> 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 ?
Israel, As others have pointed out - EN 563 can be used as a "regulatory source". The standard "... applies to "hot surfaces of all products and equipment that must or can be touched during their normal use. That includes the area of safety of machinery as well as any other applications." The standard "does not apply, if a large area of the skin (approximately 10% or more of the skin of the whole body) can be in contact with the hot surface. This standard also does not apply to skin contact with more than 10% of the head or contact which could result in burns of vital areas of the face (e.g. burn resulting in the restriction of airways). In these cases severe injuries may occur, even if the surface temperature does not exceed the values specified in this standard." Does the EN 60950 consider these exceptions relevant? For your average office printer, PC, or monitor they probably aren't. There are however some fairly large equipment which are certified to this standard (mainframes?). You stated that "70 degrees C for external equipment surface that may be touched seems pretty high to me." Figure 2 of EN 563 indicates that at 70 degrees C, contact with a smooth uncoated metal surface for more than 1 second will result in a burn. For less than 1 second of contact time, there is "no reliable data" available (possible burn). Consider any forseeable problems - like someone falling onto your equipment. At 70 degrees, breaking a fall by placing your hands against the equipment could be rather unpleasant. And don't forget head contact. Regards, Matt --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
