Fire Ratings Of Sheet Metal

The most common fire rating material used in metal buildings is gypsum wallboard.

Fire ratings of sheet metal.

Noncombustible steel construction reduces structure flammability and can provide up to a four hour rating on walls. Roof eaves overhangs are a fire hazard but they can be protected with an encasement of fire resistant material. 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. 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.

When 9 16 inch steel deck is used the restrained assembly rating 1 1 2 hr. All the mbma fire rated designs utilize the generic 5 8 inch type x gypsum wallboard as a minimum so any gypsum. Type x gypsum board is wallboard to which non combustible fibers have been added. When it comes to fire prevention because they use cold formed steel metal buildings have an integral advantage over other building types.

Sheet metal penetrations are used in rated assemblies and when correctly fire caulked become part of that assembly. One sheet of 5 8 type x sheetrock has no fire rating. When 28 gauge steel deck is used the restrained assembly rating 1 1 2 hr. 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.

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. Metal roof systems are required to be fire classified because of the concern about the combustibility of the materials under the metal panels. Astm e119 tests on loaded structural steel and composite steel concrete beams are always restrained and result in 2 ratings. 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.

But when it is used one on each side of a properly framed wall it can become a fire rated wall. Rated floors often use sheet metal pan decking most often with a pour of light weight or standard concrete on top. However this doesn t make a building fireproof. Rockwall fire rated wall panels consist of a unique rockwool mineral fibre core called conrock with laminated sheet steel permanently bonded to both sides.

It usually consists of two or three coats over metal reinforcing mesh. Quarles senior scientist insurance institute for business home safety richburg sc. I am not aware of a fire rated wall assembly using sheet metal. Other materials can be used including concrete masonry for walls and spray applied fire resistive materials.