Nov 13 2007
New research on the solar reflectance of concrete and its positive impact on limiting the heat island effect can help architects and builders reduce this phenomenon.
Announced Nov. 8 at the Greenbuild International Conference and Expo in Chicago, the research will allow projects to accrue points towards LEED certification without costly testing.
"PCA is a leader in research on how cement-based applications can play a positive role in sustainable development," David Shepherd, AIA, director of sustainable development for PCA, said. "This study shows that concrete, regardless of its ingredients, can help to limit the heat island effect."
A heat island is a local area of elevated temperature in a region of cooler temperatures. Heat islands occur where there is a preponderance of dark exterior building materials and pavements, and a lack of vegetation, typically in urban areas.
The research, commissioned by PCA and conducted by the construction research organization CTL Group, evaluated the reflective properties of concrete, using the LEED-NC SS Credit 7.1 Heat Island Effect: Non-Roof criteria, to determine concrete's effectiveness in limiting the heat island effect.
The research results, with respect to LEED certification, are significant. All 45 sets of concrete samples tested, regardless of the mix, met the required criteria. The mixes were created using a number of different components, including recovered materials such as fly ash or slag cement. The solar reflectance of the cement proved to have more effect on the solar reflectance of the concrete than any other constituent material.
This is the first time the solar reflectance of concrete has been examined in relation to LEED points and is the most comprehensive study of the solar reflectance of concrete to date.