It has been noted numerous times, in multiple studies, that building occupants often ignore or are slow to respond to standard fire alarm sounders. There is even a tendency for people to continue with their activities, oblivious to potential danger.
Bystander apathy – a condition where people ignore an emergency when they believe someone else will take responsibility – is the social psychological phenomena that can affect the pre-movement phase of an escape, prolonging the time it takes before people react to an audible alarm.
Steve Loughney of Siemens Building Technologies said: “There are multiple explanations as to why we have a natural tendency to dismiss alarms and any delay could prove critical or at worst, catastrophic. People respond to others around them and a collective position often emerges during emergencies i.e. if one person moves, there is a likelihood that others will follow with the reverse also true.
“Doubts about the validity of warning sirens might also stem from loss of confidence we have in standard fire alarm systems. Nuisance alarms or false alarms have lulled us into a situation where blaring sounds or klaxons are often casually dismissed as non-emergency or non-life threatening.”
This lack of urgency was echoed in studies by the International Rescue Committee when it found that less than 25% of occupants interpreted the sound of the fire alarm as a potential indication of a real emergency during mid-rise residential evacuation trials.
Fire experts have long queried why people do not respond to siren-based alarms with voice evacuation systems mooted as a better alternative for relaying information and prompting quicker reactions from people during an emergency.
In a related study, published in the Journal Pediatrics, that adds credence to the idea it was found that modified smoke alarms (ones that used voice warnings) were more effective at waking up children than standard fire alarm sounders. It took two minutes for high-pitched smoke detector to wake children up but just two seconds with a motherly voice. The test sample, researchers found that only half woke up to blaring noises of a conventional smoke alarm- 90% woke up to voice.
The improved reaction times were consistent and surprising with further tests planned on varying sound frequencies across a wider sample of people of different age groups.
Loughney continued: “Yes – the alarms were played when the children were in the deepest phase of sleep but the findings present a compelling case for voice or spoken systems. Simple fire alarms do not always encourage the appropriate reaction whereas voice commands are more specific and relay accurate information about any impending danger. If you could also transmit that message in multiple languages, understood by more, then further vital seconds could be saved.”
More comprehensive systems for detection, alarming, evacuation and danger management are required as buildings become increasingly more complex. Visual and acoustic alarming protects the hearing-impaired or employees working in noisy environments. Different zones of a building may, in different scenarios, require separate instructions to ensure a safe exit.
Loughney concluded: “When you’re protecting what matters, every element of protection matters. Voice systems lead to less confusion and a faster and safer evacuation.”