Hello Alex & group; For classification of hazardous areas, the definitive references are IEC 79-10 (EN60079-10)in the EU and in the US, it is NFPA no. HLH-97. However, you won't find a picture of a filling station here, with specific zone classifications. You will find the criteria and methods for classification determinations, and some common examples of areas considered to be hazardous.
I assume when your equipment is being mounted into the dispensor housing. As Mr. Woodgate pointed out, first check with the customer, check your competitors, and check similar equipment to see what the equipment in use today is rated. Next, I would call the Hazloc experts at TUV, Factory Mutual, or UL, and ask their opinion. It's easy to get carried away trying to classify a location as hazardous. For example, a Zone 2 area is defined as one where an explosive atmosphere exists only in the event of failure or spillage - sounds like the business end of a gas pump, doesn't it? However, since dispensers are located outdoors, ventilation is adequate so that the area around your automobile is not considered a Zone 2 area. Good thing, since most autos are not rated for hazardous locations. For that matter, one could apply the Zone 2 definition to a residence using natural gas - in the event of a failure, a hazardous atmosphere exists. And, there have been explosions caused by such a leak. The ignition source of these explosions is not usually an electrical fault, but rather things like smoking, or a gas pilot light, etc. Because the number of explosions caused by electrical equipment failure is small in comparison to the number of residences, requiring electrical equipment suitable for use in hazardous areas would do little to actually reduce the hazard. The best solution is to apply standards to the plumbing to make it safer, and that's what's been done. So, if your product is used in the vicinity of a petrol dispensing unit, normal use standards apply. However, if it is mounted inside the petrol dispensing unit, this may be considered a Zone 2 location, since ventilation would be poor, but the hazardous atmosphere would only exist in the event of a "plumbing" failure. I've never seen a petrol dispenser indoors - that's why your question causes me some confusion. Wouldn't there be issues with auto exhaust, spillage, and other sources of hazardous vapor build-ups that would be quite dangerous? It makes me wonder if my assumption that the product is mounted in the dispensor housing is correct. For outdoor use, your equipment may be subject to higher creepage and clearance requirements under the -950 standards, since pollution degree three may apply. If you find that your equipment needs to be rated for Zone 2 areas, the protection method to apply would be non-incendive (IEC 79-15) or encapsulation (EN50028). If you have plenty of room, use EN50028, encapsulate the unit in RTV, thereby excluding the potentially hazardous atmosphere from the electrical circuit, submit to a Notified Body and an NRTL, and be done with it. Evaluation is pretty easy if the whole thing is encapsulated. Many NB's have agreements with NRTL's in the US, making a one-stop process possible. I hope this helps. However, you did not give enough information to give a truly definitive answer. Doug Massey Lead Regulatory Engineer LXE, Inc. -----Original Message----- From: Christman, Timothy (STP) [mailto:[email protected]] Sent: Wednesday, December 05, 2001 8:27 AM To: 'Nick Williams'; Alex McNeil Cc: '[email protected]' Subject: RE: ITE equipment in Petrol Station (Gas) outlets For the US angle, the National Electric Code has an extensive discussion of Hazardous (Classified) Environments (Ch. 5?) -- it might be useful to examine those recommendations to get ideas. I'm not sure what classification applies to gas stations -- link below to OSHA has a couple good tables... http://www.osha-slc.gov/doc/outreachtraining/htmlfiles/hazloc.html Timothy J. Christman Test Engineer Tel 651.582.3141 Fax 651.582.7599 [email protected] Guidant Corporation 4100 Hamline Ave. N. St. Paul, MN 55112 USA www.guidant.com Opinions are mine, not my employer's. -----Original Message----- From: Nick Williams [mailto:[email protected]] Sent: Tuesday, December 04, 2001 3:59 PM To: Alex McNeil Cc: '[email protected]' Subject: Re: ITE equipment in Petrol Station (Gas) outlets The assessment as to whether the equipment will be installed in a hazardous area is absolutely key to this. If the installation will be in a safe area, there are no special requirements and you just treat this as any other IT application (albeit with extra environmental protection if it's appropriate). If the installation is in an area which may be subjected to flammable gases, even if only rarely, you need to consider special protection measures. For a start, the LVD does not apply so the LVD standards are not necessarily the place to start. In the UK, there are at present no formal legal requirements for flammable atmospheres (except in mines) although section 6 of the Electricity at Work Regulations has a general requirement for equipment to be suitable for the environment in which it is going to be used. The CE mark directive which applies is the ATEX directive (94/9/EC) but this is still in transition so outside the UK you have the option of complying with existing national regulations until 30 Jun 2003 (if you can find out what they are!) The requirements for electrical equipment for use in flammable atmospheres are the subject of a number of standards. These offer a number of ways of providing safe equipment, including flameproofing of enclosures, pressurisation, powder filling and intrinsic safety. Not every method can be used in every case - for example, intrinsic safety cannot be applied to high power circuits - and the standards which provide guidance on the classification of hazardous zones and on the selection of equipment (see various parts of IEC 60079 and the EN equivalents) do not permit all protection methods to be used in all locations. However, you should also be aware that for locations in the lower categories of risk, compliance with the appropriate LVD harmonised standards may be all that is required. Even though the ATEX directive is not fully in force, and is still in a state of flux in some ways, this is obviously the place to start for new designs which will last beyond the date of full implementation. There is an EU site on the ATEX directive at http://europa.eu.int/comm/enterprise/atex/index.htm where you will find information on the standards I referred to above, as well as other useful stuff. The above commentary is obviously skewed to the European angle. I know less about the requirements in the US, but I do know that essentially the same principles of classification and special protection apply. In practice, I suspect it will be difficult to avoid NRTL approval for products sold for flammable atmospheres in the US. Third party certification is also a requirement of some aspects of the ATEX Directive. I'm still learning about this, but contact me direct if you need more pointers to web sites and other sources of useful information. Regards Nick. At 11:50 +0000 4/12/2001, Alex McNeil wrote: >Hi Group, > >Can someone clarify the standards required for ITE to be placed in Petrol >Station (or Gas for our N. American friends) outlets? The ITE may be placed >indoors or outdoors at these sites. > >Normally our products are qualified for: >Europe: EN55022 + EN55024 (EMC) and EN60950 (Safety for "indoor use only" >class) >N. America: FCC Part 15, ECES-003 (EMC) and UL1950 (Safety for "indoor use >only" class) > >Petrol Station Indoors >Europe??? >N.America??? > >Petrol Station Outdoors >Europe??? >N.America??? > >Kind Regards >Alex McNeil >Principal Engineer >Tel: +44 (0)131 479 8375 >Fax: +44 (0)131 479 8321 >email: [email protected] > > >------------------------------------------- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > >To cancel your subscription, send mail to: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the >old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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