Types of Ex Protection for Flammable Atmosphere

Code	Types of protection	Description	Permitted Zone
EX d	Flame Proof enclosure	It also known as explosion proof enclosure.A type of protection  in which components can ignite an explosive atmosphere are placed in a enclosure which can withstand the pressure developed during an internal explosion and which prevent the transmission of the explosion to the explosive atmosphere surrounding the enclosure.	Zone 1,2
Ex e	Increased Safety	A type of protection in which increased safety measures are applied so as to give increased security against the possibility of excessive temperature and the occurrence of  arc or spark in electrical apparatus.	Zone 1,2
Ex ia	Intrinsically safe	Limiting the energy to a level  below that which cause ignition, even two fault in the circuit.	Zone 0,1,2
Ex ib	Intrinsically safe	Limiting the energy to a level  below that which cause ignition, even one fault in the circuit.	Zone 1,2
Ex o	Oil immersion	In which parts of electric equipment can ignite an explosive atmosphere are immersed in oil or other non-flammable insulating liquid, so that the gases and vapors above the oil level and out side the enclosure cannot be ignited by electric sparks or arc generated below the oil level.	Zone 1,2
Ex p	Pressurized / Purged Apparatus	Pressurizing, use of air or inert gas to maintain positive pressure to prevent the entry of flammable gas or vapors into the enclosure.	Zone 1,2
Ex q	Sand / powder filling	A type of protection where electrical parts capable of igniting an explosive atmosphere are fixed in position and completely surrounded by filling sand, powder or quartz to  prevent the ignition of an external explosive atmosphere.	Zone 1,2
Ex m	Encapsulation	A type of protection in which components can  ignite an  explosive atmosphere are  enclosed in a compound  (usually by resin)in such a way  that it cannot ignite an explosive atmosphere	Zone 1,2
Ex n	Equipment is non-incendive or non-sparking.	A type of protection applied to electrical equipments such that in normal operation it is not capable of igniting a surrounding explosive atmosphere,and a fault capable of causing ignition not likely to occur	Zone 2
Ex s	Special protection	It is used where equipment does not comply with the requirements of any of the established types of protection, but proven to be safe in a hazardous area	Zone 1