ATLANTA — A proposed new standard that will provide minimum guidelines for green building practices is nearing completion. Applicable to new commercial buildings and major renovation projects, it will address energy efficiency, a building's impact on the atmosphere, sustainable sites, water use efficiency, materials and resources and indoor environmental quality.

Proposed Standard 189, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings, is being developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers in conjunction with the Illuminating Engineering Society of North America and the U.S. Green Building Council. This is the first such green building standard in the United States, according to ASHRAE.

The proposed standard has been released for public review. Comments will be accepted through July 9.

"Standard 189P will become the benchmark for all sustainable-green buildings in the United States because it is being developed for inclusion into building codes," John Hogan, committee chairman, said. "This means that owners and designers will have a consensus-based document that will set the minimum criteria that a building must satisfy in order to be considered a green building. The real impact of Standard 189P is that ASHRAE, along with IESNA and USGBC, are taking advanced energy conservation guidance mainstream for the general public's benefit."

The standard is not a buildingrating system but rather a compilation of criteria that must be met in order for local building code officials to provide a certificate of occupancy for a facility, Hogan noted.

The standard's energy efficiency goal is to achieve a minimum of 30% reduction in energy cost (and carbon dioxide equivalent) over that in ANSI/ASHRAE/IESNA Standard 90.1-2007, Energy Standard for Buildings Except Low-Rise Residential Buildings.

The standard requires renewable power generation on-site. The committee wants building projects to produce a minimum percentage of peak electrical load through on-site generation such as by photo-voltaic panels or equivalent solar water heating systems.

Regarding water conservation, Hogan said the standard may require that interior water achieve a minimum of 25% reduction through improvements from the Energy Policy Act of 1992 for plumbing fixtures and strategies for reclaiming water in other areas. Exterior water systems would have more sophisticated controls and not use potable water, he said.

The committee is mulling the topic of sustainable sites, Hogan said. Members are discussing requiring construction to take place at appropriate sites where construction already exists or on a "greenfield" site that is close to high-density areas or has access to mass transit.

In the area of indoor air quality, the committee may require that supply outdoor air exceed the minimum requirements of ASHRAE 62.1-2007, Ventilation for Acceptable Indoor Air Quality. Also being discussed are the use of low-emitting materials and installation of CO₂ sensors to monitor densely occupied spaces.

The committee is looking at requirements for a construction plan, a transportation management plan and an indoor air quality management plan, Hogan said, to reduce materials and energy consumption as well as to reduce carbon emissions.

Proposed Standard 189P will be available only during public review periods. To read the addenda or to comment, visit www.ashrae.org/publicreviews.