FACADE FIRE · Numerical characterisation of fire growth in external facades and other vertical spaces

Numerical characterisation of fire growth in external facades and other vertical spaces

In modern highrise buildings, the exterior walls are often suspended from the concrete floor slabs. Examples include curtain walls and precast concrete walls. Fire growth through spreading up the façade of high-rise buildings can lead to catastrophic loss of life and property. For this reason, façades at times are required to have a fire-resistance rating, for instance, if two buildings are very close together, to lower the likelihood of fire spreading from one building to another. The issue is becoming increasingly critical because new façade materials and assemblies are being continuously introduced for better insulation and durability against rain and wind. This development is also accompanied by the advance in ‘‘smart facade’’ technologies. Fire spread on the external walls of a building can be initiated from fully involved enclosure fires at a given floor of the building, from a fire in an adjacent building or other rare events as the impact of objects such as airplanes on the building like September 9.11 of the World Trade Centre Fire. The success of devising mitigation strategy for façade fire safety should hence be based on solid understanding about the nature and hazards of fully involved enclosure fires followed by their growth along the building façade. The overall aim of the proposed research is to investigate numerically (taking advantage of past experimental and analytical study) the behaviour of ejected flames from enclosure fires in external facades and other vertical spaces such as atrium, void spaces and staircases. Full understanding of such external flame behaviour requires insight of the combustion within the enclosure. Hence the scope of the research includes enclosure fires to characterise the ejected flames as well as fire growth in facades and other vertical spaces. The specific objectives are: • Fine tune and validate the open source CFD code FireFOAM, a dedicated LES based solver for fire simulation within the OpenFOAM® Toolbox for enclosure fires; • Investigate the combustion and aerothermodynamics of enclosure fires, including travelling fires; • Characterise the spill flame extent, combustion efficiency and heat fluxes inside and outside different enclosures with different openings (office blocks, residential buildings, travelling fires, etc.); • Develop and validate a predictive approach based on FireFOAM for fire growth in external facades and other vertical spaces; and • Conduct parametric studies and draw guidance for fire safety design.

Data: CORDIS, © European Union