One of the most important aspects of fire safety is recognising a developing fire emergency in a timely manner and notifying the building’s occupants and emergency response agencies. This is what fire detection and alarm systems are for. These systems can perform a variety of roles depending on the predicted fire situation, building and usage type, quantity and kind of occupants, and criticality of contents and mission. They do two things: first, they identify a developing fire using manual or automatic methods, and second, they notify building inhabitants of a fire and the need to escape. The transmission of an alert notification signal to the fire department or another emergency response group is another common function.