ASHRAE 90.1, with 40 Percent Window-to-Wall Ratio, Approved for Final Publication
January 30, 2012

ASHRAE Standing Standard Project Committee 90.1 voted to approve final publication of Addendum bb to ANSI/ASHRAE/IESNA Standard 90.1-2007, at a meeting January 20-23 in Chicago, "with knowledge of unresolved objectors" with a fair amount of debate about the cost effectiveness of some of the new wall insulation requirements, says Thomas Culp, president of Birch Point Consulting LLC in La Crosse, Wis. "From the fenestration perspective, this final version of bb restored the window-to-wall ratio (WWR) and included the U-factors supported by the group that successfully appealed the previous version [including the] Glass Association of North America (GANA), Aluminum Extruders Council (AEC), Insulating Glass Manufacturers Alliance (IGMA), AGC Flat Glass North America, Guardian Industries and Pilkington," he says. "This now goes forward to the board for final approval, but it is almost certain there will be at least one appeal related to the wall insulation requirements, so we won't know the final fate of bb until towards the end of the year. Besides addendum bb, there was significant discussion of how to expand daylighting requirements in the code, but no action yet."

The addendum keeps the WWR at 40 percent, says Urmilla Jokhu-Sowell, technical director of GANA. "In addition, a Daylighting Task Group, which is a joint task group between the 90.1 Envelope and Lighting Subcommittees, is looking at new proposals for ASHRAE 90.1 2013 and 2016 editions," she says. "And right now, it's in the preliminary stages, but nothing seems off the table. They are discussing WWR with continuous lighting controls, clerestory and splitting vision glass and daylighting glass. It's very important that the glass and glazing industry stay involved at ASHRAE."

The addendum was first sent out for public review in March 2009, and many groups -- not just glass -- objected. In the second draft in November 2009, ASHRAE officials modified some of the requirements, but also reduced the allowable WWR to 30 percent, which was controversial with the glass and glazing industry. There was a third modification in February 2010, but it made only small changes. When it was voted for final publication in June 2010, there were several appeals filed on both wall and metal building and window issues. Within the glass industry, GANA, AEC, IGMA, AGC, Guardian and Pilkington all filed appeals, although the associations worked together. In October 2010, the appeal won, especially because of the concern over window-to-wall ratio, and Culp was appointed to the committee to help ensure that the commercial glazing industry would be represented and have a vote. In February 2011, ASHRAE released a fourth version that included a number of changes in response to the glass industry's appeal, retaining the current WWR, and U-factors and solar heat gain coefficient criteria that the industry supported.

"Overall, we are now resolved and support 'bb,' but there remains controversial items on wall insulation that could still hang up the final approval," Culp says.

Culp will have an update on this at the GANA Annual Conference's Energy Session in Sarasota, Fla., February 20-24.

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