It is related to the equipment and systems operating in possible explosive atmospheres and referred to as 94/9/EC Directive. Atex is the abbreviated form of Atmosphere and Explosive words.As of July 2003, EU organizations have established directives in order to protect the employees against explosion risks in explosive atmospheres.


 There are two ATEX directives (for manufacturers and the user of equipment):

ATEX 95 equipment directive 94/9/EC is related to protective systems to be used in equipment and potentially explosive atmospheres.

ATEX 137 workplace directive 99/92/EC is related to minimum requirements to increase health and safety protections of potential employees who are under risk in explosive atmospheres.


The aim of this directive is to determine procedures and principles for necessary safety rules and conformity assessment procedures to present equipment and protective systems which are in the scope of the directive and used in potentially explosive atmosphere to the market securely.

Its scope is equipment and protective systems to be used in potentially explosive atmosphere arising from existence of burning gas, steam, smoke or powder.Electric motors, compressors, diesel motors, lighting equipment, control and communication devices, sound locators, monitoring and searching devices can be some examples.

Protective systems are devices which prevent causing to explosion or damage arising from release.These are fire extinguishers, pressure protection panels, extinguishing systems, fast-moving closure valves etc.

Fields which are out of scope:

Medical devices, equipment and protective systems in which the risk of explosion arises from only explosive or labile chemical substances, equipment only used in house and non-commercial atmospheres in which explosive environment may arise from accidental gas leakage, personal protective equipment within the scope of the Directive on Personal Protective Equipment (89/686/EC), ship navigating on off-shore with equipments on it and portable off-shore water units, transportation vehicles, weapon, munitions and war equipment.


Product Groups Which Are Included In 94/9/Ec 

Group I

M1 / M2

M1 Category: Includes equipment designed to ensure high-level protection and endued with additional special protection devices if needed. (Equipment which must operate continuously)

M2 Category: Includes only equipment designed to ensure high-level protection. (Defines equipment which do no operate continuously, power of the system is cut in case of explosion.)

Group II

Category 1

Category 2

Category 3

Category 1Zone 0 – The area in which an explosive atmosphere exists constantly or for very long-terms and bears the highest risk.

Category 2: Zone 1 – Areas in which explosive atmosphere is seen for short-terms; however, it is aimed to cut the power of this equipment in case of period extension. Products in this category are produced to be used in more physically difficult conditions.

Category 3: Zone 2 – They are defined as atmospheres in which explosive intensity of a flammable material is not expected and as short-terms, for example atmospheres not exceeding 10 hours annually.


For explosive atmospheres, it is required to define the job, work flow and project the layout plan as draft.In the event that drawing and approval of the project are made by trained experts, many problems are deemed as resolved in practical application.However, there are many problems in risk assessment performed later in current facilities.In the event that an operating facility changes production or service in terms of explosive atmospheres, it is required to project from foundation and perform the application to take all necessary measures within the scope of ATEX 137 directive.


In the directive no 94/9/EC, certification of products according to their intended uses depends on different procedures. In other words, a product passes through different processes according to the atmosphere, namely group and category, then documented, marked and presented to the market. 

What is Exproof?

It is the abbreviated form Explosion Proof; it means Protected Against Explosion. In technical language; they are electrical products used in explosive and dangerous atmospheres (Exproof Electrical Equipment).