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ATEX with industrial valves: for advanced users

ATEX for non-electric devices

Why ATEX for non-electric devices? For a long time, the design of electric devices has already taken into account explosion protection, if such devices are to be used in explosive atmospheres.

Explosive atmospheres can result in plants due to various production processes e.g. by the handling of gases, vapours, mists or dusts in sectors like the chemical and petrochemical industry, extraction of oil & gas and food production. Combustible substances might form explosive atmospheres in combination with oxygen. An ignition would then entail severe damage to materials and persons.

Thanks to the ATEX (ATmosphères EXplosibles) Directive 94/9/EG dated 23 March 1994, the requirements in terms of explosion protection were extended to non-electric devices. The 2014/34/EU Directive dated 26 February 2014 was a fundamental amendment thereto. On the operators‘ side the 1999/92/EG Directive dated 16 December 1999 must be applied for compliance with explosion protection measures. The Directives mentioned above have been transposed into national law in the single EU states. In Germany, for example, the Production Safety Act applies.

Primary and secondary protection systems

There are primary and secondary protection systems for the prevention of explosions. In primary protection systems, for example the inertisation of a gaseous atmosphere provides for explosion protection. The secondary explosion protection relies on the avoidance of ignition sources. Consequently, valves shall be designed so that in accordance with their intended use no effective ignition source may develop also in the event of foreseeable misuse.

Manufacturer declaration and EU-declaration of conformity

For a large part of their self-acting industrial valves used in explosive areas, some manufacturers issue a manufacturer declaration stating that the corresponding component falls out of the scope of the ATEX Directive, since it does not have any potential ignition source. From a purely legal point of view this procedure cannot be contested.

However, in the light of the ever growing need for safety and security in the area of explosion protection, at least some of the valve model series of their portfolio should be certified with a EU Declaration of Conformity in accordance with the 2014/34/EU Directive. It also refers to the ATEX CE-marking which indicates clearly to the operator in which explosion zone the corresponding equipment is allowed to be used.

ATEX CE-marking

For this purpose, the relevant model series must be subjected to extensive ignition hazard assessments throughout the entire product lifecycle. Such assessments record all the potential ignition sources and evaluate their danger of ignition. Every ignition source assessed as being effective should be configured with constructive measures in such a way that it no longer represents any ignition potential within the analysed category.

Compliance with the necessary measures is monitored through an internal production control checklist covering all stages from the design until the despatch of the valve. The scope of supply then also comprises a separate ATEX instruction manual.

The entire ignition hazard assessment is summarised in a documentation and deposited with a notified body. Hereby, in the event of a damage, it can be demonstrated at any time that during design, production and intended use all the requirements of the ATEX Directive 2014/34/EU and any other accompanying applicable regulations, standards and guidelines have been taken into consideration.

Overview

Marking of non-electrical explosion-proof devices – ATEX

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