A LEED project is considering converting 75% of its existing composite roof to a vegetated roof. The project's landscape architect also suggests an open-grid pavement system for 30% of the site paving, and colored concrete for 25% of the site paving. Which of the following factors must be considered when selecting the materials for these strategies?
Correct Answer:
A
This answer is correct because these are the two factors that affect the heat island reduction potential of the materials. The SRI is a measure of how well a material reflects solar radiation and stays cool in the sun. The higher the SRI, the lower the surface temperature and the less heat absorbed by the material. The unbound percentage of the open-grid pavement system is the ratio of the area that is not covered by the paving material to the total area of the system. The higher the unbound percentage, the more permeable the system and the more water infiltration and evaporation, which also reduce the surface temperature. The vegetated roof system does not need to have a specific SRI value, as long as it uses native or adapted plant species that provide shade and evapotranspiration. The open-grid pavement system does not need to have a specific SRI value, as long as it has at least 50% unbound area.
