Providing fire protection to structural members allows for larger non-compartmentalized spaces, whether by adding gypsum sheathing or by providing a sacrificial char layer to structural elements. Table 601 of the 2012 IBC indicates the resistance required for each structural element (i.e., roof, floor, exterior walls, etc.) for a given construction type and specified level of protection—A or B. Fire resistance is measured in hours and ranges from 0 to three hours of protection.
Type IV (heavy timber) construction is considered self-protected. The prescriptive requirements for Type IV construction include sizing to accommodate charring protection in the case of a fire.
For wood members and assemblies, there are five ways to establish fire resistance as outlined in Sections 703.2 and 703.3 of the 2012 IBC. The three most common are as follows:
- Sourcing tested assemblies. Although most people think of United Laboratories (UL), there are other sources of assemblies, such as the American Wood Council.
- DCA 3 – Fire Rated Wood Floor and Wall Assemblies – American Wood Council
- Fire Resistance Design Manual – Gypsum Association
- Fire Resistance Directory – Underwriters Laboratories
- Metal Plate Connected Wood Truss Handbook – Section 17 Fire Performance of Trusses Part I and Part 2, and Section 18 on Sound Transmission and Fire-Rated Assemblies – Structural Building Components Association
- ASD/LRFD Manual for Engineered Wood Construction, Chapter M16 – American Wood Council
- Searchable engines for fire-rated assemblies:
- Specifying an assembly that matches the descriptions in the deemed-to-comply tables found in 2012 IBC Section 721.
- Calculating the fire resistance per Section 722 of the 2012 IBC. For more information:
- Chapter 16 of the American Wood Council’s National Design Specification® (NDS®) for Wood Construction
- TR 10 – Calculating the Fire Resistance of Exposed Wood Members – American Wood Council
- DCA 2 – Design of Fire-Resistive Exposed Wood Members – American Wood Council
- DCA 4 – Component Additive Method (CAM) for Calculating and Demonstrating Assembly Fire Endurance – American Wood Council