Q: Building a small machine room? Materials/costs/etc.

Jim Lux james.p.lux at jpl.nasa.gov
Wed Sep 17 17:23:09 EDT 2003

>   a) Thermal kill switch.  You may well want the room to be equipped
> with one.  This is a thermostatted switch that kills all room power if
> the ambient temperature exceeds some threshold, e.g. 90F.  The idea is
> that if AC fails and you don't get down there to shut down nodes fast
> enough, the kill switch kills power all at once rather than permit the
> nodes to overheat to where they physically break (as they will if they
> get hot enough).

Don't have the kill turn off ALL the power.. Only turn off the power to the
computers, but leave the lights and some receptacles alive.  More than once,
I had to stumble around in a computer room that was totally dark after
someone hit the Emergency OFF accidentally.

Bear in mind that if you have all that fancy UPS gear, the kill switch needs
to turn off the output of the UPS, not the line side.  There are actually
code requirements for some installations (mostly aimed at helping out
firement, who don't want to hit the Emergency OFF, and have the equipment
still energized).  This will typically be done by things like "shunt
trips".... your competent A&E person should know what's supposed to be done.

You also don't want the thermal kill to shut down the power to the blowers,
now, do you?

There are books on computer room design around, and while not everything is
applicable, a lot is.  It might be worth finding one at the library or
technical bookstore and browsing through it so that you can be an "educated

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