Schenck Process s.r.o. - Explosion protection ATEX

New Harmonized European Standards

Explosion protection is designed to ensure the safety and health of persons as well as the safety of plants and products. Potentially explosive atmospheres are defined as areas where an explosive atmosphere can arise from the mixture with air, under atmospheric conditions, of flammable substances in the form of gases, vapours, mists, and dusts.

Today two directives apply throughout the European Union:
Directive 99/92/EC on minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres, also known as "ATEX 137", has been written for the employer in his capacity as plant user. The commonly used abbreviation "ATEX" derives from the French term "Atmosphère Explosible".
Directive 94/9/EC on the approximation of the laws ... concerning equipment and protective systems intended for use in potentially explosive atmospheres, also known as "ATEX 100", has been written for the equipment manufacturer.

The present harmonization removed the barriers to trade within the European Union in the area of protection against explosions. To users of potentially explosive plants outside the EU, the respective local regulations apply. Concerning deliveries to countries outside the EU, the suppliers respect the regulations contractually agreed with the customer. A novel feature of explosion protection in accordance with ATEX is the inclusion of the mechanical equipment and the assignment of equipment categories to hazardous zones.

EU Directive 99/92/EC, ATEX 137, directed to the user
Essential features of the directive laying down the minimum requirements:

Explosion protection priorities

1.	Prevention of the formation of explosive atmospheres
2.	Avoidance of ignition sources
3.	Mitigation of the detrimental effects of an explosion

Classification into zones

The employer classifies the areas where explosive atmospheres may occur into zones. The different zones are assigned to defined equipment categories.

Explosion risk assessment and explosion protection document

The risks of explosion shall be assessed overall and documented. Also the protective measures must be documented.

Coordination duty

The employer coordinates the explosion protective measures if workers from several undertakings are present at the same workplace.

EU Directive 94/9/EC, ATEX 100, directed to the manufacturer

New plants in potentially explosive atmospheres may exclusively use equipment complying with the minimum requirements of Directive 94/9/EC.

Important novel features:

Every piece of equipment is marked with the CE label.

For every type of equipment, the manufacturer issues a declaration of conformity.

The regulations are now also applicable to non-electrical (mechanical) equipment.

The explosion protected equipment is classified into groups and categories.

Group I:	mines (not further considered).
Group II:	all except mines
Category 1:	very high level of protection
Category 2:	high level of protection
Category 3:	normal level of protection

In addition, the equipment destined for use in Gas-Ex and Dust-Ex atmospheres is identified by G and D respectively. Additionally identified by group, category and gas/dust zone, the new Ex marking of our control terminal, type DT...E ,now reads as follows:

Previously:	Eex ib IIC T6
To EU Directive 94/9/EG:	II 2 G Eex ib IIC T6

For every piece of equipment, the manufacturer prepares instructions including, i.a., instructions for safe putting into service, use, assembling/dismantling, maintenance (servicing and emergency repair), installation and adjustment. For commissioning, the original instruction in one of the languages of the European community plus a translation into the language of the user country must be supplied.

Schenck Process GmbH and ATEX

Schenck Process offers the plant designer and user important consulting and support in planning-in the Ex equipment of industrial weighing and feeding technology with special emphasis on the determination of zones under consideration of the bulk solid used and possible zone shifting due to the use of weighing and feeding systems.
The modular construction of the Schenck systems offers particular benefits since it enables the equipment to be optimally adapted to the user's process requirements and helps the user to prepare his explosion protection document. Installations mounted in potentially explosive areas ask for a lot of caution and technical expertise. Therefore the installation and commissioning service offered by the Schenck experts presents a valuable contribution to the fulfilment of the duties the plant user is responsible for.

directed to the user

directed to the manufacturer

Schenck Process and ATEX