According to ASHRAE, the energy reductions were achieved in multiple ways; the following are some examples. The scope was expanded so that 90.1 covers receptacles and process loads, including data centers. This allows future addenda to the standard to address energy consuming equipment and systems previously outside its scope. In regards to the building envelope, continuous air barrier and cool/high albedo roof requirements were added. As for lighting, most interior lighting power densities were lowered and additional occupant sensing controls and mandatory daylighting requirements were added for specific spaces, along with a new five-zone exterior lighting power density table. On the mechanical side, most equipment efficiencies are higher, energy re- covery is required in more applications, economizers are required in more climates, and more energy-conserving controls are required as well. Modeling requirements have been clarified and expanded so that building modelers can more accurately compare energy cost of their building project with an appropriate baseline building as defined by the standard.
“The 90.1 standard is a fluid document,” said Mick Schwedler, immediate past chair of the 90.1 committee. “As technology evolves, the project committee is continually considering new changes and proposing addenda for public review. The rigorous, open, public review process following ASHRAE and American National Standards Institute (ANSI) procedures results in a document that is both technically sound and reaches consensus.”
Extensive analysis work was performed by a team from Pacific Northwest National Laboratories in support of the DOE Building Energy Codes Program. Sixteen different building prototypes were modeled in 17 different climate zones for a total of 272 building types and climate zone combinations.
The standard is written in mandatory code language and offers code bodies the opportunity to make a significant improvement in the energy efficiency of new buildings, additions, and major renovations. “As we look ahead to exploring new areas of energy savings from energy consuming equipment and systems, we will seek input from materially affected and interested parties. We welcome their input to help the project committee in this endeavor,” said Steve Skalko, current chair of the committee.