The benefits of fire resistant drywall

  • Thread starter Thread starter sonical
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sonical said:
I've heard of the Ultracode core Sheetrock brand gypsum panels (phew!). Would using those or any other fire resistant type of panel improve STC?

my source: www.thermafiber.com/PDFs/TF885.pdf
Click to expand...
ThermaFiber is an insulation material, not a drywall material.

The short answer is yes, but you're making it harder than it has to be.
The UBC (Uniform Building Code), the code we use in the US, has 5/8" sheetrock listed as a fire rated panel. I beileve its a One Hour rated pannel. (It takes One Hour to burn through.)

So by the very nature of it being fire rated, in effect thicker, it would improve STC.
 
Yes i know Thermafiber is insulation, i was just posting my source. Check the PDF (page 5) and you'll see what I mean.
 
Yeah. OK. I see what you mean now.
I didn't see a density on the ThermaFiber. Typically, what's used in the stud cavity is a material called "RockWool".

I don't know what its fire ratings are, but its density is high. (3lbs/cu.ft.) or somewhere along those lines.
Its that density, in conjunction with a multi-layerd wall system that gives the improved STC rating.

So, if you can find a density for the ThermaFiber, we could compare that to the RockWool. All other things being equal of course.
 
I looked again. Looks like page 10 shows a density in lbs/cu.ft.
Its between 4 and 2.5, depending on the thickness; which seems pretty comparable to the RockWool.

I'm not 100% sure on the density of RockWool though, maybe Knightfly, or John will chime in with some numbers in that regard.
 
Michael, LoL u 're still in the dark ;)

Ok i know it's confusing but in the thermafiber PDF, they have diff. STC ratings for diff. wall constructions involving thermafiber AND the Ultracode Core fire resistant gypsum made by Sheetrock.
So my question was: does the use of fire resistant gypsum improves STC and if yes can it be ANY kind of fire resistant gypsum or is there something special about that Ultracode core gypsum?

Hope I can get the message thru this time, thanks for baring with me and my "tortuous" english :)
 
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btw ... Thermafiber is $.19/ sq. ft. for the 2" thick kind, 2.5 density , 80 sq.ft/ pack. It comes either in 16" or 24".
Not too bad i guess.
 
From what I've read about the Firecode Sheetrock, it's a little bit denser than normal, and improves STC by maybe 1-2 dB when using one layer of 5/8" per side of the wall, on Resilient channel.

However, it's very easy to make enough mistakes when building walls to completely negate any small gains, so total attention to detail is necessary.

As far as insulation, the thermafiber stuff is mineral wool, and whichever brand you get Michael is right about the best density. Optimum STC (balanced) is achieved at 2.5 to 3 Pounds per cubic foot, which is 40-45 kg/cubic meter. Lower density and your wall lets more highs through, higher density and the wall lets more bass through.

A balance of Transmission Loss at all frequencies is necessary, or the sound that DOES get through sounds "wrong", and is more intrusive... Steve
 
They list a STC of 56 for a double layer of 5/8" Ultracode gypsum on both side of a 2.5" metal stud with thermafiber mineral wood inside. So i guess with regular gypsum that will probably go down to around 50.
 
i have a couple of 2x4s left from my floating floor framing, let me know when u're ready! :D
 
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