NGA comments on ASHRAE 90.1 public review

The National Glass Association, McLean, Va., joined other industry associations in submitting comments in the public review for American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard 90.1, according to a Dec. 17 release. The revision to ASHRAE 90.1 aims to increase building energy efficiency by 30 percentby the year 2030. See story. The standard,published every three years, is the basis for both state energy codes and utility rebate programs.

NGA’s comments, developed in cooperation with the American Architectural Manufacturers Association, the Insulating Glass Manufacturers Alliance, and the Glass Association of North America, included the following:

• U-factor and SHGC valuesThe National Glass Association asserts that the U-factor and SHGC values listed in the addendum should be changed to the values proposed by NBI and AIA in EC165 to the IECC. The proposed values are appropriate and have been accepted with broad support at the ICC preliminary hearings. Adopting these agreed upon values in ASHRAE 90.1 will provide consistency within the standards and the industry

• Window to wall ratioThe current proposal reduces the window area in construction projects using the prescriptive path from 40 percentto 30 percent. The NGA does not support this reduction in the window to wall ratio. There appears to be no data to support lowering the percentage. The NGA maintains that the window to wall ratio in ASHRAE 90.1 should be left at 40 percentwhile research is completed.

• Light to solar gainThe use of VT/SHGC or LSG criterion only saves energy if lighting controls are present. Therefore, a minimum center of the glass LSG value should be required when paired with lighting controls that enable the capture of energy savings through natural daylight. The NGA suggests a modification to ASHRAE 90.1 that requires compliance with VT/SHGC criterion for the entire product only where lighting controls are used and requests that ASHRAE 90.1 reflect the DOE’s requirements to ensure consistency in the industry.

The proposed revision was opened for public review in November 2009. The committee will review comments in January 2010, with the goal of completing the new version of the standard in June.