Advocating with Evidence


Advocating with Evidence

A CM in Pennsylvania is taking a proactive approach
to dealing with exception four of IRC provision R501.3.

In the fall of 2013, as Brian Ellenberger was settling into his role as president and CEO of Allegheny Structural Components, Inc., in Emlenton, Pennsylvania, his sales staff alerted him to a building code exception that was changing the way things had to be done. “Components were being put at a competitive disadvantage to dimensional lumber. Truss- and EWP-framed floors would require additional jobsite labor to install gypsum sheathing, but sold-sawn joist floors wouldn’t,” said Ellenberger.

That meant a big additional cost for the Open Joist and Triforce open web floor trusses at the heart of his business. By Ellenberger’s own conservative estimate, “my business could be 30-40% greater if that exception hadn’t been written into the building code.”

Ellenberger’s company is fully dedicated to floor framing systems. As a consequence, the inaccurate assumption woven into the International Residential Code (IRC)—namely, that dimensional lumber provides more fire protection than I-joists—has a huge impact on Ellenberger’s business, artificially raising his customer’s costs and undermining his ability to sell his products competitively.

Ellenberger investigated the code change and evaluated his options. He could’ve done extensive equivalency testing, pitting his floor products against the burn time benchmark of dimensional lumber. He was confident his products would hold up, but the testing just didn’t make sense for him to do on his own. Fortunately, he quickly discovered he didn’t need to. Underwriters Laboratories (UL) had already conducted ASTM E119 floor assembly fire testing in 2010, and SBCA had also conducted their own testing in 2015, confirming UL’s results.

With that test data in hand, Ellenberger chose to fight the false assumption in the code that 2x10s perform significantly better than his products during a fire event.

Because Pennsylvania only modifies their residential code every three years, Ellenberger’s push to quickly correct the code meant a foray into the world of politics. He met with local legislators and gave tours of his facility, taking the opportunity to point to the loss of employees as one critical impact of this seemingly innocent code exception. He pleaded his case to everyone he spoke with: “If safety is the true concern of the model residential code, requiring all residential floor systems to be protected by a half inch layer of gypsum wallboard is essential. Protect all or nothing.”

Ellenberger worked with Pennsylvania State Representative Brian Ellis to draft House Bill 1575, omitting the exception for 2x10 dimensional lumber from the Pennsylvania model residential code. In addition, Ellenberger has continued to work with other component manufacturers (CMs) through SBCA to push for a building code based on evidence, in order that public safety and competitive markets are preserved. CMs bear the brunt of the costs imposed by the code, Ellenberger pointed out. “Dimensional lumber has an unjust benefit as an alternative to fire protection.”

SBCA members, including Allegheny Structural Components, continue to fight this code exception and advocate for science-based policy. SBCA attended the International Code Council hearings held from April 17-27 and advocated for a proposed amendment to remove the exception from the 2018 code. Results from that hearing will be shared with the SBCA membership in the near future.  In addition, Ellenberger should know soon the first result of his efforts in Pennsylvania, as a subcommittee casts its decision on House Bill 1575 within the next month.

IRC 2012

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 in accordance with Section P2904, NFPA13D, or other approved equivalent sprinkler system.
  2. Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.
  3. Portions of floor assemblies can be unprotected when complying with the following:
3.1 The aggregate area of the unprotected portions shall not exceed 80 square feet per story
3.2 Fire blocking in accordance with Section R302.11.1 shall be installed along the perimeter of the unprotected portion to separate the unprotected portion from the remainder of the floor assembly.

  1. 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.

See SBCA’s IRC 2012 R501.3 FAQs for more details.

About the Author: A self-professed Sustainability Nerd, Amelia Zimmer-man loves all things science and politics. With close to a decade of experience in technical writing for FDA–ISO–EPA compliant industries, she’s pleased to be dissecting complicated code topics and sharing her discoveries.