SPRAYFOAM Professional - Winter 2015 - (Page 19)

saFEty First inDustry takEs initiativE to imProvE EnErgy moDELing soFtWarE By JusTIn KosCHEr, spray foam CoaLITIon E nergy code compliance software used by building professionals in California has been updated to more accurately model benefits of SPF applications in residential attics. Residential building energy codes in many jurisdictions now include performance-based compliance pathways that provide an alternative to prescriptive code requirements. Performance-based energy codes provide homebuilders with flexibility and often require the use of energy modeling software to verify the performance of construction designs. Software packages help track a design's energy budget and should enable builders to take full advantage of a particular design strategy or use of a specific building material. Unfortunately, the software used in California was not producing accurate results for the energy performance of residential attics due to incorrect air leakage rates. The California Energy Commission develops and maintains a free energy code compliance software tool known as the California Building Energy Code Compliance software, or CBECC. The tool, like other energy modeling software, is used by homebuilders to verify that designs meet the state's energy efficiency requirements. For example, a builder constructing an unvented attic with SPF will use CBECC to account for the energy savings generated from eliminating air leaks through the roof. An unvented attic design will typically generate 10-15% energy savings versus a traditional vented attic design, according to industry data. However, prior to our engagement, CBECC showed a vented attic performing as well as an unvented attic with respect to energy savings. Building science and field data on unvented attics told us something in the software was not working correctly. The Spray Foam Coalition plans to draft a technical article that will be distributed to California building professionals and used to explain how CBECC now accurately models the energy savings from unvented attics constructed with SPF." The Spray Foam Coalition, together with SPFA and energy-efficiency experts in California, uncovered the cause of this error. CBECC was assigning the same percentage of air leakage to a home's roof regardless of whether the attic insulation was placed on floor or the underside of the roof deck. The industry collected field data on unvented attics and presented the findings to the California Energy Commission. Commission staff responded to the concerns and worked with the software developers to implement fixes. Today, CBECC is calculating energy savings more representative of the performance levels we see with unvented attics in the field. The SPF industry has more to accomplish. The Spray Foam Coalition plans to draft a technical article that will be distributed to California building professionals and used to explain how CBECC now accurately models the energy savings from unvented attics constructed with SPF. We also plan to examine other popular software tools that are used by building professional and energy raters to model homes across the country. Performance-based compliance pathways for building energy codes are likely to become an increasingly popular option for constructing residential homes. It is important that energy modeling software accurately reflect the performance of specified designs and building materials. Your industry trade organizations are hard at work helping to verify that the versatile performance benefits of SPF are well represented in these tools. o Justin Koscher is a director at the center for Polyurethanes industry and spray Foam coalition. He can be reached at justin_koscher@americanchemistry.com. www.sprayfoam.org | sprayfoam Professional 19 http://www.sprayfoam.org

Table of Contents for the Digital Edition of SPRAYFOAM Professional - Winter 2015

EXECUTIVE DIRECTOR’S CORNER
PRESIDENT’S POST
FOAM BUSINESS NEWS
SPFA TODAY
LEGISLATIVE UPDATE
SAFETY FIRST
Sprayfoam 2016 Convention & Expo – February 8-11, 2016
SPFA’s History Proves Our Perseverance
ABAA NEWS
SPF Research on Air Quality – PART 1
2015 SPFA CONTRACTOR AWARDS
MAKING MONEY: Paint Your Own Picture of Success
ASK THE EXPERT
UPCOMING EVENTS
INDEX OF ADVERTISERS

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