Hi Robert. Here's a suggestion that may/may not be good for you . . .
I needed to have cable ingress/egress through the bottom of a telco cabinet in addition to allowing for ventilation and yet still meet UL 1950 & EN 60950. What I did was sacrifce a couple of rack units at the bottom of the cabinet and create a 'baffle'. We had a large rectangular hole in the bottom of the cabinet. We took a piece of perforated stock (approx. 63% opening) and had it angled up about 3 inches toward the rear, with the rear overlapping the closed section of the bottom by an inch (there were sides to the baffle as well). We also had a 'lip' on the bottom plate surrounding the openings so that if a 'fluid' of some sort were to hit the plate, it was contained by the lip and could not flow out of the opening. If you'd like a sketch, contact me directly. John A. Juhasz Product Qualification & Compliance Engineer Fiber Options, Inc. Bohemia, NY 11716 USA Tel: 631-419-2324 (direct) -----Original Message----- From: Robert Legg [mailto:[email protected]] Sent: Monday, November 06, 2000 8:30 AM To: IEEE EMC-PSTC Forum Cc: athome Legg Subject: Hot Flaming Oil/ applicability in 60950 Group, The ventilation hole pattern on the bottom of Telecom Rack assemblies seems to have been adopted from older standards. This was to address the safety of assemblies that might use less-than-94V-0 flammability-rated materials, including unfilled thermoplastics, resins, insulating oils, varnishes and other potential fuels. These are materials that are avoidable at the present time, without serious cost implications. The ventilation pattern permitted by the requirement is highly restrictive in its effects on ventilation, limiting the power density that is achievable without the use of unreliable air movers. Is it possible to establish safe practice, in dedicated rack assy's, when using more practical ventilation patterns? This could perhaps be achieved by reporting oxygen index limits of the components and materials enclosed. If you can't set it on fire with a flame thrower, then obviously it doesn't pose that risk to its surroundings. Rob Legg Tectrol Inc [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
