Several raised floor issues in addition to earthquake need consideration before RBOCs make a transition.
- Does this mean a transition from front to back airflow to vertical airflow? Is the underfloor area the supply or return plenum? Vertical cooling is more susceptible to heating from adjacent products. - Should cable access designs change to bottom access rather than overhead? - Do they intend the underfloor area to contain power cords? NEC currently requires the use of DP cable styles for power cords, not SJT, SO, etc. which have lower flame ratings. - Are they establishing maintenance processes for the underfloor area? These are notorious for collecting unused cables, dust and trash. - Are they addressing fire extinguishing systems underfloor? Currently the only requirements are ventilation shutdown. Gas or vapor systems may be necessary. Accessibility for fire extinguishing is important. - They may wish to address equipment location relative to floor panels to maximize access and support. - The flame rating and fire load of flooring needs to be considered. All the frames and some panels I have seen are metal, but some panels are vinyl surfaced plywood. My opinion is that while central office practices of overhead cabling and defined aisles is not as esthetically pleasing, it is a safer, more practical and simpler to maintain approach. Bob Johnson ITE Safety -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Collins, Jeffrey Sent: Thursday, October 17, 2002 3:27 AM To: 'EMC-PSTC' Subject: NEBS, Raised Floor Substructure Standards Group, For those of you that attended the NEBS conference, I brought this topic up and was not able to get clear direction from the expert panel. My concern is, several of the RBOC's are deploying raised floors in their CO's. It appears there is not a consensus amongst them on the design of their floor substructure. Issues such as zone 4 seismic testing and floor loading analysis may require extensive research and additional testing. ( Test Labs won't complain about that ) Has anyone tested or provided calculations for their product in both a raised and non-raised floor environment? Have you had a customer reject your seismic data or floor loading calculations because they were not based on a raised floor environment? Would you consider seismic testing and floor loading calculations done for a raised floor vs. non-raised floor as worst case? * Have you seen a significant difference between any of the RBOC's raised floor design structure? * Have you seen a significant difference between any of the incumbent PTT carriers raised floor design structure? I found the Telcordia standard below which addresses raised floor requirements. GR-2930-CORE, Network Equipment Building System (NEBS) Raised Floor Generic Requirements for Network and Data Centers, Issue 1 Telcordia, November 1996. ABSTRACT: This document is a module of NEBSFR, FR-2063. This document presents the Telcordia view of generic engineering requirements for raised floors to be used in conjunction with GR-63, "Network Equipment Building System (NEBS) Requirements: Physical Protection," for the support of network and data center equipment. Requirements include physical strength, fire resistance, grounding and bonding, and test methods. These requirements are intended to help assure conformance with Telcordia NEBS requirements to provide the physical protection to equipment by the raised floor. Components of this product are: GR-2930-CORE All comments appreciated. Regards, Jeffrey Collins Sr. HW Engineering Manager EMC/ NEBS/ Reliability/ Safety CIENA Core Switching Division 10480 Ridgeview Court, Cupertino, CA. 95014 (408) 366-4806, Fax (408) 366-4867 [email protected] http://www.ciena.com ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ 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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
<<attachment: Robert Johnson.vcf>>
