Gypsum Wallboard Quiz

[Darren]

Here's something to think about:

Is Gypsum wallboard considered a non-combustible material?

[energy star]

Yes, but only for a time. Everything will burn. Some fire walls are manufactured from that material (1 or 1.5" thick) and a special paper is used for the skin.

[Gibsonguy]

Yes it can be. It is used doubled up on the garage wall and ceiling as a fire retardant, but nothing is "fireproof".

[Bill Kibbel]

Yes and no.

It's listed as a noncombustible material for fire/area separation.

It is not listed as a noncombustible material for clearance to combustibles requirements.

[Jeremy]

Gypsum board is used in firewalls, but does not mean it is non-combustable. It is used in firewalls to buy time and the amount of time it buys determines the fire rating. If it were non-combustible, it would be o.k. next to fireplace openings.

[Jeff Remas]

That all depends on what type of gypsum wallboard you are talking about.

Gypsum still has a flame and smokespread index like many other materials.

Some documentation lists a non-combustible material as one that will not ignite or flame within 5 minutes when places inside an oven at 1380 degrees F.

Even some of the best gypsum type X still states that it is not to be applied in areas that are subject to more then 140 deg F temperatures such as a wall for a wood stove.

[Jeff Remas]

Ultimately, gypsum by itself is non-combusible but I am not aware of any gypsum board assemblies that are rated as being non-combustible.

Sheetrock in general must meet the ASTM C 1396 standard and those used for fire "rated" assemblies must meet other ASTM fire restive rating tests.

[Bill Kibbel]

www.nj.gov/dca/codes/bulletins_ftos/lis ... b_90_3.pdf

[Richard Moore]

The Gypsum association has a Fire Resistance Design Manual. You can buy a copy or download sections or the whole thing for free at http://www.gypsum.org/GA60006.html . I doubt anyone here needs to read the whole thing, but section 1, starting at page 12 would be a good place to start.

I remember watching a good segment on TV a few years ago of a fire-rated wall assembly being tested along with a good explanation of what was happening, but I don't remember the show and can't find it online. Anyone?

My vote, FWIW, on the original question: (Paraphrasing Jeff) For our purposes, gypsum board, by itself, is a non-combustible material. Assemblies are a whole different beast.

[hausdok]

Hi All,

I think that the link that Bill K. posted is the clearest explanation of the issue. The question is flawed. The question really should have been two questions and should have been something like, "In the context of the building code, is gypsum wallboard considered a non-combustible material? In the context of the mechanical code is gypsum wallboard considered a non-combustible material?"

Answers would have been Yes and No respectively.

ONE TEAM - ONE FIGHT!!!

Mike

[energy star]

Mechanical code is talking about a flue or hot surface next to the sheetrock, (Like using sheetrock to keep a flue from coming in contact with wood) while the building code is talking about fire walls for buying time to exit the building.

[Darren]

Bill posted the bulletin I was going to post.

I don't believe the question is flawed at all. Here's my thinking:

98% of HI's know that gypsum can be used in fire separation walls and ceilings. Yes, there are different ratings for the type of 'assembly', but all in all, gypsum is the most common material used for separation.

I would guess more than 50% of HI's (or for that matter even builders) know you can't use gypsum as a fire/draft stop tight to a B or C vent. The quiz was thrown out there after I found another B vent going up a chase with gypsum tight to it.

I think it's easier to understand NOW than trying to make people understand the difference between building and mechanical sections of the code.

I think the bulletin (right from the NJDCA) explains it clearly.