Dry Pipe sprinkler systems contains pressurized air and heat causes a sprinkler head to open, resulting in a loss of air pressure and then a unique dry valve will trip. Water will then fill the system and be released out of the sprinkler heads. When the sprinklers go off then the alarm will sound, and transmission will reach the central station company, causing the local Fire Department to be notified. Buildings that go unheated, like parking garages or refrigerated coolers are best suited for dry pipe. The reason for dry pipe sprinkler system is so that areas that reach 40F do not have to be concerned with water freeze within the pipes, these regions have NFPA regulations.