What is a good solar reflective index?

What is a good solar reflective index?

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. SRI is a unit developed by scientists at Lawrence Berkeley National Laboratory.

Is Higher Sri better?

Thermal emittance is the relative ability of a roof to emit (or release) heat that has been absorbed. Therefore, the higher the SRI value is, the greater ability the coating has to reject solar heat absorption, maintaining a cooler indoor ambient air temperature without the use of an air conditioning.

What is the difference between SR and Sri?

However, solar reflectance, or SR, is a better way to measure materials that have more thermal mass, including nonroof materials. SR is the fraction of solar energy that is reflected by a surface on a scale of 0 to 1. It doesn’t factor in emissions of thermal radiation the way SRI does.

How is Sri value calculated?

How to use the SRI calculator?

1. Solar reflectance: the range of solar reflectance is 0 – 1, with 0 for perfect black material and 1 for perfect white. If you know your material’s solar reflectance in percentage, simply convert it to decimal (e.g. 56.7% = 0.567).
2. Emittance: it is often called emissivity.

Is a higher solar reflectance better?

Solar reflectance is the most important characteristic of a roof product in terms of yielding the highest energy savings during warmer months. The higher the solar reflective value the more efficient the product is in reflecting sunlight and heat away from the building and reducing roof temperature.

How do you read a solar reflectance index?

Solar reflectivity or reflectance is the ability of a material to reflect solar energy from its surface back into the atmosphere. The SR value is a number from 0 to 1.0. A value of 0 indicates that the material absorbs all solar energy and a value of 1.0 indicates total reflectance.

What is a good Sri value?

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.

What does Sri mean in roofing?

SOLAR REFLECTANCE INDEX
SOLAR REFLECTANCE INDEX (SRI): Incorporates both solar reflectance and thermal emissivity in a single 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.

Is SRI the same as LRV?

Solar Reflectance Index (SRI) numbers indicate how well the material reflects back instead of absorbing radiant energy and how well it radiates absorbed heat back into the environment. Light Reflectance Value (LRV) numbers indicate the percentage of visible light reflected by the surface.

What is solar reflective value?

What is Sri paint?

SRI is termed as solar reflective index and is used to determine the heat reflecting capacity or power of a roof cooling paint. The lower the SRI value, the hotter a material is likely to become in the sun.

What is the Solar Reflectance Index of Thermory wood?

The Solar Reflectance Index for a sample of Thermory wood was tested to be 39.68 under medium wind conditions. Under low or high wind it was, 39.81 and 39.56 respectively. Note: for non-metal surfaces, SRI is insensitive to changes in convection coefficient (rate of heat transfer from the surface to air induced by the air movement).

What is the Solar Reflectance Index and why is it important?

For deck coverings, pavers, or other outdoor flooring, scorching surfaces can pose a serious risk to those who come in contact with them. For roofing and outdoor walls & facades, surface temperature is a key component in energy consumption. Solar Reflectance Index measures this crucial element on a scale of 0 to 100.

What is the Solar Reflectance Index of concrete pavers?

Solar Reflectance Index varies considerably across concrete paver products. In the NW Series of Concrete Pavers, Graphite Charcoal, Platinum Grey, and Latte Brown have SRI values of 5, 30, and 34, respectively. The 4C Series in color Flint 765 has SRI of 14 compared to an SRI of 85 for Shotblast Series in color White 15.

What is the Solar Reflectance Index of gray limestone?

Standard Gray Limestone has a Solar Reflectance Index of 54. High numbers mean cooler temperature underfoot so this is an excellent choice for the decking around swimming pools. Bare human or canine feet will stay cool even on hot summer days. Solar Reflectance Index varies considerably across concrete paver products.