Visible Light Transmittance

Solar Light Testing Fast Facts

Leader in solar (visible) transmittance testing for all types of transparent, translucent, or reflectively coated materials.
Optional motorized equatorial mount on apparatus for automatic sun tracking at specific angle of incidence.
California test location maximizes hours available for solar testing.
Developed test standards in associations with ASTM and devised the first apparatus to meet ASTM requirements.

Value

Measuring the transmittance of sunlight through transparent, translucent, or reflectively coated building materials is necessary to determine the illumination of interior spaces and the effect that ultraviolet (UV) spectrum will have on interior furnishings. Architectural Testing performs two industry-standard tests on a variety of materials to provide precise measurements of solar (visible) transmittance. These values are used by architects, designers, and manufacturers to determine how to control skylights, windows, curtain walls, and other glazed structures to admit desirable amounts of sunlight.

Architectural Testing conducts testing using these ASTM methods:

ASTM E972 – Standard test method for solar photometric transmittance of sheet materials using sunlight
ASTM E1084 – Standard test method for solar transmittance (terrestrial) of sheet materials using sunlight. This method includes direct, diffuse, and reflected light. Tested products typically include windows, glass block, clerestories, skylights, shading and reflecting devices, and other passive fenestration devices that transmit daylight.

Innovations

Architectural Testing has worked closely with ASTM in developing sunlight-transmittance test standards. We devised a specially constructed apparatus that meets ASTM requirements and is adaptable to handle particular customer needs. Optionally allowed by the standard, the device incorporates a motorized equatorial mount to automatically track the sun—a feature that facilitates tests requiring light at a given angle of incidence.

To measure sunlight transmittance, the test specimen is inserted on the apparatus between the path of the rays and the measuring device (visible light sensor). The instrument is placed in a specially constructed box with a nonreflecting bottom to prevent false measurements from reflections.

The transmittance value is then determined by calculating the ratio between measurements taken with and without the specimen. Multiple points are scanned using Architectural Testing’s advanced data acquisition system to ensure accurate measurements.

Insights and Possibilities

With Architectural Testing, you get the convenience of testing solar transmittance, thermal, durability, impact, and other performance parameters administered by one firm with facilities located on both coasts and the Midwest.

Our customers draw upon our expertise in over 700 test methods performed in accordance with ASTM, AAMA, ANSI, military, and international standards, including ICC. And we continue to develop procedures and apply new test methods to meet customer requirements. For example, Architectural Testing developed the world’s largest solar calorimeter, which can measure the solar heat gain coefficient (SHGC) on specimens as large as 7 feet x 7 feet.

Because Architectural Testing is directly involved in writing test standards, we can provide accurate, unbiased information to give you a general understanding of performance-test outcomes and causes of failure. We also offer educational seminars on the general design principles that affect test results.

Learn more about how the Architectural Testing Difference can help you or Contact Us today.