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Directional Sound  Evacuation  

Link to Building Evacuation

Link to Evacuation from Aircraft

Link to Evacuation from Ships

Link to Evacuation from Tunnels





See it in action - Streaming video - Thermal image video footage of independent trials shows comparison of exit behaviour with and without DSE.

Despite advances in Fire Detection systems to detect fires, these systems do nothing to actually guide people to safety. They rely on people's ability to find their way out using exit signs.

In a smoke filled area, the emergency exits and signs may be impossible to locate by sight and an alternative method of guiding people along the nearest escape route is imperative. Voice Evacuation systems can tell people where to go, but not show them how to get there.

The use of directional sound to mark exits enables identification of exit locations that are obscured. Additionally, under non-smoke conditions, the use of The Localizer® Directional Sound Evacuation (DSE) beacons draws attention to Emergency exit signs and nearest exits which are often ignored because they are so familiar and not normally important. 

The Localizer® "audible exit sign" enhances fire alarms and lighting systems, and we are licensing the technology to multinational companies in North America and Europe. Research observed by the British Government has shown that The Localizer® can reduce evacuation times by as much as 70% in smoke and 35% in perfect visibility.

These sound-equipped beacons are obviously advantageous to people with visual impairment, and have also been shown to benefit individuals with learning difficulties and hearing loss. The broadband sound, which is totally independent of language constraints, consequently makes the beacons suitable for all nationalities.  

Commonly held myths

The fire safety industry has its roots in over a century of tradition and is, by its very nature, somewhat conservative. Many "accepted facts" of the industry are based on little or no research. Here are a few of the myths - and what research teaches us:


Myth: People do not travel through smoke when evacuating.

Reality: Given the choice, naturally people will avoid going through smoke, however people escaping fires frequently have to travel through areas filled with smoke. According to Prof J.L. Bryan of the University of Maryland who studied survivors from 400 different fires, 53% of survivors from fires admitted to travelling through smoke. P.G. Wood of the Building Research Establishment in the United Kingdom reported similar findings. In the September 11th World Trade Centre tragedy, approx 90% of the occupants survived, however people struggled to find emergency staircases because the entrances were from a lobby that was filled with smoke. 


Myth: Using new types of lighting can dramatically improve visibility in smoke

Reality: Research, carried out by the Building Research Establishment (UK), using volunteers in theatrical (white) smoke illustrates how visibility of different types of exit signs vary in smoke. It ignores the effect of real smoke on the eyes, or toxicity, however it does illustrate that NONE of these technologies is visible at over 1.5 metres in dense smoke (Optical Density 3m-1). At Optical Density 1m-1, the best technology was visible at just 4 metres whilst Photo-luminescent signs were visible at just over 1m.    

Hearing  is not affected by smoke.

Myth: Smoke rises to the ceiling and people evacuating can bend or crawl to safety in clear air, breathing normally underneath.

Reality: Whilst it is true that smoke rises when mixed with hot gases, F.R.S. Clark warns "Smoke density is not always lowest near the floor. Smoke tends to travel along the ceiling when it mixes with hot, buoyant fire gases. As these gases cool, however, the smoke sinks and eventually fills the entire space. Smoke may also be dispersed evenly through rooms by forced ventilation systems and by the action of sprinklers activated by the fire. Under these conditions low placement of exit signs may offer little advantage”. (Clark, F.R.S. Strategies for improving visibility in fires. Institute for Research in Construction, National Research Council of Canada, Canadian Building Digest 246, January 1988, 4pp.)  

Water mist extinguishing systems cool hot gases close to the seat of the fire - breaking down stratified smoke layers and eliminating the "safety gap" at floor level.

Martin Shipp, Senior Inspector of Building Research Establishment, also confirms that " whilst smoke may be stratified in a still air environment, the movement of people through the area can quickly disturb this stability and result in smoke down to floor level".


Dusseldorf Airport fire - official report extract:
Seven victims did go by lift from the parking lot on the roof top directly into the deadly smoke. When the door opened, the dense smoke hindered the light beam so that the lift doors could not be closed again. The nearest exit was 3 metres away from some of the victims but they could not find it and died."

Channel Tunnel fire - official report extract:
The driver of the incident train was unable to leave his cab to organise the evacuation of passengers because the smoke was too dense. The Chef de Train was unable to find the evacuation route within the tunnel because of the thick smoke and decided to keep everyone on-board the incident train until the arrival of the emergency services".  

Scandinavian Star fire - official report extract:
"We do know that emergency lighting and marking signs do not help to distribute people among the evacuation routes available.
The committee recommends that a requirement be introduced that audible signals with a sound that clearly distinguishes them from the alarm bells be installed by the exit doors in escape routes on board passenger ships, as directions for escape in conditions of reduced visibility."
Note: This recommendation was pursued by Governments of UK & Germany in their proposal to the United Nations

Manchester Aircraft fire - official report extract:
"Many survivors spoke of their inability to see due to the extreme density of the smoke and chemical effects on the eyes.
In addition it is also apparent that the effect of such atmospheres is to rapidly suppress any ability of those affected to shout, due to respiratory and acidic gas 'burning' effects on their throats. These sensory deprivations might be effectively countered by the use of automatic audio-attraction devices to guide evacuees towards viable exits. Research should be undertaken to assess the viability of 'audio-attraction' and other techniques designed to attract passengers towards viable exits when speech and vision is impaired in smoke and toxic/irritant gases." 

Paper by Professor Deborah Withington - The Use of Directional Sound to Aid Aircraft Evacuation

Myth: Low Location Lighting guides to safety in smoke
Reality:  What research was done prior to its introduction? There are limitations to its effectiveness:

  • It cannot provide guidance in open spaces
  • In normal installations it cannot show which way to the nearest exit.
  • In smoke, eyes are attacked so its visibility is poor
  • Electro-luminescent systems are very expensive
  • Photo-luminescent systems are largely invisible in smoke

Nieuw Amsterdam fire - official report extract:
By the time the passenger re-entered the corridor, it had become filled with smoke. Crouching to move along the corridor, the passenger became disoriented and was eventually found by a crewmember and taken to safety. The ship’s electroluminescent low-location lighting system was in operation."

Manchester Aircraft fire - official report extract:
Against this background of research and survivor evidence it is difficult to substantiate the rationale behind current regulatory moves towards the introduction of low-level 'escape-path' lighting to assist evacuations from smoke filled cabins. Under such circumstances the net safety-gains from such a requirement are likely to be minimal unless the passengers' eyes are protected.

Recently awarded the Fire Industry Council's Innovative Product Award and the Royal Institute of Naval Architecture ~ Lloyds Register Safer Ship Award, DSE beacons are the result of over 7 years of research with a substantial body of independently verified trials which have shown its effectiveness in a number of different environments:





Download Summary fact sheet on Directional Sound Evacuation (236k pdf)








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