Nomex for boiler insulation?

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INGE
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Nomex for boiler insulation?

Post by INGE »

Has anyone here tried Nomex fabric for boiler insulation under the lagging? The only caveat I am aware of would be that Nomex tends to shrink at high temperatures, but at 330F I not sure shrinkage will be a factor. I have several sets of Nomex long underwear left over from my racing days, and am planning to give it a try as boiler insulation.
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NP317
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Re: Nomex for boiler insulation?

Post by NP317 »

Ceramic fiber blankets work well:

https://www.amazon.com/s?k=ceramic+fibe ... nb_sb_noss

and are available in many different thickness and sizes.
I used 1/4" thick sheet on my boiler.

RussN
Boiler Insulation sml.jpg
Last edited by NP317 on Tue Sep 21, 2021 8:50 pm, edited 1 time in total.
Soot n' Cinders
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Re: Nomex for boiler insulation?

Post by Soot n' Cinders »

I got ceramic fiber as well, but I ordered mine from McMaster Carr in 1/8in thickness. I found two thinner layers easier to work with both to cut and to form to the diameter of the boiler
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Bill Shields
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Re: Nomex for boiler insulation?

Post by Bill Shields »

If you have it then it is not a bad choice. (Already paid for qualifies as a good price)

Just do a large overlap to cover shrinkage.

We're I purchasing I would go (and have gone) the ceramic blanket direction. My nomex coveralls that are 40 years old still fit and I use them from time to time.
Too many things going on to bother listing them.
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Dick_Morris
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Re: Nomex for boiler insulation?

Post by Dick_Morris »

In actuality, there are only a few places on our locomotives that get hot enough to need the high temperature capability of Nomex or ceramic fiber. Several of the full-sized operating locomotives use a metal strap framework to support the jacket and household fiberglass to insulate the boiler.
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Re: Nomex for boiler insulation?

Post by ccvstmr »

You're right Dick...at 125 psi, the water temperature is approx. 325 deg. Boiler insulation slows the migration of heat from hot to cold (as do all insulations). No matter what the insulation thickness is...or how many thinner layers are used...it's only a matter of time before the insulation becomes "heat soaked". The boiler jacket being a different material and also holding the insulation in place...slows down the rate of heat loss. Still, would prefer to keep as much heat IN the boiler as possible.

On the Rutland...used 1/4" thick ceramic wool insulation. Was easy to cut. Towards the rear of the tapered-looking boiler, simply wrapped another layer of insulation around the top and sides. Insulation joints were covered with adhesive-backed aluminum foil tape. If the tape comes loose, don't think the insulation is going to move around much under the jacket.

And the end result...sometimes have trouble keeping the safety down...even with the burners firing at minimum. Just another few thoughts from someone that has insulated a boiler. Carl B.
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Re: Nomex for boiler insulation?

Post by INGE »

Thanks guys, I appreciate the replies.
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Re: Nomex for boiler insulation?

Post by Glenn Brooks »

I used woven ceramic fiber on my Ottaway boiler a few years ago, replacing some old household fiberglass insulation. Three things I liked about the blanket was it didnt compress compared to fluffy household insulation, doesn’t fall apart when you take it off (hence reusable) and seems to have a decent R value, again compared to the fluffy stuff. particularity when in compression and gets wet.

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Dick_Morris
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Re: Nomex for boiler insulation?

Post by Dick_Morris »

Chuck Hackett's lagging tests. Too bad he didn't also run tests with fiberglass and/or ceramic wool. http://whitetrout.net/Chuck/844/Tests/Lagging/Index.htm
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Re: Nomex for boiler insulation?

Post by Steggy »

Dick_Morris wrote: Tue Sep 21, 2021 10:58 pmChuck Hackett's lagging tests. Too bad he didn't also run tests with fiberglass and/or ceramic wool. http://whitetrout.net/Chuck/844/Tests/Lagging/Index.htm
The lagging consists of a powdered form of asbestos that turns to a thick paste when water is added and hardens to something like a grainy, fibrous Plaster of Paris.

When I worked at Vapor Corp., I spent more than a little time working with the steam generators they built, which were standard appliances on passenger locomotives up until steam heat was phased out. I spent a fair amount of time reading through engineering notebooks and looking at test data to better understand the product line.

I learned among other things that asbestos is not that great a thermal insulator, especially the paste form Chuck describes. Vapor had used that method of insulating steam generators for many years, as it was economical and production-friendly (of course, no one back then paid attention to the hazards of asbestos). During the mid-1960s, Vapor discontinued the use of asbestos for steam generator lagging and switched to fiberglass for vertical generators and ceramic for horizontal ones (the latter are used in industrial applications). Extensive testing proved that these changes substantially raised the thermal efficiency of the generators, especially the horizontal ones. As a bonus, manufacturing costs went down slightly.

Chuck should consider a retest with ceramic the next time he has the boiler down for maintenance or repair. He might be more than a little surprised at the gain.
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Re: Nomex for boiler insulation?

Post by KarlKobel »

Hey BigDumbDinasaur,

I have been working for Vapor for the past 10 years. Although it's Vapor Bus now and our parent company is Wabtech.
We make door and other equipment for transit busses.
I find it ironic that I work for a railroad company in the bus division.

Karl

PS. There are a few people that still work there or have just retired that you may have known.

PPS. I didn't use any insulation on my boiler and I have a hard time not lifting the safety's. The jacketing is stainless (reflective) and the boiler is dark.
Last edited by KarlKobel on Wed Sep 22, 2021 5:15 pm, edited 1 time in total.
ccvstmr
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Re: Nomex for boiler insulation?

Post by ccvstmr »

BigDumbDinosaur wrote: Tue Sep 21, 2021 11:47 pm
Dick_Morris wrote: Tue Sep 21, 2021 10:58 pmChuck Hackett's lagging tests. Too bad he didn't also run tests with fiberglass and/or ceramic wool. http://whitetrout.net/Chuck/844/Tests/Lagging/Index.htm
Chuck should consider a retest with ceramic the next time he has the boiler down for maintenance or repair. He might be more than a little surprised at the gain.
Been a few years since I read that boiler test. My first thought...the test was flawed. A more realistic test, would have taken the boiler up to operating pressure (and temperature) and THEN...watch the temperature decay over time. Will get the largest temperature drop at the start before the change in temperature over time flattens out.

I've heard people swear by "no insulation on a boiler". Okay, it's their loco, they're free to do what they want. I live in one of the Chi town 'burbs. I would never live in a house that WAS NOT insulated. If I could have afforded it, would have opted for 6" exterior stud walls with 6" of insulation... instead of 4" studded walls and insulation. For the house...it's a "comfort and energy consumption" thing. For a loco...will do whatever is possible to "optimize" heat retention and extend the fuel supply. Carl B.
Life is like a sewer...what you get out of it depends on what you put into it!
I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!
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