Thanks all for your responses. š Youāve given me a few clues that I can use to start a deeper dive. šš¤
Doug Nix d...@ieee.org +1 (519) 729-5704 > On 5-Feb-19, at 15:59, MIKE SHERMAN <msherma...@comcast.net> wrote: > > I see another probably more likely interpretation of "knife edge and finger > stock" in this context. Look up a knife edge fuse on the internet. Presumably > the socket the fuse seats in would be the finger stock. > > > > Mike Sherman > > Graco Inc. > >> On February 5, 2019 at 2:34 PM "Schmidt, Mark" <markschm...@xrite.com> >> wrote: >> >> Please see test below: >> >> >> āSafety Interlocks [21 CFR 1020.40(c)(4)(i)]:Each door of a cabinet x-ray >> system shall have a minimum of two safety interlocks. One, but not both of >> the required interlocks shall be such that door opening results in physical >> disconnection of the energy supply circuit to the high-voltage generator, >> and such disconnection shall not be dependent upon any moving part other >> than the door. [Note: Safety interlock is defined in 21 CFR 1020.40(b)(11).] >> >> >> The primary door interlock should be of conventional design. The second door >> interlock must physically disconnect the energy supply circuit to the high >> voltage generator. Physical disconnection means opening the energy supply >> circuit by removing a piece of the circuit. This is usually accomplished >> with a āknife-edge and finger stockā or āplug and socketā type connection. >> It is good practice to assure the primary interlock will remove power from >> the energy supply circuit before the physical disconnection occurs. Relays, >> micro switches, and āsafety switchesā all contain moving parts and, >> therefore, cannot be used to satisfy the requirement that the physical >> disconnect interlock is "not dependent on any moving part other than the >> door."ā >> >> >> Compliance Guide for Cabinet X-Ray Systems >> https://www.fda.gov/MedicalDevices/ucm094358.htm >> <https://www.fda.gov/MedicalDevices/ucm094358.htm> >> >> >> Mark >> >> >> >> From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com] >> Sent: Tuesday, February 5, 2019 12:31 PM >> To: EMC-PSTC@LISTSERV.IEEE.ORG >> Subject: Re: [PSES] A question about FDA language and interlocking devices >> >> >> That seems to make more sense. I donāt know anything about X-ray >> requirements but the FDA requirements laser interlocks are not specific, >> only referring to āinterlocksā. >> >> -Dave >> >> >> From: MIKE SHERMAN [mailto:msherma...@comcast.net >> <mailto:msherma...@comcast.net>] >> Sent: Tuesday, February 05, 2019 12:27 PM >> To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >> Subject: Re: [PSES] A question about FDA language and interlocking devices >> >> >> Doug -- >> >> >> "knife-edge and finger stock" sounds more like the gasketing around the door >> to keep the radiation inside. I think you'll find similar gasketing on doors >> to EMC chambers. I've not heard of this term applied to interlock switches. >> >> >> Mike Sherman >> >> Graco Inc. >> >> >> On February 5, 2019 at 10:35 AM Doug Nix <d...@ieee.org >> <mailto:d...@ieee.org>> wrote: >> >> Colleagues, >> >> >> I had a question come my way yesterday that I need a little help with. >> Hereās the question: >> >> >> I have a customer that produces X-ray equipment. The FDA requires that the >> door that gives access to the X-ray source must have an interlock with a >> āknife-edge and finger stockā type connection. Also the FDA mentions that >> interlocks should be of conventional design. What is understood by >> āconventional designā? >> >> >> My reading on this requirement is that any conventional electromechanical >> interlocking device like this: >> >> <image001.jpg> >> >> will meet the basic requirements as described by the FDA as āknife-edge and >> fingerstockā connection, but I am concerned that this may not be at all what >> is meant. >> >> >> As always, any guidance you can offer will be welcomed and appreciated! >> >> >> Best, >> >> >> Doug Nix >> d...@ieee.org <mailto:d...@ieee.org> >> +1 (519) 729-5704 - ---------------------------------------------------------------- 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>
