Principles of Explosion-Protection

The history of explosion-protection and the legislativeprovisions in Germany and EuropeElexV from 1980The factory inspectorate division waschosen to be the competent authority todefine to what extent a room or plant mightbe subject to the hazard of explosion.The “Decree concerning electrical installationsin potentially explosive atmospheres(ExVO)”, which was issued in 1963, not onlyintroduced the obligation to have the explosionprotected apparatus tested by theFederal Physico-Technical Institute(Physikalisch-Technische BundesanstaltPTB) or the Mining Test Station (BVS), butalso the obligation to obtain the designapproval from the authorities of the competentfederal state.In 1975 the Council of the EuropeanCommunity issued framework directives onexplosion-protection.The European standards for electricalequipment for use in hazardous areas weredrawn up by CENELEC, the “Europeancommittee for electro technical standardization”.In Germany the new European standardsEN 50 014 to EN 50 020 were adoptedas VDE standards as part of the nationalstandards works.These new standards DIN EN 50014 to50020/VDE 0170/0171, Parts 1 to 7, designatedas VDE regulations, came into forceon 01.05.1978.The application of these European standardsfor the construction and testing ofexplosion-protected electrical apparatuswas governed throughout Europe by the“EC Directive 79/196/EC”. With the newregulation, which was now known as ElexV,among other things, on 01.07.1980 this ECDirective was implemented and explosionprotectionnewly regulated for manufacturersand operators. Furthermore, the expertiseof the testing establishments and thedesign approval were replaced by a typesample test. The type sample test was carriedout by authorized testing establishmentsof the member states of the EU(Notified Bodies). The certificates of conformityand inspection granted on the basisof the said tests were valid throughoutEurope.From 01.07.2003, Directive 94/9/EC on theapproximation of the laws of the MemberStates concerning equipment and protectivesystems for use in potentially explosiveatmospheres, issued on 23.03.1994 by theEuropean Parliament and Council, irrevocablyreplaced any previous directives concerningexplosion-protection that existed ona European level.On 12.12.1996, Directive 94/9/EC was convertedinto national law by the seconddecree concerning the equipment safety lawand the changes relating to the equipmentsafety law by the explosion-protectiondecree (ExVO). With this decree, the acetyldecree (AcetV), the decree on flammable liquids(VbF) and the ElexV were also broughtinto line with the European law.On 28.01.2000, Directive 1999/92/EC of theEuropean Parliament and Council, dated16.12.1999, the second important directiveconcerning explosion-protection, was publishedin the official gazette of the Europeancommunities. It contains minimum requirementsfor the improvement of the safety andhealth protection of employees potentially atrisk from explosiveatmospheres. This EC directive, also calledthe European Occupational Safety Directive,lays down the rules for operational explosion-protectionand is aimed at the operatorsof installations where explosion hazardsare to be expected.The directive was converted into nationallaw on 03.10.2002 in the “Decree on healthand safety protection relating to the provisionof work equipment and the use thereofduring operation, safety during the operationof installations requiring supervisionand the organisation of operationalsafety provisions (Operational SafetyDecree – BetrSichV). The BetrSichVreplaces the ElexV for explosion-protection.However, within the scope of the transitionalregulations, the ElexV could still be appliedfor installations that were commissionedbefore 03.10.2002.Explosion-protected plug and socketfrom the 60’s2