Hi Brian, I’ve dealt with many related questions on my blog, machinerysafety101.com https://machinerysafety101.com/series/emergency-stop/, but not these specific questions, so I’ll answer them now. Then I’ll add them to the blog (thanks for the inspiration!).
1) How mushroom-shaped is enough? There’s no hard answer to this, but I can say this: there are three fundamental shapes for push button operators, flush, extended, and mushroom. The intent is that neither flush nor extended head operators be used for e-stop functions. More info in IEC 60947 on that. 2) Yellow background. Yellow backgrounds have to be big enough to provide clear contrast with the red button operator. A tiny ring, or just a yellow stripe around the base of the button is not enough in my opinion. Typical rings are 2x the operator nominal size, i.e., 30 mm buttons get a 60 mm ring, 22 mm buttons get a 44 mm ring. These are common practice recommendations. 3) Printing “emergency stop” on the yellow ring is not required in any jurisdiction anymore, and has been removed from NFPA 79, as well as IEC 60204-1. Just leave it off, as the red/yellow combination is internationally recognized as the sign for e-stop and emergency switching off devices. Best, Doug Nix d...@ieee.org Mobile: (519) 729-5704 Office:(519) 650-4753 > On Apr 24, 2019, at 12:49, John Woodgate <j...@woodjohn.uk> wrote: > > Mushrooms come in all sorts of shape, so the description is not very > scientific. It's only a concern if the AHJ thinks it is! > > Whether the English is acceptable is a matter for national legislation, so > there are probably several incompatible answers. > > Best wishes > John Woodgate OOO-Own Opinions Only > J M Woodgate and Associates www.woodjohn.uk > Rayleigh, Essex UK >> On 2019-04-24 17:43, Brian Kunde wrote: >> I am constantly being asked three questions about E-Stops which I cannot >> find the answers to. >> >> 1. "Mushroom Shape" is specifically called out in some standards but the >> newer style e-stop switches are becoming less and less Mushroom Shaped. If >> this a concern? >> >> 2. "Yellow Background" is getting smaller and smaller. Some small e-stop >> switches has no yellow background but has a small area on the shaft of the >> switch that is yellow. This is not technically the "background". Is this >> acceptable or is a yellow background required in addition? The size of the >> yellow area is not specified as far as I have found. >> >> 3. English text "Emergency Stop" printed on the button or on the yellow >> background ring: Is this a problem in non-english speaking countries? Do I >> have to translate (like in French for France and Canada) or are these words >> "globally acceptable"? I have been telling our engineers to choose e-stop >> switches and yellow rings without text but some manufacturers only provide >> it with the text. >> >> Thanks to all. >> >> The Other Brian >> - >> ---------------------------------------------------------------- >> 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://www.ieee-pses.org/list.html (including how to >> unsubscribe) >> List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> Scott Douglas <sdoug...@ieee.org> >> 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://www.ieee-pses.org/list.html (including how to > unsubscribe) > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <sdoug...@ieee.org> > 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://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
