Absolutely with regard to documentation. In fact our last assessor suggested us removing it from our reports for that reason. :-)
In the case of ESD, the justification for the requirement is valid (after digging around a bit): with a difference between Denver and sea level of ~20% air breakdown potential. At the upper levels of air discharge, site to site repeatability (same ESD simulator, same DUT) would become evident. By the same token, shifts within the acceptable range of RH cause repeatability issues. With relative humidity much more is known regarding its effects on air discharge ESD testing. I'm guessing that this requirement in the standard has a sound background, but it's impact isn't well documented. Regards Dave Spencer From: Derek Walton [mailto:[email protected]] Sent: Tuesday, April 01, 2008 1:03 PM To: Spencer, David H Cc: [email protected] Subject: Re: Looking for Barometric pressure meter If the requirement is for documentation only, whats the point of doing it? Now, if it were required to adjust levels based on pressure, then it would be a worth while exercise. In reality, I doubt anyone would ever notice the difference: after all ESD is Sooooo repeatable :-) Cheers, Derek Walton Spencer, David H wrote: > > > If the ANSI ESD standard is correct, in that "Air breakdown at a fixed > distance > between arcing electrodes is approximately proportional to the > atmospheric pressure..... " and "Typically, air breakdown at sea > level will be about 40% higher than at 3000m." > > By removing it, aren't you introducing a additional undocumented source > of inconsistency? > > Dave Spencer > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of Derek > Walton > Sent: Tuesday, April 01, 2008 12:24 PM > To: Pettit, Ghery > Cc: [email protected]; [email protected] > Subject: Re: Looking for Barometric pressure meter > > More interestingly, since it seems of little significance, why not > remove the requirement altogether. One less source of inconsistency... > > Derek Walton > > Pettit, Ghery wrote: > >> Which brings up the question - if the tests may be performed at any >> pressure for which the EUT is rated, why specify a range in the first >> place? >> >> And, to my knowledge, this isn't under discussion for any of the >> documents under SC77B at this time. SC77B "owns" the 61000-4-x >> documents we're discussing here. Important enough for me to bring up >> to the US national committee? >> >> Ghery Pettit >> >> >> > > >> *From:* [email protected] [mailto:[email protected]] *On Behalf Of >> *[email protected] >> *Sent:* Tuesday, April 01, 2008 9:08 AM >> *To:* [email protected] >> *Subject:* RE: Looking for Barometric pressure meter >> >> >> In IEC61000-4-5:1995 (Line Surge Immunity), clause 8.1.1 specified a >> range of barometric pressure for testing. However, IEC61000-4-5:1995 >> Amd. 1 changes that to say: >> "... the climatic conditions in the laboratory shall be within any >> limits specified for the operation of the EUT and the test equipment >> by their respective manufacturers." >> In other words, you can do the test at any barometric pressure, so >> long as the equipment is rated for it. >> >> It wouldn't surprise me if that type of change is (or will be) >> incorporated into other IEC test documents. >> >> Pat Lawler >> EMC Engineer >> SL Power Electronics Corp. >> >> [email protected] wrote on 04/01/2008 08:34:51 AM: >> >>> In quickly checking the 61000-4-x series that are called out in >>> > CISPR > >>> 24, IEC 61000-4-2 (ESD) is the only one. Section 8.1.1 calls out the >>> acceptable climatic conditions for performing the tests, and the >>> atmospheric pressure must be between 86 kPa and 106 kPa. That's a >>> > range > >>> of 25.4 inches of Hg to 31.3 inches of Hg. As standard atmosphere at >>> sea level is 29.92 inches of Hg at 59 degrees F, and pressure drops >>> about 1 inch per 1000 feet of altitude gain, you can see that you >>> > hit > >>> the minimum pressure on a standard day at 4520 feet. Denver is at >>> > 5280 > >>> feet (one of the steps on city hall). Not sure how you can "legally" >>> perform ESD testing in EMC labs in most of Colorado. :-) >>> >>> Ghery >>> >>> -----Original Message----- >>> From: Derek Walton [mailto:[email protected]] >>> Sent: Monday, March 31, 2008 5:14 PM >>> To: Pettit, Ghery >>> Cc: [email protected]; Garnier, David S (GE Healthcare); >>> [email protected] >>> Subject: Re: Looking for Barometric pressure meter >>> >>> Hi Ghery, >>> >>> I'm curious as to which EMI test requires pressure, and has limits >>> > set > >>> for it? >>> >>> Cheers, >>> >>> Derek Walton >>> L F Research >>> >>> Pettit, Ghery wrote: >>> >>>> The information provided by the FAA and weather guessers is >>>> > pressure > >>>> corrected to sea level. It is not the actual pressure. I can get >>>> > an > >>>> altimeter setting in Denver (mile high) or Olympia (206 ft MSL) >>>> > and it > >>>> will be in the same range, even though the actual pressure in >>>> > Denver > >>>> is about 5 inches of mercury lower. This is one of my favorite >>>> questions when auditing a lab when they have a barometer on the >>>> > wall - > >>>> is that absolute pressure, or corrected to sea level? And I >>>> > usually > >>>> get blank looks. And you want to report absolute pressure. >>>> >>>> Ghery Pettit >>>> >>>> PP-ASEL >>>> >>>> >>>> > > >>>> *From:* [email protected] [mailto:[email protected]] *On Behalf Of >>>> *Cortland Richmond >>>> *Sent:* Saturday, March 29, 2008 2:44 PM >>>> *To:* Garnier, David S (GE Healthcare); [email protected] >>>> *Subject:* RE: Looking for Barometric pressure meter >>>> >>>> Why not get the air pressure from the nearest FAA control tower by >>>> radio? Critesfield Airport in Waukesha broadcasts airfield >>>> > information > >>>> that includes updated barometric pressure >>>> >>>> http://www.critesfield.com/facilities/ >>>> >>>> Cortland >>>> >>>> KAS/6 >>>> >>>> ----- Original Message ----- >>>> >>>> *From:* Garnier, David S (GE Healthcare) >>>> <mailto:[email protected]> >>>> >>>> *To: *[email protected] <mailto:[email protected]> >>>> >>>> *Sent:* 3/28/2008 10:25:25 AM >>>> >>>> *Subject:* Looking for Barometric pressure meter >>>> >>>> Hello, >>>> >>>> I am looking for advice or suggestions for the purchase of a >>>> Barometric pressure meter for our EMC lab... >>>> >>>> - ---------------------------------------------------------------- >>>> 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 >>>> >>>> >>> - >>> ---------------------------------------------------------------- >>> 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 >> >> - ---------------------------------------------------------------- >> 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 > > - > ---------------------------------------------------------------- > 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
