ASHRAE Journal - March 2010 - 8

Applying the minimum set of prescriptive recommendations in the standard resulted in weighted average site energy savings of 30% when compared to Standard 90.1-2007. thousands of volunteer hours from the world’s leading experts, including building owners, water and IAQ experts, design engineers, architects, code and compliance experts, equipment manufacturers and utility company representatives. Work on the standard first began in 2006 with four public reviews prior to publication approval. How does it differ from other guidance for sustainable buildings? Many jurisdictions have been looking for minimum green building criteria that can be used to reach their energy, environment and climate change goals. Before Standard 189.1, the guidance available was either intended to be voluntary or was limited in scope. Standard 189.1 establishes mandatory, prescriptive and performance criteria in the topic areas, allowing for adoption into building codes. Standard 189.1 is written to complement the existing green building rating systems. Does it cover renewable energy? The Standard requires that the building design provide for the future installation of on-site renewable energy systems unless the building is in a location with poor incident solar radiation through climate or other local situations. ‘Provision for future installation’ means showing allocated space for solar collectors, pathways for conduit, piping and associated equipment on construction documents. Under the prescriptive path, Standard 189.1 includes an on-site renewable generation requirement. On-site renewable energy systems must include an annual energy production equivalent of 6 kBtu/ft2 of conditioned space. There is an exception for areas with incident solar radiation less than 4 kWh/m2·day and a cumulative purchase of green power of 70 kWh/ft2 for a period not to exceed 10 years. Using the performance path, increased efficiency can substitute for the use of renewable energy. In addition, if you choose to use higher efficiency equipment, the performance requirement for on-site renewable energy drops from 6 to 4 kBtu/ft2. How does Standard 189.1 differ from Standard 90.1? Would it ever replace 90.1? Standard 189.1 covers more than just energy efficiency with its requirements on sustainable sites, water efficiency, indoor environmental quality and the building’s impact on the atmosphere, materials and resources. Think of it like this: Standard 90.1 sets the foundation for energy efficiency through its requirements. The Standard 189.1 energy efficiency section builds 8 ASHRAE Journal on that foundation with additional energy efficiency measures and renewable energy requirements. Standard 90.1 remains the basis for the model energy code in the United States. Standard 189.1 is not intended to replace Standard 90.1. The marketplace needs both standards. What would a user expect to achieve in terms of percentage energy savings improvement over 90.1? The actual energy savings will vary depending on the building type and climate zone. Standard 189.1-2009 is more stringent than Standard 90.1-2007, Energy Standard for Buildings Except Low-Rise Residential Buildings. The U.S. Department of Energy, through the National Renewable Energy Laboratory, has made a preliminary energy savings estimate based on Standard 189.1-2009. Applying the minimum set of prescriptive recommendations in the standard resulted in weighted average site energy savings of 30% when compared to Standard 90.1-2007. What provisions in the standard will be new or different for the typical ASHRAE member consulting engineer? Since the requirements in the standard impact various design disciplines, there are many areas in this standard that many consulting engineers will need to understand. Some examples of areas that may be new or different include the source contaminant emission requirements in the Indoor Environmental Quality section and the Section 10 requirements covering plans for high-performance operation of the building. How does the standard interact with the LEED rating system? How does it interact with ENERGY STAR? The standard benefited from much of the expertise and experience the market has gained in using the voluntary green building rating systems. Voluntary green building rating programs, like USGBC’s LEED ratings, have become the fundamental catalyst for raising the bar on how we can design and construct buildings to be more sustainable. However, when striving to provide the minimum mandatory requirements for green building projects, one often finds that existing voluntary green building rating systems contain few mandatory provisions that could be incorporated into green building codes. As an American National Standards Institute standard developed in model code language, Standard 189.1 provides minimum requirements for high-performance green buildings as developed through industry-wide consensus. It is designed to complement green building rating systems. ashrae.org March 2010

ASHRAE Journal - March 2010

Table of Contents for the Digital Edition of ASHRAE Journal - March 2010