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]
