Fire Ratings Of Sheet Metal

Quarles senior scientist insurance institute for business home safety richburg sc.

Fire ratings of sheet metal.

Noncombustible steel construction reduces structure flammability and can provide up to a four hour rating on walls. Rated floors often use sheet metal pan decking most often with a pour of light weight or standard concrete on top. 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.

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. When 9 16 inch steel deck is used the restrained assembly rating 1 1 2 hr. It usually consists of two or three coats over metal reinforcing mesh. And 2 unrestrained beam rating based on the period of fire exposure where the average measured temperature at any section of the steel beam.

A one inch 2 54 centimeter layer of stucco can easily lend a 1 hour fire rating to a wall source. Roof eaves overhangs are a fire hazard but they can be protected with an encasement of fire resistant material. Other materials can be used including concrete masonry for walls and spray applied fire resistive materials. I am not aware of a fire rated wall assembly using sheet metal.

Fire ratings are based on an assembly. When 28 gauge steel deck is used the restrained assembly rating 1 1 2 hr. Type x gypsum board is wallboard to which non combustible fibers have been added. 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. All the mbma fire rated designs utilize the generic 5 8 inch type x gypsum wallboard as a minimum so any gypsum. The most common fire rating material used in metal buildings is gypsum wallboard. But when it is used one on each side of a properly framed wall it can become a fire rated wall.

Fire resistance classifications the 2012 and 2015 ibc in section 1505 of chapter 15 states that fire classification of roof assemblies is based on two tests astm e108 and ul 790 that are. Metal roof systems are required to be fire classified because of the concern about the combustibility of the materials under the metal panels. When it comes to fire prevention because they use cold formed steel metal buildings have an integral advantage over other building types. However this doesn t make a building fireproof.