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]
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