safety standards for road and rail tunnels – a …tunnel2016/history/tunnel_2004_cd/pdf/37_… ·...

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International Conference „Tunnel Safety and Ventilation“ 2004, Graz

SAFETY STANDARDS FOR ROAD AND RAIL TUNNELS –

A COMPARATIVE ANALYSIS

Arnold Dix Counsel at Law,

Professor of Engineering (Queensland University of Technology) Introduction The development of common European Union directives for underground road and rail transportation provides important evidence of what constitutes a minimum safety standard for underground transportation safety in the European Union. These directives are an important articulation of European practice but are, as a matter of law, evidence (not proof) of what may constitute sound practice in Europe and potentially elsewhere in the world. This does not render each member states countries domestic regulations, practices and codes obsolete – nor does it deem them inappropriate or unsafe. However it does provide more evidence of what constitutes current European safety practices. The effect of the Directives is to provide evidence of what constitutes a minimum European level of safety. The central obligation of engineers to exercise due professional care remains intact even where there are directives in place, This paper briefly explores the regulatory frameworks of Germany, Switzerland in comparison with the EU Road Tunnel directive to illustrate the differences in approach – and then explores Japans approach to the same issues to illustrate an alternative, but none the less appropriate response. Such differences are to be expected when comparing Road and Rail tunnel guidelines from around the world. Ultimately the peculiarities of each project demand each tunnel be designed and be considered on its own merits – and even where compliance is deemed to meet all requirements there will remain circumstances were engineering judgement may still need to be exercised when determining aspects of the final design and operation. Multiple Guidelines It is to be expected that there will be many differences between what is required under European Union Road Tunnel and Rial Tunnel requirements and that which is required within each of the EU member states. The reasons for these variations are numerous – such variations are to be expected and managed. This means that for a long road or rail journey the nature of the risks may change along a single journey. The “changes” to the risk profile do not prove that the level of risk has changed unacceptably – nor does not follow logically that such changes are conclusive proof that parts of the journey is unsafe, or that appropriate standards have not been met.

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However it does mean that it is a comparatively simple task to document the differences between countries – and subsequently make assertions about the appropriateness of achieved levels of safety after a serious safety incident.. Congested Unidirectional Tunnels – Comparative Ventilation EU - D - CH A simple comparative analysis of the German, Swiss and EU directive for roads tunnels illustrates the variation in requirements in road tunnels between the Trans European network, Germany and Switzerland. For illustrative purposes the table summarises the guidelines for, unidirectional congested Tunnels of differing lengths. The simplified analysis is tabulated in figure 1. (Guidelines for unidirectional tunnels of differing lengths)

Figure 1: (Simplified summary of EU, D and CH Guidelines for unidirectional congested tunnels of differing lengths)

It is apparent from the table that there are a range of requirements between Switzerland, Germany and the EU directive for ventilation. The most notable areas of variation of approach between the EU and both member states is that in Germany and Switzerland mechanical ventilation is required in shorter tunnels than prescribed by the EU. Furthermore detailed risk analysis is critical in the ventilation choices – particularly in tunnels less than 1000m long. As between Germany and Switzerland there are also differences. For example In Germany the requirement for ventilation commences in shorter tunnels than in Switzerland, and

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Switzerland appears to retain more design flexibility for ventilation in non congested longer Tunnels than Germany. Under the draft EU road directive congested tunnels in excess of one thousand metres require mechanical ventilation, and if the ventilation type chosen is longitudinal – other safety measures are required too.

2.9.2. A mechanical ventilation system shall be installed in all tunnels longer than 1 000 m with a traffic volume higher than 2 000 vehicles per lane.

2.9.3. In tunnels with bi-directional and/or congested unidirectional traffic, longitudinal ventilation shall be allowed only if a risk analysis according to Article 13 shows it is acceptable and/or specific measures are taken, such as appropriate traffic management, shorter emergency exit distances, smoke exhausts at intervals.

2.9.4. Transverse or semi-transverse ventilation systems shall be used in tunnels where a mechanical ventilation system is necessary and longitudinal ventilation is not allowed according to 2.9.3. These systems shall be able to exhaust smoke in case of fire.

(Draft EU Directive on minimum safety requirements for tunnels in the Trans-European Road Network)

As illustrated above under Articles 2.9.3 and 2.9.4 tunnels with congested unidirectional traffic are directed not to have longitudinal ventilation unless a prescribe risk assessment demonstrates such a ventilation system is acceptable given the particular circumstances of a tunnel including traffic management, emergency exit distances and smoke exhaust intervals. The preference is for transverse or semi transverse ventilation systems which are able to exhaust smoke in the case of a fire.

The following table extracted from the draft Road Directive which appears at direction 2.1(ix) of the EU Road Tunnel Directive does not prescribe at what length smoke extraction is required nor the circumstances in which it would be necessary.

Figure 2: (Extract from draft EU Road Directive)

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In Germany the requirement for smoke requirement could arise in unidirectional tunnels exceeding 600 metres in length but would depend upon detailed risk assessment. Once such tunnels exceed 1200 metres in length smoke extraction using adjustable dampers and a false ceiling would be required. (See Figure 1)

In Switzerland smoke extraction would be required for high risk tunnels over 800 metres in length (or over 1500 metres in tunnels determined to have a lower safety risk).

In Austria the approach taken would be similar to that adopted in Germany however the ultimate decision will be dependent upon detailed design aspects of the proposal including traffic volume, length and gradient.

From the brief summary from Germany, Austria and Switzerland noted above it is apparent that a range of design options could legitimately arise by applying the local member countries guidelines. Each of these local design outcomes may legitimately be different to the minimum requirements contained in the EU Directive.

For an excellent review of the key regulatory requirements in Europe there is currently no better source of data than at www.etnfit.net. That source provides summary documentation and is continually being updated.

For the engineer responsible for the design, operation or refurbishment of road tunnels this variation in guidelines creates a potential regulatory dilemma.

Should the prudent engineer follow the EU Directive because it is comparatively recent and compiled as a result of the deliberations of many experts from all of the EU countries, or should they be persuaded by the domestic regulatory environment?

The answer – as a matter of law – is clear.

In order to discharge the engineer’s professional obligations it is necessary to turn their expert skills to the question of what is appropriate in the circumstances of the particular tunnel. Even where there are laws prescribing what must be done there is an overarching legal policy requirement that the engineer be satisfied that what is proposed is appropriate. Is there a correct engineering answer?

While the performance of each of the design outcomes under the minimum EU Directive requirements or those required under each countries laws may be different, it does not follow that any of the designs are acceptable or unacceptable.

In extreme circumstances minimal compliance with the EU Directive might not discharge the legal responsibility of the engineers.

By way of further example there could be unusual HGV traffic using the trans European network in that area which rendered the minimum treatment measures contained within the EU Directive ineffective from a safety perspective.

Likewise circumstances may exist where strict adherence to a countries tunnel regulation might discharge the engineer’s obligations.

However design construction operation of these facilities in accordance with the accepted or prescribed national regulatory regime provides strong evidence that the design in question is appropriate.

There are many cases in all jurisdictions which illustrate this point.

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For example the highest Australian Court stated it early last century as;

–“The mere fact that a defendant follows common practice does not necessarily show that he is not negligent, though the general practice of prudent men is an important evidentiary fact. A common practice may be shown by evidence to be itself negligent” Mercer v Commissioner for Road Transport and Tramways (1936) 56 CLR 580 per Latham CJ at 589 §Lettice v. Council of the Shire of Muswellbrook[2000] NSWSC 81

Or more recently,

–“a finding of want of due care can properly be made even though the defendant has obeyed all statutory requirements and followed a common or universal practice.”

Podmore v. Aquatours Pty Ltd (1984) NSWLR 111 at p 116

Accordingly as engineers there is an obligation to understand and properly apply due professional skill to tunnel safety.

Divide and conquer ?

There are differences between the regulatory environment the different member states and countries (often neighbouring each other), the EU directive and other standards (such as in the United States of America and Australasia). It is not uncommon outside the EU for neighbouring jurisdictions to have differing standards. (eg Hong Kong and Mainland China, Korea and Japan, Victoria and New South Wales – Australia, New York State and Pittsburgh USA.)

The following table summarises the requirements for safety equipment in the Japanese Road Authorities Jurisdiction.

The first stage of the Japanese process is characterisation of the tunnel type. (see fig3). From this table tunnel risks are characterised from a length/ traffic number perspective.

Figure 3: ( extracted from Bouwdienst Rijkswaterstaat Directoraat-Generaal Rijkswaterstaat

Ministry of Transport, The Netherlands Sprinklers in Japanese Road Tunnels Final Report December 2001 Chiyoda Engineering Consultants Co.,Ltd.

The second stage describes what is required. (See fig 4)

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Figure 4: (extracted from Bouwdienst Rijkswaterstaat Directoraat-Generaal Rijkswaterstaat Ministry of Transport, The Netherlands Sprinklers in Japanese Road Tunnels Final Report

December 2001 Chiyoda Engineering Consultants Co.,Ltd.)

The Japanese approach can readily be compared to the EU approach which is summarised in Figure 2. It is systematic, and considered – but different to EU and member state systems There is no “correct” approach. Each system will perform differently. The differences in performance may be critical for management of a particular event – say a vehicle fire. In a long busy Japanese tunnel (“aa” type) water deluge sprinklers are prescribed. Under a range of scenarios the use of water deluge sprinklers could impact injury rates and infrastructure damage. The nature of the impact will depend upon the scenario. The range of potential impacts extends from positive to negative. If the impact is negative (ie more injuries) it could be argued that prescribing the water deluge system was wrong. If no one is injured – it is unlikely to be more than an obscure statistical reference in an operators log book.

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Understanding regulatory differences These types of regulatory variations provide an opportunity to argue subsequent to a safety event that not only was a particular design defective but that had the design practices of another jurisdiction been followed injuries would have been avoided. The impetus for such argument should not be underestimated and the sentiments and dissatisfaction of the public towards a legal system which does not find liability subsequent to a tragedy are well illustrated by a number of engineering related tragedies in recent years. The role of standards was recently highlighted when an Austrian court in Salzburg acquitted 16 people of the responsibility for the Kaprun ski train blaze that killed 155 tourists in November 2000. In the determination of the court the Judge noted that:

“the train confirmed to the latest technical standards and all requirements were fulfilled”.

Importantly the Judge accepted the defendants’ arguments that no-one could have foreseen the chain of events that lead to the deaths and that none of the defendants had any reason to suspect that the heater was not up to standard. The importance of considered engineering decision making underlies all guidelines. These guidelines are tools to assist engineers perform – not recopies which guarantee success. Conclusions A comparative analysis between road and rail directives and member nation guidelines readily demonstrates the vast range of design and operational options articulated globally with respect to underground transportation safety. There is such variation in key safety parameters such as ventilation, lighting, emergency evacuation, control systems and pedestrian ways that expert engineering decisions are still required. The common EU position – as expressed in the draft EU Tunnel Directive is an extremely useful articulation of minimum requirements –but is not, and could never be, the safety standard for the European Union. The domestic regulations in Member States remain extremely important documents in determining appropriate conduct. The variation in approaches highlighting the importance of providing considered advice no matter what conclusion is arrived at following a systematic analysis of a safety critical issue. It is the differences between regulatory approaches which highlight the increasing importance of informed expert decision making for professional management of underground transportation safety.

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