BASEEFA Approval - What to consider
Areas where there is the possibility of the presence of an explosive mixture of flammable gas or
vapor and air are known as 'hazardous' and other areas as 'safe' or 'non-hazardous'. Any electrical equipment used in hazardous areas, must be specially tested and approved to ensure that, in use even under a fault condition, it cannot initiate an explosion.
In Europe, hazardous areas are generally defined as follows:
Zone 0 |
An area where an explosive mixture is likely to be present at all times under normal operating conditions. |
Zone 1 |
An area where an explosive, mixture is likely to occur in normal operation. |
Zone 2 |
An area where an explosive mixture is not likely to occur in normal operation, and if it does it is only for short periods. |
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In the United States, hazardous areas are classified by two Divisions. Division 1 equates to Zone 0 and Zone 1 and Division 2 equates to Zone 2. |
in Europe equipment, certified for use in hazardous areas in Europe, normally falls into one of the following categories.
Intrinsically Safe |
denoted as EEx ia or
EEx ib |
For use in Zones 0, 1 or 2
Zones 1 or 2 |
Flameproof |
denoted as EEx d |
For use in Zones 1 or 2 |
Increased Safety |
denoted as EEx e |
For use in Zones 1 or 2 |
Intrinsic safety differs from other forms of protection because it is based on the principle that the equipment is electrically safe. The definition of an intrinsically safe circuit is generally one that does not contain sufficient electrical energy, even under fault conditions, to cause a spark or generate sufficient heat to ignite a combustible gas mixture. Under the current standards, Ex ia equipment is
tested with two coincident faults applied to the system. Ex ib equipment is tested with one fault.
Intrinsic safety requirements are covered by European Standards BS EN50014, EN50020 and EN50039, and the guidance Standard EN50073. In the United States the relevant Standard is UL 913 "Intrinsically Safe and Associated Apparatus (for use in Class I, II and III Division 1, Hazardous (Classified) Locations)."
Other forms of protection are based on mechanical safety and for flameproof equipment the equipment enclosure should be capable of containing an explosion within it, thereby avoiding the possibility of the system becoming an external ignition source.
Flameproof requirements are covered by European Standard EN50018, BS4683 : Part 2 :1971, BS5001 : Part 5 1977 and the guidance Standard EN50073. In the United States the relevant Standard is UL 1203 "Explosion Protected and Associated Apparatus (for use in Class I, II and III Division 1, Hazardous (Classified) Locations)."
Product must be manufactured by a BASEEFA approved contractor.
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