Concrete is typically the material of choice for parking structures.
Leed roof sri.
Leadership in energy and environmental design.
Cool roof coating products are available for most roof types according to the department of energy.
Leadership in energy and environmental design leed is the green building rating system developed by the united states green building council usgbc.
The requirement for sri can be met by using concrete rather than asphalt for 50 of all sidewalks parking lots drives and other impervious surfaces.
Sri is a unit developed by scientists at lawrence berkeley national laboratory.
Under roof or under building.
Emissivity is a material s ability to release absorbed energy.
The environmental protection agency s energy star roof product program www energystar gov has cool roofing specifications for both low sloped and sloped roofs.
To meet leed requirements a roofing material must have a sri of 29 or higher for steep slope 2 12 roofing and a sri value of 78 or higher for low slope roofing.
A steep sloped roof must have an initial sri of 39 or a three year aged sri of 32.
This credit is worth 1 point.
The intent is to provide a standard certification process that registers buildings constructed with environmental performance efficiency and occupant health and well being as primary goals.
Green roofs and leed certification.
For leed v4 in existing buildings low sloped roofs must have an initial sri of 82 or a three year aged sri of 64.
Back to leed checklist.
Leed 2 2 sustainable sites credit 7 2 states that to receive one point building owners should use a roof with a solar reflective index sri of 78 over at least 75 percent of the roof s surface for roofs with slopes less than 2 12.
Low sloped roofs those below 2 12 and flat roofs must have an average initial albedo of at least 0 65 and steep sloped roofs must have an average initial albedo of 0 25 or more.
As shown in table 1 the minimum sri for cool roofing has increased in the newer leed v4.
Projects seeking leed v4 have the option of qualifying using either initial sri or by obtaining the 3 year aged sri value.
Sri measures the roof s ability to reject solar heat defined such that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100.