The rules of logic tell that
No sample shall: - have a calculated rate of flaming or glowing greater than: * 40 mm/min for samples of a thickness of 3 mm; or * 75 mm/min for samples of a thickness of less than 3 mm; or - have flaming or glowing reach the 100 mm reference mark.7.1.2 is NOT equivalent to A material classed HB shall (also see 7.1.4): a) Not have a burning rate exceeding 40 mm per minute over a 75 mm span for specimens having a thickness of 3.0 - 13 mm, or b) Not have a burning rate exceeding 75 mm per minute over a 75 mm for specimens having a thickness less than 3.0 mm, or c) Cease to burn before the 100 mm reference mark. See 7.5.1 and 7.5.9. The first proposition is of the form: "no sample shall have property A or property B" This is equivalent to "all samples shall not have property A AND not have property B". However the second proposition says "all samples shall not have property A OR not have property B". So there seems to be a glitch. Leen Mak Network Solutions Group - Standards and Industry Relations Lucent Technologies Hilversum - The Netherlands tel. +31 35 687 4143 email [email protected] >> -----Original Message----- >> From: [email protected] [mailto:[email protected]]On Behalf Of >> [email protected] >> Sent: Monday, May 01, 2006 17:03 >> To: [email protected] >> Subject: RE: Rules for HB material >> >> >> Cl. 7.1 of the 5th edition of UL94: 1997 reads: >> >> 7.1.2 A material classed HB shall (also see 7.1.4): >> a) Not have a burning rate exceeding 40 mm per minute over >> a 75 mm span for specimens having a >> thickness of 3.0 - 13 mm, or >> b) Not have a burning rate exceeding 75 mm per minute over >> a 75 mm for specimens having a >> thickness less than 3.0 mm, or >> c) Cease to burn before the 100 mm reference mark. See >> 7.5.1 and 7.5.9. >> >> John Radomski >> Schneider Automation Inc. >> >> - >> ---------------------------------------------------------------- >> 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/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/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
