Chimney Insulation

[Northern Heat]

Hey it's me again.

Living in a remote place where things just cost double what you might pay in the south,I like to figure out how to do things myself.

I recently put in a econoburn ewb100 and love it . I have single wall stove pipe between the boiler and the insulated chimney exit. Since the flu temperatures are so low with these things to keep the temp in the chimney as hot as possible I would like to insulate it.
Even though these boilers don't cause creasote build up I want to make sure what ever I put on the single wall pipe is good enough for a chimney fire ,even though the chances are low.

Having just put an addition on the house and put in ROXUL mineral wool insulation ,I was wondering if this would work? Ihave put a torch on it and it does sort of smolder away a bit but never when the flame is off of it and never does it catch fire.

I'm pretty sure this is the stuff in side a lot of insulated chimneys and I have a lot left over from my project.

What I was thinking of doing was wrapping it around the pipe and then wrapping it with aluminum fly screen to keep it all together,then perhaps with aluminum flashing sealed at the joints with high heat silicone.

Does anyone see a problem with this besides the fact that it is not code?

 

[stee6043]

I don't think Roxul is intended to be used in this way. It may be fire resistant but that doesn't mean it's intended for contact with surfaces regularly being heated above room temperatures. I'd say installing it as you've suggested is a big stinky mess waiting to happen. Just my two cents though...

If you really want some fun you should call Roxul and ask them about this application. I'd bet it'll take less than 8 seconds for them to explain "don't do it"...

 

[Northern Heat]

Thanks for the reply;

I thought so as well as far as the stink so I tied a some on a test patch ,on the actual chimney in question yesterday and no sign of smell and after the day was done I took it down and no sign of heat damage at all and this was 6" from the boiler chimney exit.

Roxuls site claims that the product in question cannot burn and will not release toxic off gassing when in a fire.

To quote their site" Non-combustible stone wool insulation with melting point of approx. 1177°C (2150°F)". That's as hot as the core temp of the boiler at the combustion zone. Though of coarse their lawyers would and the company itself would never admit that it was a good idea for obvious reasons .

I tried the torch on it with a layer of regular stove pipe in direct contact and there was very localized distress to the product.But that was with exterme temps likely never to be seen in a chimney fire.The heat from a bad chimney fire does not reach the actual chimney part until the fire hass reached its worse because the creasote acts as a layer of insulation,while the flame travels up the center of the pipe.

I simulated a chimney fire as well today with a bit of stove pipe held on a slight rise with the product wrapped around it with stove wire and lit a fire in the bottom end till flames were licking out the top the fire lasted 15 minutes . There was signs of light melting directly over fire and maybe a foot up . There was also discolouration of the wool to a grey colour an inch into the material.But I think this was likely some sort of colourant to make it "GREEN" that burnt away,because the insulation still has the same feeling as the coloured stuff.The worst smell was from the paint being burnt off the chimney...... granted this was a worse case scenario with what would be a huge chimney fire,with way more fuel in the chimney than would ever be found in wood gasifier boiler chimney. All that builds up in these chimneys is a light ash like coating which never seems to build up.

Not saying I am going to try it but might experiment further.

 

[ewdudley]

I would be a little concerned about insulating plain steel pipe to begin with. It wouldn't take too many stints above 400C to graphitize thin pipe.

As for the ROXUL, be careful or you may become the victim of 2-4-5 tribromocarcinogen outgassing, not to mention aldehydes of afraidium.

How about adding some ROXUL around exterior portions of the flue system? It might be safer and more effective given the larger surface area, greater delta-T, and wind. I've seen where "Canadian-spec" insulated flue pipe normally has more than twice the insulation than that sold in less demanding environments.

Cheers --ewd

 

[Duetech]

If you are using 6" pipe you might want to try a 7 or eight inch pipe around it and or a 10" around that. The Roxul sounds like it will handle the temperatures you are experiencing but if you really did have a problem it seems the aluminum would be a serious weak link.

 

[Northern Heat]

Good point on the aluminum . We should all remember the Falkland war tragedy of the aluminum cruiser destroyer.

Thanks

 

[Gooserider]

My understanding is that you are not supposed to put ANYTHING around black steel stovepipe - I do know that code says that all steel connector pipe must be visible for inspection and observation, which is one of the reasons it isn't legal to run it through a wall, not even a non-combustible one... The problem is that it's fairly thin stuff, and is prone to corrosion issues, so they don't want it hidden away where it could get holes rotted in it and not have it noticed...

If you want to insulate the connector pipe, which isn't all that bad of an idea, you might want to see if you can replace the black steel w/ stainless - the stuff is pricey, but it will last just about forever, unlike the black steel stuff.

Gooserider

 

[Duetech]

Northern heat, here is some eBay stainless stuff to look at http://home.shop.ebay.com/?_from=R4...nkw=stainless+steel+chimney+pipe&_sacat=11700

http://home.shop.ebay.com/Home-Garden-/11700/i.html?_kw=stainless&_kw=chimney&_ckw=pipe&_npmv=3

The local hardwares handle 20ga and 18 ga black pipe in my area and without a covering on it that stuff can last a long time. It was a bit of an investment but I am using some class A triple wall with stainless inner sleeve that I have been using for 20 years. I even used some of it inside the house where I had a long run just to keep the flue temperatures up and prevent creosote.

 

[muncybob]

Goose, are you saying it would be OK to insulate single wall SS pipe? I would like to insulate the 6" SS 4ft run I have from the boiler to the chimney. I was also thinking of the ROXUL if I can find somebody local that will sell me the little I need.

 

[stee6043]

This mystery is easily solved, Gent's. Call Roxul! I'd bet a six pack of beer that contact with stove pipes is something they are not going to sign up for. Insulated pipe is pricey for a reason - it's a designed solution. Wrapping stove pipe with insulation just sounds like a horrible idea no matter how you spin it, in my humble opinion.

Menards sells 3' sections of insulated 6" SS pipe for $69 last I checked....

 

[Gooserider]

Goose, are you saying it would be OK to insulate single wall SS pipe? I would like to insulate the 6" SS 4ft run I have from the boiler to the chimney. I was also thinking of the ROXUL if I can find somebody local that will sell me the little I need.

Not positive, and I would want to see a manufacturer's listing to be certain, but I believe it can be... Certainly they make insulation wraps for when you are putting an SS liner inside a chimney, what I'm NOT sure about is whether those wraps would be acceptable if NOT enclosed in a chimney. Probably where I would start asking though...

Gooserider

 

[Northern Heat]

Thanks for all the replies .

Having too much time on my hands I think of some wierd stuff. The thought of Roxul on a pipe though in theory would do the job ,you are right that it would probably not be the best solution.Even though I cannot get the stuff to burn it does discolour and that in it self is a bit disconcerting . They say its just mineral wool 100% but do you believe that ? Chances are there is something in there that ain't good for me. It might protect my house from fire when properly installed in a wall.

If I was in the Antarctic with a bag of Roxul and some old single wall pipe then the solution would be obvious. The prices up here are not that bad even though the 69.99 piece of pipe you get down there is 140.99 up here in the NWT.


As an outside solution I think this would work great as long as it was well protected from the elements and our wives would let us put the ugly solution up.HE hE

I lived on my trapline in a very remote spot for twelve years ,where only bush planes could get in and if there is a solution at hand I always explore it .The internet sure makes that easier.

Thanks

 

[Gooserider]

Purely speculation on my part, as it is not something I've looked into, but I would not be surprised if Roxul and such products had small amounts of some kind of relatively non-toxic, not-very-combustible stuff left on it from the manufacturing process, which might need to burn off, and could cause discoloration in the process - possibly like a lubricant for the processing machinery... The burn-off idea is not that different from the "New Stove Stink" we get from a new stove as it burns off the preservative residues and finishes curing the paint from manufacturing...

What I do know is that the chimney liner folks sell insulation blankets to go around liners inside a chimney, and that SS pipe is OK for the application, while black steel is quite emphatically prohibited. From the pictures and descriptions of the blankets, they sound like a mineral wool type material with some sort of facing, as you are supposed to wrap it around the pipe and then tape the seam closed with the supplied special tape... They then have a woven stainless steel mesh "sock" that slides over the insulation blanket which is supposed to hold everything together, and also protect the insulation as you stuff it down the chimney. Technically the insulation blanket is actually REQUIRED as part of the assembly when doing a proper NFPA approved chimney reline job. (i.e. if trying to bring a non-compliant chimney up to code, as opposed to just reducing the cross section of a compliant chimney) As I recall the price for an insulation kit was not all that bad, I would definitely consider it if you find out that it can be used...

What I don't know...

1. Exactly what the blanket and facing is made out of, or the tape.

2. Whether it is OK to use the blanket, etc. outside of a chimney.

3. If there are any other gotchas involved in using it...

Gooserider

 

[Northern Heat]

Thanks Gooserider

Actually had looked into those chimney liner kits and I think they are exactly what I need along with the SS steel flexable chimney insert except using it between the boiler and the the insulated chimney exit port. The only problem was the price starting at 399$ for a 25 foot kit and I only need 10.One question I would have is could they be used in a indoor environment without any possible outgassing of nasties.In a chimney lining situation all nasties go up and out of the home environment .

If I do go that way I would have to find that out . The boiler is in a room attached to the house and only accessable from the outside , it is a rather small room . To be able to flex the pipe over to the chimney exit would be great.Not to mention easy to disassemble to clean .

I do have a workshop to build next year with of coarse wood heat so perhaps I should just bight the bullet .

 

[4acrefarm]

How about a ceramic blanket? Search ebay for refractory or call the refrctory store at 1 800 325 2492. They say it is good for 2000* prolonged use. I may try this myself if they say it will work. 25'x2'x1/4'' 30 something usd.

 

[Gooserider]

Thanks Gooserider

Actually had looked into those chimney liner kits and I think they are exactly what I need along with the SS steel flexable chimney insert except using it between the boiler and the the insulated chimney exit port. The only problem was the price starting at 399$ for a 25 foot kit and I only need 10.One question I would have is could they be used in a indoor environment without any possible outgassing of nasties.In a chimney lining situation all nasties go up and out of the home environment .

If I do go that way I would have to find that out . The boiler is in a room attached to the house and only accessable from the outside , it is a rather small room . To be able to flex the pipe over to the chimney exit would be great.Not to mention easy to disassemble to clean .

I do have a workshop to build next year with of coarse wood heat so perhaps I should just bight the bullet .

It's a lot more expensive, and somewhat limited, but I will admit to preferring rigid to flex if at all possible, as it is easier to clean and doesn't have the possible leakage issues that the spiral seam flex has, but there is stuff you can do with the flex that you can't do with anything else...

I can't do much to help you on the specs, I would probably Google for some of the factory sites and ask their tech support people...

Gooserider

 

[muncybob]

How about a ceramic blanket? Search ebay for refractory or call the refrctory store at 1 800 325 2492. They say it is good for 2000* prolonged use. I may try this myself if they say it will work. 25'x2'x1/4'' 30 something usd.

I did not see anything on Ebay but I did send an email to these folks asking if they have a suitable material in the low volume that we need.
(broken link removed)
If they only sell a larger volume perhaps there are others here interested in going in on this? I was sure to ask if the material can be used in our application(living space air exposure).

 

[Northern Heat]

I did find this on E-Bay under ceramic blanket .Looks like good stuff. You would still need some kind of reflextive layer though,perhaps.
(broken link removed to http://cgi.ebay.com/SAFE-Non-Ceramic-Fiber-Blanket-1-6-dens-SW607-HT_W0QQitemZ130349087002QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1e5969391a#ht_500wt_967)

Might get this myself

Cheers

 

[4acrefarm]

I just ordered a ceramic board $30. A blanket 1/4"x2x25, $27. and 2 tubes of 3200* glue $7.50 each plus shipping. 1 800 325 2492 west coast time zone. I don't know exactly how I will use it, just experimenting with it.

 

[JTT1]

I just ordered a ceramic board $30. A blanket 1/4"x2x25, $27. and 2 tubes of 3200* glue $7.50 each plus shipping. 1 800 325 2492 west coast time zone. I don't know exactly how I will use it, just experimenting with it.

Do you know what the density of the blanket is? I noticed on the other link from this thread((broken link removed)) that their blankets are sold in various densities (4, 6, or 8pcf). They had something called Fiberfrax Durablanket S that seemed good and had a 2300deg temp rating.

 

[muncybob]

I just ordered a ceramic board $30. A blanket 1/4"x2x25, $27. and 2 tubes of 3200* glue $7.50 each plus shipping. 1 800 325 2492 west coast time zone. I don't know exactly how I will use it, just experimenting with it.

Do you know what the density of the blanket is? I noticed on the other link from this thread((broken link removed)) that their blankets are sold in various densities (4, 6, or 8pcf). They had something called Fiberfrax Durablanket S that seemed good and had a 2300deg temp rating.

Their products look like what I need for my "stove pipe"...just sent them another email for info on how to purchase.