Per ASME Y14.35M - 1997 Upper case letters shall be used in sequence beginning with A and omitting letters "I,""O,""Q.""S,","X,""Z"...the revision following "Y" shall be "AA,""AB,"... followed by "BA,""BB". Revisions shall not exceed 2 characters. Initial issue of a drawing does not constitute need for a revision letter and may be identified by the use of a - (dash).
Chuck McDowell From: [email protected] [mailto:[email protected]] On Behalf Of Robert A. Macy Sent: Monday, October 17, 2005 11:35 AM To: POWELL, DOUG Cc: [email protected] Subject: Re: Excluded Revsion Letters (english) Did not see any answers to this question. Were there any? Is there a list? Too "off topic"? - Robert - On Thu, 6 Oct 2005 09:03:29 -0700 "POWELL, DOUG" <[email protected]> wrote: > All, > > The subject has come up about allowable or excluded > revision letters for > equipment or documents using the English alphabet. I > understand this is > not strictly an EMC or Safety question but I think it > does fall under > some form of compliance. > > > > I am interested to learn if any companies have standard > practices for > allowable revision letters or a simple exclusion list of > letters that > may not be used. I have had this discussion with others > before and it > seems that each of us had slightly different experiences. > One company > says I, O, Q, X are excluded from use to avoid confusion > with hand > written numbers and symbols. Mil Std 490 says: I, O, Z, > which can be > confused with numerals, shall not be used. on occasion, > I have seen the > letter "L" excluded mainly because of the old manual > typewriters using > low case "L" for numeral "1" > > > > Also, should revision letters always be upper case? > > > > The subject of double-letter revisions after using the > last > single-letter revision has been confused by some and I > have occasionally > seen a sequence like the following: > > > > AA, BB, CC, DD, etc. > > > > Obviously this is not as efficient as: > > > > AA, AB, AC AD, ..., BA, BB, BC, BD, ..., CA, > CB, CC, CD, > ..., etc. > > > Any comments or experiences are welcome. > > -Doug > > Doug Powell, Staff Engineer > Corporate Compliance Dept. > Advanced Energy Industries Inc. > Fort Collins, Co. USA - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
