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The first addenda to the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) residential ventilation standard have been approved for publication.
ANSI/ASHRAE Standard 62.2,Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings, is the only U.S.-recognized indoor air quality standard developed solely for residences and was approved for publication at ASHRAE’s 2004 Annual Meeting.
Addendum 62.2b changes the terminology "severe cold climate" to "very cold," which is now defined as a climate that has more than 9,000 65°F degree-days.
"This makes the standard’s climate definitions consistent with the proposed revisions to the International Code Council climate zone definitions, which will simplify implementation of Standard 62.2 into code," said David Grimsrud, chair of the Standard 62.2 committee.
The primary impact of the change is to remove the Minneapolis-St. Paul, MN, U.S. area from the "severe cold" climate category. As a result, the area no longer falls under the restriction in the standard forbidding the use of mechanical supply systems exceeding 7.5 cfm/100 sq ft. The change has some effect on smaller urban areas as well.
Addendum also 62.2a removes combustion appliance backdrafting test requirements from the standard. The test was based on the best industry-accepted method found in the National Fuel Gas Code but questions arose about its application to solid-fuel burning appliances, according to Mr. Grimsrud. There also was concern about it not being possible to perform the test until the home is completed, opening the potential for having to perform remedial balancing at a difficult stage of construction and sale.
Although the proposed addendum eliminates the test requirements, it sets an upper limit of exhaust flow to 15 cfm/100 sq ft when natural-draft combustion appliances are present. It also requires designers or installers to address the level of depressurization at a stage where the problem can be fixed more easily, Mr. Grimsrud.
The addenda are subject to a 15-day appeals period to the board of directors.
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