NationMaster - Encyclopedia: Fire alarm

A fire alarm is an active fire protection item. It is an electromechanical or electronic bell, klaxon, chime, horn, speaker, strobe light, or other device that warns people in a building of a possible fire or other condition requiring evacuation. Some horns can produce several different kinds of sounds, including the Code-3 temporal pattern (0.5 second pulse, 0.5 second pause, 0.5 second pulse, 0.5 second pause, 0.5 second pulse, 1.5 second pause), which was designed to be a distinct pattern used only for evacuation purposes. Other sound patterns include march time (0.25 second pulse, 0.25 second pause, repeat), a continuous tone, hi-lo (0.25 seconds alternating between two tones of differing frequency), siren (up-and-down sweep in frequency), slow-whoop (slow rising sweep upwards in frequency), and an electronic bell sound. Fire alarms are often very loud, sounding at between 90 and 100 decibels [1]. Firefighters have been known to have hearing problems after exposure to alarms over many years. Typically, when a fire alarm is sounded, emergency responders are summoned, the building is evacuated, people gather at predetermined assembly points, and a roll call is held. Download high resolution version (1704x2272, 442 KB)Wheelock MT fire alarm horn. ... Download high resolution version (1704x2272, 442 KB)Wheelock MT fire alarm horn. ... This article contains information that has not been verified and thus might not be reliable. ... Active fire protection is one of the three types of structural fire protection. ... In engineering, electromechanics combines electromagnetism and mechanics. ... The field of electronics is the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves and semiconductors. ... A bell is a simple sound-making device. ... Klaxon is a trademark for an electromechanical horn or alerting device. ... For the musical instrument, see tubular bell. ... A horn is a tapered sound-guide designed to provide an acoustic impedance match between a sound-producing device and the characteristic impedance of free space. ... Closeup of a loudspeaker driver A loudspeaker, or simply speaker, is an electromechanical transducer which converts an electrical signal into sound. ... An animation illustrating the effect of strobe light A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. ... It has been suggested that flame be merged into this article or section. ... Evacuation can have several meanings: In wilderness first aid, evacuation is the transport of a seriously injured person out of the wilderness to the nearest point an ambulance can reach to take them to the hospital, or to the nearest emergency room. ... A bell is a simple sound-making device. ... The decibel is a dimensionless unit (like percent) that is a measure of ratios on a logarithmic scale. ... It has been suggested that Firefighter Assist and Search Team be merged into this article or section. ... Evacuation can have several meanings: In wilderness first aid, evacuation is the transport of a seriously injured person out of the wilderness to the nearest point an ambulance can reach to take them to the hospital, or to the nearest emergency room. ... A roll call is the process of checking who is in attendance, usually by calling out and checking off their names. ...

Fire alarms may be triggered automatically by smoke detectors, heat detectors, sprinkler flow switches, or manually. Manual pull stations and manual call points are sometimes protected by glass which must be smashed to set off the alarm. Protective covers may also be placed over the station to help prevent false alarms. Residential ceiling-mounted smoke detector A smoke detector or smoke alarm is an active fire protection device, subject to stringent bounding, that detects airborne smoke and issues an audible alarm, thereby alerting nearby people to the danger of fire. ... Electro-pneumatic heat detector, rate of rise and fixed temperature operation. ... A Fire-Lite BG-10 manual pull station. ... A manual call point, usually referred to as an MCP within the fire protection industry, is used to allow building occupants to signal that a fire or other emergency exists within the building. ... The material definition of glass is a uniform amorphous solid material, usually produced when a suitably viscous molten material cools very rapidly to below its glass transition temperature, thereby not giving enough time for a regular crystal lattice to form. ...

The nerve center of a fire alarm system is the Fire Alarm Control Panel, where building personnel and emergency responders are able to locate the source of an alarm, pinpoint trouble or supervisory conditions, silence alarms, and reset the system. Fire alarm control panel (top) and graphic annunciator (bottom) for Potomac Hall, at James Madison University. ...

In the United States, with the advent of the Americans with Disabilities Act of 1990, fire alarm systems changed dramatically. Along with an audible alarm, fire alarm notification appliances now have strobe lights to alert the hearing-impaired. The Americans with Disabilities Act of 1990 (ADA) is the short title of United States Public Law 101-336, 104 Stat. ...

With increasing frequency, especially in college dormitories and high schools, students commonly pulling fire alarms as pranks. Since this is a misuse of the fire department's time and resources, and initiates a needless evacuation of the building, it is often a felony offense. These false alarms can lead to apathy among occupants if they occur repeatedly, causing them to dismiss the importance of alarms or ignore them completely. This article needs to be cleaned up to conform to a higher standard of quality. ... A felony, in many common law legal systems, is the term for a very serious crime, whereas misdemeanors are considered to be less serious offenses. ...

Fire alarm horn

A fire alarm horn is a device which alerts people of an emergency, and over the years improvements have been made to these horns to NFPA standards. The horns are typically not found indoors, more for outdoor use because of the loud volume. Some outdoor horns can project as much as 115 dB, so it can alert bystanders and witnesses as well as the people who are mingling outside the building. Also it is against ADA and NFPA standards to install indoors a horn without a strobe. The strobe needs to either be on the device or within a few feet. Many companies manufacture horns, including Wheelock, Edwards (now EST), Simplex, and many others. Look up Emergency in Wiktionary, the free dictionary An emergency is a situation that poses an immediate threat to human life or serious damage to property. ... Note: This page soon to be renamed National Fire Protection Association. ... Wheelock may refer to: Wheelock Inc. ... This article contains information that has not been verified and thus might not be reliable. ...

Improvements

In the beginning horns were made with a metal plate and an electric shock would be sent to a small metal strip which vibrates the plate, causing the horn to make a vibrating horn sound. The volume was normally loud and volume could be controlled by the tightness or looseness of the metal strip. Horns such as the Wheelock 34T had this technology. However Wheelock noticed that the horn would sometimes skip, causing a skipping sound in the horn, like the sound caused when a compact disc skips. Because of this malfunction, Wheelock determined the horn useless and began developing new devices. To suggest a relevant news story for the main page, refer to the criteria then add your suggestion at the candidates page. ... The Compact Disc logo was inspired by that of the previous Compact Cassette. ...

This horn is a two-tone horn, which can be programmed either as a code-3 or continuous sound horn, and can be used either outdoors or indoors. Another horn, the Wheelock MT, was also developed. This horn has multiple tones, and can be programmed as a continuous horn, a code-3 tone, a code-3 horn, a slow whoop, a hi-lo, siren, bell, or marchtime. This model is usable both indoors and outdoors. The tone is produced using a special horn, not anywhere near the vibratone horn, and produces a high pitched chirping sound. Many horns nowadays sound like this horn.

Piezo horn

Piezo horns produce a high pitched sound, similar to that of a home smoke alarm. The horns are usually applied in smaller rooms. These are not as loud as regular horns, as they sound in the range of 70 to 80 decibels.

Fire Alarm Devices

Fire alarms have devices connected to them to detect the fire/smoke or to alert the occupants of an emergency. Below is a list of common devices found on a fire alarm.

Contents

Fire alarm horn

Improvements

Piezo horn

Fire Alarm Devices

See also

Alarm manufacturers

Contents

Fire alarm horn GA_googleFillSlot("encyclopedia_square");

Improvements

Piezo horn

Fire Alarm Devices

See also

Alarm manufacturers

Fire alarm horn