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Fire-Retardant Wood Framing
2

Fire-Retardant Wood Framing

Fire-Retardant Wood Framing

(OP)
Any there any important structural considerations when using Fire-retardant wood framing?

RE: Fire-Retardant Wood Framing

Fastener corrosion, potential wood embrittlement.  Older formulations were really bad, but they have improved.  Jury's still out on long-term effects of heat/moisture, particularly in attics.

RE: Fire-Retardant Wood Framing

I would think it'd be appropriate to use the Incision Factor - although I'm fuzzy on the actual application process of the FR so maybe it's not.

Like Ron said, a lot of light-gauge connectors have specifications where a maximum copper/preservative content of wood is stated, I bet the same spec exists for contact with FR lumber.

 

RE: Fire-Retardant Wood Framing

Use caution against the use of any FRW product in environments exceeding 150° F (down rated up to 180° F) and plywood exceeding 170° F. Check corrosivity with AWPA Standard E12-94. Design value factors should be per ICC-ES report/recommendations. Use appropriate design value adjustments if high moisture conditions. Some product do not allow ripping or planning.

RE: Fire-Retardant Wood Framing

I think as long as you're wood isn't exposed to moisture and is installed with a MC <19%, corrosion shouldn't be a huge concern.  I would still look at SS or HDG fasteners (contact a Simpson rep, they've been helpful to me in the past), but the moisture is what initiates the chemical reaction.  Similar to dis-similar metals - as long as there is no water, there is no galvanic corrosion.

RE: Fire-Retardant Wood Framing

Lion06...it is not a galvanic action issue...it is purely chemical.  The level of moisture dictates the speed of the reaction, but corrosion can occur in such materials at less than 19% moisture.

It is often not the moisture content of the wood that is at issue, but the ambient humidity that causes a surface reaction.

RE: Fire-Retardant Wood Framing

Ron, good point about the humidity.   

RE: Fire-Retardant Wood Framing

2
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