F O R U MSpec i a l i s t pe r i od i ca l fo r l i gh t i ng

41

Fördergemeinschaft Gutes Licht

ATEX: Explosion protec-tion for gas anddust atmospheres

peratures reach more than2,000 degrees Celsius, pres-sure waves normally exceedten bar.

Explosion protectionWhat triggers the reactionthat causes a mixture of gasor dust and air to explode isa source of ignition, whichcould be an ignition spark, aglowing component, a nakedflame or a hot surface. This iswhere the safety regulationsfocus first, requiring the useof explosion-protected equip-ment as a secondary safe-guard. In the case of lighting,this means Ex luminairesemploying certain types ofprotection.

The alternative to secondarysafeguards are primary pre-cautions. These can involveavoiding or restricting explo-sive substances, raising theirflashpoint, limiting their con-centration, adding inert sub-stances and/or providing nat-ural or artificial ventilation. Assuch measures are generallytoo complex or costly, sec-ondary safeguards are thesolution of choice in practice.In many instances, Ex lumi-

Presence of explo- Equipment categorysive atmosphere defined by 94/9/EC

Zone 0 constant, prolonged Category 1Zone 20 or frequent

Zone 1 occasional Category 2Zone 21

Zone 2 rare and brief Category 3Zone 22

It does not need to endin disaster, like at theRolandmühle plant inBremen, Germany (Febru-ary 1979) or the fertiliserfactory in Toulouse,France (September 2001).Statistically speaking,explosions that causemajor loss of life, injuryor damage to propertyoccur only once every tento twenty years.

But the risk of accident is stillhigh. The German chemicalindustry’s liability insurer BGChemie estimates that threeminor to moderately seriousexplosions occur across theindustry every day.

To ensure that the worsteventualities are prevented,today’s high safety standards

need to be maintained andraised even higher – for onething, to improve protectionagainst explosions caused bydust, which many nationalregulations have so farneglected. The new ATEXdirectives (ATEX = Atmos-phères Explosibles) on explo-sion protection applythroughout the EuropeanUnion: Directive 94/9/EC(ATEX 95, formerly ATEX100a) and Directive 99/92/EC (ATEX 137, formerly ATEX118a).

Hazards presented bygas and dustThe risk of explosion is pre-sent in almost every processengineering plant. Wherecombustible substances aremanufactured, processed,transported or stored, vapoursand mists combine with oxy-gen in the air to create anexplosive atmosphere. Thesame hazard arises wherecombustible dust is present.Scientists describe an explo-sion as an exothermic chemi-cal reaction giving rise to asudden – and usually simul-taneous – increase in tem-perature and pressure. Tem-

Fig. 1: The riskof explosionis present inalmost any

processengineering

plant.

The risk of accident

Zonal classification

Fig. 4: Explosion-protectedluminaires (Ex luminaires)minimize the danger ofexplosions.

Fördergemeinschaft Gutes Licht

is still highnaires need to be used inaddition to primary precau-tions to ensure that the riskof explosion is sufficientlyminimized.

Hazard potential zonesAreas endangered by poten-tially explosive atmospheresare classified into zones (see“Zonal classification” table)on the basis of their hazardpotential. Zones 0, 1 and 2apply to gases, mists andvapours; zones 20, 21 and 22(old zones 10 and 11) applyto combustible dusts. Equip-ment employing certaintypes of protection is identi-fied for each zone, classifiedinto equipment categories1 to 3.

Fig. 3: Most people associate explosions withgases, mists and vapours. But dusts, too, createa potentially explosive atmosphere.

Example of zonal classifi-cation. Zone 0 is wherethe danger of explosion isgreatest.

The type of protectionemployed by an explo-sion-protected luminaire isdefined by its design andproduction engineering.

The commonest types of pro-tection are “increased safety”(e) and “flameproof enclo-sure” (d) for use in zones 1and 21 (equipment category2) and “non-sparking” (nA)and “restricted breathing” (nR)for zones 2 and 22 (equip-ment category 3).

The table on the right showsthe protection requirementfor each type of protection,except for Ex luminairesdesigned for zones 0 and 20(equipment category 1). Thisis because zone 0 and 20luminaires are used mostly formining and for a limited num-ber of specialised lightingapplications such as drum,tank or pipe interior lighting.

Ex luminaires are designed foruse in ambient temperaturesfrom –20 degrees to +40degrees Celsius.

Types of protection of Ex luminaires

7 Luminaire employing typeof protection “nA” (non-sparking) with fluorescentlamps e.g. for zone 2

8 Floodlamp employing typeof protection “nR” (restrictedbreathing) with high-pres-sure discharge lamps e.g. forzone 2

The luminairepass

The rating plateof an Ex lumi-

naire contains allthe information

important for itsuse, especially itssuitability for use

in areas (zones)endangered bypotentially ex-plosive atmos-

pheres.

specimencompany

4712 specimen luminaireII 2 G E EX e d IIC T4

PTB 02 ATEX 08162x36W/40W IEC 81 G13

Made in Germany

IP 66Ta

<=50°C

0102

Area of application with reference to Group and Category

Type designation

Name and address of manufacturer

EC-type-examin-ation certificate

DIN VDE/EN/IEC item designation

EC identifier

Type of protection

Ex Group

Temperature class

Ambient temperature rating

CE marking with number of inspection agency monitoring the QM system

5 Luminaire employing typeof protection “e” (increasedsafety) with fluorescentlamps e.g. for zone 1

6 Luminaire employing typeof protection “d” (flame-proof enclosure) with metalhalide lamps e.g. for zone 1

5 6

87

Fördergemeinschaft Gutes Licht

Type of protection and protection requirement

Explosion protection

gases, mists,vapours (G)

Explosion protection

dusts (D)

Protection requirement

Additional design features pre-vent the occurrence of inadmissi-bly high temperatures as well assparks and electric arcs inside theluminaire and on external com-ponents.

Components which could act asa source of ignition are enclosedin a housing designed to with-stand the pressure of an explo-sion inside the housing and pre-sent transmission of the explo-sion to the surrounding poten-tially explosive atmosphere.

The design minimizes the occur-rence of electric arcs, sparks orhot surfaces which could be-come a source of ignition innormal use.

The design of the luminairehousing restricts ingress of gas:passing fumes which are poten-tially explosive do not penetratethe interior of the housing duringthe brief period of contact.

The design provides protectionagainst ingress of dust in danger-ous quantities (IP 6X) and en-sures that the surface tempera-ture is below the ignition tem-perature of air/dust mixtures aswell as below the smoulderingtemperature of dust deposits.

The design provides protectionagainst ingress of dust in poten-tially hazardous quantities (IP 5X)and ensures that the surfacetemperature is below the ignitiontemperature of air/dust mixturesas well as below the smoulder-ing temperature of dust deposits.

Zone 1

Zone 2

Zone 21

Zone 22

Type of protection

increased safety

Ex e

flameproofenclosure

Ex d

non-sparking

Ex nA

restrictedbreathing

Ex nR

protected byhousing

dust-tight

protected byhousing

dust-protected

Ex luminaires need tomeet high requirementsfor use in areas endan-gered by potentially ex-plosive atmospheres; theeffectiveness of the pro-tection provided dependson the quality of the pro-duct. This is why ATEXDirective 94/9/EC requiresmanufacturers to operatequality assurance systems:

• Conformity AssessmentProcedures

For zone 1/zone 21 lumi-naires, a quality assurancesystem needs to be imple-mented complete withdocumentation and regularmonitoring by an indepen-dent inspection agency(prescribed verification).

For zone 2/zone 22 lumi-naires, internal control ofproduction alone is enoughto satisfy quality assurancerequirements. This includescreating a technical docu-

mentation which attests tothe luminaires’ conformity tothe directive. An EC-typeexamination (voluntary verifi-cation) is recommended forzone 2/zone 22 luminairestoo, however, certified by the“EC-type-examination certifi-cate” of an accredited inspec-tion agency or by the manu-facturer’s “declaration of con-formity”.

• Operating instructions Ex luminaires are not allowedto be supplied without oper-ating instructions. As well asthe technical documentationfor assembly, installation,putting into service andmaintenance, these mustcontain all the informationrelevant for safety.

• Manufacturer’s declaration

As well as affixing the pre-scribed CE marking to Exluminaires, the manufacturemust issue and supply witheach luminaire a ”manufac-turer’s declaration”. This con-firms that the design of theluminaires conforms to thedirective and that all qualityassurance requirements aremet.

Externalverification

The regulationsgoverning Ex

luminaires arevery complex.Misinterpreta-tion is avoided

from the outsetwhere accredit-

ed inspectionagencies likePTB confirm

suitability andsafety – not justfor zone 1/zone

21 luminaires(prescribed veri-fication) but alsofor zone 2/zone

22 luminaires(voluntary veri-

fication).

Fig. 10: Accreditedinspection

agencies certifythat EC-typeexaminations

have beencarried out by

issuing “EC-type-examination

certificates” and“declarations of

conformity”.

Quality assurance for luminaires

Fördergemeinschaft Gutes Licht

Before suitable Ex lumi-naires are selected andinstalled, the lighting sys-tem needs to be carefullyplanned. Above all, haz-ard potentials need to beassessed and appropriatezones defined.

The requirements for instal-ling electrical systems inareas endangered by poten-tially explosive atmospheres– including the requirementsfor selecting electrical equip-ment – are set out, inter alia,

in VDE 0165, Part 1 (identicalwith EN 60079-14) and Part2 (see EN 50281-1-2).

Responsibility for the safetyof an electrical system restsentirely with the operator.This means that after dueinstallation and final inspec-tion before the system is putinto service, regular checksand maintenance are re-quired to ensure that thesystem remains in good con-dition. The regulatory basisfor this is provided by the

“Regulation covering electri-cal equipment in potentiallyexplosive atmospheres”(ElexV), the ATEX Directive99/92/EC (see “The ATEXdirectives”) and VDE 0165,Part 10 (EN 60079-17).Other references to mainte-nance and repair work arecontained in the explosionprotection rules (Ex-RL) ofthe Employment AccidentInsurance Fund of the Ger-man Chemical Industry (BGChemie).

Fig. 12: Planninginvolves hazardpotential assess-ment and zonalclassification byspecialists.

Fig. 13: Responsibilityfor system safetyrests with theoperator.

Installation – operation – maintenance

Operator

Competent Authority

Instal

ler en

ginee

r

Inspection agency

Stan

dard

sManufacturer

The legal basis for explo-sion protection is formedby the ATEX directives(ATEX = AtmosphèresExplosibles) of the Euro-pean Union: Directive94/9/EC (ATEX 95) andDirective 99/92/EEC (ATEX137). After defined transi-tional periods, they willsupersede the relevantnational regulations in allEU member states.

Explosion protection is healthprotection, so the EU soughtat an early stage to developharmonizing legislation: thefirst directive in this area ofregulation (Directive 76/117/EEC) came into force morethan 25 years ago.

ATEX Directive 94/9/ECsets out requirements forproducts used in locationsendangered by the presenceof potentially explosiveatmospheres. It is directedat manufacturers and its pro-visions have been applicableon a voluntary basis since

1 March 1996. From 1 July2003, its application ismandatory. Luminairesinstalled prior to this datemay still be used after thetransitional period expires.The production of all thecompanies in the ZVEI ExLighting Working Group(ZVEI Arbeitskreis Ex-Beleuch-tung) is largely based on thenew regulations already.

Fig. 15 (right):Explosion pro-

tection is healthprotection – asubject of har-monized regu-lation through-

out the EU

The ATEX directives

Directive 99/92/ECsets out requirements for work premises and is directed at OPERATORS

Directive 94/9/ECsets out requirements for products and is directed at MANUFACTURERS

Directive comes �into force

End of transitional period �for existing work premises

Application �mandatory

Application �mandatory

Application of direc-�tive possible from

28 Jan 2000

1 March1996

30 June 2006

1 July 2003

This directive was transposedinto German law by the 11thRegulation on the EquipmentSafety Act (ExVO). All therequirements which electricalsystems equipment neededto meet prior to that dateunder the “Regulation gov-erning electrical equipment inpotentially explosive atmos-pheres” (ElexV) were there-fore replaced by a referenceto the ExVO. Since that time,the ElexV has contained onlyregulations relating to assem-bly, installation and operation.

Directive 99/92/EC sets outrequirements for workpremises. It is directed atoperators. After it is trans-posed into German law, itswork safety provisions willsupersede the assembly,installation and operatingrequirements set out in ElexV.This ATEX directive came intoforce on 28 January 2000.Existing work premises needto comply with the new re-quirements by 30 June 2006at the latest, which is whenthe transitional period expires.

Fördergemeinschaft Gutes Licht

Linear lampsIn the workshops and pro-duction plants of industry,the lighting scene is domi-nated by the linear fluores-cent lamp, with its high lumi-nous efficacy and long ratedlife. The same holds true forEx lighting applications.Lamps of choice are 38 mmdia. fluorescent lamps (notillustrated) as well as 26 mmdia. three-band fluorescentlamps, which are almost in-variably operated by elec-tronic ballasts (EBs).

“Increased safety” luminaireshave special requirements:lamps need to be designedfor cold restarting (lamp elec-trodes shorted by lamphold-er). At one time, only speciallamps with Fa6 one-pin basecould be used here. For morethan 10 years, however, ithas also been possible to fitthese luminaires with normalfluorescent lamps with two-pin base.

Cold restarting shortens thelife of a lamp, owing to whatis known as the “end-of-life”effect. Today, EBs are avail-able with end-of-life shut-down circuitry to guardagainst this effect. For light-ing systems not operated bythese EBs, the only way toprevent fault scenarios is byregular lamp replacement:– after 24,000 operatinghours at the latest in the caseof luminaires in continuousoperation,– after 12,000 operatinghours in the case of lumi-naires with 1–3 daily operat-ing cycles.

Ex luminaires require specialballasts. The most commonlyused are “powder filled” and“flameproof enclosure” units.

Compact lampsCompact fluorescent lampsgenerate light in the sameway as linear three-bandlamps. Fitted with bases atone end, they have high lu-minous efficacy ratings, verygood colour rendering prop-erties and are available in alllight colours (warm white,neutral white, daylight white).CFLs are not suitable for lu-minaires employing the typeof protection “flameproofenclosure”.

Electrodeless lampsEnergy efficiency and a ratedlife of 60,000 operatinghours are the salient featuresof the bulb-shaped inductionlamp (for “flameproof enclo-sure”) and the high-perfor-mance fluorescent lamp (for“increased safety”). Bothwork on the principle ofelectromagnetic inductionand gas discharge. They haveno filaments, electrodes orother components subject towear.

High-pressure dischargelampsMetal halide lamps are eco-nomical light sources withhigh-intensity beams com-bining compact design, veryhigh luminous efficacy andgood colour rendering pro-perties with long lamp life.Even higher luminous effica-cy is achieved by high-pres-sure sodium vapour lamps(excluding colour renderinggrade 4 lamps), which areanother option. High-pres-sure discharge lamps aremainly used for floodlampsand high-bay reflector lampsemploying the type of pro-tection “flameproof enclo-sure”.

Incandescent lampsSome luminaires are still fit-ted with incandescent lamps.Here, tungsten halogenlamps based at one end area more economical alterna-tive offering longer lamp lifeand higher luminous efficacy.

Fig. 16: 1 and 2 26 mmdia. three-bandfluorescentlamps, 3, 4 and5 compact fluo-rescent lamps,6 high-perfor-mance fluores-cent lamp, 7bulb-shapedinduction lamp,8, 9 and 10metal halidelamps, 11 and12 high-pressuresodium vapourlamps, 13 gen-eral serviceincandescentlamp, 14 tung-sten halogenlamp

Powerful and economical

1

2

3

4

5

6 7

8

10

911

12

13

14

Wide-angleThe specular reflector systemof this wide-angle zone 1industrial spotlight is designedfor long-life high-perfor-mance

fluorescent lamps(60,000 operating hours).The unit is particularly suit-able for high bays and otherapplications where access isdifficult and lamp replace-ment an expensive opera-tion. It is also available with atwist clip permitting angledwall or ceiling mounting upto 45° (17).

Pendant-mountedThis zone 2 high-bay reflec-tor luminaire with cast alu-minium housing was devel-oped as an alternative toplastic luminaires. With dif-ferent beam characteristics,the pendant-mounted lumi-naires ensure optimum

lighting in rooms withceilings between fourand 15 metres high.Lamps: high-pressure

discharge lamps(18).

Products that

solve problemsThe latest from the lighting industry

TubularGas- and dust-tight (degreeof protection IP 68), thistubular luminaire is suitablefor use in zones 1 and 2.Accessories for wall or ceilingmounting include pipe clips,

wall mounting brackets, wiresand chains. A glass tube isavailable as an alternative tothe prismatic polycarbonateenclosure. Lamps: 18 W or 36W three-band fluorescentlamps for EB operation (19).

VersatileThis 2,3 or 4-lamp zone 1 lu-minaire is fitted exclusivelywith electronic ballasts (EB)for 36 W and 58 W three-band fluorescent lamps. Theangled canopy permits pla-nar or angled mounting onwall or ceiling. The

High-intensityThis high-intensity luminairefor flange-mounting on tanksis protected to IP 67. It issuitable for zone 1 and zone2. A special luminaire holderpermits mounting on inspec-tion windows (DIN 28120).The transformer for the 20 Wor 50 W low-voltage tungs-ten halogen lamp is integrat-ed in the luminaire (20).

versatile luminaires can alsobe mounted in continuousrows (21).

19

20

21

17

18

Fördergemeinschaft Gutes Licht

Selected literature on Ex lightingErich Lienenklaus, Klaus Wettingfeld: Elektrischer Explosionsschutz nach DIN VDE 0165(Electrical explosion protection in compliance with DIN VDE 0165); VDE “Normen verständlich”series, vol. 65, 2nd edition 2001 (DIN A5, 484 pp., ISBN 3-8007-2410-3)

Bruno Weis: Industriebeleuchtung (Industrial lighting); Pflaum Verlag, 1st edition 2000(154 pp., ISBN 3-7905-0762-8)

Bruno Weis: Grundlagen der Lichttechnik (Basics of lighting technology); Pflaum Verlag,2nd edition 2001 (116 pp., ISBN 3-7905-0823-3)

Statement

1. The members of the Ex lighting working group of the ZVEI Electric Luminaires ProductDivision expressly agree to abide by the rules of competition set out by the Electric Lumi-naires Product Division and lodged with the Federal Cartel Office*

2. The members confirm that the Ex luminaires which they manufacture and/or place onthe market as well as any planning or consultation services they provide conform to therelevant regulations in force and accepted industrial standards, e.g. EN 50014, EN 50018,EN 50019, EN 50021, EN 50281, IEC 60029 etc.

3. The members have been informed by a Notified Body for Annex IV under Article 9 ofEuropean Parliament and Council Directive 94/9/EC that the quality assurance systemsthey operate for their production operations are compliant with Annex IV of the directive.Under article 10 (1) of Directive 94/9/EC, the CE marking needs to be followed by theidentification number of the Notified Body monitoring production.

4. Where possible, the members seek confirmation of the suitability and safety of theirzone 2/zone 22 luminaires from a certified inspection agency (voluntary verification).

5. The ZVEI members of this working group are entitled to describe themselves in publicas a “member of ZVEI-Arbeitskreis Ex-Beleuchtung”.

* Federal Cartel Office notification no. 162/2000 of 23 November 2000

ZVEI Ex Lighting Working Group

New publications

Answers to a great many questions about lighting technolo-gy are found in Carl-Heinz Zieseniss’ book “Beleuchtungs-technik für den Elektrofachmann” (Lighting technology forelectrical engineers). Now in its 7th edition, it is a standardwork which takes account of state-of-the-art technologyand the latest industrial standards. It is one of the series of“de-Fachwissen” books published by Verlag Hüthig undPflaum (ISBN 3-8101-0156-7) and costs 24.80 Euro.

Also updated is “Licht und Beleuchtung” (Light and lighting),edited by Hans-Jürgen Hentschel, which presents a compre-hensive picture of the basics and applications of lightingtechnology. The 5th revised and expanded edition 2000.XIIhas 386 pages. The soft-cover book (ISBN 3-7785-2817-3)is published by Hüthig Verlag and costs 62 Euro.

Imprint

Published by: Fördergemeinschaft Gutes Licht (FGL), Stresemannallee 19, 60596 Frankfurt am Main.Editing: rfw. redaktion für wirtschaftskommunikation, Darmstadt.Grafics and layout: Partner of Prepress, Darmstadt.Luminaire illustr.: Eichler Graphik GmbH, Zorneding.Photos: Industrial photos; Andreas Kelm, Darmstadt(lamps).

FGL website: www.licht.de

Printed by: Druckhaus Haberbeck, 32791 Lage/Lippe04/03-00

Ex LightingWorking Group

www.licht.deEverything about lighting.

Booklet No./Title Qty

01 Lighting with Artificial Light € 9,–

02 Good Lighting for Schools and Educational Establishments € 9,–

03 Good Lighting for Safety on Roads, Paths and Squares € 9,–

04* Good Lighting for Offices and Office Buildings

05 Good Lighting for Trade and Industry € 9,–

06* Good Lighting for Sales Premises and Shop Windows

07 Good Lighting for Health Care Premises € 9,–

08* Good Lighting for Sports Facilities

09 Prestige Lighting € 9,–

10* Notbeleuchtung, Sicherheitsbeleuchtung € 9,–

11 Good Lighting for Hotels and Restaurants € 9,–

12 Economical Lighting Comfort with Lighting Electronics € 9,–

14* Ideen für Gutes Licht zum Wohnen € 9,–

16* Urban image lighting

* Booklets 10 and 14 available only in German; English version of booklets 4, 6, 8 and 16 available only as pdf file, download at www.licht.de.

Booklets 13 and 15 are out of print.

Order form for FGL publications

fax: +49 (0)69-98955-198mail: Fördergemeinschaft Gutes Licht

Stresemannallee 1960596 Frankfurt am MainGermany

email: fgl@octopus-net.deInternet: www.licht.de

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Fördergemeinschaft Gutes Licht

Members of Fördergemeinschaft Gutes LichtLUMINAIRE MANUFACTURERS: GEBR. ALBERT • ANSORG • ARTEMIDE • ASMUTH • BANKAMP • BAULING • BAULMANN • BEGA • BIG LICHTPROJEKTE •BÖHMER • BPS • BRENDEL • BRUCK • BRUMBERG • CASABLANCA • CEAG • DERUNGS • DOLIN • DURLUM • ELEKTRA • ERCO • ETAP • ETRONEX • FAGERHULT• FEESE • FISCHER • FLOS • GLAMOX • GLASHÜTTE LIMBURG • GROSSMANN • HELESTRA • HELLUX • HERA • HERNER GLAS • HESS FORM + LICHT •HIRT • HOFFMEISTER • HOLOPHANE • HOLTKÖTTER • IGUZZINI • INPROTEC • KAUFEL-NIFE • KOTZOLT • KPM • LAMPI-KORTE • LICATEC • LITE-LICHT • LMT• LOUIS POULSEN • LP LEUCHTEN • LUXO • MAEHLER & KAEGE • MENZEL • MERK • MOONLIGHT • M. MÜLLER • NARVA NEUCO • NIERMANN • NOBILÉ •NORKA • OLIGO • CHR. PALME • PETERS DESIGN • PHILIPS AEG LICHT • POPP • PRACHT • PRÄZISA • PUBLIC SCREEN • RADEMACHER • RECHLATERNEN • REGIOLUX • REIHER • REISS INTERNATIONAL • RIDI • ROBERS • RSL RODUST • RUHSTRAT • RZB-LEUCHTEN • SBF SPEZIALLEUCHTEN • SCHMITZ • GJCS SCHNEIDER • SCHOTT-GLAS • SCHUCH • SCHUPA • SEMPERLUX • SILL • SIMON & SCHELLE • SIS-LICHT • SITECO • SLI LICHTSYSTEME • SONLUX • SPITTLER• R. STAHL • STENG • STRASSACKER • SYSTEMTECHNIK • TECNOLIGHT • THORN • TRILUX • VARIALUX • VULKAN • WALDMANN • WE-EF • WILA • DR. WILLING• Z-I-LICHTSYSTEME • ZUMTOBEL STAFF • LIGHTING COMPONENT MANUFACTURERS: BAG • ECKERLE • ERC • HADLER • HELVAR MERCA • HÜCO • INSTA• LT ELEKTRONIK • LUXMATE • MAY & CHRISTE • OSRAM • PHILIPS • TRIDONIC • VOSSLOH ELEKTRO • LAMP MANUFACTURERS: AURALIGHT • BLV •GE LIGHTING • G.L.E. • LUMILEDS • NARVA LICHTQUELLEN • OSRAM • PHILIPS • RADIUM • SLI LICHTSYSTEME