Explosion protection enclosure class

A few relevant standards Combustible gas detection Explosion protection Enclosure class Intrinsically safe circuits... 

Acceptable protection techniques for electrical and electronic valve accessories used in specific class and division locations include explosion-proof enclosures intrinsically safe circuits nonincendive circuits, equipment, and components dust-ignition-proof enclosures dusttight enclosures purged and pressurized enclosures oil immersion for current-interrupting contacts and hermetically sealed equipment. Details of these techniques can be found in the National Electrical Code Handbook, available from the National Fire Protection Association. 

Safety equipment and interface Fire/explosion with detection and protection, chemical reactivity, mitigation system, enclosure class, intrinsic safety circuits, etc. 

The details discussed here shall be read in conjunction with Chapter X. In fact, engineering details for electrical enclosure class and area classification has been discussed in details in Chapter X. Here, supplementary information has been included to complete the discussion on the subject. Explosion proof and flame proof enclosures are the two most commonly used hazardous area protection techniques. 

Classification and marking of intrinsically safe apparatus concerning explosion groups (I, IIA, IIB, IIC) and temperature classes (T1-T6) are organized in the same way as for, e.g., flameproof enclosure - d (see Tables 4.1 and 4.2, Chapter 4, and Chapter 5 for marking). Some special features, however, which are of importance for type of protection intrinsic safety - i only, will be explained in the following. 

Non-electrical equipment of the equipment group II, category 2 for explosive atmosphere formed from air and gases, vapours and/or mists, type of protection flame-proof enclosure, permissible explosive atmosphere of the Ex-Group IIB, T-Class T4, ambient temperature (T ) with 0°Cdiffering from the standard values -20 °C < T. -t-TO C ... 

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