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Operation
A371-32-880 Issue C
4 Operation
4.1 ATEX directive implications
4.1.1 Introduction
This equipment is designed to meet the requirements of Group II Category 3 equipment in accordance with Directive
94/9/EC of the European Parliament and the Council of 23rd March 1994 on the approximation of the laws of the
Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres.
(The ATEX Directive)
The ATEX Category 3 applies in respect of potential ignition sources internal to the equipment. An ATEX Category has
not been assigned in respect of potential ignition sources on the outside of the equipment as the equipment has not
been designed for use where there is an external potentially explosive atmosphere.
There is no potential source of ignition within the pump during normal operation but there may be potential sources
of ignition under conditions of predictable and rare malfunction as defined in the Directive. Accordingly, although
the pump is designed to pump flammable materials and mixtures, operating procedures should ensure that under all
normal and reasonably predictable conditions, these materials and mixtures are not within explosive limits. Category
3 is considered appropriate for the avoidance of ignition in the case of a rare malfunction which allows flammable
materials or mixtures to pass through the pump whilst within their explosive limits.
4.1.2 Flammable/pyrophoric materials
When flammable or pyrophoric materials are present within the equipment you must:
z Not allow air to enter the equipment.
z Ensure that the system is leak tight.
z Use an inert gas purge (for example, a nitrogen purge) to dilute any flammable gases or vapours entering the
pump inlet, and/or use an inert gas purge to reduce the concentration of flammable gases or vapours in the
pump and in the exhaust pipeline to less than one quarter of the gases' published lower explosive limits
(LEL).
z Use an inert gas purge in to the pump gas ballast connection to prevent the condensation of flammable
vapours within the pump mechanism and exhaust pipeline.
4.1.3 Gas purges
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