Electric.ie Jan/Feb 2021

ELECTRIC.IE • The Magazine & Website for the Irish Electrical Industry • 45 Industry News the use of Ex Equipment not based on IEC standards. The procedure is effectively certification by the end user. In theory a similar route may be this available for ATEX installations but will apply Zone 2 or Zone 22 areas only since the ATEX directive prohibits certification of equipment in other zones by anyone other than Notified Bodies. The use of such equipment is restricted to items that cannot be obtained with ATEX certification. This of course does not apply to non-electrical equipment which, except combustion engines in Zone 1 and Zone 21, don’t need Notified Body Certification albeit that a dossier on them must go to the NB. Repair of ATEX equipment is covered in I.S. EN 60079-19 but the selection of used and/or repaired equipment falls within the scope of Part 14. In ATEX areas, although not mentioned in the standard, use a of second-hand and repaired equipment is restricted to those items previously carrying ATEX certification. I.S. 10101:2020 Part 14 is not a ‘standalone’ set of installation rules and must be read in addition to I.S. 10101. Working on electrical installations subject to the National Rules for Electrical Installations is considered as Controlled Works by the Commission for Regulation of Utilities and as such may only be carried out by a competent REC (Registered Electrical Contractor). Definitions of Controlled Works and REC are available on the CRU website. I.S. EN 60079 Part 17 As with Part 14, I.S. EN 60079- 17 (Part 17) Electrical installations inspection and maintenance supplements the requirements of NSAI I.S. 10101:2020 The National Rules for Electrical Installations. The primary objective of Part 17 is to ensure that the installations are maintained in a satisfactory condition for continued use within a hazardous area, either: a) regular periodic inspections, or b) continuous supervision by skilled personnel. As with the Part 14 the inspection and maintenance regimes require the personnel are suitably qualified and competent. Documentation and recording of inspection activities is an important requirement of any maintenance regime and is included in the scope of Part 17. Inspection is addressed for each type of ATEX protection with sample inspection, sheets included. The Part 17 standard addresses the complex issue of inspection and verification of unmarked equipment. That is where the certification plate or markings on explosion protected equipment is missing or illegible. Alternative methods may be used to determine traceability to the certification details of the specific equipment. Use of an equipment tag to trace the original purchase paperwork is a typical route followed by inspection teams to establish details. Where it is not possible to establish thorough documentation or inspection the certification of an item of equipment an assessment, following the procedure within Part 17 may be followed. S.R. CLC/TR 60079–32-1 Whereas Part 14 and Part 17 address the control of ignition sources associated with equipment in hazardous area and various forms of protection Ex-d, Ex-e, Ex-i etc. they do not address in detail the potential ignition due to static discharges. To assist with the control of static the NSAI has published guidance S.R. CLC/TR 60079-32-1 (Part 32) on how to avoid ignition hazards arising from static electricity. Static electricity is generated by the contact and separation of solids e.g. the movement of conveyor belts; the flow of liquids or powders, and the production of sprays. The accumulation of electrostatic charge can give rise to hazards including ignition of explosive atmospheres. It is general good practice to minimise the use of insulating materials in hazardous areas. All metal and other conductive or dissipative material should be connected to earth. Capacitance is the key parameter that needs to be controlled. The maximum allowable capacitance of isolated items depends on the ignitability of the gases, vapours and dust and should be controlled or eliminated. Isolated conductors such as metal tanks, tank structures or mobile vessels associated with liquid handling can be raised to high potentials by charges on the liquid. This can lead to spark discharges which are particularly hazardous because they can usually ignite flammable vapours. People who are isolated from earth (typically due to insulating footwear or floor) can acquire and retain an electrostatic charge. Charging mechanisms include walking, handling plastics, standing close to highly charged objects. If an electrostatically charged person touches a conductive object (e.g. pipework, structural steel, metal vessel) a spark can occur at the point of contact. Such sparks, which are unlikely to be seen, heard or even felt by the person, can cause ignitions. Sparks from a person are capable of igniting gases, vapours and even some of the more sensitive dusts. It is very important that people who may be Peat powered electricity generating station Continued on page 46>>>