This work aims to validate numerical modelling of water sprays against experiments carried out in this project. The focus has been on the influence of ventilation on water distributions on the tunnel floor, the influence of water sprays on control of smoke flow, and the modelling of pool fires and crib fires. Besides, full scale tunnel fires with FFFS in tunnels using longitudinal ventilation and point extraction ventilation systems are simulated and compared, as well recommendations for numerical modelling of such scenarios.

The ignition of natural fuels by sparks from strikes between metals and hard rock is far from understood and the ignition potential of sparks from rock strikes during heavy machinery operations is disputed in the scientific literature. This study utilises a spectrally resolved technique to study the temperature evolution of metal sparks from rock strikes. The study shows that initial temperature after collision can easily reach 1500 °C and this temperature can increase additionally by several hundred degrees as rapid oxidation processes are initiated, often leading to further disintegration of the fragment. The average temperature of fragments from such collisions is here measured to 1400 – 2000 °C and the combination of temperature, size and exothermic processes makes them viable for forest litter igniting. However, ignition on forest lands is always an unlikely, although possible outcome of heavy machinery operations and should be considered in risk assessment of the activity.

The open source CFD code FireFOAM has been verified and validated against analytical solution and real fire tests. The verification showed that FireFOAM solves the three modes of heat transfer appropriately. The validation against real fire tests yielded reasonable results. FireFOAM has not been validated for a large set of real fires, which is the case for FDS. Therefore, it is the responsibility of the user to perform the validation, before using the code. One of the advantages of FireFOAM compared to the Fire Dynamic Simulator is that FireFOAM can use unstructured grid. FireFOAM is parallelised and scales reasonable well, but is in general considerably slower in computation speed than the Fire Dynamic Simulator. Further, the software is poorly documented and has a steep learning curve. At present it is more a tool for researchers than for fire consultants.

Effective fire detection systems properly installed in bus and coach toilet compartments and driver sleeping compartments may save human lives and property loss. Rapid detection allows for early evacuation and extinguishment of a small fire, while late or no detection may allow the fire to spread. The purpose of the work presented in this paper is to provide recommendations on how to install fire detection systems in toilet compartments and driver sleeping compartments. The recommendations also cover what type of detection system is most suited. As a basis for the recommendations, full scale fire tests were performed with different detection systems. The fire tests were conducted in realistic mockups of a toilet compartment and a sleeping compartment. Different heat and smoke detection systems were analyzed at different positions for different fire scenarios to provide information on how to best install detection systems in these compartments. Five different scenarios were run and the most interesting finding was that two realistic fire scenarios in the toilet compartment did not activate fire detectors in the ceiling at realistic air flow rates. It is very rare that fire detectors are placed anywhere else than on the ceiling in toilet compartments on buses and the fire would then be very large upon detection.

In-line holography, where the reference beam coincides with the beam that is scattered against the droplets, has been found to be a versatile and simple experimental method for spray diagnostics using holography. Such an experiment was setup and a water spray was studied and holograms of high quality was obtained using a CCD-camera.

The holograms were analysed with Wavelet analysis, implemented as a Matlab program. It was found that the droplets’s size and position could be reconstructed with reasonable accuracy. Future work will focus on a dynamic analysis program that dynamically adapts the wavelet analysis parameters to each detected droplet.

Key words: spray diagnostics, laser diagnostics, holography, image processing, wavelet analysis

Radiative heat transfer accounts for around one third of the heat released from fires, and this is the most important mode of heat transfer for example at long distances and from a hot smoke gas layer to lower objects, such as to a floor for example. The possibility for reducing the absorptivity of surfaces in the infrared part of the spectrum has been discussed for several decades, mainly for energy saving purposes. Such surfaces are called low emissivity surfaces, or low emissivity coatings, and much focus has been on the spectral absorptivity up to wavelengths around 2.5 μm, e.g for solar reflective paints. Spectra from fires are distributed to longer wavelengths and this paper concerns the absorptivity for paints and thin coatings over the full spectral range where radiation from fires is important. The correlation between absorptivity and time to ignition in the cone calorimeter is also investigated.