These requirements cover portable electric lighting units for indoor use in hazardous (classified) locations@ Class I@ Division 1@ Groups C and D@ and Class II@ Division 1@ Groups F and G@ in accordance with the National Electrical Code@ NFPA 70. These requirements also cover explosion-proof electrical equipment for use in Class I@ Zone 1@ Groups IIA@ IIB@ and IIC hazardous (classified) locations. These requirements cover portable lighting units for use only under the following atmospheric conditions: a) A minimum ambient temperature of minus 25??(minus 13??; b) An oxygen concentration not greater than 21 percent by volume; and c) A nominal barometric pressure of one atmosphere.