Ex zones

In this section we present the different global standards applicable to our range of products for potentially explosive atmospheres.



ATEX Directive 2014/34/EU is a «new approach» directive that applies to protective systems against explosions as well as all equipment used in or related to explosive atmospheres, such as electrical and non-electrical equipment, components and safety devices, control and adjustments necessary for the safe operation of this equipment and protective systems. As a «new approach» directive, the European Directive defines the essential requirements for the safety and health which shall be respected by all manufacturers.
Devices falling within the scope of the European Directive (see the guidelines on the application of the directive) and responding to the essential requirements for the safety and health are identified by a marking plate on which the logo appears.

This Directive requires:
• For products: a type certification, a declaration of conformity and an instruction manual, allowing to affix the marking,
• For the manufacturers: a quality assurance system audited annually by a notified body, and the appointment of an authorised person called the Ex-Proof responsible person.
Main standards applied
• IEC/EN 60079-0: Products for use in explosive gas atmospheres - General rules
• IEC/EN 60079-1: Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures “d”
• IEC/EN 60079-7: Explosive atmospheres - Part 7: Equipment protection by increased safety “e”
• IEC/EN 60079-31: Explosive atmospheres - Part 31: equipment protection against ignition of dust by enclosure “t“.

The 1999/92/EC Directive aims to improve the safety and health protection of workers potentially at risk from explosive atmospheres.
The employer shall:
• prevent the formation of explosive atmospheres or if this is not possible, prevent ignition of explosive atmospheres
• assess the specific risks arising from explosive atmospheres and to draw up and keep up to date an explosion protection document,
• classify places where explosive atmospheres may occur into zones,
• mitigate the harmful effects of an explosion to protect the health and safety of workers (install appropriate equipment, take organizational measures such as staff training, ...). 


There is voluntary certification international scheme: IECEx.
Its aim is to facilitate the international flow of electrical equipment intended to be used in potentially explosive atmospheres and thus avoiding multiple national certifications and at the same time ensuring an appropriate level of safety. The IECEx certification scheme allows the manufacturers of “Ex-proof” equipment to obtain a Certificate of Conformity that would be accepted in Member States in which this certification scheme is recognized.


(1) Optimal conditions: pressure, concentration.
(2) Gas : Methane, Acetylene, Hydrogen… Dusts : Wood, flour, sugar, aluminum, carbon… Vapor : Ethyl alcohol, Acetone.
(3) High temperature, mechanical or electrical arc and spark, static electricity, lightning, wrong use…




Gases are divided into three groups by IEC/EN standards, four groups by the CEC (Canadian Electrical Code) and the NEC (National Electrical Code - US) standards. The groups defined in European, International and North American standards are fundamentally the same, as illustrated by the following table.


IEC/EN standards defined a classification of dust:

North-American have also defined a classification of dust:


Equipment must never be used in an atmosphere capable of ignition at the temperature indicated on the marking (temperature class).


1. Manufacturer identification:
– Name and/or trademark
– Address.

2. Conformity to all relevant European directives and/or North American standards.
3.Ž Product type.
4. Temperature class.
5. The certificate number endings:
- none: OK to use without specific recommendations
- X: equipment with special condition(s) for safe use
- U: component (complementary certification needed for use).

6. Mark for product in the scope of directive 2014/34/EU and in compliance with ERSH
Directive 2014/34/EU marking:
II: Equipment group = surface industry
2: Equipment category
G D: Gas or Dust atmosphere.
EHSR: Essential Health and Safety Requirements.


> Flameproof « Ex d » equipment
A flameproof equipment offers an enclosure in which the parts which can ignite an explosive gas atmosphere can be placed. It withstands the pressure developed during an internal explosion of an explosive mixture, and prevents the transmission of the explosion to the explosive gas atmosphere surrounding the enclosure.
A flameproof enclosure must meet three criteria:
• Contain an internal explosion without permanent distortions.
• Guarantee that the explosion cannot be transmitted to the surrounding atmosphere.
• Have a temperature at any points on the surface that is lower than the self ignition temperature of the surrounding gases or vapors.
There are two construction values which are essential for a flameproof equipment to answer to the 3 criterias:
• the length of flameproof joint (L)
• the gap (i)
These values depend on gas group and the maximum allowed gap depends on the length of flameproof joint.
It is necessary to lubricate the thread and to ensure that at least 5 threads are engaged for metric thread and that 5 threads are present on each parts for NPT threads.
Holes which are not used for cable entries must be blanked using the appropriate blanking plugs.
The equipment is supplied with the lubricated joint. When the equipment is installed, the path must be lubricated to keep them in good condition. Use a non-hardening, anti-corrosive grease (see technical note).
In order to successfully retain the flameproof character of the equipment:
• Care must be taken before starting up to ensure that all the screws for closing the covers and cable entries are firmly tightened and that the blocking device is well screwed, if necessary.
• Modification of the original predrilled holes is prohibited.

> Increased Safety « Ex e » equipment
Method of protection applicable to electrical equipment such as light fittings, sockets, switches, etc, which consists of preventing the occurrence of any accidental ignition.
The construction principles for increased safety « e » equipment are as follows:
• Use of high-quality insulation materials
• Specially dimensioned clearance and creepage distance
• Electrical connection which cannot become loose
• Minimum protection level against penetration into enclosures IP54
• Respect of the temperature classes
• Conformity of cable entries
• Labelling.
These principles are respected by screwing the cable gland directly onto the enclosure or, for untapped holes, by fixing with a locknut. Holes which are not used for cable entries must be blanked using the appropriate blanking plugs.
The equipment has a protection level of at least IP 54; it is therefore important to ensure that the sealing joint is in good condition when the product is installed.
Defective seals must be systematically replaced.
It is important to be sure that the gasket is properly positioned for the plugs and sockets and for all the luminaries before connecting the male and female parts (for plugs and sockets) and before closing the light transmitting part of the lighting fixture.
For the connection, all technical note or instruction sheet shall be followed.

> Products marked « Ex de »
Except «Ex d» enclosure, equipment having a combined protection type « d » and « e » are the most commonly used.
Some apparatuses such as power sockets, lampholders, etc, which create arcs and sparks in normal operation, cannot be designed only with protection mode «e».
• The part where the electric arc is produced is enclosed in a small flameproof chamber.
• The connection terminals are « e » increased safety.
• The assembly is mounted in an « e » increased safety enclosure.
The connection of cables to the electrical equipment shall maintain the explosion protection integrity of the relevant type of protection. When the cable gland certificate has an ‘X’ marking, this cable gland shall only be used for fixed installations. When the equipment is only portable, cable glands without ‘X’ marking shall be used.


> General requirements
Electrical installations for explosive atmosphere must comply with the requirements regarding installations in both non hazardous and hazardous locations:
• national rules (for example NFC 15-100 + BE3 condition for France),
• EN/IEC 60079-14,
• EN/IEC 60079-17.
> Equipment selection (except cable entries)