Galvanized Sheet Metal Fire Rating

The ratings are for unsymmetrical walls that require ratings from both sides.

Galvanized sheet metal fire rating. The load bearing capacity of corrugated steel without fire protection is 15 30 minutes depending on the structure. Building with fire safety in mind. When there is no insulation used on top of the corrugated steel sheet the heat goes through the metal and dissipates upwards and the. Occasionally the american galvanizers association gets the question of whether the galvanized coating is adversely affected by exposure to fire.

V421 which pro vides 1 and 2 hour fire resistance ratings for exteri or walls in metal buildings. The mbma fire tests of exterior walls in 1997 resulted in a new uldesign no. Sheet metal penetrations are used in rated assemblies and when correctly fire caulked become part of that assembly. I am not aware of a fire rated wall assembly using sheet metal.

Rated floors often use sheet metal pan decking most often with a pour of light weight or standard concrete on top. The code requirements for fire resistance of metal panels are logical and not overly burdensome. Galvanized coatings perform well under extreme cold and hot temperatures. Temperatures in fires can easily exceed 1 000 f.

Fire ratings are based on an assembly. In fact hdg coatings do not show any significant differences in corrosion rate in temperatures below 40 f. Most metal panel manufacturers have tested their roof assemblies and most if not all metal panels and shingles can be used in class a fire rated roof systems. 1 5 16 inch steel deck w clear span 91 inch supported by w6 x 18 or w8 x 18.

But when it is used one on each side of a properly framed wall it can become a fire rated wall. Chapter 8 fire resistive materials and construction nfpa 5000 building construction and safety code nfpa quincy ma 2006. There is a potential for coating damage but many have found fire damage to minimal on galvanized steel. Average thickness 119 μm temperature of galvanizing 460 c 1 specimen admixure al in galvanizing bath department of steel and timber structures training school malta motivation fire test 2010 heat transfer in fire technology fire test 2010 fire test 2011 real structure fire test 2011.

The steel sheet bends but the load bearing capability remains for a significant amount of time. If combined with gypsum or other materials in an assembly it. A galvanized sheet by itself would not have a fire rating. One sheet of 5 8 type x sheetrock has no fire rating.

Fire ratings are generally based upon testing of a structural sample. For 2 hour unrestrained assembly rating. 1 1 2 hour unrestrained assembly rating. Studies done on the effect of low temperature environments on hot dip galvanized hdg steel indicate the minimal change in the behavior of the galvanized coating.