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PNEUMATICS AND POTENTIALLY EXPLOSIVE ATMOSPHERES:
EUROPEAN DIRECTIVE 94/9/EC (ATEX)
As from 1st July 2003, all products marketed in the European Union and intended for use in potentially explosive atmospheres must be approved in compliance with European Directive 94/9/EC, also known as ATEX. This new directive also applies to non-electrical components, such as pneumatic controls, for which approval is mandatory. The main innovations introduced by the new directive 94/9/EC are:
An explosion can occur when flammable substances and a source of ignition are present simultaneously in a potentially explosive atmosphere. A source of ignition can be:
Responsibility lies both with the manufacturer of the device and whoever installs it in equipment that is to operate in a hazardous atmosphere. This requires co-operation between the parties to ensure correspondence between the category of device and the hazardous area in which it is to operate. The manufacturer of the device must comply with the specifications and classify the product according to directive 94/9/EC. The manufacturer of the equipment, who knows the area in which the device will be operating, must select a suitable device according to the category, pursuant to directive 99/92/EC. THE COMBINATION OF ELECTRICAL AND MECHANICAL PARTS According to Directive 94/9/EC, both electrical and mechanical devices are subject to approval.  It is important to note that the component which is classified in the lowest category defines the category of the entire device of which it is a part. If, for example, the coil is marked Ex II 2 ¡ and the valve is marked Ex II 3¡ the coil+valve assembly must not be put into service in zone 1 or 21, only in zone 2 or 22. GROUPS AND CATEGORIES Devices for use in potentially explosive areas are divided into the following groups:
GROUP I  DEVICES FOR SURFACE INSTALLATIONS GROUP II  CORRESPONDENCE BETWEEN ZONES AND CATEGORIES ACCORDING TO 94/9/EC. ZONE 0/ZONE 20 => CATEGORY 1: devices in this category ensure an adequate degree of safety even in the presence of rare malfunctions. These devices are used in zones in which an explosive atmosphere is present continuously for long periods. ZONE 1/ZONE 21 => CATEGORY 2: devices in this category ensure an adequate degree of safety even in the presence of a probable malfunction. These devices are used in zones in which an explosive atmosphere is present occasionally. ZONE 2/ZONE 22 => CATEGORY 3 : devices in this category ensure an adequate degree of safety during normal operation. These devices are used in zones in which an explosive atmosphere is rarely present and only for brief periods. MARKING : HOW TO READ IT CE mark CE Ex II 2 GD C T4 T120°C 20°C < aT < 60°C  TYPE OF PROTECTION AGAINST SOURCES OF IGNITION  TEMPERATURE CLAS Group I Temperature =150 °C or =450 °C according to the layer of dust accumulated on the device. Group II 
USER AND SUPPLIER: OBLIGATIONS AND RESPONSIBILITIES It is important to highlight the need for the user and supplier to collaborate and to exchange all the information required to define the types of products that can be used in full compliance with the safety standards. USER : after performing a company-wide risk analysis (pursuant to directive 99/92/EC) and identifying the risk zone in which the purchased part will be operating, the user must inform the SUPPLIER, who must check that the products supplied are compatible with the zone indicated and that the environmental conditions are within the set operating range for the parts. It is also important to make sure that the operating instructions are always attached to the products supplied. |
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