False alarm

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A false alarm, also called a nuisance alarm, is the deceptive or erroneous report of an emergency, causing unnecessary panic and/or bringing resources (such as emergency services) to a place where they are not needed. False alarms may occur with residential burglary alarms, smoke detectors, industrial alarms, and in signal detection theory. False alarms have the potential to divert emergency responders away from legitimate emergencies, which could ultimately lead to loss of life. In some cases, repeated false alarms in a certain area may cause occupants to develop alarm fatigue and to start ignoring most alarms, knowing that each time it will probably be false.

Smoke detector device that detects smoke, typically as an indicator of fire

A smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system, while household smoke detectors, also known as smoke alarms, generally issue a local audible or visual alarm from the detector itself.

Alarm fatigue or alert fatigue occurs when one is exposed to a large number of frequent alarms (alerts) and consequently becomes desensitized to them. Desensitization can lead to longer response times or missing important alarms. Alarm fatigue occurs in many industries, including construction and mining, healthcare, and the nuclear power industry. Like crying wolf, such false alarms rob the valid alarms of the value they were intended to add.



The term “false alarm” refers to alarm systems in many different applications being triggered by something other than the expected trigger-event. Examples of this those applications include residential burglar alarms, smoke detectors, industrial alarms, and signal detection theory. The term “false alarm” may actually be semantically incorrect in some uses. For example, a residential burglar alarm could easily be triggered by the residents of a home accidentally. The alarm is not necessarily false – it was triggered by the expected event – but it is “false” in the sense that the police should not be alerted. Due to this problem, false alarms can also be referred to as “nuisance alarms.”

Sociologist Robert Bartholomew explains that there are many negative effects of false alarms, such as "fear, havoc, disruptions to emergency services, and wasted resources." Health and safety can also be effected, as they can cause anxiety and encourage people to race toward an alarm or away from it, which can result in accidents in the panic. One more problem is the "Cry Wolf Effect", which can cause people to ignore legitimate alarms; "in the event of a real attack, subsequent warnings may be taken lightly or ignored altogether." [1]

The Boy Who Cried Wolf fable

The Boy Who Cried Wolf is one of Aesop's Fables, numbered 210 in the Perry Index. From it is derived the English idiom "to cry wolf", defined as "to give a false alarm" in Brewer's Dictionary of Phrase and Fable and glossed by the Oxford English Dictionary as meaning to make false claims, with the result that subsequent true claims are disbelieved.


Residential burglar alarms

In the United States, between 94% and 98% of all burglar alarm activations are falsely triggered. [2]

Causes and prevention

Residential burglar alarms can be caused by improper arming and disarming of the system, power outages and weak batteries, wandering pets, and unsecured doors and windows. [3] In the U.S. false alarms cost police agencies up 6.5 million personnel hours, according to the International Association of Chiefs of Police. [4] A 2002 study by the U.S. Justice Department estimated the cost of false alarms to be as high as $1.5 billion. [5] Due to this cost, many cities now require permits for burglar alarms, have enacted verified response protocols, or have introduced fines for excessive false alarms.

Improper arming and disarming of the system

This is typically caused by simple mistakes like entering the wrong passcode or letting too much time pass before entering the code. These types of false alarms can be prevented by taking more time to disarm systems, and entering a home with at least one hand free to properly disarm one's system. [3]

Untrained users

Untrained users can be anyone who may need to temporarily access one's home but is unfamiliar with one's system. Common untrained users include cleaning crews, repairmen, dog walkers, or babysitters. Better educating temporary users about a particular system can prevent them from accidentally triggering it. [3]

Power problems

If a power outage occurs on system with a weak backup battery it can cause the alarm to trigger. Preventing this type of false alarm requires alarm owner to periodically replace the backup battery. [3] Most people should have surge suppression on the AC power as well as the RJ31X area. If properly installed, the surges should bypass the system. So to help prevent a feedback loop up case ground, never install the RJ31X surge suppression inside the burglar alarm panel, and only ground it to the ground lug of the AC surge suppression. To even reduce more false alarms, tie three to four knots in the phone line between the RJ31X Surge suppression and the panel as well as three to four knots in the low voltage AC power source feeding the panel after the AC surge suppression.

A voltage drop, current rise is another issue caused by power induced by HVAC systems and other heavy loads. AC surge suppression will not stop this problem so a power monitoring device will work. Example, in a nursing home a fire alarm system keeps having problems with their power supply and at times deprogramming the panel every time the backup generator came on. In facilities like these, they are required to test generators every month. When the power goes out, that is one thing, but when the power comes on all the HVAC systems are on the same time delay and when they come on, the heavy load is what causes the voltage drop and current rise and the system will go into false alarm. There is technology like the 120HWCP20CBPLC that will monitor the power and when the voltage drops, the unit shuts off the power. The batteries inside the fire alarm will sustain the system until the power is back to normal.

Close proximity strikes by lightning will always set off the ground fault circuit and at times blow the system out if the system did not follow NEC code Art. 250.94 which illustrates how to get rid of grounding differentials. A good ground filter/notch filter will prevent a feedback loop up case ground which causes false alarms. Also surge suppression improperly installed inside a fire alarm panel will also cause a feedback loop up case ground and cause false alarms. So the surge suppression must be outside the box, in a plastic box and not grounded directly to the fire panel, rather the grounded to the ground side/line side of the in-line series three stage two tank circuit designed AC surge suppression. Parallel will not protect a fire alarm panel nor prevent false alarms. In series surge suppression will at least help one control where the surges are coming from and the ground filter will also help. Tie three to four knots in the low voltage wire between the low voltage surge suppress and the fire alarm panel, and tie at least one knot in the phase/neutral/and ground wire attached to the power supply. This will help mitigate false alarms, as well as help one's surge suppression do a better job. [6]


Some motion sensors will be triggered by pets moving around a home. This problem can be fixed by finding motion detectors that are not sensitive to infrared signatures belonging to anything less than eighty pounds, or by restricting the access of pets to rooms with motion detectors. [3]

Unsecured windows and doors

Windows and doors that are not fully closed can cause the alarm contacts to be misaligned which can result in a false alarm. In addition, if a door or window is left slightly ajar, wind may be able to blow them open which will also cause a false alarm. To prevent this from happening, door and windows should always be shut securely and locked. [3]

Smoke detectors

False alarms are also common with smoke detectors and building fire alarm systems. They occur when smoke detectors are triggered by smoke that is not a result of a dangerous fire. Smoking cigarettes, cooking at high temperatures, burning baked goods, blowing out large numbers of birthday candles, fireplaces and woodburners when used around a smoke detector can all be causes of these false alarms. Additionally, steam can trigger an ionisation smoke detector that is too sensitive, another potential cause of false alarms.

Industrial alarms

In industrial alarm management, a false alarm (nuisance alarm) could refer either to an alarm with little information content that can usually safely be eliminated, or one that could be valid but is triggered by a faulty instrument. [7] Both types are problematic because of the "cry wolf" effect described above.

Signal detection theory

In (signal) detection theory, a false alarm occurs where a non-target event exceeds the detection criterion and is identified as a target (see Constant false alarm rate).


Soviet Lieutenant Colonel Stanislav Petrov correctly assessed the 1983 Soviet nuclear false alarm incident, thus averting a nuclear war.

One tragic example of the consequences of continued false alarms was the Boland Hall Fire on January 19, 2000. Because of false fire alarms many students started ignoring the fire alarms. However, when an actual fire broke out, three students who ignored the fire alarms died and many others suffered injuries.

Likewise, after too many audible car alarms are found false, most people no longer pay attention to see whether someone is stealing a vehicle, so even certain experienced thieves may confess that these alarms would not deter them from stealing vehicles. [8]

Another notable false alarm was the Hawaii missile alert on January 13, 2018, in which an emergency message was sent incorrectly warning people in Hawaii of an incoming ballistic missile. [9]


The term "false alarm" is actually a misnomer, and is regularly replaced by the term "nuisance alarm". When a sensor operates, it is hardly false[ opinion ], and it is usually a true indication of the present state of the sensor. A more appropriate term is nuisance, indicating that the alarm activation is inconvenient, annoying, or vexatious. A prime example of this difference is burglar alarms being set off by spiders. (A spider crawling on a web in front of the motion detector appears very large to the motion detector.) [10]

False alarms could also refer to situations where one becomes startled about something that is later determined to be untrue.

See also

Related Research Articles

Alarm device type of signal (or device) that alerts people to a dangerous condition

An alarm device or system of alarm devices gives an audible, visual or other form of alarm signal about a problem or condition. Alarm devices are often outfitted with a siren.

A surge protector is an appliance or device designed to protect electrical devices from voltage spikes.

Car alarm

A car alarm is an electronic device installed in a vehicle in an attempt to discourage theft of the vehicle itself, its contents, or both. Car alarms work by emitting high-volume sound when the conditions necessary for triggering it are met. Such alarms may also cause the vehicle's headlights to flash, may notify the car's owner of the incident via a paging system, and may interrupt one or more electrical circuits necessary for the car to start. Although inexpensive to acquire and install, the effectiveness of such devices in deterring vehicle burglary or theft when their only effect is to emit sound appears to be negligible.

Arc-fault circuit interrupter a circuit breaker that protects against intermittent faults associated with arcing

An arc-fault circuit interrupter (AFCI) also known as an arc-fault detection device (AFDD) is a circuit breaker that breaks the circuit when it detects an electric arc in the circuit it protects to prevent electrical fires. An AFCI selectively distinguishes between a harmless arc, and a potentially dangerous arc.

Motion detection is the process of detecting a change in the position of an object relative to its surroundings or a change in the surroundings relative to an object. Motion detection can be achieved by either mechanical or electronic methods. When motion detection is accomplished by natural organisms, it is called motion perception.

Security alarm

A security alarm is a system designed to detect intrusion – unauthorized entry – into a building or other area. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders. Security alarms in residential areas show a correlation with decreased theft. Car alarms likewise help protect vehicles and their contents. Prisons also use security systems for control of inmates.

Fire alarm control panel

A fire alarm control panel (FACP), fire alarm control unit (FACU), or simply fire alarm panel is the controlling component of a fire alarm system. The panel receives information from devices designed to detect and report fires, monitors their operational integrity and provides for automatic control of equipment, and transmission of information necessary to prepare the facility for fire based on a predetermined sequence. The panel may also supply electrical energy to operate any associated initiating device, notification appliance, control, transmitter, or relay. There are four basic types of panels: coded panels, conventional panels, addressable panels, and multiplex systems.

Passive infrared sensor electronic sensor that measures infrared light

A passive infrared sensor is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors.

Manual fire alarm activation

Manual fire alarm activation is typically achieved through the use of a pull station or call point, which then sounds the evacuation alarm for the relevant building or zone. Manual fire alarm activation requires human intervention, as distinct from automatic fire alarm activation such as that provided through the use of heat detectors and smoke detectors. It is, however, possible for call points/pull stations to be used in conjunction with automatic detection as part of an overall fire detection and alarm system. Systems in completed buildings tend to be wired in and to include a control panel. Systems for use during construction can also be wireless or mechanical, however it is recommended by the Structural Timber Association in the UK that for timber-framed constructions, interconnecting wireless systems be used.

Carbon monoxide detector

A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas in order to prevent carbon monoxide poisoning. In the late 1990s Underwriters Laboratories changed their definition of a single station CO detector with a sound device in it to a carbon monoxide (CO) alarm. This applies to all CO safety alarms that meet UL 2034 standard; however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors.

Fire prevention is a function of many fire departments. The goal of fire prevention is to educate the public to take precautions to prevent potentially harmful fires, and be educated about surviving them. It is a proactive method of reducing emergencies and the damage caused by them. Many fire departments have a Fire Prevention Officer.

Motion detector

A motion detector is a device that detects moving objects, particularly people. Such a device is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. They form a vital component of security, automated lighting control, home control, energy efficiency and other useful systems.

Aspirating smoke detector

An aspirating smoke detector (ASD) is a system used in active fire protection, consisting of a central detection unit which draws air through a network of pipes to detect smoke. The sampling chamber is based on a nephelometer that detects the presence of smoke particles suspended in air by detecting the light scattered by them in the chamber. ASDs can typically detect smoke before it is visible to the naked eye.

Heat detector

A heat detector is a fire alarm device designed to respond when the convected thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. All heat detectors have this thermal lag. Heat detectors have two main classifications of operation, "rate-of-rise" and "fixed temperature". The heat detector is used to help in the reduction of damaged property. It is triggered when temperature increases.

Fire protection all measures, that prevent or avoid the occurrence of a fire or the spread of fire

Fire protection is the study and practice of mitigating the unwanted effects of potentially destructive fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as well as the research and development, production, testing and application of mitigating systems. In structures, be they land-based, offshore or even ships, the owners and operators are responsible to maintain their facilities in accordance with a design-basis that is rooted in laws, including the local building code and fire code, which are enforced by the Authority Having Jurisdiction.

Active fire protection integral part of fire protection; require a certain amount of motion and response in order to work

Active fire protection (AFP) is an integral part of fire protection. AFP is characterized by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.

Fire alarm system smoke alarm with mobile attached for giving signal to fire service&others

A fire alarm system has a number of devices working together to detect and warn people through visual and audio appliances when smoke, fire, carbon monoxide or other emergencies are present. 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.

A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection. Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line, and activating a fire suppression system. When used in applications such as industrial furnaces, their role is to provide confirmation that the furnace is working properly; in these cases they take no direct action beyond notifying the operator or control system. A flame detector can often respond faster and more accurately than a smoke or heat detector due to the mechanisms it uses to detect the flame.

Optical beam smoke detector

An optical beam smoke detector is a device that uses a projected beam of light to detect smoke across large areas, typically as an indicator of fire. They are used to detect fires in buildings where standard point smoke detectors would either be uneconomical or restricted for use by the height of the building. Optical beam smoke detectors are often installed in warehouses as a cost effective means of protecting large open spaces.


  1. Bartholomew, Robert (2018). "'Ballistic Missile Threat Inbound ... This is Not a Drill': The Formidable Threat of False Alarms". Skeptical Inquirer. Committee for Skeptical Inquiry. 42 (3): 5.
  2. Sampson, Rana; United States Department of Justice, Office of Community Oriented Policing Services (2007). False Burglar Alarms (Technical report). USDOJ. 2.
  3. 1 2 3 4 5 6 "False Alarm Prevention: The Cost and the Solution".
  4. "False Alarms: Keep Your Pet From Triggering Your Burglar Alarm".
  5. "False Burglar Alarms" (PDF).
  6. Nec Code Book Art. 250.94
  7. "A Prototype Multiview Approach for Reduction of False alarm rate in Network Intrusion Detection System" (PDF). p. 11. Archived from the original (PDF) on 2017-04-06.
  8. "Alarmingly Useless: The Case for Banning Car Alarms in New York City" (PDF). p. 8. Archived from the original (PDF) on 2012-12-07.
  9. Wang, Amy (January 13, 2018). "Hawaii officials say 'NO missile threat' amid emergency alerts". The Washington Post. Retrieved January 13, 2018.
  10. How To Avoid False Alarms Archived March 13, 2007, at the Wayback Machine