Legislation, Standards and Technology. IEC TC 41 Explosion protection of electrical equipment

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1 Legislation, Standards and Technology Ex-News Information about explosion protection by Thorsten Arnhold (Editorial Board) IEC TC 41 Explosion protection of electrical equipment In October 2009 Technical Committee TC 31 held a meeting in Tel Aviv, Israel. As one of many things discussed it was decided that the period to comment on a standard status Committee Draft (CD) from then would be variable. This means that in future the previously used period to comment of 4 months, will be changed and the Convenor will have the chance to set a period to comment of at least 2 months. This will then shorten the practical handling time in the National Committees to only one month. This may be very ambitious and does involve the risk that many useful and important comments may be lost. At the end of 2008 a new working group, WG 30 was founded to deal with the topic process sealing and to establish a new standard meant to determine the technical requirements on sealing of electrical installations (electrical wiring systems) in regards to their construction, tests, installation and maintenance to avoid ingress of an explosive atmosphere. In Tel Aviv it was announced that the work of this group has progressed well and that the first publishing of a CD may be expected in The work of WG 31 hybrid mixtures has been temporarily stopped as the previous Convenor of the group resigned and a new head of the WG needs to be found. The increasingly important topic of use of explosion-protected equipment associated with extremely low ambient temperatures was addressed. An ad-hoc working group was formed and given the following task: To investigate the issues associated with very low temperatures and their impact on equipment, for example in the arctic, and related to the installation, maintenance and protection techniques in the IEC series and future non-electrical standards. Convenor of the working group is Alexander S. Zalogin from Russia. Furthermore, TC 31 started to terminate the new standard series for dust explosion protection. As a first move parts 0 and 1 have been abandoned and the specific requirements on dust explosion protection have been taken over into the respective parts of standard series The only specific type of protection for dust Dust ignition protection by enclosures is currently covered in standard IEC (WG Convenor Edward M. Briesch USA). For simplification the previous marking td has changed to a simple t and EPLs ta, tb and tc were introduced as the other levels of protection. The standard for quality management systems ISO/IEC Ed. 1.0: Explosive atmospheres Application of quality systems for electrical and non-electrical equipment, established by ISO and IEC together, was distributed to the National Committees at the beginning of The next meeting of IEC TC31 is planned in October 2010 in Seattle USA. Page 4 Ex-Magazine 2010

2 IEC : General requirements In the middle of 2009 the CDV for the 6th edition of the basic standard was published. Comments received on this were discussed at the meeting of the Maintenance Team in April 2010 in Split. The FDIS will be distributed so that issuing of the new standard may be expected at the beginning of Focus of the discussions is still on marking. With the combination of different specifications of explosion protection (Zone 0-2; gas and dust explosion protection) and the introduction of the Equipment Protection Levels analogous to the equipment categories according to ATEX Directive 94/9/EC the information contained in the marking increased dramatically, with some information being redundant (detailed information in article p. 56). Furthermore, special requirements on ventilators have been included and the specification of plastics has been extended. In particular, the previously defined voltage limits for plug connections have been dropped in this standard. The fact that the preparations for the 7 th edition have already been started clearly shows the growing importance of this basic standard for the explosion protection of electrical equipment. Publishing of the CD is expected in IEC : Flameproof enclosures In the middle of 2009 the Document for Comments (DC) for the 7 th edition of the standard was published. Comments on this up until November last year were discussed at a meeting of the Maintenance Team in Northbrook. The CD was issued in June 2010 for discussion in the National Committees. The objective is to publish the new standard in Essential innovation of this standard edition will be the additional definition of internal release sources (Containment Systems) in flameproof enclosures. These must not have a negative influence on the safety-related requirements of the type of protection in case of leaks. IEC : Pressurization Work on the 6 th edition of Pressurized enclosure was started early in Essential changes to the text of the standard are not to be expected. For this reason the CD could be published in August this year. CDV of the first edition of IEC : Pressurized rooms was sent to the National Committees in Requirements on rooms with internal release sources far exceed the previous regulations. In practice these rooms are normally used for analysis. The topic release sources of toxic gases naturally have to be dealt especially careful, e.g. by ensuring sufficient extraction around the release sources. Additionally, the term negligible releases has been included, so that under special conditions the well-proven practice of use of compression fitting may be retained. FDIS was published in June The new standard is expected at the beginning of Ex-Magazine 2010 Page 5

3 Ex-News IEC : powder filling In the period under review there was no activity with regards to powder filling. IEC : oil immersion Work on the 4 th edition is being done by a subgroup of Working Group 22 (general requirements). Objective is to make this type of protection applicable and attractive for special uses again (e.g. for power electronics). The text of the standard has been modified almost completely. At the meeting of the Working Group in April 2010 in Split a DC was passed. To allow the use of alternative liquids the name of the type of protection will be changed to liquid immersion. Basically there should be a difference between the requirements for the housings that may be opened and for the housings that may not be opened. IEC : Increased safety In 2010 work will start on the 5th edition of the standard. Amoungst other things, the use of fluorescent lamps T5 and the increased use of LEDs are meant to be discussed in this document. A suggestion from England for the respective requirements is available as a basis. The responsible Maintenance Team started the work in April IEC : Equipment for Zone 2 FDIS of the 4th edition of the standard has been published in October 2009, basically containing the following modifications: Maximum surface temperatures: These should be determined according to point of IEC For nr- and nc-devices the outer surface is taken into account. For na-devices all internal and external surfaces that may come into contact with an explosive atmosphere. Clearance and creepage distances: table 2 and footnotes shall be brought up to edition 3 (2005). Mechanical lock of a plug connection can be a part of the same or of an additional component. Vibration test of bi-pin lamp holders now relates to the test described in IEC for rough service luminaires. For electronic ballasts the asymmetric pulse test and the asymmetric power dissipation test is done at a standard ambient temperature in the laboratory (23 ±2 C). Improvements were achieved for the specification of restricted breathing. It has been determined that seals have to be fitted in such a way that simple exchange is possible (use of glues is only permitted under certain circumstances). Exemption from routine tests to determine tightness is now only possible under certain conditions. IEC : Encapsulation m 5th edition of the standard was published in IEC : Electrical equipment for Group II Zone 0 Second edition of IEC was published in In the foreword of the respective CENELEC-standard category 1 is used instead of EPL Ga. The third edition is in preparation. IEC : Risks of optical radiation Second edition of the standard is currently being prepared. The last meeting of the Maintenance Team was in March 2010 in Germany. In this edition the increasing use of LEDs will also be discussed. Page 6 Ex-Magazine 2010

4 IEC (former ): Dust ignition Protection by enclosure The first edition of this standard was published in At the beginning of 2010 a DC for the second edition was published. The following modifications are planned: The heading of the standard has been changed to equipment dust ignition protection by enclosure t. Previous test methods A and B have been combined and the requirements on the equipment has changed in such a way that the standardized test method may be passed. Types of protection ta, tb and tc are to be introduced. An over pressure test followed by an IP degree of protection test will be included. IEC : Type of protection special protection s : In November 2009 a CD of the new type of protection was published. The comment period for this ended in March A revised CD was sent to the National Committees in May The period for comments ends in September. IEC SC 31G Intrinsic Safety Sub-committee SC 31 G met in October 2009 in Tel Aviv. Work status of the three individual standards is as follows: IEC : Equipment protection by intrinsic safety In spring 2009 the Maintenance Team met in Windsor to discuss the 6th edition of the standard. The CDV that had been established was published in October The following substantial changes have been included in the draft: provisions for id (dust explosion protection) from IEC , extension of requirements on chargers and data acquisition devices that are meant to be connected to intrinsically safe equipment outside hazardous areas, clarification and extension on Ex i-moulding of components to eliminate explosive atmospheres alternative test requirements for optocouplers, inclusion of all requirements on properties from part 27: intrinsically safe systems (Annex G), a new (alternative) procedure to test power supplies with complex electronic current limiting circuits (Annex H). The result of the voting was positive, and the FDIS is expected in January IEC : intrinsically safe electrical systems In spring 2009 the MT met in Windsor. At this meeting a FDIS was developed. As close coordination with installation standard IEC became necessary, Joint Working Group 31C/31J was re-established. In the new 2nd edition of the standard, published in February 2010, the requirements on groups I, II, III are included. Type of protection ic has been introduced and the demands on multi-strand cables have been expanded. As in the standard parts for apparatus and installation the requirements on mixed circuits with concentrated capaci- tance and inductance have been defined. System requirements on intrinsically safe fieldbus systems (FISCO) from IEC have been included in this standard. Furthermore, the standard now also contains measurement procedures for the determination of electrical parameters of cables and wires. IEC SC 31J Classification and installation The next meeting of the subcommittee SC 31J Classification of Hazardous Areas and Installation Requirements is planned in October 2010 in Seattle USA. IEC : Classification of areas explosive gas atmospheres The second edition of the standard was discussed in October 2009 in Singapore. This standard no longer provides examples as different countries have their own national legislation in this field and their own set of examples published outside the standard. Again, it has been tried to make a quantification of the area classification (occurrence of potentially explosive atmosphere given in hours per year). After a lengthy discussion the suggestion has now been dismissed. A new annex will be attached to the standard, including thermo-dynamic calculation methods to determine the expansion of zones. The preparation for the third edition has been started by the Maintenance Team. Ex-Magazine 2010 Page 7

5 Ex-News IEC : Classification of areas combustible dust atmospheres The 1st edition of this standard was published in April The areas with combustible dusts are explained and dust groups IIIA, IIIB and IIIC are introduced. In Annex D the Equipment Protection Levels (EPL) are explained. The environment (Zone 22) around Zone 21 has been expanded from 1 m to 3 m. IEC : Electrical Installations design, selection and erection Work on the 5th edition of the standard was also started in Singapore. For the first time, the requirements on qualification and competence of employees that are authorized to do installation work in hazardous areas, are described in Annex F. Requirements on installations in areas with combustible dusts have been taken from the old IEC A CD was published in July this year. IEC : Inspection and maintenance The requirements on dust explosion protection with regards to inspection and maintenance have been included in the 5th edition of the standard whose development started in Furthermore, the EPLs are introduced. In this standard the demands on experts doing inspection and maintenance work is also described in a separate annex. A CD was sent to the National Committees in July IEC : Equipment repair, overhaul and reclamation In January 2009 work on the 3rd edition was started with the publication of the CD. Provision for dust explosion protection group III, and especially for pd (pressurisation for hazards from combustible dust) were integrated into the new edition. The CDV was issued in November The results of the voting was published in July The FDIS is expected this year. CENELEC TC 31 explosion protection of electrical equipment On 29th/30th October 2009, Technical Committee CLC TC31 met in Dublin/Ireland. Besides reports on activities of the subcommittees, the WGs and the ATEX Consultant, the Interface Document, Annex ZB of EN :2008 was discussed as this annex contains wrong and missing information that needed revising. The proposal concerning the Annex ZB that was developed at the meeting on 28 September 2008 in Berlin has been accepted by all countries. It was decided to issue it for voting after editorial review. The questions posed in ATEX-guideline section 10.3, related to Directive 94/9/EC, concerning the connection between the revised state of the art and observance of the essential health and safety requirements of the Directive still causes controversial discussions. In Annex ZY of the respective standard the essential modifications will be listed and evaluated, particularly with regards to the question of if the level of essential health and safety requirements should be changed. This topic was also discussed at the joint meeting of CLC/TC31 and CEN/ TC305. It was decided that a suggestion concerning the course of action for establishing Annex ZY should be made so that a compromise may be achieved in a new WG, in which, if possible, all stakeholders are involved. A new project has been initiated, to make a start on a standard installations in mines at a European level. The first steps towards achieving this have already been arranged. Mr. A.R. Banfield has been elected chairman of CLC/SC 31-9 (gas sensors). IECEx scheme In September 2009 the meeting of the management Committee (MC) and other committees of IECEx took place in Melbourne. Along with other important topics the following matters were discussed: Working Group 12 presented the complete set of documents for implementing the certification procedure of expert staff. Currently the list of questions for the examination of competent persons to be certified has been established. 250 Swiss francs have been fixed as certificate fee for replacement certificates and 200 Swiss francs for the extension of a certificate. Unfortunately no success was achieved with regards to prevention of certification of product copies. Particularly the delegation from the US raised severe legal concerns against the measures suggested in 2007 in Denver and in Paris in Page 8 Ex-Magazine 2010

6 IECEx Management Committee Meeting and Industry Symposium in 2010 in Berlin From 30th August 2010 until 3rd September 2010 this year s meeting of the IECEx- Management Committee took place in Berlin. Traditionally, on Wednesday the IECEx Industry Symposium took place. This year s event has the motto: IECEx-Conformity Assessment Service for Industry in a Globalized World. Objective of the event was to give the industry representatives of the respective host country an impression of the current status of the IECEx-system, to give information on the advantages of the system in global business and, of course, also to receive suggestions for improvement from the industry. That this objective goes hand in hand with the industry s interests can be seen from the strong interest shown in the industry symposia in 2008 in Paris and in 2009 in Melbourne, each with more than 250 participants. But this year only about 100 participants came to Berlin, possibly a later reaction on the economic crisis. This year s event took place under the auspices of the German Committee for Electrical Engineering (DKE). It started on Wednesday September 1st, 2010 at 9 a.m. in the Mövenpick Hotel in Berlin. In seven lectures different aspects of the IECEx-system has been discussed by representatives of the industry and of the regulatory authorities. Between the lectures and during the breaks there was ample opportunity for discussion. Abbreviations EPL Equipment protection level DC CD Document of Comments Questionnaire to start a new work Committee Draft 1st stage: publication of a draft standard CDV Committee Draft for Voting 2nd stage: first vote on the draft standard FDIS Final Draft International Standard 3rd stage: final vote on the draft standard Ex-Magazine 2010 Page 9