As an alternative to glasses, several transparent plastic materials are utilized as window glazing panels. Transparent polycarbonate sheets and transparent acrylic sheets are two examples of such transparent plastic materials.
Can the standard NFRC/EN/ISO glass test methods still be employed to determine the optical & thermal properties of such transparent plastic materials?
The NFRC/EN/SIO glass test methods are for glazing materials, which are not limited to glasses. Plastics are a type of glazing material. Transparent plastic sheets can be tested by the NFRC/EN/ISO methods when the following conditions are met:
- With specular transmission and reflection only: materials with significant diffuse transmission/reflection are out of the scope (for example, frosted glasses, glasses with ceramic frits, and hazy plastic sheets).
Note: in the latest NFRC methods (2020 version), diffuse materials are supported, but our lab is not ready to test such diffuse materials.
- Homogenous and flat sheet: corrugated plastic sheets and double-wall (multiple-wall) polycarbonate sheets are out of the scope.
- Without far-infrared transmission: plastic sheets with significant far-infrared transmission in the 5 µm to 50 µm range are out of the scope.
Note: in the NFRC methods, it is possible to test materials with far-infrared transmission, but our lab is not ready to test such materials.
In principle, the scope of the NFRC/EN/ISO glass optical & thermal property test methods is based on the optical characteristics, but not on the material type. Transparent plastic sheets with the same optical characteristics as transparent glasses are within the scope.