1.1 Scope. 1.1.1* This standard shall prescribe the methodology to measure flame travel distance and optical density of smoke for insulated, jacketed, or both, electrical wires and cables and optical fiber cables that are to be installed in plenums and other spaces used to transport environmental air without being enclosed in raceways. 1.1.2 This test method shall not provide information on the fire performance of insulating materials contained in electrical or optical cables in fire conditions other than the ones specifically used in Section 6.6 of this standard, nor shall it measure the contribution of the cables to a developing fire condition. 1.1.3* Although this test uses equipment similar to that used in NFPA 255, Standard Method of Test of Surface Burning Characteristics of Building Materials, and in ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, sufficient changes have been made to the chamber so that a test conducted in the apparatus used for NFPA 255 or ASTM E 84 shall not be considered identical or productive of comparable results. 1.1.4 Because this standard does not purport to address all of the safety problems associated with its use, it shall be the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.