Important Information on the ICC-ES
Acceptance Criteria for SPF

By: Michael Beaton, Senior Vice President, International Code Council’s Evaluation Service, Inc. 
 

Foam plastic insulation has a special place in the building code.

Chapter 26 of the International Building Code (IBC) regulates the use of foam plastic in all types of construction, both combustible and noncombustible, and addresses specific applications, including attics, crawl spaces, roofing, and garage doors. The requirements apply to all foam plastic insulation, including expanded polystyrene (EPS), polyisocyanurate, and spray-applied polyurethane, all types of foam plastic insulation covered by the code. The subject of this article is the use of spray-applied polyurethane foam plastic insulation in attics and crawl spaces.

In the United States, local building jurisdictions are charged with enforcing the building code. When a material or system is used in construction, the code official must verify that the product or system complies with the applicable requirements of the code. Instead of providing this justification individually in each of their jurisdictions, many manufacturers apply for an evaluation report (ESR) from International Code Council’s Evaluation Service, Inc. (ICC-ES). The ICC-ES process is typically used by manufacturers seeking recognition of their innovative product or system, or verification through an independent review that their product complies with the requirements of the building code. ICC-ES evaluates manufacturer’s data and publishes a technical report that code officials can then use to approve products for installation in their jurisdictions.



There are two primary model codes in the United States that apply to SPUF: the International Building Code and the International Residential Code, both of which are published by ICC.  The model codes are adopted in most jurisdictions in the United States, but may be amended by building officials in those jurisdictions before being adopted into law. Section 2603 of the 2009 IBC and Section R316 of the 2009 IRC detail the requirements that must be met by SPUF. For general use, the interior of the building must be protected from the foam plastic by a thermal barrier, typically 0.5-inch-thick (1.3 cm) gypsum boards. In attics and crawl spaces, the covering requirement is reduced, so the SPUF must be covered with one of the materials listed in IBC Section 2603.4 or IRC Sections R316.5.3 and R316.5.4, as applicable.  A 0.25-inch-thick (6.4 mm) wood structural panel is an example of one of these covering materials.

Section 104.11 of both the IBC and the IRC have provisions to consider alternate means to meet prescribed code requirements, provided the alternate means also satisfy fire, durability, and other requirements. In addition, IBC Section 2603.9 and IRC Section R316.6 provide for waiving the covering in attics and crawl spaces when full-scale fire tests, such as UL 1715 or NFPA 286, are performed on materials representative of actual construction.

To address this code allowance, manufacturers approached ICC-ES, who worked with the manufacturers and their industry group, the Spray Polyurethane Foam Alliance (SPFA), to develop the ICC-ES Acceptance Criteria for Spray-applied Foam Plastic Insulation (AC377). AC377 details how ICC-ES will evaluate SPUF for code compliance and identifies the tests needed for various applications. These criteria will be updated regularly through the ICC-ES criteria development process as codes and standards change or as new information is made available.

Accompanying the push for better energy efficiency is a need for higher insulation thermal resistance (R-values) in attics. New foam plastic insulation products are being developed and installed in increasingly greater thicknesses. Because the codes were written for foam plastics in the 1970s and the requirements have not changed significantly since that time, the SPUF industry recognized that the standard tests did not reflect the best science for the intended applications. They approached ICC-ES with a plan to revise the requirements, including a staged process to transition from the current requirements to the new provisions over a three-year period.  

First, because the configurations of attics and crawl spaces are different, their testing requirements were separated. For attics, the tests are based on a room corner configuration (typical room corner tests are described in NFPA 286 and UL 1715). For crawl spaces, tests are based on a protocol developed by Southwest Research Institute (SwRI), which is designated as 99-02. Successful test performance was redefined as performing better than one of the code-specified coverings with 0.25-inch (6.4 mm) A-C or B-C plywood used for the baseline.  A pass-fail value was set based on the performance of the assembly with the baseline plywood covering in room corner tests so that systems already recognized in ICC-ES evaluation reports could be re-evaluated.  For the first stage, assemblies not meeting the baseline values will be deleted from the evaluation reports by January 2010. 

The second step was to revisit the test procedures and determine the most effective means to quality SPUF for use in attics and crawl spaces. A group of manufacturers working through the SPFA undertook an aggressive test program to evaluate various methodologies and to determine minimum acceptable performance levels. In June 2009, less than a year after starting their program, the task group presented their findings to the ICC-ES Evaluation Committee and successfully petitioned for revisions to AC377.

For attics, they proposed using NFPA 286 as the test method, but suggested modifying the construction of the test assembly and including four conditions of acceptance: time to maximum heat release rate of 1 MW, time to maximum heat flux to the floor of 20 kW/m2, time to maximum upper layer temperature of 1,112° F (600° C), and time for flames to exit the doorway of the test room.  The test is successful when the average time for attainment of the four measured test parameters is four minutes and 18 seconds or greater.

For crawl spaces, the industry group proposed using the SwRI 99-02 protocol with side-by-side comparison to 0.25-inch (6.4 mm) plywood. For both attics and crawl spaces, these new requirements will necessitate retesting by all current report holders, with revision of ICC-ES evaluation reports due by December 31, 2010.

Manufacturers of SPUF with ICC-ES evaluations reports recognizing applications in attics and crawl spaces have been notified that they should submit their data by July 2010 to ensure completion of the ICC-ES review, and any necessary report revisions, by the end of 2010.

The revisions to AC377 are the result of a huge effort on the part of the SPUF industry and demonstrate their commitment to reflecting current knowledge of codes and science.  While the new requirements represent a consensus of the industry, they were not supported by all manufacturers, so it is likely that further work will be done and alternative methodologies will be considered in the future.

Information on ICC-ES can be found at www.icc-es.org.
The ICC-ES Acceptance Criteria for Spray-applied Foam Plastic Insulation (AC377) can be found at http://www.icc-es.org/criteria/pdf_files/AC377.pdf.


Michael Beaton is a licensed mechanical engineer and is currently serving as senior vice president with ICC Evaluation Service, Inc., in Whittier, Calif. He has been with ICC-ES for 15 years.  Before that, he worked in various positions at SGS United States Testing Company, Inc., performing structural and physical property testing on building materials. He is a member of ASTM committees E-05 and F-17.  
 

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