NGA Reports from ASHRAE 90.1 Meeting

Window & Door
October 17, 2018

The National Glass Association was represented at last week’s ASHRAE 90.1 committee meeting by Urmilla Sowell, NGA’s director of technical services and advocacy; Tom Culp, NGA's technical consultant and co-vice-chair of the ASHRAE 90.1 committee; and Thom Zaremba, GICC consultant. 

Culp reported three items of good news to NGA members by email regarding outcomes of the Window Criteria Proposal, the Thermal Bridging Proposal and Envelope Backstops.

Window Criteria Proposal
This proposal is a comprehensive update to the fenestration criteria—U-factor and SHGC for windows, entrance doors, and skylights—affecting residential multifamily buildings four stories and higher, as well as commercial buildings. This proposal provides an increase in stringency while still being cost effective and practical, and also aligns the product categories to match those used in the IECC without regard to material type. 
Having been worked on for the past year, the proposal went out for public comment with only small corrections requested. The committee made the corrections at the meeting, and just those small changes will now go out for public review. Assuming there are no more comments, the addendum will go up for final approval at the January meeting.
“Due to Tom Culp’s work representing NGA at the ASHRAE meeting last week, we’re very hopeful the Window Criteria Proposal will pass in January and make it into the 2019 standard,” says Nicole Harris, NGA president and CEO. “Tom really stepped up for the entire industry and his efforts are appreciated.”  
Thermal Bridging Proposal
This controversial proposal that addresses thermal bridges that bypass wall, roof and floor insulation also completed its first public review. The portions of this wide-reaching  proposal that potentially affect the industry involved rules on the intersection between window framing and the opaque wall, limitations on attachment area for sun shades, and how thermal bridges could be traded off against wall and window performance. 

Upon receiving 250 negative comments, the subcommittee is trying to figure out next steps for this proposal.
Envelope Backstops
Envelope backstops, or limitations on trade-offs when using the performance path, are an area of concern. This limits product flexibility and, most importantly, could be used to limit window area in office and high-rise residential buildings even if you show equivalent or better energy performance. 

Three different approaches have been suggested and the subcommittee will spend more time to discuss and carefully analyze the potential impacts, meaning this would not make its way into the standard until 2022 at the earliest.