EN 50016:2002

STANDARDElektrične naprave za potencialno eksplozivne atmosfere - Nadtlak "p"Electrical apparatus for potentially explosive atmospheres - Pressurized apparatus "p"©
Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljenoReferenčna številkaSIST EN 50016:2003(en)ICS29.260.20

EUROPEAN STANDARDEN 50016NORME EUROPÉENNEEUROPÄISCHE NORMJuly 2002CENELECEuropean Committee for Electrotechnical StandardizationComité Européen de Normalisation ElectrotechniqueEuropäisches Komitee für Elektrotechnische NormungCentral Secretariat: rue de Stassart 35, B - 1050 Brussels© 2002 CENELEC -All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.Ref. No. EN 50016:2002 EICS 29.260.20Supersedes EN 50016:1995English versionElectrical apparatus for potentially explosive atmospheres —Pressurized apparatus "p"Matériel électrique pour atmosphèresexplosibles —Surpression interne "p"Elektrische Betriebsmittel fürexplosionsgefährdete Bereiche —Überdruckkapselung "p"This European Standard was approved by CENELEC on 1999-10-01. CENELEC members are bound tocomply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving thisEuropean Standard the status of a national standard without any alteration.Up-to-date lists and bibliographical references concerning such national standards may be obtained onapplication to the Central Secretariat or to any CENELEC member.This European Standard exists in three official versions (English, French, German). A version in anyother language made by translation under the responsibility of a CENELEC member into its ownlanguage and notified to the Central Secretariat has the same status as the official versions.CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

- 3 -EN 50016:2002ContentsPage1Scope.42Normative references.43Definitions.5REQUIREMENTS FOR PRESSURIZED ENCLOSURES4Enclosures and ducting.75Temperature limits.96Safety provisions and safety devices (except for static pressurization).97Safety provisions and safety devices for static pressurization.118Supply of protective gas .12ADDITIONAL REQUIREMENTS FOR PRESSURIZED ENCLOSURES WITH CONTAINMENT SYSTEMS9Introduction .1210Release conditions.1211Design requirements for the containment system.1312Protective gas and pressurizing technique.1413Ignition capable apparatus.1614Internal hot surfaces.16VERIFICATION AND TESTS15Type verification and tests.1716Routine tests.21MARKING17Marking .21ANNEXESAnnex A (informative) Ducting of protective gas.23Annex B (informative) Infallibility test for a containment system.28Annex C (informative) Function test of surveillance circuits .29Annex D (normative) Purging and dilution tests.30

- 5 -EN 50016:2002EN 50018Electrical apparatus for potentially explosive atmospheres — Flameproofenclosures ‘d’EN 50019Electrical apparatus for potentially explosive atmospheres — Increased safety ‘e’EN 50020Electrical apparatus for potentially explosive atmospheres — Intrinsic safety ‘i’EN 50028Electrical apparatus for potentially explosive atmospheres — Encapsulation ‘m’EN 50033Electrical apparatus for potentially explosive atmospheres — Caplights for minessusceptible to firedampEN 50039Electrical apparatus for potentially explosive atmospheres — Intrinsically safesystems ‘i’EN 954SeriesSafety of machinery — Safety related parts of control systemsEN 60034-11998Rotating electrical machines — Rating and performance(IEC 60034-1:1996, modified)EN 60034-51986Rotating electrical machines — Part 5: Classification of degrees of protectionprovided by enclosures for rotating machines(IEC 60034-5:1981, modified)EN 605291991Degrees of protection provided by enclosures (IP Code)(IEC 60529:1989)HD 214 S21980Method for determining the comparative and the proof tracking indices of solidinsulating materials under moist conditions(IEC 60112:1979)3 DefinitionsFor the purposes of this European Standard, the definitions of EN 50014 and also the following apply.3.1type of protection pressurization ‘p’technique of applying a protective gas to an enclosure in order to prevent the formation of an explosiveatmosphere inside the enclosure by maintaining an overpressure against the surrounding atmosphere, andwhere necessary by using dilution3.2pressurized enclosureenclosure in which a protective gas is maintained at a pressure greater than that of the external atmosphere3.3protective gasair or inert gas used for purging and maintaining an overpressure and, if required, dilutionNOTE For the purpose of this standard inert gas means nitrogen, carbon dioxide, argon or any gas which, when mixed with oxygen in theratio 4:1 as found in air, does not make the ignition and flammability properties, such as explosive limits, more onerous.

- 7 -EN 50016:20023.13dilution areaarea in the vicinity of a source of release where the concentration of flammable gas or vapour is not dilutedto a safe concentration3.14limited releaserelease of flammable gas or vapour the maximum flow rate of which can be predicted3.15unlimited releaserelease of flammable gas or vapour the maximum flow rate of which cannot be predictedNOTE This refers to liquids which can evolve flammable gas or vapour where the rate of release cannot be predicted.3.16lower explosive limit (LEL)volume ratio of flammable gas or vapour in air below which an explosive gas atmosphere will not be formed3.17upper explosive limit (UEL)volume ratio of flammable gas or vapour in air above which an explosive gas atmosphere will not be formed3.18volume ratio (v/v)ratio of the volume of a component to the volume of the gas mixture under specified conditions oftemperature and pressureREQUIREMENTS FOR PRESSURIZED ENCLOSURES4 Enclosures and ducting4.1 GeneralThe pressurized enclosure, including any apertures for moving parts but excluding apertures for the inletand outlet of the protective gas, shall have a degree of protection in accordance with at least IP 40 ofEN 60529, or in the case of a rotating electrical machine, EN 60034-5.NOTE The degree of protection of IP 44 may be required on a coal face under humid and dusty conditions.4.2 Spark and particle barriersThe pressurized enclosure and the ducting, if any, for the protective gas shall guard against the ejection ofignition capable sparks or particles into the hazardous area (see A.2).4.3 Mechanical strengthThe pressurized enclosure, ducts if any, and their connecting parts shall withstand a pressure equal to1,5 times the maximum overpressure specified by the manufacturer for normal service with all outletsclosed with a minimum of 200 Pa.If a pressure can occur in service that can cause a deformation of the enclosure, ducts if any, or connectingparts, a safety device shall be fitted by the manufacturer to limit the maximum internal overpressure to alevel below that which could adversely affect the type of protection.

- 9 -EN 50016:20024.7 Insulating materialsFor Group I apparatus, insulating materials subjected to electrical stresses capable of causing arcs in airand which result from rated currents of more than 16 A shall have a comparative tracking index equal to orgreater than CTI 400M according to IEC 60112.5 Temperature limits5.1The pressurized enclosure shall be classified in accordance with the temperature classificationrequirements of EN 50014.The maximum surface temperature shall be determined either:a) by the temperature of the hottest point of the external surface of the enclosure; orb) by the temperature of the hottest point of the surface of the internal parts which are protected by any ofthe types of protection listed in EN 50014, and which remain energized even when the supply ofprotective gas is removed (e.g. electrical heaters).5.2If during normal service the temperature of any surface within the pressurized enclosure exceeds themaximum value permitted in EN 50014 for the temperature class, appropriate measures shall be taken toprevent, if pressurization ceases, any explosive atmosphere which may exist making contact with thatsurface before it has cooled below the permitted maximum value. This may be achieved either by thedesign and construction of the joints of the pressurized enclosure and ducts or by other means, e.g. bybringing auxiliary ventilation systems into operation or by arranging that the hot surface within the enclosureis in a gas tight or encapsulated housing.When determining the temperature for rotating electrical machines the duty type according to EN 60034-1as specified by the manufacturer shall be considered.6 Safety provisions and safety devices (except for static pressurization)6.1All safety devices used to prevent electrical apparatus protected by pressurization from causing anexplosion shall themselves not be capable of causing an explosion or shall be mounted outside thehazardous area.6.2The safety devices required by this standard form safety related parts of a control system. It is theresponsibility of the manufacturer to assess that the safety and integrity of the control system is consistentwith the level of safety required by this standard.NOTE See also EN 954, Safety of machinery — Safety related parts of a control system.6.3The safety devices shall be provided by the manufacturer of the apparatus or by the user. In the lattercase the apparatus shall be marked “X” and the description documents shall contain all necessaryinformation required by the user to ensure conformity with the requirements of this standard.NOTE An example of the information to be supplied by the manufacturer is given in annex C.6.4Where the safety related control system forms part of the apparatus a functional sequence diagramshall be provided by the manufacturer, for example truth table, state diagram, flow chart, etc., to define theaction of the control system. The sequence diagram shall clearly identify and show the operational states ofthe safety devices and ensuing actions. Functional tests shall be required to verify conformity to thediagram. These tests need only be carried out under normal atmospheric conditions unless otherwisespecified by the manufacturer.

- 11 -EN 50016:20026.10When a source of protective gas is common to a number of separate enclosures, the safety device ordevices may be common to several of these, provided that the resulting control takes account of the mostunfavourable conditions in the group of enclosures. When a common safety device is fitted, the opening ofa door or cover need not switch off all the electrical apparatus in the enclosures or initiate the alarm,provided that the following three conditions are met:a) the opening of the door or cover is preceded by disconnecting the supply to the electrical apparatus inthe particular pressurized enclosure, except electrical apparatus protected by any of the types ofprotection listed in clause 2 of this standard;b) the common safety device continues to monitor the overpressure in, and where necessary the flowthrough, all the other pressurized enclosures of the group;c) the subsequent connecting of the supply to the electrical apparatus in the particular pressurizedenclosure is preceded by the purging procedure specified in 6.6.6.11Electrical apparatus within the pressurized enclosure that may be energized when type of protectionpressurization ‘p’, is not in operation, shall be protected by a type of protection listed in clause 2 of thisstandard.7 Safety provisions and safety devices for static pressurization7.1All safety devices used to prevent electrical apparatus protected by pressurization from causing anexplosion shall themselves not be capable of causing an explosion or shall be mounted outside thehazardous area.7.2The protective gas shall be inert. The concentration of oxygen after filling with inert gas shall be lessthan 1 % by volume.7.3Internal sources of release of flammable substances are not permitted.7.4The pressurized enclosure shall be filled with inert gas in a non-hazardous area using the procedurespecified by the manufacturer.7.5Two automatic safety devices shall be provided to operate when the overpressure falls below theminimum value specified by the manufacturer. It shall be possible to check the correct operation of thedevices when the apparatus is in service. The automatic safety devices shall only be capable of being resetby the use of a tool or a key.NOTE The purpose for which the automatic safety devices are used (i.e. to disconnect power or to sound an alarm or otherwise ensuresafety of the installation) is the responsibility of the user.7.6Electrical apparatus within the pressurized enclosure that may be energized when type of protectionpressurization ‘p’ is not in operation, shall be protected by a type of protection listed in clause 2 of thisstandard.7.7The minimum level of overpressure shall be greater than the maximum pressure loss in normalservice measured over a period not less than 100 times the time necessary for the cooling of enclosedcomponents according to 6.2 of EN 50014 with a minimum of 1 h. The minimum level of overpressure shallnot be less than 50 Pa above the external pressure under the most onerous conditions specified for normalservice.NOTE If the overpressure falls below the minimum specified, it is the user’s responsibility to ensure that the pressurized enclosure isremoved to a non-hazardous area before refilling.For variable speed motors, consideration must be given to the operational speed range to determine theposition and pressurization of the minimum pressure point within the enclosure.

- 13 -EN 50016:200210.2 Limited releaseThe rate of release of the flammable substance into the pressurized enclosure shall be predictable in allconditions of containment system failure. See 11.2.10.3 Unlimited releaseThe rate of release of the flammable substance into the pressurized enclosure is not predictable. Thiscondition refers to liquids which can evolve flammable gas or vapour. See 11.3. If there may be, togetherwith the liquid, entrained oxygen, the maximum flowrate of oxygen shall be predictable.11 Design requirements for the containment systemThe design and construction of the containment system, which will determine whether leakage is likely tooccur or not, shall be based on the most onerous conditions of service specified by the manufacturer.The manufacturer shall specify the maximum inlet pressure to the containment system.Details of the design and construction of the containment system, the types and operating conditions offlammable substances it may contain and the expected release rate or rates at given locations, shall beprovided by the manufacturer, in order that the containment system can be classified into one of thecategories of 11.1, 11.2, or 11.3.11.1 Infallible containment systemAn infallible containment system shall not have any intentional leakage into the pressurized enclosure. Thiscondition is satisfied when the containment system comprises metallic, ceramic or glass, pipes, tubes orvessels which have no moving joints. Joints shall be made by welding, brazing, glass to metal sealing oreutectic methods 1).Low temperature solder alloys such as lead/tin composites are not acceptable.NOTE The manufacturer should consider carefully the requirements of clause 6 of EN 50014 in relation to a potentially fragile infalliblecontainment system. Adverse operating conditions to be agreed between manufacturer and user may include vibr
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