Ignition Temperature 07 : The autoignition temperature of a flammable gas or vapor or the lower of either the layer ignition temperature or cloud ignition temperature of a combustible dust
NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment, 2008 ed. (Std: Purged and Pressurized Enclosures for Elctr Equip - Amer) {322 NFC}