Regulations for explosion protection
Explosion protection regulations in the EU member states are marked by the change of EU protection guideline 67/117/EWG ff to the two new EU guidelines 94/9/EC (ATEX 95) and 95/C 332/06 (ATEX 137). As a result of the new directives, explosion protection in European regulations will be harmonised. There will be a transitional period to adjust from the „old“ to the „new“ European law. The regulations covering the „old“ law were in effect up to June 30th 2003.

Since July 1st 2003, electric explosion proof equipment must comply with ATEX Ex-protection guidelines in accordance with 94/9/EC – on the approximation of the laws of the Member States concerning equipment and protective systems for use in potentially explosive atmospheres.

Information on the uniform classification of potentially explosive systems and its use this as a basis for selecting and classifying systems and equipment, incl. their installation, can be found in guideline 1999/92/EC (ATEX 137).

ATEX
Guideline 94/9/EC of the European Parliament and the European Council of March 23rd 1994, concerning equipment and protective systems for use in explosion risk areas, has brought the legislation of the member states into line.

Certificates
Corresponding approvals and certificates are required for electrical explosion proof equipment. Testing must be carried out by an official testing agency (for example the PTB - Physikalisch Technische Bundesanstalt in Braunschweig/Federal German Physical and Technical Institute of Braunschweig). ATEX approvals are also accepted in many countries and states outside Europe.

Responsibilities
The responsibility for compliance with all regulations and guidelines, from production and planning to installation, operation and maintenance, has greatly increased.
Each individual must be conscious about the fact that he accepts personal responsibility as part of a total project:

This has far-reaching consequences in the selection, installation, operation and maintenance of equipment within the explosion-proof zones. For the first time, not only electrical equipment is subjected to a critical examination of potential explosion risks, but also mechanical, pneumatic and hydraulic devices and components. This includes, amongst others, mechanical drives and clutches, pneumatic actuators and sensors, flange couplings as well as other plant components that were so far rated as being uncritical.

At the same time, dust explosion control is clearly given more attention. So far, there have not been own standards for construction and certification purposes for dust explosion control, but this is now rapidly changing with the new ATEX guidelines. After numerous explosions due to insufficiently secured dust zones, the regulations of dust explosion control have been considerably extended for marking and certification of equipment in these zones.

When can a danger of explosion occur?
A danger of explosion occurs when a flammable medium (gas, vapor, mist or dust) is present in a dangerous quantity.

What creates an explosion?
An explosion may occur when the following
3 components are present at the same time:

- Explosive atmosphere
- Source of ignition
- Air (oxygen)

Typical sources of ignition
Very often the reason for accidents is self-ignition, extraordinary surface temperatures and sparks due to mechanical reasons. But there are also a lot of other sources of ignition, caused by either mechanical and/or electrical equipment.

These are for example:

From fire to detonation
Effect and reaction velocity increase significantly from fire, outburst of flames,
via ignition and explosion up to detonation. Explosions are more likely with gaseous media and detonations with dust media.