UEEHA0022 — Determine the explosion-protection requirements to meet a specified classified hazardous area

Elements & performance criteria

Performance evidence

• selecting the correct standard/s relevant to each equipment type
• establishing the requirement for explosive atmospheres from a verification dossier
• examining flameproof Ex ‘d’, increased safety Ex ‘e’ and intrinsic safety Ex ‘i’ items of explosion- protected equipment and identifying any condition that would void the protection
• ascertaining the suitability of items of explosion-protected equipment for a given application and location from equipment standards, certification documents, equipment marking and the verification dossier.

Knowledge evidence

• methods for preventing ignition of an explosive atmosphere by an electrical source including: • exclusion method, including: • dust ignition protection type ‘tD’ or ‘t’ • pressurisation ‘p’ • encapsulated ‘m’ • oil-immersed ‘o’ • powder filling ‘q’ • explosion containment method - flameproof ‘d’ enclosure type • energy limitation, including: • intrinsic safety ‘i’ • protection type ‘n’ (e.g. non-sparking, hermetically sealed and enclosed break) • avoidance of ignition source, including: • increased safety ‘e’ • protection type ‘n’ • dilution-ventilation
• equipment and circuits protected by the flameproof (Ex ‘d’) enclosure type, including: • how flameproof-type enclosures work to provide explosion protection • features of flameproof enclosures and their function, including: • enclosure materials • flame paths • fasteners • gaskets • enclosure entries • breathing and drain devices • attributes of flameproof enclosures, including: • integrity under pressure • suitability for power switching equipment • situations where this type can be used • aspects that are vulnerable to voiding the protection due to defective installation or poor maintenance, including: • installed location • cable/conduit entries • flame paths • gaskets • fasteners • pressure piling
• equipment and circuits protected by the increased safety (Ex ‘e’) method, including: • how increased safety ‘e’ type works to provide explosion protection • features of increased safety and their function, including: • electrical connections • length of conductors within an enclosure • clearances between bare conductive parts • creepage distances • enclosure entries • ingress protection (IP) rating of enclosures • temperature limitation • certified components • attributes of increased safety including: • absence of sparking contacts • situations where this type can be used • aspects that are vulnerable to voiding the protection due to poor installation or maintenance, including: • installed location • electrical connections • clearances • preservation of temperature limitations • components
• purpose and characteristics of the design features of equipment and circuits protected by the intrinsic safety (Ex ‘i’) type, including: • how the intrinsic safety type works to provide explosion protection • features of intrinsic safety and their function, including: • associated equipment • simple devices • dependant components • infallible components, assemblies and connections • external wiring • safety barrier • attributes of intrinsic safety including: • levels of protection • ignition energy limiting • entity versus integrated system concept • situations where this type can be used • aspects that are vulnerable to voiding the protection due to poor installation or maintenance, including: • installed location • stored energy sources • insulation ratings • external wiring • methods of earthing/bonding
• purpose and characteristics of the design features of equipment and circuits protected by the type of protection ‘n’ (Ex ‘n’) technique, including: • how type of protection ‘n’ works to provide explosion protection • features of type of protection ‘n’ and their application, including: • non-sparking device ‘nA’ • range of devices and components designated ‘nC’ • energy-limited equipment ‘nL’ • associated energy-limited equipment ‘[nL]’ or ‘[Ex nL]’ • self-protected energy-limited equipment ‘nA nL’ • restricted-breathing enclosure ‘nR’ • aspects that are vulnerable to voiding the protection due to poor installation or maintenance, including: • installed location • enclosures • cable/conduit entries • external connections
• purpose and characteristics of the design features of equipment protected by the encapsulation (Ex ‘m’) technique including: • how the encapsulation type works to provide explosion protection • features of type of protection ‘m’ and their function, including: • levels of protection • temperature limitations • protective devices • situations where this type can be used • aspects that are vulnerable to voiding the protection due to poor installation or maintenance
• purpose and characteristics of the design features of equipment by the oil immersion (Ex ‘o’) technique, including: • how the oil immersion type works to provide explosion protection • features of type of protection ‘o’ and their function, including: • protective liquid • limiting temperature • immersion depth • situations where this type can be used
• purpose and characteristics of the design features of equipment protected by the powder filled (Ex ‘q’) technique, including: • how the powder-filling type works to provide explosion protection • features of the type of powder-filling ‘q’ and their function, including: • permanently sealed enclosures • enclosures intended to be opened for repair • temperature limitation • types of devices • situations where this type can be used
• purpose and characteristics of the design features of equipment and circuits protected by the pressurisation enclosure (Ex ‘p’) technique including: • how the pressurization enclosure type works to provide explosion protection • features of the type of pressurization enclosure ‘p’ and their function, including: • types of pressurisation • pressurisation system • purging • temperature limitation • safety devices • containment systems • protection types • situations where this type can be used • aspects that are vulnerable to voiding the protection due to pressure failure, including: • inadequate cable/conduit entries • poorly secured doors and covers • failed safety devices • negating purging requirements after maintenance
• purpose and characteristics of the design features of equipment protected from dust ignition by enclosure (Ex ‘t’), including: • how the dust ignition by enclosure type works to provide explosion protection • features of dust ignition by enclosure ‘t’ and their function, including: • level of protection • protective devices • gaskets • cable/conduit entries • situations where this type can be used • type protection ‘pD’ in legacy systems • aspects that are vulnerable to voiding the protection due to poor installation or maintenance, including: • cable/conduit entries • sealing • dust layer accumulation
• common characteristics of explosion-protection types, including: • criteria on which equipment protection levels (EPLs) are assigned • the purposes of ‘temperature classification’ and ‘equipment grouping’ • equipment markings (nameplate) • limitations of non-metallic or specific alloy enclosures • the purpose and use of conformity and certification/approval for equipment used in explosive atmospheres • environmental conditions that may impact on explosion-protection techniques • the principles and applications of other and mixed explosion-protection techniques
• standards to which explosion-protected equipment is required to comply, including • standards to which the protective features of each type of explosion protection are required to comply • typical content of equipment (Ex) certificates, including: • explosion-protection parameters • electrical parameters • instruction and limitation of use • verification dossiers, including: • purpose • content • Ex certification schemes to accepted standards, including • purpose and scope of certification schemes • accepted certification schemes • processes for having equipment certified under the acceptable Ex schemes, including: • scheme procedures • quality management requirements • conformance testing and assessment • requirements for ongoing certification.

Foundation skills

• Foundation skills: Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

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