When Fire Suppression Causes a “Sonic Boom/Wave”

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I had a bit of a read about that issue you were talking about with the fire suppression system causing system outages for Channel 4 recently (article). The reports all used seem to use the phrase “sucked the air out of the room”, this would imply a vacuum, which it wouldn’t have been.

So in these fire suppression systems they essentially work by flooding the room with an inert gas (Inergen in our case I believe that is a mix of Nitrogen, Argon and Carbon Dioxide) although the exact type of gas doesn’t matter. This gas displaces the oxygen in the “air” thus removing one of the 3 key requirements of fire, extinguishing the flames without damaging equipment (by covering it in water, foam or powder).

The issue in this case for Channel 4 is that the fire suppression system released the gas with such gusto (to try to put the fire out) that at the nozzle the gas was going so fast it went super-sonic, creating a sonic boom (shock wave) that travelled through the room and vibrated equipment so violently that systems crashed, disks failed and general broken-ness occurred.

In our case we have such systems (which is fine), but what we don’t know is if the nozzles have this issue, anything built in the last 5 years shouldn’t have these nozzles that cause an issue, but before that it appears that these could be used.

Proximity of equipment to the fire suppression system is also relevant. As is if the equipment is solid state. Essentially if the kit in close by and has spinning rust hard disks it may well be at risk by the supression if the nozzle issue is present.

Where the fire suppression kit is basically right next to the racks the risk is greater if the kit has spinning rust disks which are much more susceptible to the vibrations.

https://www.datacenterdynamics.com/en/news/uk-tv-broadcasts-disrupted-over-weekend-after-fire-suppression-system-triggered/

To show you the affects of small vibrations on operation of systems see the below video, the issue caused by the sonic wave (sonic boom) is like this but worse. BEWARE of the video its a bit noisy, so turn your volume down!

Other such events: https://www.bbc.co.uk/news/technology-37337868

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