For occupancies such as stores, apartments, offices, and other commercial and industrial uses, building codes commonly require floor/ceiling and wall assemblies to be fire-resistance-rated in accordance with standard fire tests. The 2012 International Building Code permits fire-resistance-rating to be established by several methods. Testing is the primary means (703.2, 2012 IBC), but not the only one. The five alternatives shown in 703.3 permit the code official to allow fire-resistance-rating to be established using a number of methods and principles of fire resistance in the code and elsewhere:
- Fire-resistance-rated designs documented in sources.
- Prescriptive designs of fire-resistance-rated building elements, components, or assemblies as prescribed in IBC Section 721.
- Calculations in accordance with IBC Section 722.
- Engineering analysis based on a comparison of building element, component, or assemblies designs having fire-resistance-ratings as determined by the test procedures set forth in ASTM E 119 or UL 263.
- Alternative protection methods as allowed by IBC Section 104.11.
For tested assemblies, AWC’s DCA 3 – Fire-Resistance-Rated Wood Floor and Wall Assemblies describes how interior and exterior wood-frame walls and wood I-joist floors can be used to meet building code requirements for fire-resistance-rated assemblies.
Additional assemblies not shown in DCA 3 can be found in the 2005 ASD/LRFD Manual for Engineered Wood Construction Chapter M16.
Performance of finger-jointed lumber in fire-resistance-rated wall assemblies is also a common question. In 2009 the American Lumber Standards Committee (ALSC) modified the ALSC Glued Lumber Policy to add elevated-temperature performance requirements for end-jointed lumber adhesives intended for use in fire-resistance-rated assemblies. End-jointed lumber manufactured with adhesives which meet the new elevated-temperature requirements is required to be designated as “Heat Resistant Adhesive” or “HRA” on the grade stamp. 2012 IBC Section 2303.1.1.2 on End-Jointed Lumber states “Approved end-jointed lumber is permitted to be used interchangeably with solid-sawn members of the same species and grade. End-jointed lumber used in an assembly required to have a fire-resistance-rating shall have the designation “Heat Resistant Adhesive” or “HRA” included in its grade mark.”