FAQs Regarding IRC12 R501.3 and IRC15 R302.13

Originally published by: SBCAJanuary 8, 2016

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The following are answers to frequently asked questions regarding  IRC-12 R501.3  and IRC-15 R302.13. Click on a question below to be taken to the answer:

  1. Why has this not been fixed through the normal ICC International Residential Code process?
  2. Has SBCA submitted ICC code change proposals to fix this?
  3. This code provision allows for equivalency, but what does that mean?
  4. In the event of a fire, what is the expected floor performance under IRC-12 R501.3  and IRC-15 R302.13?
  5. What does the code establish as safe floor performance in the event of a fire?
  6. It has been suggested in the market that fire assembly testing at 50% design load is acceptable?
  7. It has been suggested in the market that IRC-12 R501.3  and IRC-15 R302.13 are based on the fire service comfort around the known fire performance of traditional products. Is this true?
  8. It has been suggested in the market that acceptance criteria used in evaluation reports issued by the International Code Council Evaluation Service (ICC-ES) is recognized by the code as an approach to establish equivalency. Is this true?
  9. It has been suggested in the market that ASCE 7 Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 7-10) contains an approach recognized by the code to establish equivalency. Is this true?
  10. It has been suggested in the market that independent fire experts such as Frank Brannigan, and other professional entities like the National Association of State Fire Marshals, International Association of Fire Chiefs, International Association of Fire Fighters, NAHB, and ICC-ES have supported the science and widespread acceptance of unprotected solid sawn lumber in sizes greater than or equal to 2-inch x 10-inch nominal in residential construction. Is this true?
  11. Given all of the science available in the market, why is there still dispute over this issue

 

Q1. Why has this not been fixed through the normal ICC International Residential Code process?

A1. The code development process is a political and not a science-based process. In the case of IRC-12 R501.3 and IRC-15 R302.13, the American Wood Council (AWC) and the National Association of Homebuilders (NAHB) authored and defended these code proposals, disregarding the harm they caused the truss industry through endangering the floor truss market.

Beyond the political relationships AWC and NAHB have within the ICC model code development process, it isn’t possible to adequately provide logical and scientific arguments on a complicated topic like the fire endurance performance of various floor assemblies in the two minutes allowed for comments and one minute allowed for rebuttals during the code hearings.

It is also unreasonable to expect building officials attending these hearings to have the depth of knowledge needed to be able to process highly detailed information. Given that building officials have to rely upon two-minute advocacy statements and one minute rebuttals, it is not difficult to understand how reputation and presentation style can win out over actual substance and scientific fact.

This issue is far too serious to wait for the code development process to eventually get it right. Given code changes are only reviewed and approved every three years, there are significant obstacles to addressing this issue before the damage is done and the market is artificially altered for good. Besides, the vested interests that succeeded in getting this code change proposal adopted in the first place have continued to fight hard to protect it.

 

Q2. Has SBCA submitted ICC code change proposals to fix this?

A2. Correcting IRC-12 R501.3 and IRC-15 R302.13 is a continuing effort for SBCA and other affected industries. SBCA’s code change proposals to remove exception 4 in the past were denied.

While APA-The Engineered Wood Association supports the current code language and the competitive advantage it creates for 2x10s over I-joists, all other affected industries have at one point or another submitted IRC code change proposals on this topic.

There may be gaps in submission because of miscommunication among affected industries, but not because IRC-12 R501.3 and IRC-15 R302.13 is viewed as a code requirement that is correct based on the science available from 1992 to the present. 

 

Q3. This code provision allows for equivalency, but what does that mean?

A3. IRC-12 R501.3 and IRC-15 R302.13 state: Floor assemblies, not required elsewhere in this code to be fire resistance rated, shall be provided with a 1/2-inch gypsum wallboard membrane, 5/8-inch wood structural panel membrane, or equivalent on the underside of the floor framing member.

IBC Section 722.6.2, which provides counsel with respect to wallboard membrane equivalency, defines “time assigned to wallboard membranes.” In this section, a 1/2-inch gypsum wallboard membrane is assigned a 15-minute membrane rating.

The actual performance of the floor system is this 15-minute membrane rating plus the endurance time of the structural member attached to it.

This seems to be intended to fit into the fire service’s traditional “20-minute rule.”

Equivalent fire ratings are determined through standardized ASTM E119 testing. For example, this test is used to determine the requirements of a 1-hour rated assembly and can be used to verify alternate assemblies that perform equivalently. Page 24 of a UL test report summarizing recent ASTM E119 testing shows that an unprotected 2x10 floor assembly performance was 7:04 minutes. It is important to note this ASTM standard testing protocol requires 100% design load for benchmark comparison purposes. UL clearly indicates this in the table on page 24.

 

Q4. In the event of a fire, what is the expected floor performance under IRC-12 R501.3 and IRC-15 R302.13?

A4. Again, IRC-12 R501.3 and IRC-15 R302.13 state: Floor assemblies, not required elsewhere in this code to be fire resistance rated, shall be provided with a 1/2-inch gypsum wallboard membrane (GWP), 5/8-inch wood structural panel (WSB) membrane, or equivalent on the underside of the floor framing member.

The law as defined by IRC-12 Section 722.6.2 and IBC-15 Chapter 7 indicate GWB and WSP are assigned a fire rating of 15 minutes.

The law as defined through exception 4 of IRC-12 R501.3 and IRC-15 R302.13 implies 2x10s provide a fire rating of more than 15 minutes while trusses and I-joists are stipulated to perform at a fire rating of less than 15 minutes. This is due to the fact that 2x10s are not required to have GWB or WSP applied, but trusses and I-joists do.

 

Q5. What does the code establish as safe floor performance in the event of a fire?

A5. The public and fire service expect a minimum level of fire endurance performance to be 15 minutes. The actual expected time should be greater than 15 minutes, based on Harmathy’s protected member theory. Therefore, 1/2-inch GWB protected floor assemblies should provide an endurance time of greater than 15 minutes.

 

Q6. It has been suggested in the market that fire assembly testing at 50% design load is acceptable?

A6. 100% design load on a 2x10 joist is the maximum load that it can carry via the resistance properties of the 2x10 using National Design Specification design values.

ASTM E119 states explicitly the following: 29. Loading 29.1 Throughout the fire endurance test, apply a superimposed load to the specimen to simulate a maximum load condition. This load shall be the maximum load condition allowed under nationally recognized structural design criteria unless limited design criteria are specified and a corresponding reduced load is applied.

Clearly, ASTM E119 states that any other type of E119 testing has to be designated as limited design criteria tests. This is why UL used 100% design load as the benchmark in their fire testing of floor assemblies.

 

Q7. It has been suggested in the market that IRC-12 R501.3 and IRC-15 R302.13 are based on the fire service comfort around the known fire performance of traditional products. Is this true?

A7. UL suggests this perceived comfort, if actually true, is misplaced.

Page 24 of the UL test report shows that ASTM E119 testing found an unprotected 2x10 floor assembly performance was 7:04 minutes. It is important to note this ASTM standard testing protocol requires 100% design load for benchmark comparison purposes. UL clearly indicates this in the table on page 24.

The Structural Building Components Association (SBCA) recently undertook testing at NGC Testing Services (NGC), an International Accreditation Service (ICC-IAS) accredited ISO/IEC 17025 ASTM E119 fire testing facility. SBCA chose to test at NGC versus UL so that the SBCA ASTM E119 test procedure and the resulting test data would be an independent verification of floor assembly performance. SBCA testing shows 2x10 floor assembly performance was 10:35 minutes. This result confirms UL testing results.

UL states on page 67 of their test report, “There are little if any warning signs of collapse so it is very important to understand the hazards associated with a basement fire because the consequences of falling through a floor into a basement fire are pinnacle.”

UL concludes on page 66 of their test report that basement floor assembly fires are a challenge to the fire service where, “This [the fire service scenario] assumes that the fire is witnessed, called into the fire department, the fire department is dispatched, the fire department arrives and the fire department begins their firefighting operation in 8 minutes. While possible, this is not the case for the majority of fires that occur across the United States. This emphasizes the importance of protecting all types of flooring systems, including dimensional lumber.”

 

Q8. It has been suggested in the market that acceptance criteria used in evaluation reports issued by the International Code Council Evaluation Service (ICC-ES) is recognized by the code as an approach to establish equivalency. Is this true?

A8. ICC-ES acceptance criteria are not referenced in the building code and therefore are not a recognized approach to establish equivalency.

Acceptance criteria are defined by the ICC-ES as follows: 5.1. Acceptance criteria are established by the committee to provide a basis for issuing ICC-ES evaluation reports on products and systems under codes referenced in Section 2.0 of the Rules of Procedure for Evaluation Reports.

With regard to IRC-12 R501.3 and IRC-15 R302.13, equivalency is determined through the standardized ASTM E119 test, which requires 100% design load testing to establish apples-to-apples fire performance equivalency.

The Structural Building Components Association (SBCA) recently undertook testing at NGC Testing Services (NGC), an International Accreditation Service (ICC-IAS) accredited ISO/IEC 17025 ASTM E119 fire testing facility. SBCA chose to test at NGC versus UL so that the SBCA ASTM E119 test procedure and the resulting test data would be an independent verification of floor assembly performance. SBCA testing shows 2x10 floor assembly performance was 10:35 minutes. This result confirms UL testing results, which showed 2x10 performance to be 7:04 (see table below).

SBCA ASTM E119 testing shows that a product deemed equivalent by the ICC-ES, Flak Jacket, has an ASTM E119 100% design load performance of 6:37 minutes, which is less than 2x10 performance, and less than half the 15-minute membrane performance expected by IRC-12 R501.3 and IRC-15 R302.13.

 

Q9. It has been suggested in the market that ASCE 7 Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 7-10) contains an approach recognized by the code to establish equivalency. Is this true?

A9. Currently, documentation regarding how ASCE 7 applies to IBC-12 Section 722.6.2 or IRC-12 R501.3 and IRC-15 R302.13 has not been published.

Equivalent fire ratings are determined through standardized ASTM E119 testing. For example, this test is used to determine the requirements of a 1-hour rated assembly and can be used to verify alternate assemblies that perform equivalently. It is important to note the ASTM E119 standard testing protocol requires 100% design load for benchmark comparison purposes.

 

Q10. It has been suggested in the market that independent fire experts such as Frank Brannigan, and other professional entities like the National Association of State Fire Marshals, International Association of Fire Chiefs, International Association of Fire Fighters, NAHB, and ICC-ES have supported the science and widespread acceptance of unprotected solid sawn lumber in sizes greater than or equal to 2-inch x 10-inch nominal in residential construction. Is this true?

A10. Currently, documentation from any of these groups incorporating a review of the 2012 UL test report, Improving Fire Safety by Understanding the Fire Performance of Engineered Floor Systems and Providing the Fire Service with Information for Tactical Decision Making (which includes significant independent conclusions on this issue), or the recent ASTM E119 standardized testing undertaken by SBCA at NGC Testing Services (NGC), is unavailable. 

Assembly ratings generated through ASTM E119 testing using 100% design load for comparison purposes should be incorporated into any analysis of this issue.

 

Q11. Given all of the science available in the market, why is there still dispute over this issue?

A11. Again, the code development process is a political and not a science-based process. In the case of IRC-12 R501.3 and IRC-15 R302.13, the American Wood Council (AWC) and the National Association of Homebuilders (NAHB) authored and defended these code proposals, disregarding the harm they caused the truss industry through endangering the floor truss market.

The NAHB’s approach to this issue, and their documentation surrounding their point of view, provides good insight into the code development process and how special interests like theirs operate within the ICC code development process.

In the case of IRC-12 R501.3 and IRC-15 R302.13, the artificial competitive advantage created by exception 4 within these code provisions creates significant economic benefits for special interests who continue to fight hard to protect it.

 

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