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Does heat damage wood?

Does heat damage wood?

Does heat damage wood?

(OP)
Does exposure to extreme heat damage wood in any significant way? Or does only contact with fire damage wood?

I'm thinking of wood members that are exposed to extreme heat during a fire, but never actually got burned or charred?

RE: Does heat damage wood?

They can be... there are several older threads about this in the various fora (forums?)

Dik

RE: Does heat damage wood?

abusementpark - let me know if you find a good thread or reference, I would be interested as well.

EIT

RE: Does heat damage wood?

Hey dik...we should have done that FAQ we talked about a year ago!!!

The attached paper, by Robert H. White, is a good treatment on the property changes in wood due to heat exposure.  Wood does not have to be charred to be affected by heat.

Bob White is probably the most knowledgeable person in the US on fire damage and fire effects on wood.  He is at the National Forest Products Lab and has written extensively on the subject.

 

RE: Does heat damage wood?

Anything above 150F will eventually affect most lumber  See APA wood.

RE: Does heat damage wood?

(OP)
Thanks for the info guys!

So the next logical question a forensic engineer would ask is: How can you figure out if a wood member was exposed to that kind of heat?

I guess you could look at nearby materials that have melted and find out what their melting point is.

RE: Does heat damage wood?

That is one way and the 150F was considered a "long" term temp.  Short blasts of heat can be tolerated.

In many very hot fires, the steel will melt before the lumber burns through.  I have seen roof trusses still standing where the steel I-beams were melted to floor level.

If the lumber is just soot coated and not charred - you might be just fine - except for the smell.  Any charring means replacement.

My 2 cents....

RE: Does heat damage wood?

Thinking back about wood framing behind fireplace chimneys, such framing would be affected by the heat transfer thru chimney brickwork and ultimately burn afteryears of  exposure.

RE: Does heat damage wood?

chicopee,

I seem to remember seeing a post on another site regarding the repeated exposure of wood to heat will ultimately lower the combustion point of the lumber.  This was in reference to the design of fireplaces and was posted on a chimney forum when I was doing research about a zero clearance gas fireplace.  This is why the have minimum clearances to members shown in the installation manuals.

I assume this is what you are referring to?

RE: Does heat damage wood?

Ron... I sent you the outline... probably been almost as busy as you <G>.

Dik

RE: Does heat damage wood?

Mike... that comes from two causes... As temperature goes up, both the Fy and Es values decrease.

Dik

RE: Does heat damage wood?

dik...didn't get the outline...please send again.

Ron

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