Ken, The concept that you are describing is that of intrinsic safety, i.e. there is not sufficient voltage/current/energy/power available to cause ignition of a flammable atmosphere. If the intention is to deploy this device in a potentially explosive atmosphere, even if that may only occur very infrequently, then you will need to certify the apparatus as intrinsically safe. Intrinsic safety tends not to require many tests, but rather detailed examination of the circuits by a certification body. The design usually has to employ a number of techniques to limit the current/power/energy in each part of the circuit under either single or double fault conditions depending on the certification that you require. Relevant standards that you might certify to are UL913 for the US, or EN50014 + EN50020 for Europe. EN50020 contains many detailed parameters and is a useful design manual as well as a conformance standard. You cannot self-certify for intrinsic safety, and these requirements are imposed by the NEC in the US and by the ATEX Directive 94/9/EC in the EU. Some useful links that you might visit for further information are: - http://www.siraservices.com http://www.fmglobal.com http://www.ul.com http://www.csa-international.org
Best regards, Neil R. Barker C.Eng. MIEE MIEEE MSEE Manager Compliance Engineering e2v technologies ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: +44 (0)1245 453616 Fax: +44 (0)1245 453410 e-mail: [email protected] Web: http://www.e2vtechnologies.com From: Ken Javor [mailto:[email protected]] Sent: 19 January 2004 16:28 To: [email protected] Subject: explosive atmosphere qualification List members, HERF question. I am looking at a small, low power, non-rf battery-operated device. Are there any guidelines under which one could say that the device is/is not possibly an ignition source? Max battery potential is 7.2 Volts. What I am trying to find out is, is an explosive atmosphere test a requirement, or are there conditions under which it is not necessary? Thank you. Ken Javor This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [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: http://www.ieeecommunities.org/emc-pstc
