Insulation

Ed2

We just replaced our boiler and I need to insulate the near boiler piping. I'm looking for the right fiberglass insulation thickness to use. Two sources seem to say 1.5 inch thick for 2-inch pipe or smaller and 2 inch thick insulation for larger pipe. Sound right?



I checked the insulation on the mains (a mixture of 2" and 1.5" pipe) and found it is only 1/2" thick. Is it worth the cost of replacing it with 1.5" insulation? Here's a photo of what's on the mains now (I put it on about 8 years ago). (This is actually from a smaller pipe, but the same stuff is on the mains)

Rod

Insulation Info

Hi- 1 inch insulation seems to be the most common used for steam piping as it gives the biggest "bang for the buck"  Here is a link to a good posts on insulation by "Crash", one of the contributors to this board. http://www.heatinghelp.com/forum-thread/137178/Insulation#p1236446

This link is a source for insulation that some of the pros use:

http://store03.prostores.com/servlet/buyinsulationproducts/StoreFront

I've also attached a graph done by David Nadle showing insulation thickness comparisons.

You also might want to use the "Search the Wall" feature as there are a lot of past discussions on insulation available there.

- Rod

Ed2

Thanks

Thanks. I did see Crash's page when I did a search but had trouble finding comparisons of gains for each thickness. Your graph answers everything, though- I need to replace the 1/2" stuff. It isn't doing anything. What really steams me is that I didn't know enough to check back then and the difference in cost between 1/2" and 1" is very small.



Okay, what I'm going to do is insulate with 2" around the header because there's not much pipe there but it is 3" pipe and radiates more. All the 1/2" insulation will be junked and replaced with 1 or 1.5 after I look at cost a bit more. What a waste. Maybe I'll cut up the 1/2" stuff, layer it, and use duct tape to handle the various tees and elbows along the mains. That'll get back a bit of the value spent on that stuff.

Ed2

ExpressInsulation

By the way, does anyone have experience with http://expressinsulation.com ? Their prices seem lower than others.

Long Beach Ed

Compare

I've compared the two suppliers listed above. One has cheaper prices for the Fiberglas, the other is cheaper for the PVC fittings.   We use 1" for the reasons stated above.



As we're in New York, we use the one closest to us. Our orders wind up here the next day.  Shipping is costly and there's nobody to talk to if you need help.  Their customer service is non existent.  They also charge sales tax no matter where you are or if you have a resale certificate.  Typical, unfortunately for many Internet sales.



But we've ordered from them for years and never had a problem.

Ed2

Which?

Are your comments about customer service for the ExpressInsulation site or for the BuyInsulation site?



Thanks.

Ed2

Another way to look at it.

Okay, here's another way to look at it... I estimate there are 76 feet of 1.25" uninsulated pipe in the walls that I can't do anything about. There are another 126 feet of 2" and 1.5" pipe that can be insulated. If I use the numbers in your chart for heat loss and if I use the chart here (http://www.engineeringtoolbox.com/heat-loss-steam-pipes-d_268.html) to estimate loss from the pipes in the walls to be 155 BTUH/lin-foot, then the 1/2" insulation I have on the pipes right now gives me a pick-up factor of 1.50. If I put 1 inch insulation on, using your chart, the pickup is 1.27. If I put 1.5 inch insulation, it only falls a little bit more to 1.24. In fact, if there were zero loss from the pipes in the basement, it only falls to 1.21 because of the losses that I can't do anything about.



So, it looks like more than just return on cost of the insulation. If I stay with 0.5", the new boiler may struggle (the old one was over sized by almost 2 fold). If I put on more than 1 inch, it just doesn't do much.



So, one inch it is (except for the 3" piping near the boiler where I'll go thicker).

Mark_125

Should I add another 1/2 inch?

Wow, I really wish I hadn't read this thread. (

I too insulated my pipes a few years ago after inheriting a steam system and reading Dan's books. I just went to the orange big box store and picked up pipe insultation. I measured it last night and it too is only 1/2 inch.

Looking at the graph above there really is a big difference between 1/2 inch and 1 inch in terms of insultation value, but little difference in price.

So i'm wondering now if I can just wrap what I already have in more 1/2 inch to bring it up to 1 inch total - anybody have any thoughts on this? I probably have about 60 feet of 2.5 inch main in the basement.

Thanks,

Mark

ChrisJ

Insulation thread

There is a recent insulation thread on this forum started by Crash2009.  It contains all you could ever want to know about insulating steam pipes.



Insulate the steam pipes and insulate them well, theres just no reason not to.

Dave in QCA

Good Experience

I have purchased from them with good experience.

David Nadle

Rewrap

I think if you can find 1/2" insulation with an ID that is fairly close to the OD of your current insulation you can add another 1/2".



One thing you might do is add a couple of rings of foam double-sided tape to each length of the original insulation before you add on the second set to help make them an integral unit and stop air flow. But check the service temperature on the tape. If I was doing it I would also stagger the seams.  

crash2009

I'll second that David!

If the existing half inch is sound and installed good and tight, theres nothing wrong with adding another layer.  I don't know exactly what size you would need but for example, if you have a 2" main, and it has a half inch on it, get some ID 2.5" by 1 inch thick.  You would end up with 1.5" and would save yourself the hassle of removing the old.  Plus, layers are better than one peice anyway.

Ed2

Cheaper to use right stuff

For 2" main (OD 2.375") and 1/2" insulation, you'd have an OD of 3.375 for the new 1/2" to wrap around. That would be a rough fit of a 3" pipe insulation. But the 3" half-inch is $6.21 and the 2" one-inch is $5.67.



So, it's cheaper to just use the right stuff and throw the old stuff away, at least for one vendor.

Ed2

That graph

Hmmm. Be careful with that graph. It's not what I thought it was. It's not the heat loss for the different thicknesses. It's how much you more you gain going to the next thickness. So, going from bare to 1/2" you save 130 btu/ft. Going 1/2" to 1" you only save 16 btu/ft more.



I think that's what is plotted. Would you ever earn back the cost of throwing away 1/2" and putting in 1"?