The UL 723 Surface Burning Characteristic of Building Materials test is a standard of Underwriters Laboratories (UL) that measures the burning properties, or fire resistance, of building materials that may be exposed to flames. Results obtained from this test are used by code officials in the acceptance of interior finish materials for wall and ceiling applications in commercial spaces. The scope of testing involves exposing test specimens to a test fire and measuring both the flame spread over the surface of the specimen and the density of smoke developed.
The UL 723 Flammability test method is similar to the ASTM E84 Flammability test as they both determine surface burning characteristics by measuring flame spread and smoke density. This test has also been adopted by the American Society for Testing and Materials (ASTM) into its own ASTM E84 Flammability standard.