One Hour Fire Rated Roof Assembly

Fire resistance ratings are expressed in the number of minutes or hours a structure can withstand a fire simulation test.

One hour fire rated roof assembly.

Table 1 one hour fire rated loadbearing wood frame wall assemblies. Do the plans call for a 1 hour assembly or a 2 hour assembly. Keep in mind that most of the wood truss fire rated assemblies call for a minimum depth of 12 in. Fire resistance ratings time temperature include structural elements and everything above including the roof membrane and its surfacing.

With 1 2 wood structural panels with. 2 fire rated wood frame wall and floor ceiling assemblies. Elements of buildings the fire resistance rating classifies the ability of an assembly to confine and isolate fire within a zone comprised of fire resistance rated walls ceiling and floor assemblies. 2x4 16 o c.

Sheathing on both sides. Assemblies rated from both sides. Fire safety caution passing a fire test in a controlled laboratory setting and or certifying or labeling a product as having a one hour two hour or any other fire resistance or protection rating and therefore as acceptable for use in certain fire rated assemblies systems does not mean that either a particular assembly system. 5 8 type x gypsum wallboard h 2 6 type s drywall screws 12 o c.

Usg provides resources here for our ul wall assemblies for seamless integration into any construction project. Users must consult the listed agency s documentation for complete information. Ibc table 721 3 item 21 1 1 describes a single prescriptive 1 hour rated floor or roof assembly that includes wood trusses. A one hour rating would mean the structural elements have not yet reached their yield point when exposed to a under deck heat load defined in astm e119 for steel structural members as reaching 1 070 degrees f.

If trusses are specified then these assemblies can be used to achieve the desired fire rating as long as all the details of the assembly requirements are met. Generic fire rated assembly listing construction elements 1 5 hr rating 1. The ratings relate to fire tests designed to determine how quickly fire can raise the temperature to unacceptable levels. The following tables are only summaries of the fire rated assembly reports.

3 mineral wool batts. According to the engineered wood association a one hour rating indicates that a wall constructed in a manner similar to the one tested will contain flames and high temperatures and support its full load for at least one hour after the fire begins. Test reports are available from reporting agencies or wtca where indicated.