In message <20674C50F7E3794CA35FDCAD2B0E4940071AF9549A@hubmail>, dated Wed, 28 Jul 2010, Kannan Dhamodharan <kan...@india.tejasnetworks.com> writes:
>NEBS GR63 talks about Acoustic requirement for "Equipment to be Located >in Telecommunications Room (attended) - 78dB (A-weighted sound power)". > >Question: Does this level suits for all sizes of equipment? Is the spec >same for 1U and 20U rack mounted equipment? > >Reason asking this, In a rack one could install multiple 1U system than >one single large system. When adding multiple system there can be noise >addition that could exceed the standard requirement. There WILL be addition, RMS-wise. For a 20U rack of 1U units that are individually just compliant (i.e. 78 dB A), you can expect 91 dB A! You make a good point. It's something we try to deal with in EMC standards. Otherwise, one gets a situation where you can put twenty 1U systems on shelves in a room with impunity, but if you put them in a rack, you cannot achieve compliance. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I should be disillusioned, but it's not worth the effort. But I support unbloated email http://www.asciiribbon.org/ - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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 <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
