What are you doing by way of detection Buzz? How will you strike a balance between early detection and unwanted discharges?
And is CO2 wise if its IT equipment? Would inergen or similar be a better bet?
Will you interface to the power supply if it discharges? Otherwise the ignition source will remain?
If I recall correctly didnt the firetrace have fusible pipes that melted and discharged the media?
Where I have looked at this in the past for a specific job we decided that early detection using HSSD equipment in the cabinet followed by manual intervention was the best balance in our case.
Having looked at the cabinets originally and taking into consideration their size (their volume is less than 2m3) it was hard to achieve an extinguishing system for such a small quantity of the agent (due to available cyllinder size etc.), which includes Inergen.
I had then came up with the solution that you have indicated using an aspirating system for early detection,with the decision then left to those investigating to discharge a portable into the risk if necessary.This wasn't acceptible to the client as his insurers have asked for an extinguishing system to protect the cabs.
The client doesn't want to use FM200 for reasons which we know and prefers to use CO2 or a nitrogen based extinguishant (Inergen is installed elsewhere along with CO2).
As far as unwanted discharge prevention goes,if I do use smoke detection as another or sole means of activation then it will be a double knock as per normal procedure.
http://www.firetrace.com/images/pdf/en-electrical.pdfhttp://www.firetrace.com/index.php?lang=en