1. What are false alarms?
False alarms1 are related to the exchange of information and also occur as a side effect of alerts [1]. The exchange of information is based on an assessment since warnings usually refer to facts that are important and/or urgent from a subjective standpoint – or that have been objectified – such as hazards. Hazard-related events, such as a fire, often are associated with considerable damages and require fast reaction from the persons involved, such as occupants, emergency and rescue forces, as well as in a general context from other decision-makers. Warnings about hazards are characterized by the identification of hazards – in a technical point of view often referred as detection – and the alerting of persons. In terms of safety engineering, false alarms are alarms that are not based on any dangerous situation. When referring to fire, a false alarm is a fire alarm when, in fact, there is no real fire condition at all [2]. False alarms occur in many situations, such as: (a) exchange of information, message or report (e.g., journalism), (b) diagnosis of diseases (e.g., skin, breast and prostate cancer) or (c) warning about accidents, malfunctions and attacks (e.g., fire, hazardous materials, intrusion, and terrorism). Hazards can be detected in a variety of ways. If hazards are critical in terms of time, their detection is often accomplished automatically. In this case, use is made of defined triggering mechanisms that are based on characteristic parameters of the observed phenomenon. In case of fire, such parameters are, e.g., triggering temperature, temperature gradient, light scattering, or the concentration of substances that are typical of fire. Usually installed Fire Detection & Fire Alarm Systems (FDAS) are used for the identification of fires in an early stage thanks to highly sensitive sensors. These sensors allow fire detectors to detect fires quickly, but they also makes installed FDAS susceptible to false alarms.
So far there is no reliable evidence on the ratio of false alarms of installed FDAS in Germany. The studies, which are described in the present paper, aim to close this gap on the basis of an empirical analysis of fire brigades data.