Clearance to noncombustible Shield.

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RetsooR

New Member
Nov 21, 2019
42
41224
Hey Fellas. I have looked and haven't really found an answer.. Say I am allowed 6.5" of clearance for stove to combustible wall. And i put a Shield behind. Lets say a 3 5/8" thick brick wall with 1" air gap . Total of 4 5/8". That leaves 1 7/8" between stove and shield. Is there a minimum distance for this? What if I moved my air gap in back out to 2" inch. Stove would be 7/8 inch from front of shield. Could it be 1/2 inch from front of shield?
 
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coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,271
NE PA
It would be up to the manufacturer for air flow clearance to a noncombustible wall. This creates uneven heating of stove parts since less air flow does not allow that part to cool from radiation like the rest of the stove.

Your heat shield doesn't make sense. A heat shield is air cooled. It must have an air space at the bottom for intake air and be open at top to allow heated air to escape. The 1 inch air space (I believe you're calling "gap"?) allows the heated air to rise up and out keeping wall cool. Increasing the air space does not affect the wall temperature. It literally stays cold with 1 inch. That only puts the heat shield closer to stove for no reason.

Measuring the clearance to wall is from stove to wall as if the shield isn't there. You're already at the required clearance it passed the UL test criteria for. (115*f over ambient air temp) As long as the mfg. has no problem with the clearance to noncombustible wall material, you're building a heat sink behind the stove with mass more than a needed heat shield. Normally it would be 1/2 inch cement board set up on brick spacers to create the bottom intake with 1 inch wall standoffs and tile, stone or brick faced. If you were building an approved heat shield needed for clearance reduction, no wall connector standoff can be in centerline of stove. The wall will stay cold behind it. The reason is the air space that ventilates the heated air out the top. The thinner shield gives you plenty of clearance to stove with less weight, work and expense of steel (normally brick angle) to support brick, brick, mortar and standoff supports.

To prove a point of how much air insulates, heat a pot on any stove or kitchen range. Hold your finger close at 1 inch, then get very close right down to 1/8 inch. It feels hot, but won't burn. That is 1/8 inch layer of air. A touch is an instant burn without air cooling. It won't feel any different going from 1 inch to 2 inches away. The larger the air space behind a shield, the slower the air rises. It doesn't keep the wall any cooler.

If you really want a solid brick wall behind the stove it can be in direct contact with wall and use the minimum clearance to brick treating it as a combustible wall. (solid brick width decreases clearance by 33% for an unlisted stove, so it does offer protection) Is the floor capable of the added load?
 
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RetsooR

New Member
Nov 21, 2019
42
41224
It would be up to the manufacturer for air flow clearance to a noncombustible wall. This creates uneven heating of stove parts since less air flow does not allow that part to cool from radiation like the rest of the stove.

Your heat shield doesn't make sense. A heat shield is air cooled. It must have an air space at the bottom for intake air and be open at top to allow heated air to escape. The 1 inch air space (I believe you're calling "gap"?) allows the heated air to rise up and out keeping wall cool. Increasing the air space does not affect the wall temperature. It literally stays cold with 1 inch. That only puts the heat shield closer to stove for no reason.

Measuring the clearance to wall is from stove to wall as if the shield isn't there. You're already at the required clearance it passed the UL test criteria for. (115*f over ambient air temp) As long as the mfg. has no problem with the clearance to noncombustible wall material, you're building a heat sink behind the stove with mass more than a needed heat shield. Normally it would be 1/2 inch cement board set up on brick spacers to create the bottom intake with 1 inch wall standoffs and tile, stone or brick faced. If you were building an approved heat shield needed for clearance reduction, no wall connector standoff can be in centerline of stove. The wall will stay cold behind it. The reason is the air space that ventilates the heated air out the top. The thinner shield gives you plenty of clearance to stove with less weight, work and expense of steel (normally brick angle) to support brick, brick, mortar and standoff supports.

To prove a point of how much air insulates, heat a pot on any stove or kitchen range. Hold your finger close at 1 inch, then get very close right down to 1/8 inch. It feels hot, but won't burn. That is 1/8 inch layer of air. A touch is an instant burn without air cooling. It won't feel any different going from 1 inch to 2 inches away. The larger the air space behind a shield, the slower the air rises. It doesn't keep the wall any cooler.

If you really want a solid brick wall behind the stove it can be in direct contact with wall and use the minimum clearance to brick treating it as a combustible wall. Is the floor capable of
 

xman23

Minister of Fire
Oct 7, 2008
2,332
Lackawaxen PA
Have you looked at heat shields on the stove? Easier to do and the stove manufacture defines how far you can reduce the clearances.
 

RetsooR

New Member
Nov 21, 2019
42
41224
Thanks for the reply. I understand how the air space works . You brought my attention to the possible problem of air flow behind the stove making parts heat uneavenly. I aslo understand that I dont need the shield in the first place. Just for appearance.

This is a new install. I'm not planning on building a shield as I already have the minimum clearances but I may in the future . Just trying to decide on distance from wall I want to install. If there is a minimum clearance to non combustables I would like to know now so I can move the install out away from the wall.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,548
South Puget Sound, WA
The clearance is measured to the nearest combustible. In the example posed this would be the drywall and studs behind the brick wall. Remember too that it never hurts to exceed minimums if possible.