2 Hour Fire Rated Wall Thickness

203 mm limestone aggregate concrete masonry wall with a maximum control joint width of in.

2 hour fire rated wall thickness.

13 mm a 1 in. Cover wood framed walls with a single layer of 3 4 inch type x drywall rated for 120 minutes of fire resistance. In addition to the usual gypsum found in regular drywall fire rated drywall contains glass fibers to form a super tough core. Accepts no responsibility for proper application of the rated wall assembly above or responsibility for the construction of such assemblies.

The ratings relate to fire tests designed to determine how quickly fire can raise the temperature to unacceptable levels. Use thicker drywall for a two hour rating if double sheeting is not an option with fire resistant insulation between the wall studs. Linear interpolation from table 721 3 2 of the 2007 florida building code. Type x drywall is 5 8 inches thick.

For example for an 8 in. A 2 hour rating can be achieved by a wall with an equivalent thickness of as little as 3 1 5 inches when expanded slag or pumice is used or 4 1 2 inches when siliceous gravel is used as the aggregate. The fire resistance rating of the wall shall not exceed the lower of the two values. It is also referred to as a fire rating fire resistance classification or hourly rating.

A fire resistance rating is based on a fire resistance period and usually given in half hour or hourly increments. 51 mm thickness can be used in the joints of a 4 hour wall. Thickness and composition drywall typically comes in 1 4 inch 3 8 inch and 1 2 inch thicknesses. 25 mm thickness measured perpendicular to the face of the wall of ceramic fiber in the joint can be used in walls with fire resistance ratings up to 3 hours while a 2 in.

For a wall having no finish on one side or different types or thicknesses of finish on each side the calculation procedures of sections 722 2 1 4 1 and 722 2 1 4 2 shall be performed twice assuming either side of the wall to be the fire exposed side. Minutes per inches of equivalent thickness. Rockwall fire rated wall panels consist of a unique rockwool mineral fibre core called conrock with laminated sheet steel permanently bonded to both sides. 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.

As an example a wall with a fire resistance period of 2 hours and 25 minutes may only attain a fire resistance rating of 2 hours. The fire resistance rating of concrete masonry walls depends on the type of aggregate used in the units. This is an alternative code recognized method to the underwriters laboratory ul listing service.