Proposals to Improve Water Efficiency Made for Green-Building Standard

Measures to improve water efficiency proposed for ANSI/ASHRAE/USGBC/IES Standard 189.1-2011, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings, are open for public review.

Open for public review through Jan. 14 is Addendum v, which would limit the full-flush volume of all toilets to 1.28 gal. per flush and limit kitchen-faucet capacity to 1.8 gpm. Research shows dual-flush toilets in non-residential settings are not used in the 2:1 full-flush-to-partial-flush ratio, as anticipated. Instead, the full-flush option almost always is employed.

“There is no evidence that the dual-flush toilets use significantly less water than the full-flush in commercial settings,” Thomas Pape, a member of the Standard 189.1 committee, said. “We have found that 90 percent of the flushes from dual-flush toilets are full flushes. Since many models of dual-flush toilets would meet a maximum of 1.28 gal. for the full flush, the maximum volume for dual-flush toilets has been decreased to match the maximum volume for single-flush toilets.”

The kitchen-faucet maximum capacity is being changed to reflect the current water-efficiency standard of 1.8 gpm established by various green codes.

Addendum v also would set limits on the use of municipal reclaimed water for irrigation. Municipal reclaimed water is highly treated—usually, to drinking-water standards—and often in short supply. Furthermore, the growing use of municipal reclaimed water for groundwater recharge of potable-water supplies increases its value.

“It is unreasonable to allow the unfettered use of reclaimed water, considered a precious resource, as a means to save energy when there are more viable alternatives,” Pape said. “Therefore, the use of municipal reclaimed water would be prohibited for roof-cooling applications and for permanent irrigation of vegetated roofs using either in-ground or above-ground irrigation systems. There are many other alternative water sources that can be used for this puprpose, including graywater, condensate recovery, rainwater, and cooling-tower discharge.”

The temporary use of reclaimed water in above-ground irrigation systems is allowed during the vegetation-establishment period required for vegetated roofs.

Also open for public comment through Jan. 14 is Addendum u, which significantly expands and strengthens the standard’s stormwater-management requirements.

Open for public review through Dec. 30 is proposed Addendum z, which changes minimum efficiency requirements for open refrigerated display cases. The addendum adds efficiency requirements in Table C-16 in Appendix C, which covers efficiency requirements for commercial refrigeration equipment. The current Table C-13 for commercial refrigerators and freezers would remain unchanged.

Addendum z also clarifies the requirements for field-installed covers, curtains, and doors on open display cases. Lastly, it includes changes to Section 7.4.7.4 that were not included in the first public-review version of the addendum.

Also are open for public review through Dec. 30 are:

• Addendum b, which clarifies requirements for flooring systems.

• Addendum r, which adds references to ANSI/ASHRAE/ASHE Standard 170, Ventilation of Health Care Facilities.

For more information and to comment on the proposed changes, click here.