More than 300 delegates gathered in the picturesque lakeside setting of the Lucerne Culture and Convention Centre to attend the Swiss Colloquium on Fire and Safety for rail and road tunnels, followed the next day by an attendance of some 1,300 professionals for the meeting of the Swiss Tunnel Congress.
Spirits among the delegates were understandably high coming as the Conference did just two weeks after the proud tunnelling nation celebrated its greatest ever engineering achievement, the Gotthard Base Tunnel. The 57km trans-Alpine rail link was officially opened on June 2, a high-profile event that attracted global attention. The Swiss Tunnelling Society (STS) plans to publish an English-language version of its celebratory and detailed book on the construction of the Gotthard Base Tunnel in November this year (2016), although a German language version priced at CHF80 (€74), and released for publication last month, was selling at the Conference.
On Day 1 delegates heard presentations on fire safety in tunnels. The broad line-up of speakers had been deliberately crafted by STS Vice President Stefan Maurhofer – who takes over as President next month – to offer a wide diversity of speakers from across the supply chain to discuss aspects of tunnel design, operation and emergency support.
A common point emerging from the seven key, and quite different, presentations, was the importance of the “interface” between different specialisms, and the need to pursue and deliver ever-greater understanding and collaboration through the supply chain.
The Swiss Federal Office of Transport set the scene with a discussion on the fire and safety aspect of rail tunnels. It noted that the importance afforded to tunnel safety can only increase given the wide range of underground links in Switzerland; the approval authority will continue to assess safety on criteria that will also include effectiveness, cost efficiency and environmental factors.
Factors in ventilation in road and rail tunnels, respectively, were discussed by consultants Amberg Engineering and Poyry Management Consulting (Schweiz).
Amberg examined the control of smoke movement, which it was noted can provide favourable conditions for self-rescue and also intervention. Emphasis was placed on the benefits of adequate maintenance, but also on the importance of simulations; and points were raised on the interplay of ventilation systems and equipment options with design and construction choices for new tunnels as well as refurbishment projects.
Marco Bettelini, a safety specialist with Amberg, further noted that with emergency services being trained on tunnel ventilation systems they can seek operations to be adapted to complement their intervention strategies.
“Control of ventilation is one of the biggest tasks we have in road tunnels,” said Bettelini. He added that 3D simulations featuring computational fluid dynamics (CFD) were an “indispensable tool” for helping to develop effective ventilation plans.
Severin Walchli, Head of Business Development for the transport section of Poyry, and previously Head of Ventilation/Fluid Services, discussed railway tunnel ventilation for the Zurich cross-rail scheme. The project was developed by the Swiss rail authority, SBB, and incorporates the 5km long Weinberg double-track tunnel, an escape and rescue tunnel, and an underground station. The emergency ventilation design has been optimised for the entire, complex, integrated underground system.
Walchli described the planning of emergency ventilation – including the tunnel cross-section as a variable in smoke propagation and as a factor affecting visibility and the prospects of passenger self-rescue in the initial minutes following an incident. For the Zurich project the smoke extraction system was discussed, as well as hot smoke tests and CFD modelling.
Escape doors and lighting were discussed by manufacturers Elkuch and GIFAS-Electric, respectively, with less focus on products and more on the approach and options available, including test experiences.
Michael Lierau, Chief Executive of specialist door manufacturer Elkuch, noted that different rules exist for surface and underground space, and emphasised the crucial importance of maintenance of installed systems. He also noted the need for simplicity in initial concept: the aim is not to ensure that doors are obstacles, but rather that they are part of an overall safety system. To that end, and with videos of tests for delegates to watch, the manufacturer showed over- and under-pressure testing of hinged and sliding-type escape doors, and the variation in force to be applied to open, and then pressure-induced closure.
Developments in lighting technology as fixed infrastructure in tunnels and for use in emergencies was discussed by Yves Rodiger, Chief Executive of lighting specialist GIFAS-Electric. Again the Zurich cross-rail scheme was a case in point, with delegates learning that an LED lighting system has been installed that integrates lighting directly into handrails. Discussion, too, was given to the 550m-long Entlisberg tunnel on the A3 national road, near Zurich, where a modernisation project saw new guidance lighting planned and installed in under a week.
Urs Kummer, Chief Executive of the Switzerland-based International Fire Academy (IFA) (www.ifa-swiss.ch) that provides integrated training for all fire services in the country, informed delegates that earlier this year his organisation had produced the English-language version of its publication Firefighting Operations in Tunnels, which also has a dedicated website (www.tunnelfire.info).
One of the key points raised by Kummer was the recommendation that tunnel asset owners hold short but frequent command-post exercises, the prime reason being to help decision-makers get to know each other and gain familiarity with their approaches to fire safety and fire response prior to incidents actually occurring. He also urged project developers, designers and builders to make a concerted effort to get to know the fire services teams at the earliest stages in order “to get the optimal concept” developed for fire fighting, and to help also in the operation and maintenance of the infrastructure asset.
Fire services should be integrated into the planning, design and construction of infrastructure, said Kummer, rather than simply regarded as “musketeers” to be called in to help when there are problems.
Beat Walther, Deputy Commandant of the Gotthard road tunnel fire service team, told delegates the emergency teams there are called to about 600 incidents a year; and that for such interventions the dedicated and unified emergency service team has a fleet of 54 vehicles distributed equally at each portal to ensure maximum flexibility. Generally speaking, the team enters both portals at the same time in response to any incident.
Amberg’s Bettelini had earlier noted that the aim should be to design for self-rescue within five minutes, and picking up on the point of response time, Walther explained that for interventions at Gotthard the teams have to be ready in two minutes, and total time to intervention at an incident site is 12 minutes – which is crucial in about 90% of the call-outs.