BUILDING PROGRAMS AND CODES

(Please note: this section was current at the date of publication. Please make sure to check with the individual code body or program for updates.)

Increased recognition of the benefits of cool roofing has led to the adoption of cool roof measures in energy codes and the inclusion of cool roofing as part of green building initiatives.

National energy codes developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the International Code Council (ICC) are not mandatory regulations unless adopted by a jurisdiction as part of a regulation or law. Many states and cities have adopted either the ASHRAE or ICC codes or have adopted their own building codes. ENERGY STAR, California's Title 24, ASHRAE, LEED® and Green Globesâ„¢ are codes and programs that have all included a cool roof measure of some description.

Voluntary Green Building Programs
There are many resources from the Department of Energy to various sustainable and green design organizations which assist architects in making the right choices for green buildings. The following two programs are examples, but may not be all-inclusive:

Green Globesâ„¢
The Green Building Initiative's Green Globesâ„¢ program is a green management tool that includes an assessment protocol and a rating system and guide for integrating environmentally friendly design into both new and existing commercial buildings. Green Globes â„¢ provides credit for cool roofs as a component of their rating system.

LEED
The U.S. Green Building Council's LEED® program provides certification for the energy and environmental design in the planning and construction of a building. From North Dakota to North Carolina architects are planning LEED buildings which can attain silver, gold or even platinum certification. The LEED program includes a credit for cool roofs under the sustainable sites category in recognition of the importance of urban heat island reduction.

Senior architect Dave Stafford, AIA, of FourFront Design in North Dakota, designed the South Dakota National Guard Headquarters Building. This is to be a LEED Silver project and will use a standing seam metal roof in Dove Gray to meet the LEED Credit 7.2 requirements of an SRI less than 29 for a steep-sloped roof. Dave's design team learned that, "About a third of the pastel and metallic colors available for metal roofs will meet or exceed that requirement. Metal roofs are fairly popular around here - they look good, they work, they have minimal maintenance. All that was needed was a color selection with an SRI high enough to get the job done."

Recent budget evaluations, however, required the production team to replace the metal roof and the whole pitched roof structural system with a conventional flat roof. The design team can still meet the requirements for LEED Credit 7.2, which require an SRI value of 78 for low sloped roofs. The team has selected a white PVC membrane surface with an approximate SRI value of 104.

From the North to the South, LEED credits are obtainable by using cool roof systems, which are an important part of an effective energy savings strategy and environmental design.

LEED® PROJECT - ImaginOn: The Joe & Joan Martin Center, Mecklenberg, SC

Cheryl Walker, FAIA, LEED AP, of Gantt Huberman Architects, PLLC, obtained the LEED® SS Credit 7.2: Heat Island Effects (Roof) for a project in Mecklenberg, South Carolina. The Joe & Joan Martin Center, also called ImaginON, received a LEED − NC® Silver rating in 2006. The roof of the large children's theater slopes from one end of the building to the other and has to accommodate huge theater and light monitors incorporated into the roof structure. The roof design combined: • Standing seam milled aluminum used on the theater forms and light monitors, and • A high-albedo liquid rubber polymeric membrane coating over a modified bitumen roof The high albedo membrane made up 83 percent of the total roof area (63,100 square feet), and met both the Energy Star label requirements and the emissivity required by LEED. The spray on material is water-based, low volatile organic compound that cures to form a seamless rubber membrane. Walker notes that the liquid coating "can be used over a variety of roof types - metal, modified bitumen, hypalon, BUR, wood, concrete, and PVC - to reduce building temperatures." [See photos on page 1]

 

Energy Codes

ASHRAE
ASHRAE standards allow designers to reduce roof insulation when a cool roof surfacing material is used on the roof. ASHRAE 90.1, the Energy Standard for Buildings Except Low-rise Residential Buildings, section 5.3.1.1, defines cool roofs as having a minimum solar reflectance of 0.70 and a minimum thermal emittance of 0.75. The 2007 version of ASHRAE 90.1 adds an alternative of achieving a minimum SRI of 82. ASHRAE 90.1 only credits cool roofs in climate zones one, two and three, based on the DOE climate zones map.^vi

ASHRAE also produces an Advanced Energy Design Guide for Small Office Buildings and an Advanced Energy Design Guide for Small Retail. These guides provide suggestions for achieving greater energy savings than standard 90.1. The guides include the use of cool roofs in climate zones one, two and three.

International Energy Conservation Code
The International Energy Conservation Code (IECC) also contains both prescriptive and performance measures for energy savings and references ASHRAE 90.1 in defining acceptable performance levels.  

California - Title 24
Although cool roofs are not a mandatory measure for California's Building Energy Efficiency Code, Title 24, these regulations outline a clear prescription for the use of a cool roof as part of a building envelope. Under Title 24, if a cool roof is not used in situations where it is prescribed, the energy savings must be made up in another way, such as insulation with a higher thermal resistance (R-value), or windows with a lower thermal conductance (U-value), etc. Title 24 promotes energy efficiency by outlining energy standards and requiring compliance to a strict energy code. The code recognizes that cool roof surfaces can save 15 percent of the electricity needed to cool a building and that cool roofs reduce urban heat island effect and ambient air temperatures causing an improvement in air quality.

A cool roof must be installed as part of prescriptive compliance to the code, or an allowed tradeoff among the building envelope components may be substituted. The performance method allows for the cool roof to set the energy budget for the proposed building. There are qualifications for conditioned and unconditioned spaces, but the main thrust of the regulations is that roof materials must obtain a third-party product rating by the Cool Roof Rating Council^vii, must be properly labeled and meet the minimum specified reflectance and emittance values set by the code. As of October 2005, Title 24 defines a cool roof for low-slope, non-residential buildings as having a minimum solar reflectance of 0.70 and a minimum thermal emittance of 0.75. As of August 2009, Title 24 includes a prescriptive requirement for steep-slope and residential buildings in certain California climate zones.

City of Chicago
The City of Chicago is one of many cities who have begun to mandate cool roofs as a way to mitigate the urban heat island effect. Chicago requires cool roofs in low-sloped roofing applications. New roofs must meet the ENERGY STAR criteria for reflective roofs.^viii

REBATES AND TAX CREDITS

Because of the importance of reducing our carbon footprint and dependence on fossil fuels, there are numerous rebate programs and tax credits offered for energy efficiency measures, including cool roofing. Lists of rebate programs can be found online, as well as through local utility companies and the California Energy Commission.^ix