There are 2 sides:
- produced energy at the ignition side should heat up material to the point of ignition - the burning energy produced by the ignited material must be higher than the cooling rate by the material around it. Glue a thin piece of paper to an aluminum plate and try to ignite: no success The same piece of paper in free air will burn fiercely. Scouts use a knife to make curled wood to ignite with a lighter, they will never ignite a tree at once. Thin sheets of PE burn rather quick, where thicker sheets of same quality and size fail to burn after the test. Gases do burn so well, as the burning particles are extremely small and thus easy to heat up to the point of ignition, and are well thermally isolated (gas) from their neighbor particles. Once ignited the energy produced will be sufficient to heat up them to. I have been involved in developing a safe ESD discharge device for petrol vans. When being filled up from a petrol ship, the chances of static discharges are 100%. Add a combustible mix of petrol and air and: boooomh caused by the discharge spark. I have done investigations to the discharge levels that may create an ignition in gas air mixtures. This has lead to a failsafe disconnect clamp, able to equalize the charge levels between big vans and ships (or other storage facilities). A discharge can be initiated and controlled that does not create enough heat to ignite explosive mixtures of evaporated petrol and air Regards, Ing. Gert Gremmen, BSc g.grem...@cetest.nl <mailto:g.grem...@cetest.nl> www.cetest.nl Kiotoweg 363 3047 BG Rotterdam T 31(0)104152426 F 31(0)104154953 Before printing, think about the environment. Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens IBM Ken Verzonden: Thursday, August 16, 2012 8:41 AM Aan: Doug Powell CC: John Woodgate; EMC-PSTC@LISTSERV.IEEE.ORG Onderwerp: Re: [PSES] Ignition sources and exposure time And also in 950 with the cheesecloth, tissue paper, and wood. On Wed, Aug 15, 2012 at 3:20 PM, Doug Powell <doug...@gmail.com> wrote: Conversely, it seems possible to use a "standardized" ignitable material to evaluate ignition sources. And this has been done to some extent in IEC 610101-1 section 9.2 "Eliminating or reducing the sources of ignition within the equipment" and 9.4 "Limited-energy circuits". But the aspect of time is not considered in either case, only magnitude. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
