ATLANTA - Lessons learned from 30 years of ventilation practices, as well as user input and developments in research, led to key changes to the American Society of Heating, Refrigerating, and Air-Conditioning Engineers' (ASHRAE's) 2004 ventilation standard.

ANSI/ASHRAE Standard 62.1-2004, "Ventilation for Acceptable Indoor Air Quality," specifies minimum ventilation rates and IAQ requirements for commercial and institutional buildings.

"While the purpose of the standard has remained consistent since it was first published in 1973, the means of achieving the goal of providing acceptable indoor air quality have evolved," said David Butler, chair of the Standard 62.1 committee. "The 2004 standard provides users with better tools to help get the job done."

Among the major changes is a revision of the ventilation rate procedure to reflect recent information on how ventilation impacts IAQ, and to clarify the adjustments necessary for space air distribution and system efficiency of multizone recirculating systems. The breathing zone ventilation rate now includes both an area-related component and an occupant-density-related component, which are added together to determine the required ventilation for the space, Butler said.

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Publication date: 02/07/2005