Fire-Treated Wood
Fire-Treated Wood
(OP)
I have an assembly building that requires the exterior bearing walls to be a fire-rated assembly.
Where can i find adjustment factors for fire-treated sawn lumber AND OSB Sheathing. I've used NDS Table 4B for Preservative-Treated wood. Is there a similar NDS reference that i am over-looking?
Thank you!
Where can i find adjustment factors for fire-treated sawn lumber AND OSB Sheathing. I've used NDS Table 4B for Preservative-Treated wood. Is there a similar NDS reference that i am over-looking?
Thank you!






RE: Fire-Treated Wood
RE: Fire-Treated Wood
RE: Fire-Treated Wood
Around here if I were to ask for fire rated lumber the cost would likely outweigh LGS
RE: Fire-Treated Wood
Where can i find adjustment factors for fire-treated sawn lumber AND OSB Sheathing. I've used NDS Table 4B for Preservative-Treated wood. Is there a similar NDS reference that i am over-looking?
Thank you!
RE: Fire-Treated Wood
RE: Fire-Treated Wood
RE: Fire-Treated Wood
mike - Thank you. Your information may very well come in handy in the future! Balloon framing not necessary for this 1-story building.
Thank you you all!
RE: Fire-Treated Wood
RE: Fire-Treated Wood
Thank you for the caution advice. I did check with the Fire-Retardant-Treated Wood Impregnator. They sent a Technical Note stating that their "...treatment is not significantly more hygroscopic that untreated wood."
It certainly is the responsibility of our firm to determine for ourselves a comfortable definition of what is the assumed magnitude of "not significantly more". In our case, since the rated wall system will be confined within the building envelope, we are comfortable with the verbage of proprietary note.
For what it's worth for anyone in the future, It appears as though fire-treated sawn lumber and wall sheathing with carbon-steel fasteners may be a reasonably design-efficient fire assembly.
Due to the efficient service and information, to include an ICC, ESR report and more than one Technical Note within minutes of request, I would like to share the name of the proprietor, but, i understand that this may be considered as promoting which is against Posting Guidelines, which i DO respect. Therefore, i will post the question in another post to see if this incidental, inadvertent promotion, intended solely for the purpose of assistance to other engineers, would be considered as acceptable.
Thank you all for your assistance!
RE: Fire-Treated Wood
One question I had for them was whether I needed to use an incising adjustment factor for their fire treated wood, but was informed that they are pressure treated and just need to apply a coefficient to my NDS values.