I hope this is a question that someone here can answer for me.
I am in the middle of building a gun safe. I would like some type of
fire protection. I am thinking fire rated sheetrock and fiberglass
isulation. what would you suggest the thickness (how many sheets) of
sheetrock should I line the interior with. Keeping in mind that the safe
will be located in my Basement. I would like to be able to keep the inside
temp. of the safe down to a level that would protect my guns. I do not care
about the safe at all. Would a thickness of 3 inches be sufficient?
OK, heres my thoughts,
1/16 steel + 3 " fire rated S/R + 1/16 steel inner liner = Time for the fire
dept to get there and put out the fire!
Sound about right?
Now if I can find a locking system....
I was thinking about that too. Also, Creating the outer skin and placing the
inner liner in place and filling with cement. You'd think 3 " of cement
would do the trick. It would actually be less work for me.
Gypsum undergoes calcination at ~180 F. That means that the chemically
bound water is released and can be driven off as steam. The calcination
progresses through the gypsum and the temperature doesn't rise much
above 212 F ahead of that progression. From what I can tell from a quick
google search, basic portland cement doesn't undergo calcination until
it hits 800 - 1200 F. Based on that, I'd guess that gypsum is the better
choice if you want to keep the internal temperature down.
If you'd like to pour something, maybe gypsum plaster would make more
sense than cement.
As an aside, gypsum is pretty weak once it's undergone calcination.
Firecode (type x) drywall is impregnated with reinforcing fibers to keep
it from disintegrating as easily as regular drywall.
I was writing of the board, not poured solid cement. James Hardie claims that
1/4" backerboard can be made part of a 1 hour fire rating. The board is totally
non-combustible. Beyond that, I don't have any facts. I'm sure some googling
would bring more up.
"Man is the only animal that blushes. Or needs to." Mark Twain
5/8" Type X gypsum board on each side of a 4" stud will give you a
1-hour fire rated wall. You could even go to a layer of 1/2" on each
side with the 2x4 and still get close to a 1-hour wall. You have to
have the studs at about 16" OC. You could also do two layers of rock
on one side (shaft liner approach) and get the 1-hour. Double layers
on each side will give you a 2-hour wall. The UL tests for various
walls also regulate the screw placement and rock placement, but I
think you could do alright as described. The cemetous board mentioned
will also give you some rating.
Per the International Building Code here are the ratings of gypsum
3/8" - 10 minutes
1/2" - 15 minutes
3/4" - 20 minutes
2 layers of 3/8" - 25 minutes
1 layer of 3/8" and 1 layer of 1/2" - 35 minutes
2 layers of 1/2" - 40 minutes
1/2" - 25 minutes
5/8" - 40 minutes
These values are usually additive when applied to studs. You even get
10-minutes typically for a 2x4 stud.
If you want real protection, put a layer of "kaowool" in thre somewhere
between two fire-resistant something-or-others. It's basically fireproof
and will also hold up to direct flame if teh first layer were to
Just be prepared to spend a bit more as it's not an easy material to track
down all that cheaply.
Joe Agro, Jr.
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