North American Network Operators Group

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Re: Building a NOC

  • From: Sean Donelan
  • Date: Sun Mar 22 17:51:11 1998

>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.

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.  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.

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.
Sean Donelan, Data Research Associates, Inc, St. Louis, MO
  Affiliation given for identification not representation