The ASTM D1494 test method determines the diffuse light transmission factor of translucent reinforced plastics. The relation between the reflected light and the incident light is termed the light transmission factor or the reflection factor. This ratio is 6-8% in clean glass, 70-80% in cement and concrete, 10-60% in light wood, 10-15% in dark wood, and 5-20% in prismatic glasses. ASTM D1494 (Standard Test Method for Diffuse Light Transmission Factor of Reinforced Plastics Panels) test obtains the diffuse light transmission factor of both corrugated and flat translucent building panels with the help of a simple apparatus.
ASTM D1494 Diffuse Light Transmission Factor of Reinforced Plastics Panels
What is ASTM D1494?
ASTM D1494 Equipment and Sample Preparation Guide
The translucent reinforced plastic panel test samples should be a minimum of 610 mm (24 inches) long and more than 610 mm (24 inches) wide, as per ASTM D1494. The maximum desired width is 711 mm (28 inches).
What are the Testing Procedure and Requirements for ASTM D1494?
The test samples are conditioned at 23 ± 2 °C (73.4 ± 3.6°F) and 50 ± 5% relative humidity for about 40 hours before the ASTM D1494 test is performed. The test sample is then placed in the test cabinet, completely covering the 610 × 610 mm (24 × 24 inches) inside space as specified by ASTM D1494. The transmission is read on the test instrument as a percentage.
ASTM D1494 Analysis Results and Interpretation
The Diffuse Light Transmission Factor test by ASTM D1494 determines the diffuse light transmission factor of translucent reinforced plastics.
The following data are collected in ASTM D1494:
- The percent transmission of the test sample.
- The source and identity of test samples.
- The average thickness of the test sample in inches
Updated on July 21, 2026
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