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What is Disabled Sound and Light Emergency Exit Guidance?

 

In service buildings open to public use and in all social and cultural areas, when an emergency occurs such as fire, flood, earthquake, etc. , alarm sirens, flashers, horns and warning loudspeakers placed in various parts of the building work simultaneously in as wide an area as possible to warn people against a sudden danger. . There are exit signs and exit signs used to direct the users inside the building to the emergency exit. However, in a smoke-filled environment, emergency signs created by visual guidance may be less pronounced or completely ineffective. Building occupants may not be familiar with the building and associated emergency exit routes, but they can still access emergency exits somehow with directions and signs.

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So how will people in panic and shock, hearing and visually impaired individuals reach the emergency exit doors without help !!

For visually impaired people to evacuate the building quickly without additional support during the evacuation processes of buildings, conventional emergency direction luminaires and signs will not be sufficient and they will experience serious difficulties. Are there any signs? Solutions that will answer the question should be applied.

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Disabled audible light guiding luminaires are new generation emergency exit evacuation routing solutions. In short, you can define it as a sound exit armature.


The human ear can hear sound signals in the range between 20 Hz and 20000 Hz. The human brain provides time differences between the ears with the difference in sound intensity between the ears.

Due to the development of directional sound technology, many studies and researches are carried out to compare the escape times of users from the building with the help of directional sound makers with the escape times made with classical visual signals and signs. These studies have generated a large body of data, with research showing that the use of guided sounders has consistently shown a significant reduction in escape times.


Experiments were carried out to confirm this information.

Wideband tested at different frequency bandwidths.

In addition, pure tone signals were also tested as a reference.

The tested sound level is fixed at 75 dB.

NFPA's Fire Code [11] Annex-A has shown what ambient sound levels can be for different applications.

Fire alarm siren sounds should be higher than ambient sound level.

The sound of the fire alarm siren, the voice alarm speaker must be at least 15 dB higher than the ambient sound level . In addition, the sound of the directional disabled emergency audible and light directional luminaire should be at least 15 dB lower than the fire alarm, taking into account the comparability between the two sounds. For this reason, two ambient sound levels were taken into account in the tests;

For the accuracy of the aforementioned statements, experts have conducted experiments.

One below 60 dB, the other 75 dB. In the test, 36 loudspeakers were placed in a 3 meter diameter circle around the subjects.

The circle is marked from 0° to 360° and each sound box is placed at the specified degree.

Before starting the test, the subject needs to know:

1) Does not move his head during the test,

2) Different sounds will be played and the subject will be asked to indicate where the sound comes from,

3) Each sound will be played 10 times from a randomly changing sound box each time. 5 seconds between each sound. space will be given and the subject will talk about the place of the voice for 5 seconds. must make a decision in

4) In noise impact tests, a noise sound will be played continuously, during which the subject will distinguish and say the location of the guiding sound signal.

For each sound, there are 100 test results. In each test, the direction pointed by the subject has a deviation from the audible sound box, and if the deviation is greater than ±5°, the percentage correct numbers will decrease by one. The results are listed in the analysis. Background noise has some influence on identifying the sound source. Where the background noise level is close to that of the test sound, pure tone (mono-frequency) forms are more difficult to locate, whereas broadband sounds with a larger frequency range are more easily located.

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When the ambient sound level is below 60 dB, three sounds with bandwidths 0.02-20 kHz, 0.3-16 Khz and 0.5-10 kHz met the above condition. But when the mid sound level was 75 dB, only two sound conditions with bandwidths 0.02-20 kHz, 0.3-16 Khz were provided.

Besides, it is easier to pinpoint the exact location of wideband audio; however, the frequency bandwidth should be as wide as possible. The Test concluded accordingly, with test subjects correctly locating the sounder at least 75% of the time, according to the British standard BS PAS 41:2003.

The engineering application of directional audio technology faces some problems. Commonly used emergency fire alarm sounds cause confusion for building occupants. Users in buildings may not know what to do when they hear the sound. For this reason, there is a need to clarify escapes in addition to the voice alarm and siren. Users who try to go out into the corridor and steer towards the escape stairs after the siren sound at which the emergency warning is made, will proceed confidently to hear the announcements that they will understand that they can reach the fire stairs for emergency escape when they approach the audible and illuminated emergency exit direction luminaire, when they move in the direction of the sound, and that they are approaching with an increasingly clear sound announcement.

 

This message will enable them to move quickly and safely without the need for visual guidance and evacuation sign systems without having knowledge of the Building.

Conventional fire alarm and voice alarm systems both emit an audio signal when an emergency occurs in the building. Disabled emergency exit guidance system with audible light is an additional evacuation aid;

however, it is not a system that replaces the above-mentioned fire alarm and voice alarm system. Disabled emergency exit sound and light announcement fixtures should be placed above emergency exit doors and in complex corridor turns. However, emergency audio and light guidance products only on fire escape stairs and emergency exit doors may not provide enough directional sound to reach most of the users. In addition, there may be more than one exit in large, open and large buildings, but the sounds of more than one disabled audible lighted emergency exit routing product may interfere with each other and create confusion. For this reason, detailed project work should be done for disabled emergency sound and light guidance device equipment placement and integrated with the fire scenario.

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Considering this information
It is possible to reach the fire doors and escapes with audible and illuminated announcements from the emergency exit doors.
In an emergency, the environment can be noisy due to siren sounds.
The emergency voice guidance warning sound should be at least 15 dB lower than the ambient sound level.
Despite the ambient noise, it can be heard easily. Orientation can be determined
It will make it easier to reach the exit points with the increasing sound level as you get closer.

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RESOURCES

1 : PAS 41:2003, Directional Sounders-Requirements and tests. BSI, 17 February 2003.

2: Sime, Jonathan. Movement Toward the Familiar Person and Place Affiliation in a Fire Entrapment Setting. Environment and Behavior 17:6(1985) 697-724.

3 : MeClintock, T., et al. A Behavioural Solution to the Learned Irrelevance of Emergency Exit Signage. 2d International Symposium on Human Behavior in Fire, March 26-28, 2001, Boston, MIT InterScience Communications, 23-33.

4 : SFPE Engineering Guide, Human Behavior in Fire, Society of Fire Protection Engineers, Bethesda, Maryland, 2003.

5: DJ Withington, M. Lunch. Directional Sound Evacuation- An Improved System for Way Guidance From Open Spaces and Exit Routes on ships. RINA Passenger Ship Safety Conference, London, UK 2003.

6 : DJ Withington. Faster evacuation from ferries with sound beacons [J]. Fire, 2000: p. 30.

7 : Withington D J. Lifesaving applications of directional sound [J]. Pedestrian and Evacuation Dynamics (Berlin/New York: Springer), 2002.

8 : Withington D J. Localisable alarms [J]. Human factors in auditory warnings, 1999: 33-40.

9 : Van Wijngaarden SJ, Bronkhorst AW, Boer L C. Auditory evacuation beacons [J]. Journal of the Audio Engineering Society, 2005, 53(1/2): 44-53.

10 : Boer LC, van Wijngaarden S J. Directional sound evacuation from smokefilled tunnels[J]. Safe & Reliable Tunnels. Innovative European Achievements, Prague, Czech Republic, 2004.

11 : NFPA72-2013, National Fire Alarm and Signaling Code. NATIONAL FIRE PROTECTION ASSOCIATION OF America. August 29, 2012.

12 : BS8456-2005, Code of practice for design and installation of directional sounder evacuation systems. BSI, 18 Aug 2005.

13 : DANIEL J. O'CONNOR, PE, FSFPE. The psychoacoustic basis and implementation of directional sounders. 2006, National Fire Protection Association.

14 : Directional Sounder with Voice Messaging, Application Guide by System Sensor, 2007

15 : Wenhui Dong, Chunyu Yu, Mei Zhibin Shenyang Fire Research Institute, China 2018

16 : Fire Safety Magazine November -December 2020

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