What is a "protected surface"?

[drobbins]

Hey Again,

I've installed a new dutchwest stove and done 2 breakin firings.
Things went great.
The stove sits in front of a fireplace with a sheetmetal prefab insert in a frame lumber chase covered by cultured stone. There's a hearth in front of it with lumber framing and a 1-1/2" flagstone top and the same cultured stone on the vertical surfaces. The stove is only a couple inches from the hearth. In my mind this looks like a fine setup but the manual seems to imply the hearth is a "protected surface" and needs more clearance. Am I pushing this too far?
Pic below

 

[begreen]

A stone veneer over wood is not a protected surface. Stone can be a good conductor of heat. The measurement to the nearest combustible surface should be to the wood behind or underneath the stone.

 

[drobbins]

Yikes!! I gotta get a longer flue pipe.
I've also ordered a rear heat shield.
I thought the hearth was getting mighty warm.

 

[begreen]

Is there a rear heat shield on the stove? If not, consider adding one. That will help a lot to reduce rear heat radiation and will reduce rear clearance nicely, perhaps enough so that no change is needed other than the rear heat shield addition.

Edit - was: What parts are getting "hot" and where? It looks like there is adequate clearance to the stone face surrounding the fireplace. Only the hearth seems to be in question. Long horizontal runs are to be discouraged. If you are reading high temps on the hearth face I hate to say it but for the current configuration it might be better to remove the hearth in front of the ZC fireplace and replace at floor level or rebuild with metal studs.

 

[drobbins]

What was "getting hot" was top surface of hearth, but I could still lay my hand on it.
I've already started "de-constructing" the hearth. Not too bad, already saved the nice flagstone top surface.
Just gotta decide exactly how to replace it.
Wife votes for just continuing the slate floor right up the the fireplace and not have a hearth.
Might be easiest solution. This is over a slab.
Would also let me shorten that horizontal run.
Could also rebuild hearth with concrete block and put stone vernier back on it.
Test burns went very well so far. Not sure if the horizontal run is a problem.
Rear heat shield is on order.
If stone over wood isn't a "protected surface" what is??

Dave

 

[begreen]

A protected surface has several definitions. The best and most protected surface has a ventilated heat shield on the wall on 1" spacers that is open at top and bottom. It's good that you are adding the rear heat shield to the the stove. That will make a notable difference. Does the stove have the bottom heat shield already attached?

 

[drobbins]

So you're referring to a metal heat shield with 1" air gap?
I don't think that would fit in for my situation but good info to know.
No bottom shield yet but it'll be installed before next fire

 

[begreen]

A bottom shield on the stove is strongly recommended in the manual. It makes the hearth requirement much simpler. Good that you are adding a rear shield. That may be enough. If the stone gets warm but you can still hold your hand on it for say 3-5 seconds it's ok. That's within safety limits. If you have an IR thermometer that would probably be around 120-130F.

 

[drobbins]

Well I'm already well on the way to removing the hearth.
This is one of those time you don't want to push the envelope.
Thanks for the advice, this'll be a much safer installation

 

[begreen]

With the rear heatshield on the stove you can move the stove back to 14" from the fireplace. (Actually 14" to the studs behind the stone veneer but that might be hard to measure and a little extra clearance never hurts.)
FWIW I agree with your wife and would probably just continue the slate up to the fireplace face.

 

[drobbins]

I think just continuing the slate wins.
Any kind of hearth also gets in the way of a blower.
I don't have one yet but suspect I'll get one down the road