HEALTH AND SAFETY

Problems with current Emergency Vehicle sirens
solved by the Quadrasonic Siren System.

PERMANENT HEARING DAMAGE
to EMERGENCY SERVICES PERSONNEL
(click or tap image to enlarge)

Freedom of Information response from London Fire Brigade

QUADRASONIC Directional Sirens are effective
in reducing the liklihood of hearing damage.

CAUSES of NOISE INDUCED HEARING DAMAGE

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Research indicates that electronic yelp sirens can cause hearing problems in personnel.  The wail siren takes around 1.92 seconds to emit 75% of its peak volume (amplitude) in 30% of its total cycle time. Although its initial rise time is steep, it is spread over a long time period and is unlikely to cause hearing damage. 

However, a yelp siren  reaches 75% of its peak amplitude in around 0.08 seconds and repeats it up to 250 times a minute. 

When our ears hear loud noises and the sounds are increasing and decreasing in intensity very quickly the muscles in the inner ear become overstretched and in time can lose their elasticity, leading to permanent hearing problems. 

Overstimulation by high frequencies can damage the fine sensor hairs in the inner ear causing permanent hearing loss.

Unfortunately, damage to hearing is cumulative and adds up over time. Hearing loss is usually permanent.

In contrast to electronic sirens the Quadrasonic™ sirens emit sinusoidal soundwaves which have gentler rise and fall times allowing the eardrum muscles and inner ear sensor hairs to have more time to adapt to the increase in volume levels.

The Quadrasonic siren's sinusoidal sound waves are unlikely to cause hearing damage. The sensor hairs are activated at a slower rate and are not stressed by the type of sound waves used in Quadrasonic Siren Systems.

"Occupational exposure to noise can increase the risk of temporary or permanent hearing loss"

​" One of the most prevalent occupational health problems is the control or moderation
of high sound levels in the interior of emergency vehicles"

QUADRASONIC  SIRENS WOULD SIGNIFICANTLY REDUCE THE INCIDENCE
OF HEARING DAMAGE AMONG EMERGENCY SERVICE PERSONNEL
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