Analysis of SBCA's E119 Test Data Reveals Nothing Equivalent to 15-Plus Minutes

Originally published by: SBCRI-SBCA Investigative Report #2October 19, 2015

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In March of 2015, SBCA undertook ASTM E119 floor assembly fire testing, yielding the following results:

Note: 100% design load is the same as full-design stress level tests. This testing yields much different results than non-standardized 50% design load tests, applied 40 psf floor load tests, or 250 lb. dummy standing tests as some have suggested are allowed for public policy decision making. ICC-ES allows both non-standard testing and some kind of char rate calculations to prove equivalency as well.

SBC Industry News has shared a series of news items reflecting on a change to the International Residential Code (IRC) R501.3 (adopted by Ohio as R502.14) that effectively bans the use of trusses and I-joists from residential markets that have basements.

We have published the information that we have in a three-part series intended to place what we know in the public domain:

The hope is to foster immediate change for better firefighter safety and also to highlight the risks to those who adopt R501.3 as written. The consequence will be felt when the first firefighter falls through a 2x10 or Flak Jacket floor having expected that floor to meet the traditional 20 minute rule (i.e., 15 minutes plus the performance of the structural member). This expectation is fostered by the use of a 15 minute membrane (1/2-inch regular gypsum wallboard membrane), to which a 2x10 and Flak Jacket are said to be equivalent.

The SBCA-SBCRI Investigative Report Series will continue to provide detailed analysis of the fire performance of structural members with the hope that this information, being accessible in the public domain, will lead to voluntary advocacy for immediate change. The simple code update that could be endorsed by APA/AWC and NAHB is:

R501.3 Fire protection of floors. 
Floor assemblies, not required elsewhere in this code to be fire-resistance rated, shall be provided with a 1/2-inch (12.7 mm) gypsum wallboard membrane, 5/8-inch (16 mm) wood structural panel membrane, or equivalent on the underside of the floor framing member. 


1. Floor assemblies located directly over a space protected by an automatic sprinkler system [...]

4. Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch (50.8 mm by 254 mm) nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance. 

SBCA-SBCRI has found that change is hard and changing adopted code and then law is even harder.

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