New Standard 55: 'Cool People, Not Buildings'

Recent updates to the industry standard for thermal comfort in buildings, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 55, will for the first time recognize elevated air speed as a component of thermal comfort, giving building designers and operators the ability to turn up the fans, rather than the air-conditioning, to help occupants stay comfortable when building temperatures rise.

According to Standard 55 committee chair Stephen Turner, a growing body of research indicates that having some degree of air movement within a space can keep people just as comfortable, if not more so, than do uniform, still-air conditions at lower temperatures. Based on this research, the change to the standard represents a move away from “the pursuit of uniformity” inside buildings and toward allowing a wider variety of conditions. "The main application of the elevated air speed changes is to provide designers and building operators with the flexibility to reduce air-conditioning energy use by keeping people comfortable with local air movement in warmer conditions," Turner told EBN. This flexibility carries the potential for energy savings, and should give designers more latitude in creating spaces like atria, which are high-performance features for daylighting and cold-weather solar gain, but difficult and energy-intensive to condition efficiently to more traditional, uniform thermal conditions.

Other significant changes to the standard should help smooth over the documentation process for LEED project teams pursuing thermal comfort credits. Working closely with the Center for the Built Environment at the University of California–Berkeley, the committee brought the standard into closer alignment with the surveys many project teams use to verify occupant comfort in order to comply with LEED thermal comfort credits. The committee also worked with the U.S. Green Building Council to develop a new LEED template for documenting thermal comfort. “By simplifying and clarifying and making more meaningful the documentation requirements for designers, we've allowed a significant alignment for project teams using the standard to show LEED compliance," Turner told EBN.Standard 55 has historically struggled to account for the variety of factors at play in defining thermal comfort, which has sometimes led to the over-conditioning of spaces and excessive energy use (see EBN May 2009). By thinking about thermal comfort in terms of “cooling people, not buildings,” as Turner says, these changes to the standard should enable more high-performance design and give building operators more control over energy use.

–Andrea Ward