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
timothy.christ...@guidant.com
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:nick.willi...@conformance.co.uk]
Sent: Tuesday, December 04, 2001 3:59 PM
To: Alex McNeil
Cc: 'emc-p...@majordomo.ieee.org'
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: alex.mcn...@ingenicofortronic.com
>
>
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