Rich, Good Response! I can't agree with you more!
Tin In a message dated 4/21/99 11:38:08 AM Pacific Daylight Time, [email protected] writes: << Hi Jeff: > If a component abnormal test generates excessive and sustained smoke > (several minutes), but does'nt breach reinforced or double insulation, nor > emit flame from the enclosure, is it considered a failure? Intuitively, it > seems like it would be, because of toxicity, but I have been unable to find > anything in the safety standards to support this. I have checked EN 60950, > EN 50178, UL 1012, and CSA C22.2 No. 107.1. For the purposes of product safety and compliance with safety standards, smoke is a "permitted" emission during fault testing. The safety issue is whether a safeguard is damaged or breached due to the heat which produced the smoke. If insulation is not damaged (as per the hi-pot test), and excessive heat or flame does not breach the enclosure (as per the cheesecloth test), then the product is considered acceptable for the purposes of product safety. Typically, product safety standards do not address the toxicity of smoke. This is because all smoke contains toxic materials. The only solution to smoke toxicity is to eliminate smoke, which means eliminating all overheating situations. Which is nearly impossible. However, any smoke from a product is likely create fear and anxiety in the mind of the user and nearby persons. Any smoke in a clean room will likely be cause for scrapping all stock in the clean room. While smoke always contains toxic materials (e.g., carbon monoxide), the concentration of the smoke (toxic material) in the volume of the room together with the room ventilation determines whether or not inhalation of the smoke is likely to cause an injury. If the volume of smoke is small compared to the volume of the room, then it is likely the concentration of toxic material will be below the TLV (threshold limit value) for that material. So, it is a good idea (for the satisfaction of your customers) to eliminate or reduce any significant smoke emissions that might occur during fault testing. Best regards, Rich ------------------------------------------------------------- Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 619 655 3329 Effective 6/12/99: +1 858 655 3329 16399 West Bernardo Drive FAX : +1 619 655 4979 Effective 6/12/99: +1 858 655 4979 San Diego, California 92127 e-mail: [email protected] ------------------------------------------------------------->> --------- 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).
