Group moves forward on international window energy rating
A working group for the International Standards Organization of Switzerland is nearing completion of ISO 18292: Energy performance of fenestration systems – calculation procedure.
The group met last month in Helsinki, Finland, to go over final edits to the voluntary standard that can be used by the industry to rate the energy performance of a window, door or skylight, rather than just the thermal performance. According to the standard’s scope in the draft document, the standard will provide a procedure to calculate performance of systems based on the effects of the frame, sash, glazing and shading components.
Energy performance is based on thermal conductance, solar heat gain coefficient and air leakage, says Hakim Elmahdy, principal research officer for the Institute for Research in Construction, which is part of the National Research Council of Canada in Ottawa. Elmahdy met with the other international members of the working group in June.
“There are standards out there to calculate thermal performance where we can calculate heat transmission through windows, but there is almost nothing out there to calculate the whole energy performance—nothing from [ASTM International of West Conshohoken, Pa.] or [the American Architectural Manufacturers Association in Schaumburg, Ill.],” Elmahdy says. “[The National Fenestration Rating Council of Greenbelt, Md.] has been trying to develop a standard for the last 15 years, but there’s nothing yet. The only one is here in Canada. It came from [the Canadian Standards Association of Mississauga, Ontario].”
Representatives from Australia, Austria, Belgium, Canada, China, Denmark, Finland, Germany, Japan, The Netherlands, Sweden, Switzerland, the United Kingdom and the United States make up the working group, Elmahdy says.
The international participation to create the international standard is critical before individual countries begin developing their own standards, possibly creating trade barriers, according to the draft document.
“ISO standards are accepted to all countries and provide best vehicle for achieving international harmonization,” says Bipin Shah, president of WinBuild Inc. in Fairfax, Va. Shah is also a member of the ISO energy rating working group.
A draft of the standard should be completed by November 2007. “[Drafts] usually go back for a ballot among the country members of the committee,” Elmahdy says. “In May 2008, we will have a final draft, with the publication date of November 2008.”
—By Katy Devlin, e-newsletter editor, e-glass weekly