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.
St Albans (/sənt ˈɔːlbənz/) is a cathedral city in Hertfordshire, England and the main urban area in the City and District of St Albans. It lies east of Hemel Hempstead and west of Hatfield, about 20 miles (32 km) north-north-west of central London, 8 miles (13 km) south-west of Welwyn Garden City and 11 miles (18 km) south-south-east of Luton. St Albans was the first major town on the old Roman road of Watling Street for travellers heading north and it became the Roman city of Verulamium. It is within the London commuter belt and the Greater London Built-up Area. With a population of 82,146, it is the fourth-most-populous settlement in Hertfordshire.