[bayindirh]

I understand the concerns you have, however I think there's a good middle ground. Would you consider the following procedure acceptable?

    - Isolate all rooms with fire-proof doors.
    - Keep fire supression system at manual.
    - When fire breaks try to contain (we have 24h watch).
    - If fails trigger fire supression system. It has 90 second delay and activated per room.
    - Leave premsises, make the calls.

Fire control and supressant control is not inside the system room. Also fire-proof doors seal the room reasonably well, so chemical doesn't move freely. Also there are better chemicals which break down faster and less harmful to everything.

BTW, We use Novec.

[pcl]

Other industries use lock-out keys when people are in harm's way. It seems like it'd be easy enough to design an oxygen-replacement system that has lock-outs that people engage whenever they need to enter the protected rooms.

https://en.wikipedia.org/wiki/Lockout–tagout

[Symbiote]

I think it's a bit more complicated, since the extinguishing system is intended to be used in emergencies.

The usual system, e.g. in a train maintenance depot:

- Employee is going to work underneath the train, which therefore must not be moved. He isolates the power supply, and locks this isolation with his padlock.

A situation in which it's suddenly very important to reconnect the power is extremely unlikely. If the employee forgets to remove his padlock, it's disruptive but not dangerous. (I've seen this system once, and when people left for the day they were supposed to lock their padlocks on a special board as part of clocking out.)

For the datacentre, if the fire alarm goes off, everyone is supposed to leave by the nearest exit -- not go back the way they came in, unlocking their padlocks to allow the extinguishing system to be used.

[okl]

"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools." -- Douglas Adams

[bayindirh]

"Any attempt to make any system idiot proof will only challenge God to make a better idiot" is the version I like more actually.