Insulating Steam Pipes

Brycewvu

I am working to insulate my one pipe steam system near Baltimore, MD, and looking for some advice on a few items before ordering the insulation.

I plan to use 1" thick fiberglass insulation on the main line, radiator branches, and the returns located in the house's main basement (approx. 185 feet total). I also have a few pipes located under our kitchen in a dirt crawl space (estimating about 40-50 feet total). For those pipes in the crawlspace, is it worth the extra money to insulate those pipes with 1.5" thick insulation vs 1"? Based on pricing that I have found, it would be about 70% more expensive to jump from 1" thick to 1.5" thick insulation, but I realize that area is exposed to colder temperatures.

Also, I have several sections of near boiler piping that are T'ed very close together. In the case of the supply main, that is the only area where 2.5" pipe is used (approx. 1.5 foot long when you account for the fittings). Examples of both are attached. What is the best method for insulating these areas? Should I overlap T fittings or cut small spacers of pipe insulation? If I can overlap the 2.5" fittings, that would prevent me from having to buy a full length of insulation for about 8" of that pipe.

trivetman

If u are talking about the pvc covers for the Tees,  you can install them that close together but it will take some work with a scissors to cut them down and make it work.  Its doable but it takes some customizing when the fittings are that close together.

Mad Dog_2

Zeston Fittings..Make sure yiu use Owen's Corning, the Box store stuff is lame. ..Its probably not worth it, but if you have the extra $$ now, a BTU saved, is always a good thing.  Take your time with the insulation and make sure you get a good roll of the white tape for the joints. Use a brand new utility 🔪 for easy cutting,  parsing the joints. Wear a long sleeve shirt   mask is a good idea.  When all done, wash down your exposed body parts with cool water, not hot.  Good luck.  Mad Dog 🐕 

Intplm.

Zeston fittings are the way to go. As @Mad Dog_2 states above.
When you make your purchase, get the white thumbtacks, maybe a roll of their white tape, and the white paste that they use for sealing the insulation joints. And be sure to have the insulation inserts that come with the joints. Sometimes they are forgotten. This will make for the best installation possible.
As for the wall thickness of the insulation. Get the best you can afford.

Mad Dog_2

I forgot the White tacks...must have em!  Mad Dog 🐕 

trivetman

For insulation thickness…I put 1.5” on most of my pipes and barely feel the heat with my hand on the insulation jacket.  Cant say how much less a job 1” would have done.

for the small section of 2.5” pipe, you can use the 1.5” insulation meant for 2” pipe,  and cut a bit out of the center to make it fit the bigger pipe.  That way you don’t need to buy a full piece for only an 8” stretch.

and yes….definitely get the tacks and tape to seal things up.  I didn’t use the paste (and don’t think I needed to)

Mad Dog_2

The Paste neatens up and binds the Fiberglass fibers.  The Professional Union Installers that I've seen use it.  No matter how long you take and careful you are, it will never look better than what those guys do...8 hours a day!  Mad Dog 🐕 

Brycewvu

Thanks for the advice. I found a local insulation distributor that is willing to work with me on pricing rather than go through an online retailer. They originally quoted me for insulation based off copper pipe. When I called them about the change to iron pipe, they said they would honor that pricing and give me the iron pipe size for the copper size price. Is that actually cheaper?

They recommended that I don't need to buy union fittings and can simply cut out a portion of the insulation to accomodate the fitting diameter. Should I look at specifically buying union fittings? I feel like it is obvious that the thinner I make the insulation at the union, the less efficient it will be. Is that trouble/extra pricing for union fittings worth it?

ethicalpaul

No

Brycewvu

ethicalpaul said:

No

I'm assuming you are saying no to the pricing? haha

ethicalpaul

Sorry, I was answering your last question about if the extra pricing and effort for fittings was worth it

Big Ed_4

From nothing to something it is a good factor with insulation . Adding 50% more the factor bumps up less than you expect . I would give the ok on 1"for heating . It does add up , I know ...

Brycewvu

If the upfront cost outweighs the benefits, I think I'm going to stick with the 1" insulation and use the savings toward other improvements. I purchased this house last year and got raked over the coals on heating costs. I installed a smart thermostat which seemed to make a bit of a dent, but my plan is to insulate the bare pipes, install main vents, and replace radiator vents to get everything as efficient as possible.

trivetman

Pvc covers made it much easier to deal with elbows and tees.  For unions you can definitely get away with cutting a bit of the insulation out of the inside to extend the pipe insulation out to the nut and just leave the nut bare.   A little bare metal wont make much difference.

1” should be fine.  The extra half inch would just be a little extra.  Going 1” also will make things a little easier to work with.

copper pipe has a smaller outside diameter than iron for the same nominal pipe size.  So insulation that fits 1” iron is slightly bigger around than 1” copper.  It’s probably a different price bit not by that much 

ethicalpaul

Don't expect to see any noticeable change in your heating bill based on insulating your pipes. It's especially difficult to compare given all the other variables

trivetman

I didn’t have the pipes uninsulated long enough to measure the expense.  After we had the asbestos removed the basement was a solid 80 degrees for a couple weeks.  I figured I couldn’t afford to wait to see how much it was costing!

ethicalpaul

Yes, then it will help for that! But some of that 80 degrees was helping to heat your first floor presumably, so you might see some balance issues after you insulate. But yeah I would insulate too if my basement were 80

In fact, I insulated mine even though my basement wasn't that warm. I think my payback is going to be like 30 years