A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations. Alarms can be either motorized bells or wall mountable sounders or horns. They can also be speaker strobes which sound an alarm, followed by a voice evacuation message which warns people inside the building not to use the elevators. Fire alarm sounders can be set to certain frequencies and different tones including low, medium, and high, depending on the country and manufacturer of the device. Most fire alarm systems in Europe sound like a siren with alternating frequencies. Fire alarm electronic devices are known as horns in the United States and Canada and can be either continuous or set to different codes. Fire alarm warning devices can also be set to different volume levels.
Peterborough (/ˈpiːtərbərə, -ˌbʌrə/ (About this soundlisten)) is a cathedral city in Cambridgeshire, England, with a population of 202,110 in 2017. Historically part of Northamptonshire, it is 76 miles (122 km) north of London, on the River Nene which flows into the North Sea 30 miles (48 km) to the north-east. The railway station is an important stop on the East Coast Main Line between London and Edinburgh. Peterborough is also the largest city and borough in Cambridgeshire and the East Anglia area of England.
The local topography is flat, and in some places the land lies below sea level, for example in parts of the Fens to the east of Peterborough. Human settlement in the area began before the Bronze Age, as can be seen at the Flag Fen archaeological site to the east of the current city centre, also with evidence of Roman occupation. The Anglo-Saxon period saw the establishment of a monastery, Medeshamstede, which later became Peterborough Cathedral.
The population grew rapidly after the railways arrived in the 19th century, and Peterborough became an industrial centre, particularly known for its brick manufacture. After the Second World War, growth was limited until designation as a New Town in the 1960s. Housing and population are expanding and a £1 billion regeneration of the city centre and immediately surrounding area is under way. Industrial employment has fallen since then, a significant proportion of new jobs being in financial services and distribution.