NationMaster - Encyclopedia: Fire alarms

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 which 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 Yamaha loudspeaker. ... 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 a safety device 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. ... This article refers to the material. ...

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. ...

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. ...

Especially in college dorms and high schools, there has been an epidemic of students pulling the fire alarm as a prank. Since this wastes the fire department's time and resources for no reason, as well as initiates a meaningless evacuation of the building, it is often a felony offense. If performed repeatedly, and at inconvenient times (e.g. late at night), such false alarms can lead to apathy among residents, causing them to take a real alarm much less seriously, or even ignore it. In epidemiology, an epidemic (from Greek epi- upon + demos people) is a disease that appears as new cases in a given human population, during a given period, at a rate that substantially exceeds what is expected, based on recent experience (the number of new cases in the population during a... 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; misdemeanors are considered to be less serious. ...

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 a horn without a strobe indoors. 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 outdated technology. However Wheelock noticed as well as other fire alarm fanatics that the horn would sometimes skip, as in cause like a skipping sound in the horn, like the typical sound of when a CD skips. Wheelock then determined the horn useless, and then started drawing up some new ideas. For example the AH multitone pictured below: To suggest a relevant news story for the main page, refer to the criteria then add your suggestion at the candidates page. ...

This horn is a two tone horn. And can be programmed to do either Code-3 Horn or Continuous Horn Sound. This can be used both outdoors and indoors. Another horn was to soon follow, the Wheelock MT. This horn is a multitone horn and can be programmed to do Continuous Horn, Code-3 Tone, Code-3 Horn, Slow Whoop, Hi-Lo, Siren, Bell, and Marchtime. This can mount onto an outdoor box or can be flush mounted to an indoor wall. 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