ASHRAE has proposed that the ventilation rate calculation procedures from ANSI/ASHRAE Standard 62.1-2004, "Ventilation for Acceptable Indoor Air Quality," be adopted into the IMC published by the International Code Council. The code establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions.
The current ventilation criteria in the IMC are based on ASHRAE Standard 62-1989. Through research, information on indoor air quality and ventilation has evolved. In response, ASHRAE has enhanced its standard to include the new rate procedure. This code change would make the IMC consistent with the standard and the 2006 Uniform Mechanical Code.
The procedure requires designers to account for pollutant sources other than occupants and to account for the efficiency of ventilation systems to deliver outdoor air to the breathing zone, according to Steve Taylor, an ASHRAE member who oversaw development of the proposal.
"Ventilation systems designed using the new procedure will result in somewhat lower outdoor rates for most occupancies compared to the current code, reducing first costs and energy costs," he said.
The proposed changes are scheduled to be evaluated in September 2006 for possible inclusion in the 2007 IMC Supplement.
Publication date: 05/08/2006