(Re)insulating basement steam mains - questions

hockeyman001

Just had the magic mineral removed downstairs. Mundane questions, but I want to do this part correctly. Contractor already removed/disposed of the asbestos as per code and placed a sealing coat over the exposed pipe.

Will be reinsulating with fiberglass (DIYing this part to save $$), contractor gave me the measurements I need. Contractor said a couple of things that I wanted to put to the test of the experts here:

1-Elbows and tees. Contractor says not necessary to insulate, and it might be more trouble than it's worth. The fiberglass "rolls" with the sticky flap on one side to complete don't seem to have a tee or elbow shaped option, just standard. Searching online for "elbow and tee steam pipe insulation" just took me to a page where some company was bragging about a fiberglass product contained in a PVC shell which just sounds like a bad idea...Is there a good way to insulate elbows and tees, or will the heat loss through them be relatively negligible?

Details: It's approximately 45' of steam main that will be reinsulated (22' or so that won't be which runs through the currently unheated garage - for heat obviously - that will be offset by the 30' of risers running through the first floor of the home that will be getting insulated for the first time). Of the 45' there are approximately 12-14 elbows/tees (I didn't take an exact count, but can if asked).

2-Seam facing. The contractor mentioned that the insulation should be installed with the "seam" up. Does the direction the open part of the insulation faces matter before the flap is sealed over it? I've never heard anything like this before, but he mentioned it so I wanted to ask here.

3-Painting over the seal coat. Is this recommended before re-insulating? If so, what is generally regarded as the best "high heat" paint on the market nowadays, and what are its instructions for application (IE corresponding primers, etc.)?

Thanks for all your help!

New England SteamWorks

1. The insulation for elbows and tees are called PVC Fittings. They can be found here. Don't forget to buy tacks and 2 rolls of 2" tape. I always insulate the fittings. Seems silly not to. If you are going to do something...do it right.
2. Seam facing doesn't matter far as I know.
3. No need to paint the pipes.
4. Be sure to insulate with 1". Twice the insulation value of 1/2". I did my own pipes in 1-1/2", but that is probably overkill.

You can see a finished insulation job with PVC fittings here. Look for the dog.

Good luck and have fun. Send us a pic or two when you're done.

Jamie Hall

A word on that uninsulated section of main "for heating" in the garage. I can't recommend that. For two reasons. First, it will produce remarkably little heat -- a 2" main has an effective area of half a square foot per foot, or 15 square feet for a 30 foot length. Somewhere around 3600 BTUh. That's less than a 15 amp electric barn heater.

While it's producing those 3600 BTUh, though, it will also be condensing like mad -- and if you seriously plan to leave it open, you really should slope it away from the boiler -- generously -- and place a drip at the end of the uninsulated section to handle the condensate. Otherwise, you may find yourself with a nifty water hammer.

It will also reduce steam output to any radiators beyond it.

gerry gill

you can also buy 1-1/2'' thick or 2'' thick fiberglass and miter the corners and carve out for the fitting thickness, as seen here.

http://www.gwgillplumbingandheating.com/webapp/p/678/jordan-boiler-repipe

gerry gill

here is another method using high temperature insulation cement similar to how the old timers used asbestos cement.

http://www.gwgillplumbingandheating.com/webapp/p/246/tudor-drive-repipe

Fred

Do insulate the piping in the garage.
No need to paint any of the pipe

hockeyman001

gerry gill said:

you can also buy 1-1/2'' thick or 2'' thick fiberglass and miter the corners and carve out for the fitting thickness, as seen here.

http://www.gwgillplumbingandheating.com/webapp/p/678/jordan-boiler-repipe

Interesting. I see the miter box technique for the elbows...how did you cut the tees using this method?

hockeyman001

Jamie Hall said:

A word on that uninsulated section of main "for heating" in the garage. I can't recommend that. For two reasons. First, it will produce remarkably little heat -- a 2" main has an effective area of half a square foot per foot, or 15 square feet for a 30 foot length. Somewhere around 3600 BTUh. That's less than a 15 amp electric barn heater.

While it's producing those 3600 BTUh, though, it will also be condensing like mad -- and if you seriously plan to leave it open, you really should slope it away from the boiler -- generously -- and place a drip at the end of the uninsulated section to handle the condensate. Otherwise, you may find yourself with a nifty water hammer.

It will also reduce steam output to any radiators beyond it.

My issue and reason for wanting to do this has nothing to do with comfort and only due to the fact my water main is in the unheated garage (northeast US) and I'd rather have a safer way of doing things than leaving a space heater unattended in there on the coldest days of the year. I'm aware it won't generate enough heat to make the garage comfortable, nor am I hoping for that, just enough to keep the garage warm enough I don't have to worry about the water pipe.

There is a drip in the middle of the section, towards the end of the long run. Basically, the line runs down one side of the garage, then a short rise goes up before crossing the garage near the door, where a second riser goes into the radiator. The drip is basically off the main underneath (but offset from, of course) the first rise I described.

Further, the radiator fed from the line in the garage is one of two in the front entry room/future laundry room, which is huge and there is more than adequate heat between the two of them (the other is fed by a line that will be completely insulated). So if there is a little heat loss from this, it's not a big deal. My concerns on this would be mainly related to water hammer. I can say, however, that last year, when running the system from a cold start all last year with the asbestos insulation still there (ie coming back from a vacation where the heat was turned significantly down during winter), it didn't really generate any water hammer on the first long cycle to bring it back up to normal temp.

gerry gill

hockeyman001 said:

gerry gill said:

you can also buy 1-1/2'' thick or 2'' thick fiberglass and miter the corners and carve out for the fitting thickness, as seen here.

http://www.gwgillplumbingandheating.com/webapp/p/678/jordan-boiler-repipe

Interesting. I see the miter box technique for the elbows...how did you cut the tees using this method?

kind of like a straight piece with a hole in its side..kind of hard to explain.

JUGHNE

When I did this for tees, I would "whittle" the inner layers of FG out enough to slide over the hubs of the Tee. Whittle 1/2 a hole in each length for the takeoff pipe. Then for the take off run I would do a little whittling for that smaller hub. This would push the FG insulation right together.
Tape around the Tee up towards the branch, then tape around the first taping on the branch.
I would do the fittings by this method first then fill in between with straight lengths.

The 90's never looked good without a lot of tape and patience.

I think Gerry had a method with the gauze and some compound that made this look as good as the asbestos you removed.

The factory covers look really good but the FG you wrap on the fitting first is pretty thin/wimpy in comparison to the straight lengths.

hockeyman001

JUGHNE said:

When I did this for tees, I would "whittle" the inner layers of FG out enough to slide over the hubs of the Tee. Whittle 1/2 a hole in each length for the takeoff pipe. Then for the take off run I would do a little whittling for that smaller hub. This would push the FG insulation right together.
Tape around the Tee up towards the branch, then tape around the first taping on the branch.
I would do the fittings by this method first then fill in between with straight lengths.

The 90's never looked good without a lot of tape and patience.

I think Gerry had a method with the gauze and some compound that made this look as good as the asbestos you removed.

The factory covers look really good but the FG you wrap on the fitting first is pretty thin/wimpy in comparison to the straight lengths.

Sounds reasonable enough. Do you recommend the "whittling" method for a few couplings I have also, or would it be sufficient to just compress the insulation over them? If I whittle couplings/tees, should I get the next pipe size up insulation (and just whittle/tape really well at seams), or is it OK to use same size sleeves as the surrounding pipe (ie they'll "close" well enough around the larger diameter of the couplings/tees)?

Putting the order in over the next few days, and definitely want to get it right.

JUGHNE

If you go the next pipe size up and cut a length to match the fitting, that might avoid the whittle work. However the exposed edges of FG would show up on the oversized section.
The sealing tape does not stretch like electrical tape would.

See Gerry Gill posting up the page for the gauze/cement.

This FG will compress very little as it is pretty dense.

If all else fails, you could order the fitting covers later. Freight on those would be minimal.

steamhouse

http://www.bing.com/videos/search?q=how+to+cut+steam+pipe+insulation&&view=detail&mid=A45927C29D6DE1A76513A45927C29D6DE1A76513&FORM=VRDGAR

hope this link works.

hockeyman001

Got some supplies and have started (more are on order). What is the best way to deal with pipe hangers? Is it best to just butt the insulation up close to them and cover with tape, or do I really have to try to raise the pipe to get the insulation around the pipe (and under the hangers)? Don't want to mess up the pitch of the pipe in doing so, plus that seems like it might be difficult to do correctly. Wondering what the pros would do.