Roof Solar Reflectance Index

The solar reflectance index sri is a measure of the constructed surface s ability to reflect solar heat as shown by a small temperature rise.

Roof solar reflectance index.

A value of 0 indicates that the material absorbs all solar energy and a value of 1 0 indicates total reflectance. Solar reflectance index sri indicates the roof s ability to reject solar heat and is the combined value of reflectivity and emittance. 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. It is defined so that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100.

This latter spectrum is used to obtain the coefficient of solar reflectance or reflection which appears in the formula for calculating the sri figure 1. It is defined so that a standard black is zero reflectance 0 05 emittance 0 90 and a standard white is 100 reflectance 0 80 emittance 0 90. What your roof does with reflecting the sunlight determines its solar reflectance. Installing a cool roof can cut your energy costs while contributing toward a better environment.

The us department of energy defines the solar reflectance index sri as a measure of the roof s ability to reject solar heat as shown by a small temperature rise. It is defined so that a standard black surface reflectance 0 05 emittance 0 90 is 0 and a standard white surface reflectance 0 80 emittance 0 90 is 100. The solar reflectance measurement ranges between 0 0 and 1 0 with 1 0 representing 100 reflectance with no absorption. The more waves that are bounced back into the atmosphere the higher the solar reflectance of the asphalt roofing shingle.

By lessening the demand for energy it decreases carbon emissions that cause pollution. Energy star requires an initial sr value of 0 25 or higher for steep slope 2 12 roofs and 0 15 or greater after three years. The value the better the roof radiates heat. The guide to choosing a cool roof.

Incorporates both solar reflectance and thermal emissivity in a single value. Sri calculations 01 aged reflectance listed with crrc 02 crrc listed aged solar reflectance 03 initial solar reflectance 04 calculated aged solar reflectance 05 thermal emittance c. Solar reflectance index sri. Results 01 solar reflective index registration number.

06 roof pitch b.