Emergency alarms are designed to help warning people in the vicinity of an imminent danger or of a breach in security or that an otherwise emergency situation has arisen. Emergency alarms come in many forms and have in some way, shape or form been present throughout most of human history.
There are many types of emergency alarms; one of the most common a fire alarm or smoke detector. Emergency alarms also come as warning sirens, like those posted on beaches to warn of shark sightings; as personal-use alarms linked to emergency services; as trespasser alarms in cases of robbery or entry into unauthorized areas; as sirens atop police vehicles or ambulances; and as general warning alarms or sirens that can even contain a vocal message.
Bells and gongs were the first type of emergency alarm system used after the human voice. In the walled or fortified communities of most cultures there was always a watch-tower with a bell or gong that was rung or struck only in cases of emergency: this instructed everyone to move within the walls of the community compound. Sound is still the preeminent element in emergency alarms today, but with the advent of batteries and electricity, lights have also been included in most emergency alarms. According to the Great Idea Finder, the first battery-operated fire alarm was developed in the 1960s and has since been incorporated into almost every dwelling and building in the United States and the developed world.
An emergency alarm’s primary function is as a warning system. When activated, an emergency alarm will give out a loud sound, usually repetitive in tone and often accompanied by flashing lights. Once activated, most emergency alarm systems continue to emit both light and sound until the system is deactivated. Emergency alarms can be a warning that danger is imminent, such as with fire alarms, shark alerts or general warning alarms; they can be an indicator to move aside or look out for emergency vehicles as in fire trucks, ambulances and police cars. They also can also be used for security measures, as is the case with burglar alarms and unauthorized access alarms.
Emergency alarms can be identified in a number of ways. Often it is a legal requirement in public buildings or workplaces for emergency alarms to be clearly marked, usually with an official sign or sticker. Emergency alarms are often accompanied by a mounted light, usually red, which is another way of identifying the location of an alarm. In homes, most fire and security alarms are fitted with a small blinking light to indicate that the alarm is functional and/or activated.
One of the main problems with emergency alarms like fire and security alarms is that they tend to go off unnecessarily. According to the Sacramento, California, County Sheriff’s Ordinance on emergency alarms, more than 97 percent of all emergency alarm activations are false. Sensitivity and electrical malfunctions are the usual causes. Emergency alarms can be overly sensitive in detection of security breaches or emergency situations; for instance, household pets will often set of security alarms and burning toast is the biggest culprit for fire alarms. Concurrent with this, all modern emergency alarms are electrically wired, which means faults abound—many false alarms are set off by insects chewing through cabling or simply malfunctioning hardware.