Fenestration consumes 32 percent of primary energy in nonresidential buildings. With that in mind, the National Fenestration Rating Council (NFRC) is one organization that is involved with helping those in the building industry comply with the ever-evolving and continuously stringent energy codes.
NFRC senior program manager Ray McGowan hosted a webinar this week outlining and explaining how the council helps provide the industry with high-performance fenestration for energy-efficient commercial construction.
All codes require NFRC 100/200 window rating and labeling, prescriptive or performance, and McGowan cautions that it’s important to remember that the ratings are not only required in new construction, but renovations, as well.
NFRC 100 determines U-factor, and NFRC 200 determines solar heat gain coefficient and visual transmittance. “It’s always based on the whole window’s energy performance,” McGowan adds, “so the center of glass is not acceptable.”
In residential and smaller commercial projects, each window gets an NFRC sticker, which includes energy performance ratings such as U-Factor and solar heat gain coefficient. Also included are performance ratings such as visible transmittance and air leakage. Larger commercial projects get a label certificate with more information.
NFRC offers simple verification methods for window energy ratings. Its online database, for example, offers the ability for users to look up numbers in the Certified Product Directory for residential products and project label certificates for commercial products.
For residential, the online database has approximately 9.5 million rated products, while the database for commercial enables project-specific label certificates to be downloaded at no charge.
According to McGowan, the basis of all of NFRC’s ratings is computer simulation at standardized sizes and environmental conditions. Simulated U-factors are validated by physical testing, which the association does about 4000 of per year.
McGowan pointed out that IECC-09 and ASHRAE 90.1-07 are the most common codes, though most states will soon move to IECC 2012/ASHRAE 90.1-2010. He explained ASHRAE 189.1 is a stringent green code, which the US Army requires. The International Green Construction Code is being required in other places, as well, such as the state of Maryland.
One tool McGowan said can be helpful is the site, http://energycodesocean.org/code-status, which breaks down commercial and residential code adaptation by state. He offered a reminder to builders, though, to check with local code officials on specifics, as local jurisdictions can adopt and enforce their own versions of the codes.