CHALLENGES FOR FIRE SAFETY IN ETIC SYSTEMS WITH POLYSTYRENE INSULATION

摘要

Several fires involving external thermal insulating (ETIC) systems with polystyrene in Germanyrnstarted an extensive discussion about fire safety of such systems. The Frankfurt fire service started torncollect reports about real fire cases which involved ETICS with polystyrene two years ago. This collectionrnshows that especially fires, which started in front of the buildings led to more severe fires of the facadesrnthan fires inside the buildings. In several fires the ignition sources were burning waste containers. Three ofrnthe real cases are discussed in more detail: a serious fire in Frankfurt on a building site and two fires ofrnapartment buildings, which developed quite differently. Additionally the plastic waste containers, whichrnstarted several fires are investigated regarding ignitability and heat release rates. The investigation showsrnthat plastic waste containers are very effective as ignition source and that the usual placement directly inrnfront of combustible facades can be a problem for fire safety. Moving these containers and unintentionalrncontact with the facade can lead to damage of the facade coating. These damages were investigatedrnqualitatively and quantitative on a wide collection of buildings. After classifying the damage intermediaternscale tests were performed in a modified Single Burning Item (SBI) Test. The damage of the coating wasrnvaried as well as the power of the sand bed burner of the SBI apparatus. The damage significantlyrninfluenced the fire development on the specimen. In some tests the damaged rendering of the ETIC systemrncollapsed and resulted in a sudden fire growth: after the collapse of the rendering the whole specimen wasrnsuddenly on fire. Several effects, which could be seen in the intermediate scale tests correspond tornobservations which were made in the real cases. As a consequence of the investigations challenges andrnpossible measures to enhance fire safety of ETIC systems are discussed.