Session 1 ‐Historical Background And Perspective

I xSession 1 ‐ Historical Background and Perspective

I xDevelopment of Technology comesfrom Tragedy

I xHistorical PerspectiveThe first hazardous location to be discovered was inearly coal mines where there was a double hazard:methane gas and coal dust. When methane was ignitedit was usually followed by a much more violent dustexplosion which is raised into a dust cloud from theinitial explosion. The first solution was to hire miners toignite the gases each day with a very long pole with aburning ember at the end. This list of volunteers soonran short so convicts from local prisons were recruited.Criminals yes, but fools they were not. Eventually,ponies were enlisted and outfitted with special saddlesthat carried a lighted candle. The ponies were dousedwith water and sent running through the mine shafts inhopes of creating only very small explosions.The first methods of protection in the mining industrywas to ventilate the mines with fresh air to effectivedilute the explosive gas to below the explosive limits.The first electrical equipment that were used were theadvent of explosion proof motors. Mine operatorsrealized that other electrical equipment could be usedby housing them in cast enclosures with tight fittingjoints.

I xOne of the first recorded Oil RefineryExplosions

I xHistorical Perspectivein 1815 Sir Humphrey Davy invented the Davy lamp, which was a kerosene lanternwith a fine brass mesh surrounding the burning wick. The mesh emitted some lightbut was fine enough to not let the flame propagate through the screen. Later,mechanical ventilation was introduced into the mines, which dispersed the methaneto the point where there was not sufficient fuel left to ignite. The method ofproviding adequate ventilation is still in use today in reducing hazards.Later, low voltage signaling bells were introduced to control the operationof the hoists. Since these operating at 12VDC, these were believed to besafe. However, in 1912 and 1913, two disastrous mine explosions weretraced to mine signaling bells. With careful design into the bells, it wasdetermined that these products could be made safe with the use of‘intrinsic safety’, hence the beginning of electrical equipment forpotentially hazardous locations.

I xHistorical PerspectiveThe first German standards, "Protection of ElectricalInstallations in Hazardous Areas", were published in1935 as guidelines for the installation of electricalequipment in hazardous areas. The product designstandards included the basic types of explosionprotection such as flameproof enclosures, oilimmersion and increased safety. The componentswere designed to be explosion protected and housedin industrial type enclosures that were weatherproof.Apparatus designed according to this standard weremarked with the symbol (Ex).In the 1960s, the European community was foundedto establish a free trade zone in Europe. To reach thisgoal, technical standards needed to be harmonized. Asa result the European Organization forElectrotechnical Standardization (CENELEC) wasestablished. This new set of European standards (EN50014 ‐ EN 50020), published in 1972, was based onthe Zone classification system as IEC 60079‐10.

I xHistory of the IECOn 15 September 1904, delegates to the InternationalElectrical Congress, being held in St. Louis, USA, adopted areport that included the following words:" steps should be taken to secure the co‐operation of thetechnical societies of the world, by the appointment of arepresentative Commission to consider the question ofthe standardization of the nomenclature and ratings ofelectrical apparatus and machinery."As a result, the IEC was officially founded in June 1906, inLondon, England, where its Central Office was set up.In 2001 the Commission published the most recent editionof the IEC Multilingual Dictionary. It is a compilation of theIEV, which now contains 18,500 electrotechnical conceptsdivided into 73 subject areas, containing full definitions inFrench and English and equivalent terms in 12 languages,including an index in German.Lord Kelvin

I xTimelines of IEC and NEC standardsKey Date to remember

I xHistory of CenelecCENELEC was established as a de‐facto associationwithout formal legal status. The daily affairs wereentrusted to the Belgian ElectrotechnicalCommittee. On 25‐26 November 1976 new Articlesof Association were signed with the intention toestablish an AISBL, French acronym for Non ProfitInternational Organization. The formal legal statuswas granted in the fall of 1978In 1977 Spain joined CENELEC, in 1978 Luxembourgparticipated formally for the first time. Greece in1980 and Iceland in 1988 also joined CENELEC.The Czech Republic became member of CENELEC inNovember 1997, followed by Malta in October 2001,Hungary and Slovakia in June 2002 and Lithuania inJune 2003. Estonia, Latvia, Poland and Sloveniajoined in January 2004. Cyprus in mid 2004. Bulgariawas the last country to join CENELEC, so far, in June2007 bringing the number of members to 30.Blue – EURed – EFTA not ratifiedGreen – EEHA membersYellow – Provisional EU

I xExplosion Protection Standards – Therole of CENELECThe explosion protection standards applicable in the European Community areproduced on the basis of the EC guidelines under the directive of CENELEC(European committee for electrotechnical standardization. Since standardizationat the international level has greatly increased in significance in the meantime asa result of the high dynamics in the IEC, CENELEC has decided to only passstandards in the so‐called parallel procedure with the IEC. This basically meansthat almost all European standards in the electrotechnical sector are beingproduced or revised as harmonized EN standards on the basis of IEC standards.These are mainly the standards of the EN 60079‐xy series for the explosionprotection sector.EN 60079‐1 : 2002Harmonized European StandardNumber of StandardDate of Standard

I xCurrent World Standards – Why weshould be interested IECEx worldwide

I xWhat are the relevant wiringregulations I should follow in theInternational World?Australia/New Zealand – AS3000:2007United Kingdom – BS7671:2008International – Many Different IEC standards

produced or revised as harmonized EN standards on the basis of IEC standards. These are mainly the standards of the EN 60079‐xy series for the explosion protection sector. Explosion Protection Standards –The role of CENELEC Harmonized European Standard Number of Standard Date of Standard EN 60079‐1 : 2002