The Shading Coefficient (SC) is a measure of the ability of a window or shading device to block heat from the sun. It is the ratio of the solar heat gain through a IR polycarbonate sheet to the solar heat gain through a standard clear polycarbonate panel under the same conditions. A lower shading coefficient indicates better heat-blocking properties.
FOR EXAMPLE,
Standard polycarbonate clear glass 3 mm with 88% light transmission. SC is 0.9.
IR polycarbonate glass 3mm is 75% and SC is 0.55.
The lower the value, the more convenient it is to stay under the material on warm, sunny days. In commercial architectural projects, the SC should usually be between 0.3 to 0.5.