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.
Derbyshire (/ˈdɑːrbɪˌʃɪər, -ʃər/) is a county in the East Midlands of England. A substantial portion of the Peak District National Park lies within Derbyshire, containing the southern extremity of the Pennine range of hills which extend into the north of the county. The county contains part of the National Forest, and borders on Greater Manchester to the northwest, West Yorkshire to the north, South Yorkshire to the northeast, Nottinghamshire to the east, Leicestershire to the southeast, Staffordshire to the west and southwest and Cheshire also to the west. Kinder Scout, at 636 metres (2,087 ft), is the highest point in the county, whilst Trent Meadows, where the River Trent leaves Derbyshire, is its lowest point at 27 metres (89 ft).:1 The River Derwent is the county's longest river at 66 miles (106 km), and runs roughly north to south through the county. In 2003 the Ordnance Survey placed Church Flatts Farm at Coton in the Elms (near Swadlincote) as the farthest point from the sea in Great Britain.
The city of Derby is a unitary authority area, but remains part of the ceremonial county of Derbyshire. The non-metropolitan county contains 30 towns with between 10,000 and 100,000 inhabitants. There is a large amount of sparsely populated agricultural upland: 75% of the population live in 25% of the area.