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Author Topic: Piping exhaust outside, safe options needed  (Read 30513 times)

clytle374

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Piping exhaust outside, safe options needed
« on: November 24, 2007, 04:41:18 AM »
I'm getting ready to do the intake and exhaust plumbing. 
The intake is easy, but how does one run a hot exhaust pipe through a insulated wall?  Without catching anything on fire.

The wall is 4".Consisting of 1/2" OSB board, insulation, another 1/2OSB board, and siding in the future.

Suggestions?
 

Stan

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Re: Piping exhaust outside, safe options needed
« Reply #1 on: November 24, 2007, 05:00:09 AM »
Accepted practice up here in Western Canada is to make a hole through the wall at least 1 1/2" larger D. than the Diameter of the hot pipe, put what is called an Alaskan stove pipe fitting through the wall and run the hot pipe through the center of that.  The Alascan stove pipe fitting is like a double walled pipe with holes in both "sides" (front and back so to speak)  to allow cooling air to circulate between the two walls.  You can heat up the center pipe section, but the air circulating between it and the outer pipe (which is in contact with your flammable wall,) keeps the fire hazard low.
Stan

Here's how they do it through the wall of a yurt  ::)  (click on the second small pic)

http://www.coloradoyurt.com/yurts/yurt_custom_features/and_more/index.php#
« Last Edit: November 24, 2007, 05:03:43 AM by Stan »

Tom

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Re: Piping exhaust outside, safe options needed
« Reply #2 on: November 24, 2007, 05:26:35 AM »
Being as a stack fire is a distinct possibility I would suggest a short section of wood stove chimney also known as class A flue. When I build my generator room the exhaust will go out under ground.
Tom
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Stan

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Re: Piping exhaust outside, safe options needed
« Reply #3 on: November 24, 2007, 05:52:20 AM »
Even if the exhaust pipe doesn't always get extremely hot, constant high temps will dry out wood and insulation to the extent it will become much more flammable over time, pitch may seep out of a knot, then one hot summer's day, look out!
Stan

rbodell

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Re: Piping exhaust outside, safe options needed
« Reply #4 on: November 24, 2007, 12:50:17 PM »
Being as a stack fire is a distinct possibility I would suggest a short section of wood stove chimney also known as class A flue. When I build my generator room the exhaust will go out under ground.
Speaking of underground, I have a buried 30 gallon drum as a silencer. The engine is 10 feet from my house and I use no muffler at all. I have to turn off the television and really try to hear it. The exhaust coming out out it is warm enough to hold your hand on it. Earth really cools it well
The shear depth of my shallowness is perplexing yet morbidly interesting. Bob 2007

clytle374

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Re: Piping exhaust outside, safe options needed
« Reply #5 on: November 24, 2007, 02:27:54 PM »
I really like the underground idea, but I'm not braking up the amount of concrete needed.
So run the pipe through a piece of stove pipe where I exit the wall?  Something like the "all fuel" pipe sold?



JohnF13

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Re: Piping exhaust outside, safe options needed
« Reply #6 on: November 24, 2007, 03:26:55 PM »
O.K;

From the "don't ask me how I know" category......

If you want to run an exhaust pipe through a wood wall, the safest way to do it is inside a 36" (or longer is needed) piece of 2100 degree wood stove piping - the heavily insulated kind you see on the outside walls of houses.  Usually the 6" or 7" size is good, simply cut a suitable sized hole, push the wood stove piping through leaving about 6" or more protruding on each end, then put your engine exhaust pipe through that. Seal the whole thing up with concrete and off you go.  Try to get the exhaust pipe off the walls of the stove pipe by putting non-flammable blocks under it until you can get the concrete in and set.

Generally the exhaust pipe of a Lister is not hot enough to set a wood wall on fire, but WHEN you have an exhaust fire caused by burning soot deposits then the red-hot pipe most certainly will ignite things - please refer to the first sentence........
John F
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Doug

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Re: Piping exhaust outside, safe options needed
« Reply #7 on: November 24, 2007, 04:58:22 PM »
Just as an example:

Your local Onan dealer sells what they call a wall thimble.

This is an aproved collar sleave assembly that you install in a combustable wall. If mememory serves I have to cut a 12 inch square in the shed wall at the camp and screw this in for the exhaust to pass threw the wall on my CK 205.

Doug
It's a Good Life, If You Don't Weaken

clytle374

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Re: Piping exhaust outside, safe options needed
« Reply #8 on: November 24, 2007, 05:40:33 PM »
When I call the dealer for one of these thimbles, should I be sitting down?

Stan

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Re: Piping exhaust outside, safe options needed
« Reply #9 on: November 24, 2007, 06:08:43 PM »
John's idea of using a "metalbestos" insulated chimney pipe is a great one.  I've seen 6" D, 24" lengths on sale for under $50.
Stan

Doug

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Re: Piping exhaust outside, safe options needed
« Reply #10 on: November 24, 2007, 06:22:01 PM »
You could, or you may stand.

You may stand on your head if you like.

You could curl up in a fetal position.

You could lay flat on your back.

You could even call several different places and try asking them if they sell a simmilar part. More than just Onan made an exhaust thimble. But I will cut myself off right here before I start down another one of those what is an aproved device for a specific aplication things that no one seems to want to discuss...

Another Thought"
About 20 years ago I set a brush pile a light up at the camp. The next days I had some smoke about 10 feet from the burned up pile. Turned out were some roots burning from a stump.  If I was going to burry an exhaust pipe maybe lining the trench with some pea gravel and sand would be a good idea just in case as John pointed "WHEN you have an exhaust fire caused by burning soot deposits " you don't risk a igniting any roots or clutter in realy dry conditions like I did.

The family camp is on a rocky island cover with pine and cedar so the ground cover is very flamable especialy durring a hot dry spell.

 
It's a Good Life, If You Don't Weaken

clytle374

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Re: Piping exhaust outside, safe options needed
« Reply #11 on: November 24, 2007, 06:37:21 PM »
You could curl up in a fetal position.
Thats what I'm afraid of.

oliver90owner

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Re: Piping exhaust outside, safe options needed
« Reply #12 on: November 24, 2007, 07:30:45 PM »
The saying : 'Don't spoil the ship for a hapeth of tar'  comes to mind.

Even a smoke fire can render a whole house uninhabitable for some time, because of the smell, and lead to great expense for new decoration, furnishings and cleaning irreplaceable items. That does not include the items which cannot be saved.  First hand experience was cleaning out afriend's house where some clothes had been left part covering a TV.  No flames but the whole house smoke-logged.

If the whole thing goes up in flames, all is lost and maybe life as well.  It is just not worth skimping on a safety issue.  It may come back to haunt you.

Regards, RAB

clytle374

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Re: Piping exhaust outside, safe options needed
« Reply #13 on: November 24, 2007, 08:37:41 PM »
I'm trying to be sure there is no chance of fire.  I won't sleep well until that is throughly addressed.

I'm starting to think that my idea of a stainless pipe cooled with a water jacket is more and more worth the time and expense.

Automotive exhaust is too thin for comfort and I can't get a gradual bent with iron pipe.

 

clytle374

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Re: Piping exhaust outside, safe options needed
« Reply #14 on: November 24, 2007, 09:56:03 PM »
Will the bender in a automotive exhaust shop do it?