Statistics
High pressure cylinders operate with the air pressure over 500 pounds per square inch (psi). Low pressure cylinders operate between 40 and 499 psi.
Temperature
Nitrogen compressed cylinders maintain a temperature of 70 F to work properly.
Warning
Despite extinguishers being designed to fight fires, compressed nitrogen extinguishers may explode or rupture if exposed to high heat. Lower the temperature of a overheated extinguisher by spraying it with water.
Precautions
Although in the heat of an emergency you may not be able to find eye protection or gloves, it is best to protect yourself from the fire extinguisher chemicals as much as possible. Rinse off your skin immediately if is exposed to chemicals.