Dynamic elaboration on the Art & Science of Hazardous Area Protection
Only certified explosion-protected electrical equipment should be used in the hazardous areas.
In order to facilitate the process of selection of appropriate electrical equipments , once the area has been classified into zones, standardized & certified electrical equipment ,incorporating standardized protection techniques may be used.
Each technique is based upon engineering and safety principles . The philosophy is continuously being evolved and monitored. The protection techniques are globally recognized and specified.
Specifications for each protection technique is well documented and supervised by international specification/standards bodies, which include:
Hazardous Area Electrical Equipment manufacturers may incorporate one or a combination of following standard techniques, as per requirement of the manufactured product.
The most common techniques used globally are as follows:
Flameproof (d )
Intrinsic Safety ( i)
Increased Safety ( e)
Increased Safety Control Panel (Ex ed , to be exact)
Pressurized Encasement ( p)
It is obvious that electrical equipments certified for ZONE1 can be used in ZONE2 & ZONE21 in ZONE22 but not vise versa
Ignition Source Monitoring : Reference EN 13463-6 & R.Stahl
Sensors are integrated in the equipment to detect hazardous conditions to come , and to take steps against them before potential ignition sources become effective.The measures can be initiated automatically by means of a direct connection between the sensors and the ignition protection system or manually by issuing a warning message intended for the operator of the equipment.
Liquid Immersion k Reference : EN13463-8 & R.Stahl
Ignition Sources are rendered inactive by immersion in a protective liquid or by constant moistening using a liquid film.