11.1 Introduction

Knowledge of smoke spread and fire development in tunnels is generally obtained from large-scale testing and laboratory testing (e.g. scale models). The aim is usually to investigate some specific problems such as the influence of different ventilation systems on smoke and temperature distribution along the tunnel, the fire development in different type of vehicles or the heat exposure to the construction. Large-scale testing is generally expensive, time consuming and logistically complicated to perform and therefore the number of large-scale tests in tunnels is limited. The information obtained from these tests is often incomplete due to the low number of tests and lack of instrumentation. Large-scale testing is, however, necessary in order to obtain acceptable verification in realistic scale and the information obtained from many of these large-scale tunnel fire tests provides the basis for the technical standards and guidelines used for tunnel design today.

In this chapter an overview and analysis of large-scale tests performed in road and railway tunnels is given. A general analysis of the results have been carried out and wherever possible, presentation of following parameters is given:

• measured peak heat release rates (HRR)

• measured peak gas temperatures

• flame lengths.

These parameters are important for engineers and scientists working with tunnel fire safety.

11.2 Overview of Large-scale Tunnel Experiments

The diversity of the large-scale tests found in the open literature is in the scales, the type of fire source and size (HRR), instrumentation, documentation, tunnel geometry and ventilation conditions.