The interest in the use of textile membranes as a building material has grown. They are already on the market and used in a wide range of buildings, such as sports arenas, exhibition halls and other common rooms. The use of membranes in large constructions gives the constructer a possibility to create new, creative and often complex forms in buildings. This use is new and understanding of how these materials behave in fire is inadequate. However research is underway in the area, including an inter European project called Contex-T “Textile Architecture – Textile Structures and Buildings of the Future”, where the Technical Research Institute of Sweden (SP) is a party. This thesis is one of the tasks SP has shouldered in the project.