Re: 130 db can knock you out and disorient you
0: Far too few organisations with these systems have done proper H&S and liability assessments.
1: Tests aren't supposed to discharge the system. Inergen bottles are around £1000 a pop to refill. If you're substituting other gasses for the discharge you still shouldn't be testing this shit in a live server room.
2: Whatever initiates discharge of the gas is supposed to shut the power off (ie, heads should park _after_ the discharge secondary alarm sounds and _before_ the discharge valve is opened), in order to remove any potential ignition sources. This is supposed to be interlocked.
3: It's possible to quieten the gas discharge noise without impeding gas flow. A H&S review needs to be implemented if it really was 130dB. The mere possibility of someone being exposed to this would expose a company to near unlimited damages claims if it actually happened.
4: You have to be extremely careful with discharge design. A data centre in Sydney had its floor tiles go several feet in the air during a discharge. Again, H&S and damage liability - especially if someone's been rendered incapable of dodging them by the sound - those tiles have sharpish edges and weigh 10-15kg apiece which means they're capable of breaking bones or more when gravity takes over.
5: Inergen systems work by reducing oxygen levels in the room to under 10% (most things won't burn in that low a concentration), which equates to about the same partial pressure as being around 5-8000 metres higher in altitude - ie, 15-20,000 foot pressure altitude and can have major cognitive effects (up to and including death if someone's got impaired cardiopulmonary function)
Note the effects listed as oxygen percentage goes down.
6: Inergen bottles sometimes leak (We've had this happen) and anyone who doesn't have oxygen level alarms in both the discharge(*) and storage areas could face unlimited liabilities if someone is affected as a result.
(*) Our leak was into the gas bottle cupboard via a popped o-ring in the meter seal and that was also the electrical switchroom
In other words, these things are EXTREMELY FUCKING DANGEROUS (so are older (mostly banned) halon systems as the gases get changed to toxic fumes when exposed to fire) and need to be treated as such.