Selection of explosion protected apparatus

Not all explosion protected electrical apparatus can be used in all zones of hazardous areas. This is because in some protection techniques the integrity 

Historically, there has been no duty on users of electrical equipment in flammable atmospheres to select equipment that has been approved or certified for use in such environments. The duty on employers, under the Health and Safety at Work Act, section 2, and the Electricity at Work Regulations, Regulation 6, has been to select equipment that is safe, so far as is reasonably practicable. However, guidance published by the HSE and others is that the best way of ensuring compliance is to use equipment that has been approved or certified against published standards by an appropriate test body. Similarly, suppliers of such equipment have been advised to ensure that their products are tested by an independent third party against the relevant standards before placing them on the market. 

In the UK, the type testing and certification work has been carried out by the Electrical Equipment Certification Services (EECS), which is part of HSE, and by SIRA Test and Certification Ltd. The Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996 will change this, because they introduce a legal requirement for compliance with the Essential Health and Safety Requirements (EHSRs) and the application of the CE mark using the applicable conformity assessment procedures, which may involve the participation of a notified body. This is a complicated area but, in summary  

The overall aim of this is to ensure both that equipment is safe and that it is 

---

Table 5.5 gives a guideline for the selection of explosion protected electrical apparatus, i.e. the appropriate choice of temperature class and group referring to the hazardous substances in the plant to be considered. Very generally Tower temperature classes do comply with the requirements for... 

Table 3.11 lists the notified bodies according to Directive 94/9/EC. It is noteworthy that competence and responsibility of a notified body may be restricted to certain types of explosion protected equipment (e.g. non-electrical apparatus only), to one group only (e.g. Group II) or to a selection of modules, e.g. to quality assurance related modules. The notified bodies are not obligated to cover the complete field of explosion protection. Nevertheless, some notified bodies cover the total range and can provide a single-stop-procedure to their clients. 

Selection in this chapter is strictly focused on safety related data in the field of explosion protection, neglecting all the other aspects like maintenance or financial considerations (this will be the objective of Chapter 9). Here, selection means the appropriate choice of electrical apparatus according to temperature class and MESG or MIC/MIC (CH4) grouping, taking into account the combustible raw materials and products in the relevant plant. 

The selection of electrical apparatus is related to the assignment of risk, e.g. Zone 0, 1 or 2 as specified in International Electrotechnical Recommendation lEC 79-10. The Zone determines the method of explosion protection required for the electrical equipment, and this affects the cost of installation. 

Table 5.5 Examples for selection and marking of firedamp-proof and explosion protected electrical apparatus according to IEC and EN Standards1...

Withdrawn) 1989 AMD 3 Code of practice for selection, installation and maintenance of electncal apparatus for use m potentially explosive atmospheres (other than mining applications or explosives processing and manufacture). Part 1 General recommendations (AMD 7871) dated 15 September 1993. Withdrawn, superseded by BS EN 60079-14 1997 (Withdrawn) 1978 AMD 1 Code of practice for selection, installation and maintenance of electncal apparatus for use m potentially explosive atmospheres (other than mining applications or explosives processing and manufacture). Part 6 Recommendations for type of protection. Increased safety (AMD 5557) dated 30 November 1989. Withdrawn, superseded by BS EN 60079... 

---