Fireproofing / Insulating and general Newbie Questions

[ExhibitGuy]

Hey all,
New to Pellet Stoves - Installing my first stove in a week or so. I've been watching this board for a while now and there are some really knowledgeable people here!

I have the location (Basement) and what I believe the necessary venting figured out. What I'm looking for is a recommendation on the following:

1. I'm passing the 3" venting thru a CMU foundation wall (Concrete Block, not poured concrete). What spray foam insulation/fire retardant should I use within the CMU cavity once I punch my hole into the block?

2. What RTV adhesive should I use on the Vent connections (if at all) or should I stick with Foil Tape?

3. Lastly - my basement is sub-grade. So my venting has to go "Up - Out thru Thimble - Up" I've attached an image I found on the web that is conceptionally what I'm trying to do. Any suggestions or recommendations on this configuration? I do not have the ground clearance to go straight out with the vent, I do not have the ability to go straight up thru the roof so I must stick with this "Z-clip" configuration. I'm concerned that cleaning the venting will be difficult - what do people use to clean the venting of a pellet stove?

Thanks for all your comments,

 

[hwdemers]

something like duravent pvp would allow you to skip the rtv and the tape. You can use the dubbel t on the outside to aid in cleaning.

In regards to the thimble, you can use anything to insulate with, as long as it is on the outside of the outer ring. Rock wool is always a good choice.

 

[Bioburner]

I like to use self bonding silicone tape on the outside of joints. Easy to get a good seal, neat and easier to remove if needed.

 

[hwdemers]

I like to use self bonding silicone tape on the outside of joints. Easy to get a good seal, neat and easier to remove if needed.

I have seen you mention this before, how dose it look painted over?

 

[ExhibitGuy]

Good info on the Silicone tape. I ordered the Vent Kit already from Home Depot and was told that it twists and locks together. I will also use the tape as well for a good seal.

What tools are used to clean the vent once installed? I figure my config has at least 10' of vertical rise with about 3.5' of horizontal run (between the thimble (2') and out the back of the stove itself (1.5')). Is there something I can attach to a rope to pull from the termination cap all the way thru to the inside "T" behind the stove?

 

[Papelletman]

With all that venting I would use 4"

 

[SmokeyTheBear]

Please post a picture of the outside of the house where you propose that the vent passes through the foundation.

Here is a link to the self fusing stuff, be certain that what you get can handle at least 500 if you plan on using it. http://www.amazon.com/s/ref=sr_kk_1...e&keywords=rescue+tape&ie=UTF8&qid=1409837969

4" vent if you are going to use that set up, I requested you post a picture so we could perhaps find a way out of the 4" and/or such a mess of bends.

 

[Snowy Rivers]

I would skip the clean outs and use standard elbows instead.

The hard right angles will really mess up the air flow.

Come cleaning day, just open the stove up and remove the ash baffles and such, the hook the suction side of the leaf blower to the pipe and let it rip

The super high velocity will take care of any of the crud in the pipe as well as in the stoves inaccessible innards.

 

[BobMA]

I would also advise that you check your stove manual for recommendations as well as local building code requirements....if where your stove pipe exits the building is over 18" above grade (mass building code) then you might be able to avoid the whole top section of your exhaust scheme (and avoid the need to go to 4" pipe). Check your stove manual too as recommendations from my stove manual suggest 36" above the ground.

My local building inspector will inspect to stove and vent manufacturers recommendations first and then default to NFPA standards (NFPA 211) if not covered in the manuals.

Just as another point of interest, I have oil heat as well and you need to locate the stove a minimum of 5 feet from the oil tank unless the two are separated by a 1 hour fire rated wall which extends 1 foot beyond the tank itself (NFPA 31 - 7.2.7.2)....sorry to cloud the issue with all the regulatory stuff but better to do it once correctly than to have to redo after being inspected. Might want to check with your insurance company too, all my insurer requires for coverage is a signed off copy of the building permit.

Are you going to do anything for outside air supply? Congrats on the new stove!...this will be my first year burning pellets too

Best

Bob

 

[ExhibitGuy]

Bob and all - thanks for the continued support.
I spoke to an installer 'friend' of mine and he agreed about going to 4" however I can keep to 3" if I do the following:

From Stove - direct to "T" vertical 5' pipe - this is recommended by the mfgr for optimal vent drafting.
90deg. bend at top towards Thimble. Pass thru wall about 24" (clearance inside and out) to another "T" (Exterior).

Option A:
I have about 12" of clearance above grade at this point which is not good. So I'm thinking of going up about 24"-36" depending on what pipe I have. The vent kit I purchased gave me 5x 12" sections.This will get me out of the snow drift zone and at that point I'll 90deg bend and terminate. This is NOT a public way so it's safe for me to keep the pipe termination low'ish to the ground. I must keep the total rise above grade to less than 4' to keep the min 48" clearance away from operable windows. This varies from the diagram since the overall total rise is 8' not 10' as I posted above.

Option B:
Keep the termination at 12" above grade - straight out and install a 60" dia. Window Well. This will require a little digging and a few wheelbarrows of gravel but it should give me the necessary 24" clearance to a non-combustable surface. As long as I keep the leaves and crap out of there I should be fine me thinks.. Keeping the termination low will keep me 6'+ away from any operable windows. * Also - the Stove is located on the Leeward side of the building so I have never had any snow drift issues.
My overall total rise with this configuration is 5'

I'm at work so I dont have pictures to upload - but will do so tomorrow.

BTW.. the stove Manual specifies minimum 12" clearance to grade - but that doesn't cut it in New England.

 

[ExhibitGuy]

Here is my proposed Vent Location for refrence. I'm boring my hole thru the 2nd course of CMU so effectively 12" off grade. I do have one more course of CMU but I would rather not bore thru that layer of CMU.

Note: The distance from Window to Window horizontally is less than 96" but there is a sweetspot below the Right window and to the Right of the Left Window. I'm placing the vent 60" or so from the Basement Casement Window (that lands nicely in the middle of a CMU).

The bush is gone.. ( I hate that thing...) , The sensor will be moved (regulates my Butera Furnace).

As you can see, keeping the vent to 24" height will a) keep the termination more than 48" from the upper right window , b) allow easy access to the vent, c) keep me from digging a window well at the thimble.

Thoughts... am I running into code issues with my placement? My termination will be approx. 36" from grade (24" venting + 12" clearance).

 

[mik_kane]

Your EVL adds up to more than 15. You are going to need a 4" vent with all those bends.

EVL = Equivalent Vent Length

Every piece of pipe has a rating:
1 Ft. horizontal = 1
1 Ft. Vertical = .5
45 degree bend = 2.5
90 degree = 5

On 3" pipe, anything that adds up to more than 15 EVL needs to be increased to 4" pipe, up to a max of about 33.

(broken link removed)

(broken link removed)

 

[SmokeyTheBear]

Can you exit from the basement above the sill plate and not have to break any block?

 

[BobMA]

Looks okay to me....just need to make sure at least 6" out from your siding, looks like you'll be far enough below your soffit .....can't see anything else in the way. Is the CMU wall finished on the inside?

 

[ExhibitGuy]

Mike, smokey..

I'll look into the EVL. .find out if that's code or suggested. If it's code then I have to go the widow well route and return some venting.. If it's suggested then I'll probably take my chance and be dillegent with cleaning. Question: can I use a 45deg bend at the top and still use a horizontal termination cap? This may save me a few..

Unfortunately I can't go out above the sill in that part of the house without a lot of pain ... from my wife and wallet.

I'll be using a bracket to stabilize the exterior vertical vent (even if its so short) so I'll get that 6" clearance.

Thanks again.. hopefully I'll have some better information and some pics in the next few weeks.

 

[SmokeyTheBear]

EVL is not code but if you are planning on not paying attention to that, you will have burn issues caused by poor combustion air flow. You are already going to be fighting what the heating from the basement situation usually results in. You have to pay attention to indoor air circulation, the added chimney effect on stove’s combustion air supply and possible smoke spillage.

Non ducted stoves should be placed where you want the heat. To make a very long story short and a new burner’s life a lot more pleasant.

 

[mithesaint]

I'm with Smokey...go with the 4" vent. Even if it's not technically needed, you stove will thank you. It will be much more forgiving if you get behind on cleaning.

 

[canuck_22]

That install is identical to mine, I used Duravent 4". I core drilled the foundation with a rental drill, cut like butter, took 20 minutes.

 

[ExhibitGuy]

Hey all - So my installation went smooth and inspection passed with no problems.
I ended up simplifying the Venting as discussed above. Up 4' and out through the concrete wall. My vent termination ended up about 8" from my grass so I dug out a crude 32" square of grass about 16" deep.... filled it with a few 16" x 16" x 1.5" pavers from home depot to keep the weeds in check and then covered everything with a light layer of gravel I had around. The distance from the tip of the vent cap to the gravel is 14" or so. YES I'll have to plow it out if there is a big snow but it's better than having extra bends in the venting.

Come Spring, I will make it pretty but for now it will work.

I used Fireproof expanding foam inside the cavity of the concrete wall. That stuff really expands! I used RTV around the vent adapter and around the vent as it went through the thimble - I used the Silicone Tape as suggested and it worked great. A picture of my stove is on my profile.

The stove is burning great - so far so good. Wife is happy with reclaiming the basement.. now that it's heated. We almost doubled our living space now that we can hang out in the basement without winter coats.

Thanks for everyone's help!

 

[Mr. Spock]

Maybe I am going blind but I don't see any pictures of the install? Folks around here might say it never happened.

 

[SmokeyTheBear]

Hey all - So my installation went smooth and inspection passed with no problems.
I ended up simplifying the Venting as discussed above. Up 4' and out through the concrete wall. My vent termination ended up about 8" from my grass so I dug out a crude 32" square of grass about 16" deep.... filled it with a few 16" x 16" x 1.5" pavers from home depot to keep the weeds in check and then covered everything with a light layer of gravel I had around. The distance from the tip of the vent cap to the gravel is 14" or so. YES I'll have to plow it out if there is a big snow but it's better than having extra bends in the venting.

Come Spring, I will make it pretty but for now it will work.

I used Fireproof expanding foam inside the cavity of the concrete wall. That stuff really expands! I used RTV around the vent adapter and around the vent as it went through the thimble - I used the Silicone Tape as suggested and it worked great. A picture of my stove is on my profile.

The stove is burning great - so far so good. Wife is happy with reclaiming the basement.. now that it's heated. We almost doubled our living space now that we can hang out in the basement without winter coats.

Thanks for everyone's help!

Please name the "Fireproof Expanding Foam"

I haven't seen one yet.

There air infiltration foams that slow the spread of fire by blocking air flow but they aren't fireproof.

 

[ExhibitGuy]

Smokey,
Correct.. fireblock. Greatstuff fireblock foam from HD is what I used. It does say fire retardant and resistant so I bet you're right.. prevents oxygen as well as non-flamable.

My profile pic has the stove but I'll try and upload a lower resolution file.. it wouldn't let me upload the pic I have ..lol

Btw.. lesson learned - washing machine hose busted last evening. Dumped 2" of water in the previously dry basement before we got home to find it at 1130pm. . Lost ONLY a 1/4 bag of pellets and I consider myself lucky. The rest of the ton is in the garage. Get your pellets off the ground people.

 

[SmokeyTheBear]

Smokey,
Correct.. fireblock. Greatstuff fireblock foam from HD is what I used. It does say fire retardant and resistant so I bet you're right.. prevents oxygen as well as non-flamable.

My profile pic has the stove but I'll try and upload a lower resolution file.. it wouldn't let me upload the pic I have ..lol

Btw.. lesson learned - washing machine hose busted last evening. Dumped 2" of water in the previously dry basement before we got home to find it at 1130pm. . Lost ONLY a 1/4 bag of pellets and I consider myself lucky. The rest of the ton is in the garage. Get your pellets off the ground people.

You might want to shoot some of that stuff on a piece of wood, let it set up, then scrap it off the wood into a non combustible place like a fire pit and touch a match to it, it will likely easily burn. As such it doesn't meet the requirements to be used in contact with a flue. It must be on the outside of the thimble's inside wall. It is considered combustible.

Then we can discuss where you sealed the thimble, they are only supposed to be sealed on the outside of the structure. This allows any leaks inside the wall to become noticed (lots of folks make the mistake of having a joint inside the thimble).