Evidence shall show that knowledge has been acquired of safe working practices and installing and maintaining integrity of fixed gas detection equipment. All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies. KS01-EM077A Gas detection installation and maintenance Evidence shall show an understanding of gas detection installation and maintenance to an extent indicated by the following aspects: T1 Explosion-protection equipment — Ex certification schemes encompassing: Purpose and scope of certification schemes. Schemes accepted in Australia and New Zealand. Schemes commonly used in countries other than Australia and New Zealand. Processes for having equipment certified under the acceptable Ex schemes — scheme procedures; quality management requirements; conformance testing and assessment; and requirements for ongoing certification. T2 Flameproof (Ex ‘d’) explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the flameproof (Ex ‘d’) technique. (Examples of characteristics and design features are flame paths, integrity under pressure, pressure piling, and enclosure entries). Typical situations where the flameproof explosion-protection technique is used; Actions or conditions that would void the protection provided the Flameproof technique; The use of Standards in determining the requirements to which the installation of flameproof explosion-protected apparatus shall comply. T3 Increased safety (Ex ‘e’) explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the Increased safety (Ex ‘e’) technique (Examples of characteristics and design features are temperature rise, maximum power dissipation, protection devices, certified components, creepage and clearance distances, absence of sparking contacts and enclosure entries). Typical situations where the Increased safety explosion-protection technique is used; Actions or conditions that would void the protection provided the Increased safety technique; The use of Standards in determining the requirements to which the installation of Increased safety explosion-protected apparatus shall comply. T4 Non-sparking (Ex ‘n’) explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the Non-sparking (Ex ‘n’) technique (Examples of characteristics and design features are creepage and clearance distances and restricted breathing). Typical situations where the Non-sparking explosion-protection technique is used; Actions or conditions that would void the protection provided the Non-sparking technique; and The use of Standards in determining the requirements to which the installation of Non-sparking explosion-protected apparatus shall comply. T5 Intrinsic safety (Ex ‘i’) explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the Intrinsic safety (Ex ‘i’) technique (Examples of characteristics and design features are field devices, cables, safe area devices, earthing, entity versus integrated system concept, simple devices and interface devices and their parameters, segregation, infallible components, current and voltage limiting, creepage and clearance distances). Typical situations where the Intrinsic safety explosion-protection technique is used; Actions or conditions that would void the protection provided the Intrinsic safety; The use of Standards in determining the requirements to which the installation of Intrinsic safety explosion-protected apparatus shall comply. T6 Pressurization (Ex ‘p’) explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the Pressurization (Ex ‘p’) technique (Examples of characteristics and design features are exclusion and dilution; purge periods, controlled shut down, monitoring and sources of internal release). Typical situations where the pressurization explosion-protection technique is used; Actions or conditions that would void the protection provided the pressurization technique; The use of Standards in determining the requirements to which the installation of pressurization explosion-protected apparatus shall comply. T7 Enclosures for dusts (Ex ‘tD’) - explosion-protection technique encompassing: The purpose and characteristics of the design features of apparatus and circuits protected by the techniques for dusts (Examples of characteristics and design features are for enclosures; pressurization; encapsulation; and intrinsic safety). Typical situations where the each dust explosion-protection technique is used; Actions or conditions that would void the protection provided the each dust technique; The use of Standards in determining the requirements to which the installation of dust explosion-protected apparatus shall comply. T8 Common characteristics of explosion-protection techniques encompassing: The purposes of ‘temperature classification’ and ‘gas grouping/apparatus grouping’. Compliance plate markings. Limitations of non-metallic or specific alloy enclosures. The purpose of conformity and certification/approval for equipment used in hazardous areas. Environmental conditions that may impact on explosion-protection techniques. The principles and applications of other and mixed explosion-protection techniques (Other techniques include encapsulation Ex ‘m’; oil-immersion Ex ‘o’; powder-filling Ex ‘q’, ventilation Ex ‘v’ and special protection Ex ‘s’). Features and purpose of conduit seals and cable termination devices designed for use in hazardous areas (These include conduit seals and barrier and compression glands for cables with or without armouring, screening and/or drain wires). T9 Preparation to install and maintain explosion-protected equipment in hazardous areas encompassing: OHS procedures to be followed when working in a hazardous area; the significance of information provided on the certification documentation and schedules for a given item of explosion-protected equipment; the typical contents of a verification dossier and their purpose; and limitations in the use of tools and testing devices in hazardous areas. T10 The relationship between explosion-protected equipment, their certification documents and required locations given in specifications and layout drawings and/or written instructions encompassing: the purpose of markings on the compliance plate and certification documents for a given item of explosion-protected equipment; matching explosion-protected equipment with certification documents and the equipment specified for an installation; and the location the items of explosion-protected equipment for an installation from specifications and layout drawings and/or instructions. T11 Installation Standards and requirements applicable to hazardous encompassing: the wiring systems permitted and not permitted in or above hazardous areas; equipment not permitted in or above hazardous areas; the regulations and Standards to which explosion-protected equipment and wiring must be installed in a hazardous area and how these are applied; and the documentation required as a record of the installation process, including certification documentation. T12 Maintenance procedures in hazardous areas that will ensure the integrity of the explosion-protection technique encompassing: the purpose of a maintenance schedule; the purpose and extent of ‘close’, ‘sample’ and ‘periodic’ inspections; the features of each explosion-protection techniques that should be included in a maintenance schedule; the impact of environmental conditions on explosion-protected equipment, including corrosion and frequency of maintenance; the documentation requirements for recording the maintenance process and results; the use of Standards in determining the requirements with which the design of explosion-protected apparatus shall comply. T13 Cable termination types suitable for use in hazardous areas encompassing: explosion protection features of cable terminations devices. selecting compliant cable termination devices. T14 Terminating cables suitable for use in hazardous areas encompassing: installing conduit systems, where applicable, including seals to meet hazardous areas requirements. (Gases only.) terminating a cable with a barrier gland. (Gases only.) terminating a multipair, SWA, overall screened, individual screened cable into an enclosure. testing termination/connections of installed cables/circuits. T15 Techniques for the installation and maintenance of fixed gas detection equipment encompassing: Use of manufacturer’s instruction manual; for example, operating instructions, adjustments procedures and operational limitations. Installation and maintenance of Standards and/or Codes of Practice for gas detection equipment. T16 Location of fixed sample points or sensors encompassing: optimal sensing; maintainability and ease of calibration; and protection against environmental and mechanical damage. T17 Gas and vapour releases encompassing— the nature of a site; and natural and mechanical ventilation. T18 Common problems with fixed gas detectors. T19 Calibration and response checking. T20 Factors to consider in the evaluation and selection of portable and fixed gas detection equipment encompassing: Requirements for gas detection for a given situation: sources for obtaining data on physical chemistry of the gas to be detected; and sources for obtaining data on the conditions under which the gas may be present. processes of assessing the specifications of gas detection equipment against established requirements. T21 Detecting gases and vapours encompassing: apparatus capability and users’ knowledge; propagation of gases - This includes release of gas and vapours, ventilation, density, temperature and location. gases to be detected and not to be detected; intended application; environmental effects; safety when monitoring for flammable gases where personnel could be present; common properties of gases and vapours - This includes density of gases, vapours and their mixtures; effect of temperature on density; LEL and UEL of combustibles and toxicity. the differences between detecting gases and vapours - These include added complication of evaporation, condensation and temperature effects of vapours and their effect on propagation, calibration and detection, including sampling. T22 Oxygen deficiency and effects on safety encompassing: chemical reaction of oxygen with solid products; •hemical reaction of oxygen with gaseous products; and dilution of the air by displacement by some other gas or vapour. T23 Measuring principles of catalytic sensors, electrochemical sensors, infrared sensors and semi-conductor sensors encompassing: common applications; limitations and safety; interferences of other gases with the measurement; and poisoning of the sensor. NOTE: Detailed information on gas detection is given in AS/NZS 60079.29.2. |