EXPLOSION PROOF ENCLOSURES
An explosion proof is the capability or capacity of enclosures to withstand or contain the explosions, internally as well as externally. Internally means that the flash or flames produced inside the enclosures will not come out but will be subsided or decimated internally while as externally means the unit will contain all the external environmental hazards that may be caused due to any reason. Usually we use explosion proof enclosures in the potentially explosive atmospheres & hazardous areas, such as petrochemical fields, oil refineries, LNG facilities etc.
The hazardous area are simply the areas were concentrations of flammable gases, vapors and possibility of leakages occur. As such locations are not safe in case on any eventuality like spark in an LNG facility can burn everything into ashes, hence the situation of using explosion proof cameras arise.
ATEX & IECEx are the important standards following in surveillance industries to define the compliance of enclosures with explosion proof standards.
ATEX, is often referred as ATmospheres EXplosibles, is the French title of the 94/9/EC directive. ATEX standard is the combination of two directives initially, one for manufacturer & other for the user as mentioned below
DIRECTIVE ACT TYPE USER
ATEX 95 94 / 9 /EC* MANUFACTURER Devices & Enclosures intended for use
in potentially explosive atmospheres
ATEX 137 99 / 92 /EC USER Minimum requirements for improving the
safety & health protection of workers
potentially at risk from explosive atmospheres.
*94 / 9 /EC have been replaced by new directive 2014/34/EU
In accordance with the ATEX 137, 99/92/EC, it is the prime responsibility of the employer (workplace supervisor) to identify the areas on basis of below mentioned zone details:
ZONE DESCRIPTION
0 Explosive atmosphere: Air of dangerous substance (mixture with
air of gas, vapor, and mist) continuously or frequently or often.
1 Explosive atmosphere: Air of dangerous substance (mixture with
air of gas, vapor, and mist) occasionally.
2 Explosive atmosphere: Air of dangerous substance (mixture with
air of gas, vapor, and mist) is not likely to appear in normal
operation. In case it occurs but exists for the short period.
HAZARD
20 An explosive atmosphere in the form of a cloud of combustible
dust in air is present continuously or frequently or often.
21 An explosive atmosphere in the form of a cloud of combustible
dust in air occurs occasionally.
22 An explosive atmosphere in the form of a cloud of combustible
dust in air occurs but for very short period.
IECEx is governed by IEC (International Electro-technical Commission), compliance for the equipments that can be used of hazardous locations of different classifications in accordance with the IEC 60079 series of standards of IEC technical committee 31. In general cases, IECEx certification provides one Certificate of Conformity for testing & assessment report of samples (ExTAR), Assessment & Auditing of manufacturer facilities (QAR) and recurring surveillance audits at manufacturer facilities.
In general, Explosion Proof Enclosures have IECEx, ATEX, KCs, NEPSI certifications with explosion grade of Ex d IIC T6 Gb IP67, EX tb IIIC T85?C Db, IP67
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