations that would probably flow behind pipe and fill the pipe chase -- usually a single brick -- through holes in the interior finish -- usually L&P.  I believe a "pre-mixed" (and pre-expanded -- I call 'em "pump-in-place") insulation is a better bet to flow behind pipe than one- or two-part UF or polyisocyanurate foam.  Air Krete does not seem a good bet as I doubt it will tolerate pipe expansion / contraction.  Urea-based foam shrinks some, and may crack.  Tripolymer (brand name) and similar phenolic based foams seem the best bet, though I'm told the DOE has no funding to research basic insulation performance that will assess their corrosiveness.  I'll re-check with DOE "Insulation Factsheet" researchers and report back, though I hope someone using this knowledge exchange may have experience with insulating riser pipes through the interior finsish.  What I learn will be reported (and acknowledged) at "



Steam

Heating: Past, Present, & Future" at the Affordable Comfort conference in April.  Thanks!