Fire Ratings Of Sheet Metal

When 9 16 inch steel deck is used the restrained assembly rating 1 1 2 hr.

Fire ratings of sheet metal.

Rated floors often use sheet metal pan decking most often with a pour of light weight or standard concrete on top. 1 restrained beam rating based on the period of fire exposure where the beam sustains the applied design load but not more than twice the corresponding unrestrained beam rating and provided the later is 1 hour or more. One sheet of 5 8 type x sheetrock has no fire rating. Astm e119 tests on loaded structural steel and composite steel concrete beams are always restrained and result in 2 ratings.

The most common fire rating material used in metal buildings is gypsum wallboard. However this doesn t make a building fireproof. All the mbma fire rated designs utilize the generic 5 8 inch type x gypsum wallboard as a minimum so any gypsum. I am not aware of a fire rated wall assembly using sheet metal.

But when it is used one on each side of a properly framed wall it can become a fire rated wall. Fire ratings for roofs are classified as either class a class b class c or are unrated if a roof covering cannot meet the requirements for any of these classifications. Sheet metal penetrations are used in rated assemblies and when correctly fire caulked become part of that assembly. Fire ratings are based on an assembly.

Other materials can be used including concrete masonry for walls and spray applied fire resistive materials. When 28 gauge steel deck is used the restrained assembly rating 1 1 2 hr. According to the book commercial drafting and detailing a typical one hour fire rated wall consists of 2x4 studs spaced 16 inches from the center of one stud to the center of the next covered by 5 8 inch type x gypsum board. Once rockwall panels have been installed according to the specific intertek warnock hersey certification guidelines the assembly provides 1 2 and 3 hours of fire resistance with a 4 5 and 6 core thickness respectively.

It usually consists of two or three coats over metal reinforcing mesh. Type x gypsum board is wallboard to which non combustible fibers have been added. Metal roof systems are required to be fire classified because of the concern about the combustibility of the materials under the metal panels. Noncombustible steel construction reduces structure flammability and can provide up to a four hour rating on walls.

When it comes to fire prevention because they use cold formed steel metal buildings have an integral advantage over other building types. Roof eaves overhangs are a fire hazard but they can be protected with an encasement of fire resistant material. Quarles senior scientist insurance institute for business home safety richburg sc. Rockwall fire rated wall panels consist of a unique rockwool mineral fibre core called conrock with laminated sheet steel permanently bonded to both sides.