Rich,
You state: "Unfortunately, the authors of our various safety standards chose the BOGSAT* method of determining safety rather than doing research." Why don't you discuss the BOGSAT with Richard Pescatore, the Chairman of the WG7 Technical Committee; I believe he represents your company Hewlett Packard and the US ITE industry in the IEC Technical Committe for 950. You and others should be more involved in these meetings to understand how the requirements evolve. There is a lot of research involved. So before you mention the word "BOGSAT", I suggest to talk to Rich and to check how the requirement came about. OK? Peter At 17:42 07/10/99 -0700, Rich Nute wrote: > > > >Hello Israel: > > >Unfortunately, safety standards only address one of the >critical parameters, temperature, when specifying >requirements for protection against a burn injury. > >You are absolutely correct that a metal surface with a >temperature exceeding 50 C is capable of producing a burn >injury. > >There are four parameters that must be taken into account: > > 1. temperature > 2. thermal conductivity of the material > 3. thermal capacity of the material > 4 duration of contact > >One can easily touch aluminum foil at 100 C and higher for >an indefinite duration because its thermal capacity is very >low. > >One can easily touch plastic at 100 C for an indefinite >duration because its thermal conductivity is very low. > >One cannot touch a 25 mm or larger cube of aluminum at 50 C >for longer than 10 seconds without burning the skin because >its thermal conductivity and thermal capacity are high. > >There is no regulatory source that addresses all four >parameters. Instead, you must consider your training in >the field of thermodynamics, and you must consider the >literature where the burn parameters of human skin are >published. If you look, you will find published data >relating skin temperature and duration to pain and to skin >burns.** > >Unfortunately, the authors of our various safety standards >chose the BOGSAT* method of determining safety rather than >doing research. > >The requirements you mentioned are indeed inadequate. But, >you have already determined that. So, using your training >as an engineer, you can make your product safe for both the >hot surfaces and the hot air in spite of the standard. > > >Best regards, >Rich > > > >------------------------------------------------------------- > Richard Nute Product Safety Engineer > Hewlett-Packard Company Product Regulations Group > AiO Division Tel : +1 858 655 3329 > 16399 West Bernardo Drive FAX : +1 858 655 4979 > San Diego, California 92127 e-mail: ri...@sdd.hp.com >------------------------------------------------------------- > >* BOGSAT = Bunch Of Guys Sitting Around Talking. > >** Stoll, Alice M., "Thermal Properties of Human Skin related > to Nondestructive Measurement of Epidermal Thickness," > Journal of Investigative Dermatology, September, 1977, > pp. 328-332. > > > > > >--------- >This message is coming from the emc-pstc discussion list. >To cancel your subscription, send mail to majord...@ieee.org >with the single line: "unsubscribe emc-pstc" (without the >quotes). For help, send mail to ed.pr...@cubic.com, >jim_bac...@monarch.com, ri...@sdd.hp.com, or >roger.volgst...@compaq.com (the list administrators). > > > Peter Merguerian Managing Director Product Testing Division I.T.L. (Product Testing) Ltd. Hacharoshet 26, POB 211 Or Yehuda 60251, Israel Tel: 972-3-5339022 Fax: 972-3-5339019 e-mail: pmerguer...@itl.co.il website: http://www.itl.co.il THE UL 1950 SEMINAR: 12-13th October 1999 Check it out! http://www.itl.co.il/seminar.htm --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
