Fire Alarm System
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.
Derby (About this soundlisten) DAR-bee) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, of which it was traditionally the county town. Derby gained city status in 1977, and by the 2011 census its population was 248,700.
Derby was settled by Romans – who established the town of Derventio – Saxons and Vikings, who made Derby one of the Five Boroughs of the Danelaw. Initially a market town, Derby grew rapidly in the industrial era. Home to Lombe's Mill, an early British factory, Derby has a claim to be one of the birthplaces of the Industrial Revolution. It contains the southern part of the Derwent Valley Mills World Heritage Site. With the arrival of the railways in the 19th century, Derby became a centre of the British rail industry.
Derby is a centre for advanced transport manufacturing, being home to the world's second largest aero-engine manufacturer: Rolls-Royce. Bombardier Transportation are based at the Derby Litchurch Lane Works and were for many years the UK's only train manufacturers. Toyota Manufacturing UK's automobile headquarters is southwest of the city at Burnaston. To the east lies Nottingham, separated by the M1 motorway.