Light Transmitting Plastics:
NFPA 101 (section 6-5.3) refers use of light-transmitting plastics for interior applications to authorities and organizations having local jurisdiction. Such authorities and organizations typically adopt the US Model Building Codes, which are supported by the organization listed below:

ASTM E84/UL723 tests do not accurately characterize the flame and smoke performance of light-transmitting plastics. These tests, virtually identical in methodology and criteria, measure the Flame Spread Index and the Smoke Density of a material relative to red oak in ceiling position. Both standards recognize the problem with thermoplastic materials that soften and melt before burning, unlike wood. Materials that fall to the floor of the 12” high tunnel may contribute to ceiling burning which is unrealistic in actual installations. Because of this, the smoke generation may become artificially high in these test conditions.

Light transmitting plastics usually melt, burn and smoke more readily than glass, metals or wood. As a result, for such materials, there are three specific ASTM tests, evaluation of which forms the basis for a plastic material to become recognized by BOCA, ICBO and SBCCI. These three ASTM tests are required in the 2000 International Building Codes (IBC), upon which the three organizations rely for material compliance.

ASTM D 2843-99 Smoke Density Rating
ASTM D 635-98 Combustion Rating
ASTM D 1929-96 Self Ignition Temperature

ASTM D635 and ASTM D2843 also measure Flame Spread and Smoke Density, as does ASTM E84, but these tests are for light transmitting plastics.

Polycarbonate and PETG have been tested according to DIN 4102 and achieve a B1 rating. Polycarbonate and PETG materials typically are approved as an accepted light transmitting plastic, however, NFPA 101 (section 6-5.3) refers use of light-transmitting plastics for interior applications to authorities and organizations having local jurisdiction. Therefore, final approval is under their jurisdiction.