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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Building a NOC
At 16:32 -0600 3/22/98, Sean Donelan wrote: >>Yes. And your consultant must know local practices as well. If you are >>building a facility in Fairfax County, Virginia (a major technology suburb >>of Washington DC), avoid, in your plans or anything the building inspector >>may see, the term "computer room." "Communications room," "network room," >>etc., all prevent the problem: if they see "computer room," they will >>demand a mainframe-style central emergency power off control, which greatly >>increases electrical wiring cost. > >The psychology of dealing with building inspectors would fill an entire >book, however this is a good example of understanding the "Why." If building >inspectors and computer room designers were logical, they would realize >why this requirement exists. They would also realize when the requirement >didn't apply. Building inspectors cover an incredibly wide range. At the low end, you really would have to delve into plant psychology. I'd say mushroom management applies at times, but I've never encountered a carnivorous mushroom with delusions of self-importance. At the other end, Emory Rodgers, the head of code compliance in Arlington County, where I live, next to Fairfax County, is a delight to work with, is an active participant in evolving building codes standards, and actually believes his department should help get the job done, safely. > >The reason why the requirement exists is computer room wiring often doesn't >meet all the safety and fire retardation requirements of normal occupancy >space because the entire computer room is treated as if it was a restricted >access area and fire retarding space. Hence the requirements for a seperate >HVAC system, fire-rated walls, and a single disconnection means (i.e. EPO) >for the entire room INCLUDING the UPS(s). On the other hand, if you followed >normal occupancy wiring practices, one would expect the space could be >treated as normal occupancy space by the building inspector. I know, that's >not how inspectors think. > >I'm not sure eliminating the EPO would really be cheaper. Its not simply >a matter of eliminating the EPO, but also replacing much of the raised >floor cabling with conduit, plenum rated cable, and other changes. In some of our local codes, they don't have any requirement for raised floor, but a great fascination with EPO. Over the years, certainly in networking areas, I have come to prefer overhead cable tray as much easier to maintain. Some urban archaeologist is going to take up a research project that investigates why certain artifacts predominate under raised floors. In various mainframe data centers I have recabled, there was always one sort of discarded item that seemed to predominate under the floor. Soda cans I could understand. Beer cans I could understand. But huge numbers of pocket combs? Razor blades? I have no clue, but only can report. In a more directly relevant way when talking about experience, people really need a high index of suspicion when untangling cables that have formed the usual tangle under a raised floor. There definitely may be a shock hazard. The worst combined hazard I ran into personally was when I started tugging on what appeared to be a black PVC cable, different, so it seemed, only in color from most other cables. As I pulled the black cable, and moved other grey ones, I began to feel it come free...and then suddenly discovered my pants were soaking wet. Ignoring my associates' rude comments about toilet training, and feeling rather at risk for electrocution, I discovered that what I had been pulling was actually a flexible drain pipe from one of the air conditioners, which had been loosely stuck into an underfloor drain. Do think of underfloor drains. They are your friend. In close to 30 years of working with computer rooms, with all the emphasis on fire protection, I've never had a computer room fire. I have, however, had several major floods related to fire protection -- a couple from water running downhill from a fire fought on a higher floor, two from burst sprinkler lines (improperly protected from freezing), and more from ordinary plumbing emergencies such as clogged and overflowing toilets. Putting equipment on high, rather than low, floors can protect it. >Not >just power cables, but also communications cables, such as the cable >connecting a disk cabinet to the CPU cabinet. And worse, from the building >inspector's point of view, having some assurance someone won't install >some cable next week without having it inspected. Another local factor that MUST be considered in certain cities, and can be far worse to deal with than building inspectors, is the local electrical union. Some are great craftsmen and incredibly helpful. But there are also cities where a union may perceive the data people running low-voltage circuits as under their jurisdiction...and cables have been known to be cut. Some of my New York friends have worked out very specific personal procedures to get on good terms with the shop steward Local 3 of the IBEW before starting a specific project. > >I realize in most offices there are more computers on people's desktops >than in the computer room. At this point I get to critize designers for >how they think. Electronic equipment is spread throughout the organization, >and the infrastructure to support it can't be limited just to the computer >room. But the building codes are always going to be playing catchup, so >designers and inspectors have their negotiating work cut out for them. > >>Wasn't thinking of MILSTDs as much as some of the DISA documents, and often >>relating to base practices. The DoD manual on grounding, bonding, and >>shielding is excellent. > >This was precisely the one I was thinking about. Since the IEEE Emerald >book was published in 1992, gounding, bounding and shielding practices >for electronic equipment have been getting updated. There is a LOT of >techno-babble floating around about computer room grounding (pun intended). >Make sure you have the updated manual. There are some old ideas about >practices such as isolated grounds for electronic equipment which are >dangerous, and have been revised/clarified in the updates. I wonder if any of the TEMPEST manuals have been declassified? THey never were at a terribly high level, and had some very nice general engineering in them. Now, full disclosure here -- I am NOT an electromagnetic compatibility person, and, when it comes to working on hardware, I tend to think of myself as an eletrostatic discharge waiting to happen. As I remember, DoD had created a special technical slot for their grounding and bonding expert, Bill Bergman if I remember correctly -- don't know if he's still around or might have retirred.
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