1 Hour Fire Rating For Roof vs Wall

Many ask if there’s a difference between a 1 hour fire rating on a wall product vs a 1 hour fire rating on a roof product. If you think about it, fire (AKA heat) does behave differently as it rises vs. spreads.  In fact, there is a difference:

In the Florida Building Code (2020), & the International Building Code (2015, 2018) Section 1505.1, roof assemblies rated for a fire classification need to be tested to ASTM E 108 or UL790.

 

A comment received on the topic:

The roof panel construction must have a 1 hour fire rating and shall be non-combustible.  Although the panel does not qualify as non-combustible, it appears that it meets FBC CH 6, 603.1, Exception 1, with a flame spread index of not more than 100. However, you must still provide documentation that the panel has also been tested in a ceiling application with a 1 hour fire rating, since FBC CH 6, T601 requires 1 hour fire rated roof construction for type 1B construction.

 

The MSDS sheets for the stone veneer do include the required fire rating information for walls. You must either provide specific test information, UL information or calculated fire resistance per FBC CH 7, 722. Note that the required 1 hour fire rating at the column must be continuous and no portion of the column may be exposed.

 

Other helpful information regarding fireproofing of roofs:

FBC 712.1.15 Skylights:  (IBC 18 & FBC 20)

Skylights and other penetrations through a fire-resistance-rated roof deck or slab are permitted to be unprotected, provided that the structural integrity of the fire-resistance-rated roof assembly is maintained. Unprotected skylights shall not be permitted in roof assemblies required to be fire-resistance rated in accordance with Section 705.8.6. The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported.

FBC 705.5 Fire Resistance Ratings (walls) (FBC & IBC)

Exterior walls shall be fire-resistance rated in accordance with Tables 601 and 602 and this section. The required fire-resistance rating of exterior walls with a fire separation distance of greater than 10 feet (3048 mm) shall be rated for exposure to fire from the inside. The required fire-resistance rating of exterior walls with a fire separation distance of less than or equal to 10 feet (3048 mm) shall be rated for exposure to fire from both sides.

2304.11.2.2 Interior Walls and Partitions (FBC & IBC)

Interior walls and partitions shall be of solid wood construction formed by not less than two layers of 1-inch (25 mm) matched boards or laminated construction 4 inches (102 mm) thick, or of 1-hour fire-resistance-rated construction.

 

 

 

Last Update: March 18, 2021  

March 1, 2021 309 admin  Codes & Standards  
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