Many facilities have generators that are tied to the fire system and will not provide electricity when there is an alarm. A diesel generator tank is designed around (sized based on) the amount of time the facility is expecting to have fuel delivered. A more central location will have small tanks, remote locations will have larger. Gas powered generators are a great option because they do not run out of fuel, although they are dependent on the gas grid. Facilities running gas generators require an automatic safety shutoff valve (electronically actuated) to be tied to the fire system to prevent explosion.