The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recently published the 2010 version of its residential ventilation standard. The latest edition, ANSI/ASHRAE Standard 62.2-2010, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings, includes many updates and addenda since the previous version, published in 2007.
The only nationally recognized indoor air quality (IAQ) standard developed specifically and solely for single-family and low-rise multifamily homes, Standard 62.2-2010 defines the roles of and minimum requirements for mechanical and natural ventilation systems and the building envelope intended to provide acceptable IAQ through a three-pronged approach: whole-house mechanical, local exhaust in kitchens and baths, and source-control measures.
The 2010 version outlines satisfactory alternative methods for meeting the ventilation requirements in existing kitchens and baths. Exhaust fans are required by the standard in kitchens and baths, but because installations in existing homes can be problematic, an alternative compliance path established in the updated standard allows the home’s overall whole-house ventilation rate to be increased to compensate for insufficient or nonexistent kitchen or bath exhaust fans.
“This change makes the standard much easier to use in home retrofits, which is very important considering massive federal and state government efforts in this area,” says Steven Emmerich, chairman of the standard’s development committee.
Other updates to the standard include: more accurate factors for intermittent whole-house systems, as well as changes to more effectively limit unintended air transfer from garages, leaky ducts, adjacent housing units, and other such spaces. Also, an exception allowing the use of windows in place of fans in certain climates has been deleted based on research showing that windows frequently are not used and supply unreliable ventilation.
A user’s manual for the updated standard will be published in September 2010. The text of Standard 62.2-2010 is available for purchase at www.ashrae.org/bookstore.
