4. Protection Techniques

Types of Protection (from Ignition) Techniques for Electrical Equipment

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:

• IEC
• NEC
• CSA

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)

 Intrinsically safe Isolator

Increased Safety ( e)

 Increased Safety Control Panel (Ex ed , to be exact)

Pressurized Encasement ( p)

Oil Immersion ( o)

Encapsulation ( m)

Powder Filled ( q )

Protection for Zone 2

It is obvious that electrical equipments certified for ZONE1 can be used in ZONE2 & ZONE21 in ZONE22 but not vise versa

Interesting protection techniques for NON-ELECTRICAL Apparatus in Explosive Gas Atmosphere and Combustible Dust

                                                          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.

Application

Pumps

Belt Conveyors

       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.

Application

Submerged pumps

Gears