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What do the ATEX 95 andATEX 137 DirectivesCover?ATEX 95 is concerned with thesupply of equipment whilst ATEX137 is concerned with the protec-tion of workers. The directives arebriefly outlined in Table 1. Itshould be remembered that thesedirectives deal only with explosive

atmospheres and not with otherhazards.

Together they have the effect ofturning what had until now beenaccepted best practice within theprocess industries into mandatoryrequirements. In doing so com-bustible dusts have been specifi-cally included within the scope of

dangerous substances. The defini-tion of equipment within thesedirectives is very broad and nowincludes mechanical equipment(both rotating and static).

"The inclusion of mechanicalequipment represents one of themain compliance issues for bothequipment suppliers and users."

Area classification andequipment selectionATEX 137 requires that hazardousareas are classified into zones onthe basis of frequency and dura-tion of the hazard, as outlined inTable 2.

"Responsible operators in the Oiland Gas Sector will have donearea classification exercises ontheir assets but they should nowreview them to ensure they areup to date. Operators who in thepast relied on the blanket zon-ing of whole plant areas shouldseek to establish the necessaryextent of individual zones. Withblanket zoning the measuresrequired by ATEX 137 will haveto be applied to more equipmentthan is really necessary, therebyincurring unnecessary costs."

As from 1 July 2003, only equip-ment complying with ATEX 95can be installed in a hazardousarea. Equipment is divided intogroups and categories with differ-ing requirements for design, test-ing, certification and documenta-tion. The use of equipment withinhazardous areas is restricted asalso shown in Table 2.

H S E S A F E T Y

On 30 June 2003, the "Atmosphères Explosibles" Directives ATEX 95 and ATEX 137 became effectivethroughout the European Union (EU). A major consequence of these directives is that the operatorsof oil and gas facilities now must carry out risk assessment of equipment located within hazardousareas for potential sources of ignition and provide technical and organisational measures to eliminateor reduce the identified risks. There are implications for the Oil and Gas Industry, particularly withregard to issues associated with ignition source risk assessment of mechanical equipment located inpotentially flammable atmospheres.

BY ANDY HOLLINS

Mechanical Equipmentand the ATEX Directives

Figure 1: Gas Compressor Ignition Sources

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As far as electrical apparatus isconcerned, these requirements arenothing new. Electrical engineershave been dealing with theseissues for many years and thereare established standards andequipment certification proce-dures. In contrast the equivalentstandards for non-electricalequipment are still largely at thedraft stage, with only EN 13463-1being published so far.

"There are bound to be someinitial problems with the certifi-cation of new mechanicalequipment. Nobody wants to befirst, but project timescalesmean that the issues cannot beavoided for long."

Existing facilities andignition source riskassessmentOperators of oil and gas facilitieswill need to be able to demon-strate that the equipment in usewithin zoned areas does not result

in active ignition sources. The tol-erability of active ignition sourcesvaries depends upon the zone inwhich the equipment is located.The requirements are laid out inTable 3.

For certified electrical equipmentthis is relatively straightforwardand activities will include:

• Inspecting the equipment toconfirm correct for the zone

• Replacement, if necessary, withapparatus appropriate to thezone

• Undertaking any necessaryremedial work.

For mechanical equipment it willfirst be necessary to undertake anignition source risk assessmentexercise. Once this has been com-pleted, the required mitigatingmeasures can then be implement-ed and the necessary inspectionsundertaken. Operators have until30 June 2006 to complete the

whole process and bring theirexisting facilities into compliance.

Typical ignition sources for aprocess gas compressor are shownin figure 1. Other mechanicalplant items will have similarpotential ignition sources.

"With thousands of installedplant items operating in zonedareas, this represents a signifi-cant challenge to operators inthe Oil and Gas Sector."

To meet this need ABB EutechProcess Solutions has developedan ignition source risk assessmentmethodology that identifies anyeffective ignition sources createdby the operation of equipment inhazardous areas. Appropriate mit-igating measures are then selectedto reduce the residual risk to anacceptable level. The use of soft-ware tools enables the efficientrisk assessment of large volumesof equipment and allows quickupdating following plant modifi-cations.

Mitigating measures include:

• Maintenance and operationalprocedures and checks

• Condition monitoring

• Trips and alarms

• Hardware devices (e.g. torquelimiters, relief valves).

These are then summarised in therisk assessment report for the itemof equipment and the associatedinspection sheets, to enable theuser to implement and managethe required mitigating measures.The methodology enables theequipment user to demonstratecompliance with the ATEX direc-tives.

ABB Eutech Process Solutions pro-vides a full range of ATEX compli-ance services and "route to com-pliance methodology" includingprocess hazard reviews, area clas-sification, training and a compre-hensive set of hazardous areaproject documentation and man-agement procedures.

ABB Eutech Process Solutions is apart of ABB’s AutomationTechnologies division serving cus-tomers in the petroleum, chemi-cals, life sciences, manufacturing,metals, paper and utility indus-tries.

REFERENCESATEX 95European Union directive 1994/9/EC

ATEX 137European Union directive 1999/92/EC

En 13463-1Non-electrical equipment for poten-tially explosive atmospheresPart 1: Basic method and require-ments. ■

H S E S A F E T Y

Table 3: Tolerability of Ignition Sources according to Zone

Table 2: Area Classification and Equipment Categories

Table 1: Overview of ATEX 95 and ATEX 137

The Author:

Andy Hollins graduated fromCambridge University in 1981with a degree in Engineering. Aprofessional mechanical engineer,he joined ICI in 1985 where heheld a series of posts in processplant operation and maintenance,engineering department and R&D.He later transferred to Eutech,which was then acquired by ABBin 2001.

Now a senior consultant withABB Eutech Process Solutions, hehas a specific interest in the safeoperation of mechanical equip-ment. In September he delivereda paper on ATEX compliance tothe Institution of MechanicalEngineer’s InternationalConference in London onCompressors and their Systems.e-mail: andy.hollins@gb.abb.com