Ex-Richtlijnen
Explosieveilige Richtlijnen
ATEX=ATmosphères EXplosives
The European directive regulates the problem of launching products and safety systems designed for use in environments with explosion hazards due to the presence of combustible gases, vapours, mist or dust across the whole of Europe. The directive concerns electrical and mechanical equipment. Directive 94/9/EC replaces the older directive 76/117/EEC and must ensure that products to which the older directive applies are in conformity also with other directives, the so-called “Directive regarding new approach to CE marking.� After 30 June 2003 only those apparatus may be put on the market that meet the requirements for safety and health protection according to the directive 94/9/EC and that have undergone the prescribed procedure of the proof of conformity.
There are two ATEX directives:
Article 95 is focused on the free movement of goods.
Article 137 concerns the minimum requirements for improving the safety and health of persons exposed to a potential hazard due to an explosive environment. This directive defines individual risk zones for underground mines and other industrial sectors.
The ATEX directive field of application includes:
- All apparatus with safety systems designed for use in environments with explosion hazards.
- All safety, control and regulating devices designed for use in outdoor environments with explosive hazards and that are necessary for the safe functioning of apparatus and safety systems as regards explosion hazard.
Differences between the new and old directive
Major differences:
- Introduction of the CE marking for non-explosive devices and security systems apart from the existing CE marking for low-voltage systems, machine systems and EMC safety and introduction of an additional marking, among others also “Conformity category.�
- The CE-(ATEX-) marking including the "epsilon-x� character may also be, in principle, awarded based on other CENELC standards (if the “Basic requirements for health protection and safety� are met).
- All devices and security systems designed to be used in “dangerous areas.�
- It is also used for safety, control and regulating devices that are designed for use in “other than dangerous areas� and that are necessary for (or contribute to) the safe functioning of devices and security systems as regards explosion hazard.
- Transition from safety against explosion of gas and vapours to safety against explosion of gas, vapours and dust.
- Evaluation based on the “Basic requirements for health protection and safety� give by the ATEX directive.
- New authorizations for approval authorities within Europe.
- The directive is applicable also for other than electric apparatus in explosive environment.
- Technical specification is required.
- Documentation in conformity with the observed quality management system.
- Instructions regarding materials (in the original language and in the language of the country where they are to be used).
The following are excluded from the effect of the directive:
- Medical aids designed for use in medicine.
- Apparatus designed for use in households.
- Sea ships and mobile offshore installations; including the equipment of these ships or installations.
- Personal protective equipment to which directive 89/686/EEC applies.
- Means of transport apart from those designed for use in “dangerous areas.�
- Military products.
Explosion hazard areas (dangerous area).
An area with explosion hazard is an area in which explosive mixtures may occur by mixing oxygen with combustible substances (gases, vapours, mists and dust) in such amounts that certain measures are necessary to take as regards possible sources of ignition.
Apparatus groups
�Group I� apparatus and “Group II� apparatus are distinguished.
Group I
Group I apparatus are designed for the underground parts of mines and mine equipment, in which an explosion hazard may threaten due to the presence of mine gas and/or combustible dust.
Group II
Group II apparatus are designed for other places where an explosion hazard may threaten.
Conformity category
Two conformity categories are defined for Group I apparatus:
M1: Very high protection level
Apparatus must not stop working in an explosive environment owing to at least two elements that guarantee sufficient protection or that guarantee sufficient protection even in the event of two independent faults.
M2: High protection level
The aim is to interrupt power supply to these products if there is an explosion hazard. Apparatus guarantee such a safety level that is also satisfactory in normal faultless operation even under the heaviest conditions. Three conformity categories are defined for Group II apparatus:
1 : Apparatus designed for areas where, in most probability
an explosion hazard will threaten.
Apparatus must offer a very high protection level. Apparatus must not stop working in an explosive environment owing to at least two safety elements that guarantee sufficient protection or that guarantee sufficient protection even in the event of two independent faults.
2 : Apparatus designed for areas where there is probability of an explosion hazard.
Apparatus must offer a high protection level. They are secured in such a way that even in the case of a fault of the apparatus they guarantee a sufficient protection level.
3 : Apparatus designed for areas where there is only small probability of an explosion hazard.
Apparatus must offer a common protection level. They are designed in such a way that they offer a sufficient safety level in faultless operation.
Representations in the table:
| Group | Category | Combustible substances | Security level | Protective action |
| Group I apparatus (mines) | M1 | Methane, dust | Very high | 2 independent safety elements or even safe in the case of an occurrence of two mutually independent faults |
| M2 | Methane, dust | High | Safety elements that secure a high safety level | |
| Group II apparatus (above-ground) | 1 | Gas, vapour, mist, dust | Very high | 2 independent safety elements or even safe in the case of an occurrence of two mutually independent faults |
| 2 | Gas, vapour, mist, dust | High | Safety elements that secure a high safety level | |
| 3 | Gas, vapour, mist, dust | Normal | Guarantee of a sufficient safety level |
Division to zones for industry (not for mines)
To formulate measures with regards to possible sources of ignition, dangerous areas are divided to individual zones. They include six partial areas that are distinguished based on a chance that an explosive mixture and duration times will be present in them.- Zone 0
Area where an explosive atmosphere is present continuously or for a long time. - Zone 1
Area where there is a big chance of the presence of an explosive atmosphere in normal operation. - Zone 2
Area where there is a chance of occurrence of an explosive atmosphere in normal operation and where this atmosphere – if occurs – will only last for a short time. - Zone 20
Combustible dust is present in the form of a cloud in normal operation continuously or frequently in such an amount that may produce an explosive concentration. - Zone 21
Combustible dust is present in the form of a cloud in normal operation occasionally and in a sufficient amount to make an explosive concentration. - Zone 22
Combustible dust is present in the form of a cloud rarely and for a short time, or combustible dust deposits or layers may produce explosive concentrations.
Zone (for industry) | Group of apparatus | Category |
| 0 | II | 1G |
| 1 | II | 2G (1G) |
| 2 | II | 3G (1G and 2G) |
| 20 | II | 1D |
| 21 | II | 2D (1D) |
| 22 | II | 3D (1D and 2D) |
| G = Gas, D = Dust | ||
Division to zones is made by the authority that issues permission and on the recommendations of the environmental inspection.
Material group, gas group
Electrical material designed for dangerous areas is divided into two material groups:
Group I: electrical material designed for mines.
Group II: electrical material designed for other situations.
Group II is divided to 3 gas groups:
| | high | |
| A |
| Ignition energy |
| B | ||
| C | ||
| | low | |
Group IIC is a group that contains especially dangerous combustible substances (hydrogen, acetylene, hydrogen sulphide, and ethyl nitrate).
Temperature class
The maximum surface temperature of apparatus must always be lower than the ignition temperature of the atmosphere present. Division to temperature classes is as follows:
| Temperature class | T1 | T2 | T3 | T4 | T5 | T6 |
| Maximum surface temperature | 450°C | 300°C | 200°C | 135°C | 100°C | 85°C |
Ignition protection methods
There are several methods of protection against ignition in an explosive atmosphere. Depending on the zone, gas group, temperature class, and field of application it is possible (necessary) to choose, among others, from the most common protection methods given below.
| d | Pressure resistant sheath | Insulation against explosion in a pressure resistant sheath |
| o | Oil filling | Ignition source to be insulated from the atmosphere by closing into an oil/sand/cast material |
| q | Sand filling | |
| m | Cast material | |
| N | Non-sparking material | No sparking occurs in normal use |
| e | Increased safety | Prevention of sparking in normal use |
| p | Inner overpressure | To eliminate an explosion hazard due to an overpressure |
| i | Intrinsic safety | Prevention of sparking / thermal effect by reducing the power content in electric circuit |
