Determining the effect of fire from external air conditioning units on buildings' facades

This paper considers the issue of assessing the possible impact of fire in external air conditioning units on the evolution of façade fires using the example of a typical façade of the building. Current methods for assessing the effectiveness of limiting the spread of façade fires do not take into account the possibility of external fire load. Existing methods of studying the effects of combustible components in façade systems are intended only to investigate the reaction to the fire of façade systems. At the same time, it should be understood that modern façade systems include additional components that not only have a significant fire load but can be the cause of a fire. Taking that into consideration, a study was conducted on the impact of a possible fire of external air conditioning units on the development of its evolution by vertical structures in buildings. During the FDS modeling, the possibility of facing materials from a low combustibility group, which are typical for modern façade systems, is taken into account. Analysis of the fire load of the components included in the design of air conditioning units has made it possible to recreate the model of the combustion reaction of the main components and determine the value of its maximum intensity. The data on the thermal distributions on the surface of the façade made it possible to make assumptions about the necessary structural parameters that should be observed when determining the places of installation of baskets for air conditioners. The established dependences are a prerequisite for revising the criteria for assessing the potential fire danger of façade systems, which may include additional engineering systems. The derived dependences will make it possible to revise approaches to existing field procedures for assessing the fire danger of façade systems. The practical result of the implementation of these data may be amendments to building codes to increase the level of fire protection of façade systems and buildings in general