Definition(s)
High-temperature devices
High-temperature devices are defined as those devices whose maximum operating temperature exceed 80 % of the autoignition temperature in degrees Celsius (°C) of the gas or vapor involved.
Source: API Recommended Practice 14FZ, Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations, Second Edition, May 2013. Global Standards
High-temperature devices
A device whose maximum operating temperature exceeds 80 % of the auto-ignition temperature, expressed in degrees Celsius (°C), of the gas or vapor involved, or whose maximum operating temperature exceeds 100 % of the auto-ignition temperature, expressed in degrees Celsius (°C), of the gas or vapor involved when listed or labeled or otherwise approved by the authority having jurisdiction.
API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2, Third Edition, December 2012, Global Standards
High-temperature devices
High-temperature devices are defined as those devices whose maximum operating temperature exceed 80 % of the ignition temperature in degrees Celsius (°C) of the gas or vapor involved. The maximum operating temperature refers to the skin temperature of components in the interior of enclosures and to the surface temperature of lamps inside lighting fixtures. For offshore applications, the most commonly encountered explosive gas is natural gas, composed primarily of methane. The ignition temperature of natural gas is usually considered to be 900 °F (482 °C) and any device whose operating temperature exceeds 726 °F (386 °C) in natural gas environments should be considered a high-temperature device. The ignition temperature of hydrogen sulfide is usually considered to be 500 °F (260°C) and any device whose operating temperature exceeds 406 °F (208 °C) in H2S environments should be considered a high-temperature device. A review of production installations should be made to determine the presence of other gases with lower ignition temperatures.
Source: API RP 14F, Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class 1, Division 1 and Division 2 Locations, Fifth Edition, July 2008. Global Standards