Fire fighters have a dangerous, challenging job, but airport fire fighters have to contend with an additional pressure – the issue of dangerous surrounding noise.
Operating and training every day close to taxiing and departing jet airplanes - and therefore experiencing the continual roar of jet engines - fire fighters’ hearing is put at real risk as noise levels regularly reach beyond the accepted safe level of 85 decibels (dB).
A taxiing Airbus A320 50 metres away for example emits 93 dB of sound, which experienced over prolonged periods can cumulatively damage a person’s hearing. A jet aircraft taking off 25 metres away meanwhile creates much greater sounds, of up to 140 dB; a level that can immediately and irreparably damage the inner ear.
“We work in an environment in which our hearing is always being challenged,” explains Commandant Amiguet, who is in charge of Geneva International Airport’s Safety Division, comprising 180 fire, medical, nurses and surveillance service staff.
“Our own vehicles’ sirens are very loud and while direct interventions don’t usually present a hearing problem, the jet engines around us definitely do,” he adds. “There’s a joke in this industry that if you ask an airport fireman of 20 years a question, his first response will be, “What?” There’s a reason this joke exists.”
In the past, like a great many professionals who work in dangerously loud environments, the fire fighting team had access to traditional foam ear plugs to protect their hearing. However these products were rarely used.
“Initially the team didn’t have professional hearing protection, they only had access to disposable ear plugs,” explains Martial Hofer, Geneva airport’s Security, Quality and Health at Work Coordinator. “However staff couldn’t communicate with each other wearing these plugs – which is obviously crucial for such a close-working team – meaning they simply didn’t wear them.”
Electronic Ear Protection
The first was a performance analysis the team ran at Teesside fire training centre in England. “This facility creates real-life airplane fires of the kind that are crucial to our team’s ongoing development, particularly because we are not able to run such extensive fire tests in Geneva, nor have we ever had a serious airplane fire there. In these tests, the noise of the plane’s engines and the fire itself meant our team struggled to communicate as we would like, even though they have radio loudspeakers and bond conduction radio transmission built into their helmets. They simply couldn’t hear what other colleagues were saying well enough, and therefore they struggled to accurately understand what actions were required.”
The second reason was that two of the Commandant’s fire fighters had already been diagnosed with a hearing loss. “Our doctors warned us that if these guys didn’t get protected, this hearing loss would get worse and could eventually lead to them losing their driving licenses and their jobs,” the Commandant explains.
On the team’s return from Teesside, the Commandant and Hofer reflected further on how they could ensure their team’s hearing was fully protected, without diminishing their ability to communicate. A subsequent thorough search of intelligent hearing protection providers led Hofer to Switzerland’s Phonak Communications.
“The fire fighters needed protection, yes, but this shouldn’t and couldn’t be a barrier to communication,” Hofer recalls. “Ideally any protection had to allow them to hear sounds selectively – in other words hear only the necessary, important sounds - not the sound of the airplane engines but the voices of colleagues and passengers.”
A second Teesside training exercise was observed by Phonak’s hearing protection specialist, during which the Commandant’s fire fighters trialled the company’s Serenity DP level-dependant protection system.
Comprising custom-molded eShells and a neck-worn control box, Serenity DP was worn under each fire fighter’s protective clothing. Using miniature binaural ear microphones, this system’s electronics continually ‘hear’ and measure the surrounding noise levels. The system then dampens excessive loud noise down to 82 dB, while localizing important signals such as voice commands and warnings (meaning these can be heard as normal). In short, Serenity DP provided Hofer and the team with the ‘selective’ hearing capability they had been looking for.
“The difference in performance was immediate,” says Commandant Amiguet, “and what’s extraordinary is that we didn’t hear any of the annoying surrounding noises we used to hear. The Serenity ear protection reduced the background noise but improved our perception of sound signals and in turn improved the safety of the team.”
Intelligent Hearing Protection
The 70 Serenity DP systems Geneva’s aviation fire fighters subsequently purchased not only improved their communication but should extend their careers - including those of the two firefighters mentioned - by ensuring that any potential hearing losses are eliminated and staff meet the medical standards required by the country’s aviation authority.
Hofer explains: “All of our fire fighters undergo regular medical checks as demanded by Switzerland’s Federal Office of Civil Aviation (FOCA). These checks are once every two years for those under the age of 40 and every year for those above that age, and a full hearing test is part of these exams.”
These days Geneva’s aviation fire fighters wear their protection as standard, slotting in their eShells each time they suit up to leave the station.
“For our people the system has become just another part of our professional equipment, like our protective trousers or gloves,” Commandant Amiguet explains. “Nobody even discusses hearing protection now as it’s as logical as protecting our hands. We just do it.”