Galvanized Sheet Metal Fire Rating

Fire ratings are based on an assembly.

Galvanized sheet metal fire rating.

V421 which pro vides 1 and 2 hour fire resistance ratings for exteri or walls in metal buildings. Galvanized coatings perform well under extreme cold and hot temperatures. Occasionally the american galvanizers association gets the question of whether the galvanized coating is adversely affected by exposure to fire. The steel sheet bends but the load bearing capability remains for a significant amount of time.

Temperatures in fires can easily exceed 1 000 f. A galvanized sheet by itself would not have a fire rating. 1 1 2 hour unrestrained assembly rating. 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.

When there is no insulation used on top of the corrugated steel sheet the heat goes through the metal and dissipates upwards and the. There is a potential for coating damage but many have found fire damage to minimal on galvanized steel. Sheet metal penetrations are used in rated assemblies and when correctly fire caulked become part of that assembly. Rated floors often use sheet metal pan decking most often with a pour of light weight or standard concrete on top.

But when it is used one on each side of a properly framed wall it can become a fire rated wall. Specifications methods to determine fire resistance ratings for generic designs can be found in most building codes e g chapter 7 fire resistance rated construction international building code international code council falls church va 2003. 1 5 16 inch steel deck w clear span 91 inch supported by w6 x 18 or w8 x 18. If combined with gypsum or other materials in an assembly it.

For 2 hour unrestrained assembly rating. The ratings are for unsymmetrical walls that require ratings from both sides. 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. Chapter 8 fire resistive materials and construction nfpa 5000 building construction and safety code nfpa quincy ma 2006.

1 5 16 inch steel deck w clear span. One sheet of 5 8 type x sheetrock has no fire rating. The load bearing capacity of corrugated steel without fire protection is 15 30 minutes depending on the structure. I am not aware of a fire rated wall assembly using sheet metal.

In fact hdg coatings do not show any significant differences in corrosion rate in temperatures below 40 f. Building with fire safety in mind. The code requirements for fire resistance of metal panels are logical and not overly burdensome. The thickness and number of the layers of type x gypsum wallboard are specified for each.