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SRR No. 1509-02 Calculation of a 2-Hour Fire Endurance Assembly for Metal-Plate-Connected Wood Truss Structural Floor and Roof Framing Systems
There will be instances when materials and assemblies used in a building may not be readily available from prescriptive tables and tests. Theoretical methods have been developed that offer an alternative to full scale fire tests. For example, historically, Section 704.1.1 of the 1996 BOCA National Building Code, Section 703.3 of the 1994 Uniform Building Code and 701.2.1 of the 1994 Standard Building Code permit fire resistance ratings of building assemblies and structural elements to be determined in accordance with an approved analytical method.1 Current versions of the International Building Code also offer guidance regarding fire-resistance ratings in 2015 IBC Sections 703.2 and Section 703.3 as follows: 

703.2 Fire-resistance ratings. The fire-resistance rating of building elements, components or assemblies shall be determined in accordance with the test procedures set forth in ASTM E119 or UL 263 or in accordance with Section 703.3. . .  
703.3 Methods for determining fire resistance. The application of any of the methods listed in this section shall be based on the fire exposure and acceptance criteria specified in ASTM E119 or UL 263. The required fire resistance of a building element, component or assembly shall be permitted to be established by any of the following methods or procedures: 
  1. Fire-resistance designs documented in approved sources.
  2. Prescriptive designs of fire-resistance-rated building elements, components or assemblies as prescribed in Section 721.
  3. Calculations in accordance with Section 722.
  4. 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 E119 or UL 263.
  5. Alternative protection methods as allowed by Section 104.11.
  6. Fire-resistance designs certified by an approved agency.
The analysis in this research report used the method listed in IBC Section 703.3, method number 4, Engineering analysis. Note, the calculation in accordance with Section 722 (#3) for wood are limited to a maximum of 1 hour (Section 722.6.1.1), however, that limitation does not apply to method 4. Also note that Section 721 (#2) Table 721.1(3), item 28-1.1, includes a prescriptive ceiling design using I-joists2, 3 layers of 5/8” Type C gypsum and 7/8” furring channel with a 2 hour rating. 
This legacy SBCA Research Report represents information and code requirements current as of the publication date shown. However, codes and standards change periodically. The user is encouraged to verify the referenced information is still current and conforms to current code requirements.
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