Hello Israel, I've not checked your numbers but believe the rationale is, in the case of Item 1) below: that should one come into contact with a surface at these temperatures, one will withdraw quickly and no damage is anticipated.
And, in the case of Item 2) below: should one come into contact with this surface (even though "unlikely" one will withdraw even more quickly than in the above case; again, no damage is expected. Also, one can, and in some cases "shall" mark surfaces with the IEC symbol for "Hot Surfaces" (I don't have that symbol number at hand - sorry). Regards, Art Michael Int'l Product Safety News A.E. Michael, Editor P.O. Box 1561 INT Middletown CT 06457-8061 U.S.A. Phone : (860) 344-1651 Fax : (860) 346-9066 Email : i...@connix.com Website: http://www.safetylink.com ISSN : 1040-7529 ------------------------------------------------------------------------------ On Thu, 7 Oct 1999, Israel Yeshurun wrote: > > > Dear Group Fellows > > I would like to raise the following two issues: > > 1) UL1950 / EN60950 Safety standards, Subclause 5.1 - Heating, Table > 16 part 2, specify permissible temperature rise for external surfaces of > equipment in Operator Access Area.. > For external surfaces, made of metal which may be touched, it allows > temperature rise of 45 degrees Kelvin, assuming ambient temperature of 25 > degrees Celsius it allows surface temperature of 70 degrees Celsius = 158 > degrees Fahrenheit ! > Note (4) in this table applies to external surfaces that are not likely > to be touched in normal use and measure less than 50 mm, in this case it > allows a temperature rise of 75 degrees K, that under 25 degrees C ambient > allows > 100 degrees C = 212 degrees F !! > > Now, 70 degrees C for external equipment surface that may be touched > seems pretty high to me. 100 degrees C metal surface will, I believe, cause > a burn to that part of the human body that touched it. > So maybe my interpretation is not true ?? and, can someone point > another regulatory source for Hot surface permissible temperature ? > > 2) Regarding Hot air flowing out of equipment, in UL1950 / EN60950 I > could not find a requirement or limit for the maximum permissible > temperature for it, Can someone point another regulatory source for Hot air > permissible temperature ? > > Note: The equipment I relate to is ITE or Office, but information from > Machinery standards or other sources is welcome ! > > > Many Thanks > Israel Yeshurun > > --------- > 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). > > > --------- 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).
