The idea to photograph fire experiments in a popular form on a larger scale and to prepare an exhibition came randomly. "We needed photographs for a technical article on the development of the charred layer of wooden columns in a natural fire. The photographer was given a few instructions on what we needed to capture, but otherwise he had a 'free hand' in the work and the shots were up to him. When we saw the resulting photographs, both we faculty and other colleagues working on fires were thrilled with them. We had never been able to capture flames photographically like this ourselves. We therefore agreed to photograph further experiments," says Ing. Jakub Šejna from the Department of Steel and Timber Structures, who professionally conducts research in the field of combustion of timber structures and protection of steel structures against the effects of fire and also initiated the whole exhibition.
Photographing the experiments was not easy, getting the photographer this close to the flames during the fire test was very challenging. Care had to be taken both for the progress of the experiment and for the safety of the photographer and the whole team of scientists. "Everyone entering the vicinity of the test furnace was fully dressed in firefighter's suits, boots, firefighter's helmet and filter mask. The photographer was not allowed to remove these items for the duration of the experiment. We were also arranged on signals so that he would know if there was any danger," says Ing. Jakub Šejna.
The project was also challenging from a photographic point of view. "My distance from the fire depended on the intensity of the burn. The smallest distance could have been as little as one metre, but for the experiment with the columns in its most intense phase at about 850 °C it could have been as much as five metres and I had to shoot through the 'door' with a telephoto lens," says photographer Jiří Ryszawy from the Computer and Information Centre of the Czech Technical University in Prague. "Photographically, I also had to deal with the very contrasting environment of the dark test chamber and the glowing fire. It was necessary to manage everything very quickly due to the exposure of the technique to the heat of the fire and at the same time not to interfere with the researchers during the experiment," adds Jiří Ryszawy.
The exhibition consists of photographs depicting a total of four experiments and exhibits such as the world's smallest fire extinguisher or the effect of OSB cladding on the fire resistance of steel beams, always accompanied by the remains of the experiments. Around one hundred and twenty photographs will be on display. These contain both a documentary view and an unusual artistic aspect. "Professionals benefit from seeing the spread of the flame across the surface or the extent and position of the release of water vapour from the wood in detail thanks to the photographs. The fire can be studied in much greater detail. At the same time, the tremendous power of the fire is captured here and a moment that cannot be seen in real time with the naked eye without technology," says Prof. František Wald, project leader and guarantor of the Fire Safety of Buildings specialisation at the Civil Engineering programme at Faculty of Civil Engineering. Visitors will see a photographically captured fire of wooden columns, the development of cracks in the wooden cladding during a fire, a fire test to measure the amount of heat released during a carriage fire and the handling of molten clinker mineral, which is contained in cement, at a temperature of 1400 °C implemented in a special suit. "The footage shows in a unique way the power of fire, which - when one becomes aware of it - can be too late," adds Ing. Jakub Šejna.
Experiments are the basis of knowledge for experts. Their course and results allow us to thoroughly investigate the behaviour of building materials during fire, e.g. how to protect steel structures from its effects, to test new fire-fighting equipment and to create better procedures for safer buildings not only from the point of view of building users but also from the point of view of the firefighters.
"The experiments provide important insights on which national building design regulations can be adapted. We also use the results in our teaching at the faculty, where we introduce students to modern structural design techniques that transfer to practice, for example with advanced numerical modelling. In practice, our results are then used by our colleagues in building fire safety to properly assess structures in a fire, identify critical areas and what to take extra care of," explains Ing. Jakub Šejna.
The experiments are most often conducted in the Fire Laboratory of the UCEEB CTU in Buštěhrad, which has a special test chamber for testing the behaviour of fires in the corner where the fire is most intense, and a small numerically controlled test furnace for testing the behaviour of materials and structures with a possible maximum temperature of up to 950 °C. For experiments focused on the burning of concrete components above 1000 °C, a test furnace is used, which is located directly at Faculty of Civil Engineering in the laboratory of the Experimental Centre of Faculty of Civil Engineering.
According to the words of Prof. František Wald and Ing. Jakub Šejna, students are interested in the specialisation of fire safety of buildings. "Their application in practice is high. At present, there is a great shortage of authorized engineers in fire safety of buildings in the country and we strive to educate new good specialists. Experiments help us a lot with this effort," says Prof. František Wald from the faculty.
The exhibition "The Power of Fire - Fire Experiments of the Faculty of Civil Engineering of the CTU through the Eyes of Science and Photographer's Eyes" will be on display in the Atrium of Faculty of Civil Engineering from 18 to 27 September 2023.It will be open free of charge daily, including weekends, 9.00-17.00. It will include guided tours with interpretation of individual experiments.
More info at www.fsv.cvut.cz