Hi, For rack mounted equipment, UL requires all vent openings be blocked. See 4.5.1 "...Equipment intended for building-in or rack-mounting, or for incorporation in larger equipment, is tested under the most adverse actual or simulated conditions permitted in the installation instructions."
If it is not rack mounted, then they are over testing. Ned Devine Entela Inc From: Peter L. Tarver [mailto:[email protected]] Sent: Tuesday, November 25, 2003 12:32 PM To: PSTC Cc: Robert Johnson Subject: RE: Blocked ventillation testing Bob - You're quite right that the proposed test constitutes a multiple fault condition and is not supported by any UL standard that I am aware of. I have never had any agency request blocking of all equipment ventilation openings. UL HK should provide you with a rationale for this testing and the issue can certainly be referred to a higher authority within UL if there is disagreement. The only time a more onerous test method should be used is with the agreement of the customer (you or your customer), with the understanding that a noncompliant test result would not necessarily indicate noncompliance with the standard. Regards, Peter L. Tarver, PE Product Safety Manager Homologation Services Sanmina-SCI Corp. 2000 Ringwood Ave. San Jose, CA 95131-1749 V: 408-904-2081 F: 408-904-2095 M: 408-234-3529 [email protected] > From: Robert Johnson > Sent: Tuesday, November 25, 2003 7:56 AM > > I have been requested by UL-HongKong to the blocked > ventillation abnormal testing with all vents on all side > blocked simultaneously. My previous experience > has been that > one side is blocked at a time. Blocking more than > one side at > a time was considered multiple faults. If it > passes blocking > all vents at once shortens test time, but is this method > necessary? > > What is the experience of others? > > Bob Johnson > ITE Safety This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is confidential and intended only for the individual to whom or entity to which it is addressed. If you are not the intended recipient or addressee, or an employee or agent responsible for delivering this message to the addressee, you are hereby notified that any dissemination, distribution, or copying, in whole or part, of this message is strictly prohibited. If you believe that you have been sent this message in error, please do not read it. Please immediately reply to sender that you have received this message in error. Then permanently delete all copies of the message. Thank you. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
