Critical Review of ASHRAE Standards Addressing VOC Mixtures

ASHRAE Standards addressing VOC mixtures were developed with considerable scientific uncertainty. The IAQ Procedure is being used to lower ventilation rates based on assumptions that Contaminants of Concern (COC) can be used as surrogates for overall IAQ and that concentration limits suggested by “Cognizant Authorities” can be used to determine if IAQ is acceptable. Standard 189.1 specifies a list of 32 VOCs for pre-occupancy sampling, with high performance credits awarded when measured concentrations are below State of California target values. This review examines assumptions underlying Standards 62.1 and 189.1 in view of recent studies and field experience. The authors propose that ASHRAE organize a Multi-Disciplinary Task Group to review issues associated with VOC mixtures and make recommendations to update current standards.