PowerPoint Presentation

Selection of Explosion Protected Equipment for Hazardous Locations

Pieter CoetzeeExplosion Prevention ConsultantSouth African Flameproof Association

MIE workshop 2015

ContentsIntroductionStandards Occupational Health and Safety Act. (Act 85 of 1993) & ARP 0108 Area ClassificationMarking of Ex equipmentEquipment protection levels (EPL)Gas GroupsTemperature ClassificationSelection of Explosion Protected EquipmentConclusion

IntroductionHazardous Location DefinitionAn area in which an explosive gas atmosphere or combustible dust, in the form of a cloud is present, or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of equipmentExplosion protecteddescriptive of apparatus designed and approved for use in hazardous locations in accordance with a suitable protection method, including Ex d, Ex i, Ex e, Ex p, Ex nA, Ex m and Ex q

Standards IEC/SANS 60079-14IEC/SANS 60079-17 IEC/SANS 60079-19

Three components are required for an explosion or fire to occur

OxygenFlammable SubstanceIgnition Source

Ignition Source

Possible results from explosions, incidents and firesIncludes: loss of life loss of production (Financial Impact)damage to plantsEnvironmental impact14Killed Many HospitalizedFebruary 7, 2008Sugar Involved

Explosion in Reynosa Mexico, Unofficially a leak of gas. Reynosa Mexico reported the death of 30 contractors/PEMEX workers and 42 injuredLoss of life

Act The Act shall refer to the latest issue of the ActIndustry: Mines - Mines Health and Safety Act (Act 29 of 1996)

Industry: Surface Occupational Health and Safety Act (Act 85 of 1993)To meet safety requirements as per section 44 of the OHS Act.

Acts and regulations9 EMR 9(1)Every employer or user shall identify all hazardous locations and classify them EMR 9(2)The equipment must be appropriate to the area classification EMR 9(3)The end user shall be in possession of a certificate in a form acceptable to the chief inspector - IA certificates as per ARP 0108 etc.

Electrical Machinery Regulation (EMR)Area classification is:is a method of analysing and classifying the explosive environment,takes into account gas groups and temperature classes. is to facilitate proper selection and installation of apparatus to be used safely in that environment, The basic underlying philosophy is SAFETY of life and property by quantifying the location.

STEP 1 EMR 9(1)Area Classification /Map

Objectives of Area ClassificationsAn approximate structure of the procedure is outlined in the following block diagramEMR 9(1)Area Classification /Map

Important informationArea divided into ZonesImportant information on Area Classification drawing/Map Zones/EPL (0/Ga; 1/Gb; 2/Gc for gas or 20/Da; 21Db; 22/Dc for dust) Material name (flammable substance) Flash point Ignition temperature Gas group (IIA; IIB; IIC) Temperature class for flammable substance( T1- T6) Extend of the zones ( vertical and horizontal in meters)Equipment Protection Level (EPL)The level of protection assigned to equipment based on: its risk of becoming a source of ignition, and distinguishing the differences between explosive gas atmospheres, explosive dust atmospheresThe higher the risk like zone 0, 20 - a higher level of protection is required like Ex ia; ma.The lower the risk like Zone 2, 22 - a lower level of protection is required like Ex ic, p .

EPL-ScaleEquipment Protection Level (EPL)GroupEx riskRiskZoneEPLMinimum type of protectionI (mines)energizedVery high0MaSame as GaI (mines)de-energized in presence of Ex atmosphereHigh1MbSame as GbII (gas)explosive atmosphere > 1000 hrs/yrVery high

0Gaia, maII (gas)explosive atmosphere between 10 and 1000 hrs/yrHigh

1Gbib, mb, px, py, e, o, q, dII (gas)explosive atmosphere between 1 and 10 hrs/yrLow2GcnA, ic, pzIII (dust)explosive surface > 1000 hrs/yrVery high

20Data; ia; maIII (dust)explosive surface between 10 and 1000 hrs/yrHigh

21Dbtb, ib, mb, p

III (dust)explosive surface between 10 and 10 hrs/yrLow22Dctc, ic, p

Safety Height and HazardDepth

Typical example and interpretation of an Ex markingTemperature Classification (T-Class) identifies the maximum ignition- capable surface temperature which the equipment will exhibit.(T6 =85C)Unless otherwise stated, the maximum ambient temperature to which the equipment may be subjected (and thus the maximum ambient temperature for which the T-Class will be true) is 40C

Gas Group/ Apparatus GroupThe roman II indicates surface industry (not mining). IIC is the most onerous subgroup in Group II.Equipment which is suitable for IIC will also be suitable for IIA and IIBCode letters indicate the type of protection (or types) of protection utilized by this equipment:ia indicates Intrinsic SafetyEx: is the symbol for explosion protectionThe initial E indicating conformity with European EN standards.This E is no longer used so it will not be shown on equipment which has been designed and certified since around 2007E Ex ia IIC T6 GaEquipment protection level STEP 2 Gas Groups - Ex d IIC T4 Gb

IndustryGas GroupSubstanceMIESelection of equipment Mining Industry Group IIMethane200JEquipment only suitable for mines unless it is additional approved for surface: Marked I/IICSurface IndustryGroup IIIIAPropane180 J and higherIIA; IIB and IIC certified equipment may be use in an IIA area.IIBEthylene60 J -180 JIIB and IIC certified equipment may be used in an IIB area.IICHydrogen20 J 60 JOnly IIC certified equipment is allowed to be used in an IIC area.According to SANS 60079-0, 2009, equipment group for dust is to be group III - IIIA, IIIB or IIIC for electrical equipment for places with an explosive dust atmosphere.

(The gases noted in the table are typical gases for each group.)MIE Minimum ignition energyGas Group IIC is the most severe gas groupVerification of gas groups:

The equipment requirements increase from II A to II C

STEP 3 Temperature Classes - Ex d IIC T4 GbT-ClassMaximum surface temperatureof the equipmentIgnition temperatures of combustible substancesT1450C> 450 CT2300C> 300 CT3200C> 200 CT4135C> 135 CT5100C> 100 CT685C> 85 CExplosion proof equipment, installed within the Ex area, is divided into 6 temperature classes (T1 to T6).Temperature class is not as it is often wrongly believed the operating temperature range of the equipment, but the maximum permissible surface temperature of the equipment, in relation to + 40C ambient temperature on any surface area, and should not be exceeded at any time. The maximum surface temperature must remain below the ignition temperature of the all flammable substances at all times. The equipment requirements rise from T1 to T6.Modification of Ex e enclosures

Special terminalsEx e Special terminals

HAC Temperature Classes Zone 2 IIC T1All flammable gases and vapours are placed in a gas group and a temperature class as per table.

STEP 4EMR9(2) Selection of Explosion Protected Equipment (EPE)Selection of EPE will always follow the area classificationType of protection must be suitable for the Zone/EPL of use.EPE must be covered by an approved Inspection Authority (IA) certificate issued by an ATL.Ingress protection (IP) Ratings application.Ambient temperature rating 20C to +40C if not on certification.

Different Ex Techniques TechniqueProtection TypeSymbolApplicationTypical applicationPrincipleEnergy LimitingIntrinsic SafetyEx iaEx ibEx ic Ex iaDZone oZone 1Zone 2Zone 20Instrumentation; control gearContainmentFlameproofEx dZone 1 & 2Switchgear; motors; pumpsRefined Mechanical designIncrease SafetyEx eZone 1 & 2Motors; Light fittingsRefined Mechanical designNon-sparking Ex nA (ec)Zone 2Motors; Light fittingsSegregation(Isolation)PressurizationExp; Ex pDZone 1& 2Zone 21Motors; analysers;control roomsSegregation(Isolation)Encapsulation Ex ma Ex m; Ex mDZone 0Zone 1& 2Zone 20Solenoids; fuses; relaysSand fillingEx qZone 1 & 2

Strip heaters,capacitors

EMR9(2) Selection of Explosion Protected Equipment (EPE)EPE for use in different zonesEPLsHazardous area divided into zones and EPE allowed in these zones012Zone 0 EPE - Ex ia; maGaZone 1 EPE - Ex ib; d; e; m; p; qGbZone 2 EPE - Ex ic; nA; nR; nC; Gc

Verification sheetAreaEquipmentComplianceZone1d (Gb)SuitableGas GroupIIBIICSuitable

Temperature classT4T5Suitable

Ambient temperature- 20 to 40C- 20 to 40CSuitable

Verification of EPE for hazardous locationsHazardous Area ClassificationZone 1; Gas Group IIB; Temp: T4

Equipment markingEx d IIC T5 Gb - 20 to 40C

Practical Exercise: Equipment selection and verification for hazardous locations

Equipment (EPE)Hazardous Location InformationYes/NoClassificationChemicalGas GroupTemp. ClassExample:Ex nA IIB T2Zone 1NIlluminating ParaffinIIAYT3NNComments: EPE protection type (nA) not applicable to the Classification Zone 1. Equipment (EPE) temperature class too high for the location temperature class.Ex o IIB T2Zone 1Carbon DisulphideIICNT6NEx m IIB T4Zone 2Ethyl NitriteIIAYT6NEx ib II T4Zone 0Ethylene OxideIIBYT2YEx n IIB T2Zone 1AcetyleneIICNT2YEx ib IIB T6Zone 1OctaneIIAYT3YComments: YNYNNNNNYYPractical Exercise: Memorandum

Equipment (EPE)Hazardous Location InformationYes/NoClassificationChemicalGas GroupTemp. ClassExample:Ex nA IIB T2Zone 1NIlluminating ParaffinIIAYT3NNComments: EPE protection type (nA) not applicable to the Classification Zone 1. Equipment (EPE) temperature class too high for the location temperature class.Ex o IIB T2Zone 1YCarbon DisulphideIICNT6NNComments: Gas group incorrect; temperature class too high.Ex m IIB T4Zone 2YEthyl NitriteIIAYT6NNComments: Temperature class too high.Ex ib II T4Zone 0NEthylene OxideIIBYT2YNComments: Protection type can only be used in Zones 1 and 2.Ex n IIB T2Zone 1NAcetyleneIICNT2YNComments: Protection type incorrect; Gas Group incorrect.Ex ib IIB T6Zone 1YOctaneIIAYT3YYComments: People are our most valuable asset and the industry must ensure a safe work environment as per Section 8 and Electrical Machinery regulation 9 as per the latest issue of the Occupational Health and Safety Act and Regulations (85 0f 1993).