Thanks Doug. Still a bit surprising that they use 90 or even 85 - particularly in a clinic. When that alarm goes off at that level the startle reaction means that somebody would be getting a scalpel through the spleen. I can see it on a loading dock (although we used to fill the forklifts backup beeper speaker with expanding foam to keep it quiet - college kids what-a-you going to do with them?)
>From a standards perspective this is the chart from ETSI 300 753 Equipment >Engineering (EE) Notice that an office area - 55 dB, and the power room is 83dB. I would expect the clinic to be more like the office. Telecommunication equipment room (attended) bels 7.2 (72 dB) Business area (< 4 m from desk work locations) 6.8 bells Business area (<4 m from desk work location) 6.3 bell Office (floor-standing equipment) 5.5 bels Office desktop equipment 5.0 bels Power room 8.3 bels. I think you want sound pressure rather than sound power. One being the measure of the maximum noise something can put out and the other being how loud it is at the position of interest. I think the analogy often used ins sound power is how hot a radiant heater CAN get, the other is how hot it is at a specific desk location relative to the location of the heater. They are measured completely different - for medical equipment we get requests for sound pressure occasionally expressed in dbA (a scale weighted for the response of the human ear) Try looking at Bruel and Khae http://www.bing.com/search?q=Bruel+%26+Kjaer+Instruments&FORM=QSRE1 Site. They make sound measuring equipment and they may have some app notes about the subject and maybe a more appropriate standard reference. Equipment Engineering (EE); Acoustic noise emitted by telecommunications equipment From: Doug Nix [mailto:[email protected]] Sent: Tuesday, September 04, 2012 2:19 PM To: McInturff, Gary Cc: [email protected] Subject: Re: [PSES] Buzzer loudness standard? Gary, No. " ...3dB above the maximum OSHA 8 hour day background limit @ 3 meters..." See the table in 1910.95. These are the absolute limits. Other jurisdictions, like Ontario where I live, have lower limits. 85 dB(A) TWA 8h here. Also see the ACGIH tables in the TLV's and BEI's. You'll find corroborating data. The EU is considering lower limits. Having said that, if you know that your intended use environment is quieter than that, then feel free to spec it lower, BUT that will not conform to the text of the standard originally quoted. -- Doug Nix [email protected]<mailto:[email protected]> "Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein On 4-September-2012, at 11:53, McInturff, Gary wrote: Doug, doesn't OSHA have different levels for different environments - machinery rooms where they have to have ear protection can go up to 90, but offices would certainly be less than that. I think a "quiet office" is around 55 dBA Gary From: Doug Nix [mailto:[email protected]] Sent: Tuesday, September 04, 2012 8:42 AM To: [email protected]<mailto:[email protected]> Subject: Re: [PSES] Buzzer loudness standard? Actually it does. OSHA 1910.95 tells you that the maximum time-weighted average (TWA) noise exposure for 8 hours is 90 dB(A). Based on the instrument standard you quoted, this means the buzzer must emit at least 93 dB(A). See 29 CR 1901.95, Table G-16, http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9735 Doug Nix On 4-September-2012, at 00:34, Curt McNamara wrote: We have a customer product where they desire to reference an industry standard for the loudness of a buzzer. They started with OSHA 3dB over ambient: the instrument shall have an audible indicator detected 3dB above the maximum OSHA 8 hour day background limit @ 3 meters. However that doesn't really tell us how loud it needs to be. It is used in a clinic where animals are treated. Any suggestions? Thanks! Curt - ---------------------------------------------------------------- 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 <[email protected]<mailto:[email protected]>> 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://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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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 <[email protected]<mailto:[email protected]>> 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://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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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 <[email protected]<mailto:[email protected]>> 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://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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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 <[email protected]> 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://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]>
