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Emergency announcement

Voice sounders provide clear and unambiguous messages in the event of a fire or other emergency, and are an effective technology for public and commercial buildings

Facilities managers are responsible for fire safety and emergency planning. As such they must anticipate and plan for a possible large-scale evacuation. Some kind of audible warning system is essential – but many buildings have different kinds of alarms, which can create confusion. How are people to distinguish the fire alarm from emergency exit alarms, intrusion alarms and public safety alerts? And how are safety messages to be conveyed promptly and clearly amid the cacophony of sound?

When hundreds of people have to be evacuated from a building or retail site in a hurry, the clarity of public address announcements is a safety-critical concern. One solution is to install a voice alarm (VA) system. The concept of voice commands is increasingly recognised as an efficient and sensible way to instruct and direct people on how to leave a building or other area during an emergency.

There is well documented research into people’s behaviour in the event of a fire. One notable finding is the variation in speed of response to different types of alarm signal (see box, reference note 1):

  • 13 per cent of people react in a timely manner to bells
  • 45 per cent of people react to text information
  • 75 per cent of people react in a timely manner
    to voice messages.

Further research shows that people’s behaviour varies according to the environment, and in an emergency they may attempt to exit the building using the same door they used to enter (2). A clear voice message greatly increases the response rate and provides the opportunity to advise occupants of the safest emergency route.

Voice sounders are a good example of how voice technology can reduce delays and increase response during an evacuation, either used as a single-message 24V conventional voice sounder on a sounder/notification alarm circuit or as part of a sophisticated, multi-message, multilingual evacuation system.

The trend towards integrating voice sounders into automated fire systems is growing. With multiple sounder circuit synchronisation and the ability to pre-record several messages, voice sounders can be incorporated into both new and existing alarm systems. They can be used as a drop-in replacement for basic tone sounders or as part of a sophisticated engineered solution.

Multi-message versions of Vimpex’s Fire-Cryer, for example, have been used in shopping malls like the Arndale centres and Gunwharf Quays, museums including Liverpool Maritime Museum, areas of mass transit such as the London Underground, schools (for fire, lock down and class change), and a raft of mixed-use residential, retail and commercial spaces. Voice sounders can be supplied with foreign language and bespoke messages where required. Use of a high-quality rocking armature capsule technology ensures the broadcast of clear, audible, unambiguous messages.

When designing a new fire alarm system, the first task is to agree the evacuation strategy and whether there is any requirement for a staged or phased evacuation. The alarm tones and recorded messages must be agreed with the client; with up to seven messages available in a single sounder, a fire alarm system can be expanded to include inputs for bomb alerts, terrorist threats, coded warnings, water leakage alerts, class change announcements, system tests, ‘all clear’ notifications, machinery shutdown warnings, health and safety reminders, general alert messages, and, of course, warnings of fire. The potential is huge.

Look who’s talking…

Behavioural science studies reveal that the persuasive power of a voiced announcement is reliant on the vocal characteristics and perceived credibility of the speaker (3). And for most people, that means female. Think of virtual assistants Siri and Alexa, and most satnavs (the default voice for GPS navigation systems tends to be female). Alpha male tends not to be a popular choice compared to a steady, calm female voice. Similarly, for emergency alert systems it’s been shown (4) that women’s voices are more persuasive, particularly when the announcement concerns a non-gender issue.

James Jones, Managing Director of Vimpex, a manufacturer and distributor of fire detection, alarm and evacuation products and accessories, is familiar with the analytics behind the issue of voice-based alerts to convey authority. “It’s commonly accepted that the female voice is more appropriate for the vast majority of applications, and in fact the female voice ‘carries’ somewhat better in many environments,” he says. “That’s why women’s voices in seven languages are available with our products.”

When Vimpex developed its Fire-Cryer voice sounder ranges, it looked at the difference between male and female voices and measured such aspects as instinctive reaction and empathetic acceptance.

“Another important aspect is the behaviour of the female voice when used in sounder technology,” Jones continues. “The female voice is ‘purer’ in that it actually has a narrower frequency range at the same sound pressure level (SPL) than the male equivalent. This means that it is much more easily reproduced through the Fire-Cryer sounder and, for any given sound level, requires less current than a male voice.”

He adds that even in products supplied to national regions that are arguably more traditional and patriarchal, the female voice has been deemed appropriate.

REFERENCE NOTES
(1) ‘Misconceptions about human behaviour in fire emergencies’, by Guylčne Proulx PhD. Published in Canadian Consulting Engineer, 1997. Also Studies of Human Behaviour in Fire: Empirical results and their implications for education and design, by David Cantor. Published by BRE, July 1985.

(2) University of Greenwich. Studies have shown that occupants tend to use familiar routes – typically using the exit through which they entered the building. Research conducted by the University of Greenwich, which has undertaken a study called Human Behaviour in Fire Networks (HUBFIN), discovered that only 38 per cent of people see passive signage in an emergency.

https://www.risk-uk.com/building-evacuation-let-your-voice-be-heard/

(3) CNN. From voice-mail systems to GPS devices to Siri and beyond, why are so many computerised voices female? One answer may lie in biology. Scientific studies have shown that people generally find women’s voices more pleasing than men’s.

https://edition.cnn.com/2011/10/21/tech/innovation/female-computer-voices/index.html

(4) CCN (above). When it comes to consumer applications of computerised voices, the sex of the voice is usually determined by what service or product is employing it. For example, transit systems such as the San Francisco Area’s BART [Bay Area Rapid Transit] often use higher-pitched voices because they are easier to hear over the clatter of the train cars.

About Sarah OBeirne

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