Proposed revisions to the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) thermal comfort standard include the addition of an equation for assessing thermal comfort.

ASHRAE Standard 55-1992R, “Thermal Environmental Conditions for Human Occupancy,” specifies the combinations of indoor thermal environmental factors and personal factors that will product thermal environmental conditions acceptable to a majority of the occupants within the space.

Environmental factors include temperature, thermal radiation, humidity, and air speed, while personal factors are activity and clothing.

The standard was approved for public review at ASHRAE’s 2001 winter meeting held in Atlanta, Jan. 27-31.

A major proposed change is the addition of the predicted mean vote (PMV) calculation method, which is used to assess thermal comfort, according to Daniel Int-Hout, chair of the committee revising the standard.

This addition includes a computer program as part of the standard, Int-Hout said. The PMV also is included in International Organization for Standardization (ISO) thermal comfort standard 7730.

“This equation will enable engineers to make better design decisions regarding thermal comfort,” Int-Hout said. “The equation has been validated by research.”

Other proposed revisions include new data on adaptive response in passively ventilated buildings, based on ASHRAE-sponsored research, and an update of data tables, also based on new research.