Fifteen proposed addenda to ANSI/ASHRAE/IESNA Standard 90.1-2010, Energy Standard for Buildings Except Low-Rise Residential Buildings, are open for public review.

Among 11 addenda open for public review until May 7 is ap, which recognizes the role system efficiencies can play in reducing data-center energy consumption.

“We recognize that equipment used in buildings is reaching maximum capabilities in energy efficiency," Drake Erbe, vice chair of the Standard 90.1 committee, said. "We now must examine the role that system efficiencies play in saving energy.”

The 2010 version of Standard 90.1 requires most data centers to have economizers. Some in the data-center industry, however, maintain economizers are subject to static discharge attributed to low humidity and gaseous contaminants.

Erbe said the Standard 90.1 committee worked with the data-center industry and ASHRAE Technical Committee 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment, to develop an alternative path known as power-usage effectiveness (PUE) to allow the use of developing technologies for which there are no energy-modeling tools.

“This is a significant issue to design professionals in that, without a simulation program available to model these systems, they have to receive approval from the authority having jurisdiction for an exceptional calculation method, which, in most cases, is beyond the jurisdiction’s knowledge level,” Erbe said. “The PUE values were developed using water-cooled chillers with water-side economizers and air-cooled chillers with air-side economizers using prescriptive requirements currently in the standard. The PUE values for all climate zones are able to be achieved by both of these conventional system types.”

Also open for public review until May 7 is:

• Addendum ao, which establishes a less-complicated alternative set of lighting requirements and more-stringent lighting-power-density (LPD) limits for smaller, simpler buildings. This compliance path would replace the current whole-building LPD table and apply only to smaller, simpler buildings. The use of this method would be optional, with the full space-by-space method used for larger, more complex facilities remaining for application to any building type, Eric Richman, chair of the standard's lighting subcommittee, said.

• Addendum al, which would make the minimum code baseline for determining energy savings in Appendix G of the standard consistent, regardless of the choice of fuel.

“This is done by setting rules to determine the fuel to be used in the baseline building for space and water heating,” Don Brundage, a member of the Energy Cost Budget subcommittee, said. "These rules are based on climate zones for space heating and type of building usage for water heating. This would make energy-savings estimates using Appendix G more consistent and fair than under the current version of the standard.”

Other addenda open for public review until May 7 are af, ag, ai, am, an, aq, ar, and at. Open for public review until April 22 are addenda ad, ah, aj, and as. To review and to comment, click here.