This happened during initial testing, within the first 24 hours. Not good, but this is what testing is for.
Still I'm not sure if it's a good idea to have the individual units stand so close to each other, in the pictures it looks rather tight when you consider possible fires.
I assume at a certain pack scale you just have to assume fires will happen on a regular basis. You need to make sure the fire doesn't spread, doesn't pollute too much, and goes out by itself without needing emergency services etc.
At that point you can just have a dashboard with "percentage of fleet offline due to fire damage", and in your annual maintanance you replace those.
Still I'm not sure if it's a good idea to have the individual units stand so close to each other, in the pictures it looks rather tight when you consider possible fires.