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.
South Yorkshire is a ceremonial and metropolitan county in England. It is the southernmost county in the Yorkshire and the Humber region and had a population of 1.34 million in 2011. It has an area of 1,552 square kilometres (599 sq mi) and consists of four metropolitan boroughs, Barnsley, Doncaster, Rotherham and Sheffield. South Yorkshire was created on 1 April 1974 as a result of the Local Government Act 1972. Its largest settlement is Sheffield.
Lying on the east side of the Pennines, South Yorkshire is landlocked, and borders Derbyshire to the west and south-west, West Yorkshire to the north-west, North Yorkshire to the north, the East Riding of Yorkshire to the north-east, Lincolnshire to the east and Nottinghamshire to the south-east. The Sheffield Urban Area is the tenth most populous conurbation in the United Kingdom, and dominates the western half of South Yorkshire with over half of the county's population living within it. South Yorkshire lies within the Sheffield City Region with Barnsley also being within the Leeds City Region, reflecting its geographical position midway between Yorkshire's two largest cities.
South Yorkshire County Council was abolished in 1986 and its metropolitan boroughs are now effectively unitary authorities, although the metropolitan county continues to exist in law. As a ceremonial county, South Yorkshire has a Lord Lieutenant and a High Sheriff.
South Yorkshire was created from 32 local government districts of the West Riding of Yorkshire (the administrative county and four independent county boroughs), with small areas from Derbyshire and Nottinghamshire.