ATLANTA – Public input to help shape the technical requirements in Standard 90.1 is being sought through 21 proposed addenda, which could become part of the 2010 standard.

ANSI/ASHRAE/IESNA Standard 90.1-2007, Energy Standard for Buildings Except Low-Rise Residential Buildings, provides minimum requirements for the energy-efficient design of buildings except low-rise residential buildings. The proposed addenda cover a range of topic areas, including day lighting, air leakage, EER and IEER values, and requirements for VRF air conditioners and heat pumps.

“Our goal is to produce a standard to increase energy efficiency in buildings,” said Mick Schwedler, Standard 90.1 committee chair. “Public input from the industry into development of the standard has proven invaluable since it was first published 35 years ago.”

If no comments are received on the addenda, they likely will be incorporated into the 2010 version of the standard slated to be published this fall. If comments are received, the substance and volume of those comments will determine whether they are incorporated into the 2010 standard.

Among the proposed addenda is addendum bu that would modify computer room efficiency requirements based on comments from an earlier public review.

“The 90.1 committee worked closely with manufacturers, designers and owners of computer rooms to address comments and produce the language in this addendum,” said Drake Erbe, Mechanical Subcommittee chair. Below is a listing of proposed addenda available for public review until April 19:

• Addendum bu would modify the computer room efficiency requirements based on comments received during the first public review.

• Addendum cd would strengthen the language to actually require exterior control rather than just require the control capability; add bi-level control for general all-night applications such as parking lots to reduce lighting when not needed; and add control for façade and landscaping lighting not needed after midnight.

• Addendum cn would add two versions of a combined advanced control to the control incentives table. These control system combinations involve personal workstation control and workstation-specific occupancy sensors for open office applications. The control incentive will apply only to the particular controls when they are applied in open office areas.

• Addendum co would make three major amendments to Table 6.8.1A: update EER and IEER values for all condensing units and water and evaporatively cooled air conditioners with cooling capacities greater than 65,000 Btuh; establish a separate product class for evaporatively cooled air conditioners with different energy efficiency standards; and replace the IPLV descriptor for condensing units with the new IEER metric and amends the EERs with more stringent values.

• Addendum cp would establish, for the first time in Standard 90.1, efficiency requirements for VRF air conditioners and heat pumps, including heat pumps that use a water source for heat rejection.

• Addendum cq would modify the duct sealing requirements in 90.1.

• Addendum cr would set a definition for an unmet load hour currently lacking a throttling range or limit to the set point. It was decided that the baseline and proposed shall have the same thermostat throttling range. This required additional language in the unmet load hour definition as to how throttling range effects determination of an unmet hour along with additional language in Table 11.3.1 and Table G3.1, Design Model sections.

• Addendum ct would reduce the threshold for daylighting from 1,000 square feet to 250 square feet.

• Addendum cy would make several revisions to the economizer requirements in section 6.5.1 and in section 6.3.2.

The proposed addenda to ASHRAE/IESNA Standard 90.1 are available for comment only during their public review period. For more information, visit

Publication date:04/05/2010