Case study

A tough test for Phonak hearing protection in the Gotthard tunnel

A tough test for Phonak’s intelligent hearing-protection systems on one of the largest present-day tunneling projects. When Strabag Tunneling Switzerland needed a new hearing-protection system to protect its team working on Switzerland’s record-breaking Gotthard Tunnel project, it chose Phonak Communications AG and its Serenity SPC intelligent system. 

As construction projects go, they do not come much bigger than Switzerland’s Gotthard Base Tunnel. Construction of the 57 km-long tunnel - the heart of the new rail link - began in 1993 and the tunnel was ready for operation in 2016. The tunnel through the Swiss Alps cuts an hour off the travel time between Zurich and Milan. Business people, vacationers and cargo firms can now make the trip in just under three hours. 

The project 
Several companies were originally contracted by AlpTransit Gotthard AG to build the tunnel. One of them was Strabag Tunneling Switzerland, a subsidiary of global construction giant Strabag SE, whose specialities include mechanical tunnelling. Strabag Tunneling Switzerland’s safety manager, Daniel Schäublin, explains: “The two tunnel boring machines, ‘Gabi I’ and ‘Gabi II’, used to bore the two single-track tunnels make a lot of noise. When fully operational, this can easily give rise to a noise level of 90 decibels or more. Once the tunnel had been excavated, the inner lining was executed with a layer of concrete in thicknesses of between 30 and 60 cm, depending on the geological profile. This lining work was carried out with steel formwork, which in turn exposed the workers to high noise levels at times. Furthermore, our teams use various power tools and equipment in a very confined space, such as pneumatic drills, which alone can generate a noise level of 100 decibels. Against this background and so as to actively protect workers’ hearing from long-term damage, it is essential that employers and their employees can rely on reliable, high-quality hearing-protection systems.” 

What was decisive in choosing Phonak’s Serenity SPC products was not only the best possible state-of-the-art hearing protection, depending on the needs of the individual worker, but also the possibility of combining it with existing radio communication equipment. The Serenity SPC hearing-protection system brought some decisive competitive advantages for foremen and supervisors to carry out their duties and, in particular, to communicate with the locomotive drivers. Furthermore, despite wearing hearing protection, employees needed to be able to communicate with their colleagues and at the same time to hear without any limitation approaching hazards such as construction machinery or the service train. 

Hearing protection by Phonak: Serenity SPC The customized, modular system provides static hearing protection for constant-noise-level environments. The attenuation level can be increased or reduced simply by replacing the acoustic filters. In addition, this special Serenity model can be combined with 2-way radios, thus enabling interference-free communication without the hearing protection having to be removed and without any risk of hearing damage. 

Strabag Tunneling Switzerland was positive about Serenity SPC from the outset. “What I particularly liked about the system is not just that it protects your hearing but that workers can also communicate reliably with it and hear their working environment. That's crucial for us”, said Schäublin. 

“Our foreman and locomotive drivers, who need to be able to communicate all day long using radios, can easily connect Serenity to their 2-way radios," he went on to say. “They just connect the hand-held microphone they wear over their work suit to the Serenity system via a short cable. Our non-radio users simply wear the Serenity SP standard filters, which enables them to talk quite normally to their colleagues without having to remove the hearing protection.” Serenity is now used by around 400 employees of Strabag AG Tunnelbau Schweiz. They share Schäublin's consistently positive opinion. 

Serenity SPC, passive hearing protection with phone/radio communication 
► perfect understanding of radio/phone conversations even amid noise
► transmits only speech and suppresses ambient noise
► simply click out the fully modular eShells and use with another Serenity system
► static (passive) hearing protection with interchangeable acoustic filters
► custom-molded eShells
► lightweight, ergonomic and very comfortable to wear

Employees’ opinions
As tunnel worker Milorad Ristic commented:
“I don’t actually wear Serenity all the time, but when I’m working in a noisy environment like this, I can easily wear it for eight and a half hours a day and so communicate reliably with my colleagues. I can also hear the service train approaching.”

Site train operator Dominic Gruber now uses Serenity SPC in combination with his 2-way radio all day long:
“I’m very happy with the protection it offers. With Serenity, I can communicate very well with my colleagues, both by radio and directly. I wear it for eight hours a day, every day, and regularly clean it in the washing machine.”

Marcus Koplenig uses Serenity SP in his work on the tunnel boring machine “Gabi”. He too is convinced of its functionality:
“I wear the custom-molded ear shells all day long and got used to them very quickly”