There's also an aspect where pieces of infrastructure control systems (valves etc) can freeze over externally, and some systems will have cooling system that can't run at too low temperature - Essentially, you have either not enough heat entering the cooling system and the system freezing itself, or the system cooling the heat exchange materials too much thanks to increased efficiency from cold air - freezing the system again. Happens for example when you install in a server room a too powerful HVAC system that can't "dial down" low enough to actual heat that your room gives out, freezing the HVAC heat exchanger resulting in cooling system downtime.