Fire Ratings Of Sheet Metal

Metal roof systems are required to be fire classified because of the concern about the combustibility of the materials under the metal panels.

Fire ratings of sheet metal.

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. And 2 unrestrained beam rating based on the period of fire exposure where the average measured temperature at any section of the steel beam. 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.

Noncombustible steel construction reduces structure flammability and can provide up to a four hour rating on walls. A one inch 2 54 centimeter layer of stucco can easily lend a 1 hour fire rating to a wall source. 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. Astm e119 tests on loaded structural steel and composite steel concrete beams are always restrained and result in 2 ratings.

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. Rockwall fire rated wall panels consist of a unique rockwool mineral fibre core called conrock with laminated sheet steel permanently bonded to both sides. The most common fire rating material used in metal buildings is gypsum wallboard.

Fire ratings are based on an assembly. I am not aware of a fire rated wall assembly using sheet metal. However this doesn t make a building fireproof. 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. When it comes to fire prevention because they use cold formed steel metal buildings have an integral advantage over other building types. One sheet of 5 8 type x sheetrock has no fire rating. Sheet metal penetrations are used in rated assemblies and when correctly fire caulked become part of that assembly.

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