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Summary: The serious fire incident at Grenfell Tower in London, involving a combustible façade system that was installed as part of a major refurbishment of the building, has raised concerns regarding the fire risk that these systems pose. The fire spread over the façade of the Tower was previously numerically modelled and this model was validated by comparison with observational data. This model was used to determine the fire behavior of the façade and the fire's propagation into apartments through windows. In the present paper, impact models are used to evaluate tenability conditions inside the Tower, especially for the apartments in the first corner of the Tower that caught fire. The source of toxic effluents includes the components used in the refurbishment of the façade and the apartment furniture. Different hypotheses of gas yields are tested to assess variability and unknowns in the burning conditions. An extensive literature review was conducted to investigate the toxic yields to be considered in the simulations. Tenability conditions are assessed for each apartment during the fire spread over the façade. This leads to the quantification of the thermal and toxic environment inside the apartments. Two different models are tested for thermal and toxic threats, and the influence of the insulation material used in the façade is investigated. The results showed that the same conclusion can be made regardless of the input data for toxicity and the model used, within the limits of the studied dataset and conditions. Fires from the apartments quickly drive tenability conditions, independently of the dataset and model used, and even if mineral wool is used instead of poly‐isocyanurate as façade insulant. [ABSTRACT FROM AUTHOR]

Summary: The recent dramatic events at Grenfell Tower in London involving a combustible façade system have raised concerns regarding the fire risk that these systems pose. The spread of fire over the façade of the Tower was previously modelled numerically and the results of this modelling were validated by comparison with observations of the real fire. This model was used to determine the fire behaviour of the façade and the propagation of the façade fire into the apartments through windows. The modelling used an impact model according to ISO 13571 and included fire loads from the façade and, when relevant, from apartment contents. Tenability levels inside the apartments were quantified by an analysis of the toxic and thermal conditions due to the combustion of the façade materials and the apartment contents. In the present paper, the conditions inside the lobbies and stairs of the Tower are investigated, building on the previous analysis of the apartments. This allows an understanding of the evolution of toxic and thermal conditions whilst the fire spread, and their impact on egress during the fire event. [ABSTRACT FROM AUTHOR]

Summary: The tragic events at Grenfell Tower in 2017, involving a combustible façade system, have raised concerns regarding the fire risk that these systems pose. In this series of articles, so far published, fire development inside the initial apartment has been investigated using an appropriate computational fluid dynamics (CFD) model. Several scenarios including different fire sources and ventilation conditions were addressed. Fire propagation through the window to the external façade and to higher apartments was modelled. This model was validated by comparing the numerical results with the visual observations reported in the Grenfell Inquiry. A CFD model of the complete east face of the Grenfell Tower was then created. This paper details CFD modelling of the complete Grenfell Tower façade during the late horizontal phase of fire spread. As the physics of lateral flame spread is different from that for upward flame spread, it is important to assess the validity of the model, thus far developed, for this configuration. Fire propagation over the whole façade is modelled and compared with observations from the real disaster. This provides a better understanding of its fire behaviour and of the contribution of architectural details and their impact on fire spread. [ABSTRACT FROM AUTHOR]

Summary: The Grenfell Tower fire occurred on 14 June 2017, killing 72 people. The pattern and speed of vertical and horizontal fire spread characterize this catastrophic event. Plentiful video and photographic data of the fire spread available has been carefully verified and concatenated into a database. The verified data have been superimposed on a projection of the Grenfell Tower in order to track the development of the fire. The surface that is unburnt, burning, or extinguished, as well as the presence of internal fire at any given location, is thus recorded for the duration of the fire. An analysis of the results showed that the initial vertical propagation can be divided into three phases. After the façade ignited at the fourth floor, vertical propagation over time is linear, with a vertical fire spread rate of around 3.5 m/min until the fire reached the sixth floor. Then fire propagation decelerated. Finally, fire spread accelerated with a power four dependence. The maximum vertical fire spread rate was around 8 m/min as the fire reached the crown at the top of the building. Horizontal spread proved to be greatest at the level of the crown (0.293 ± 0.005 m/min). There is a linear relationship between speed of horizontal fire spread and height. These correlations and observations yield important conclusions, and eight different hypotheses capable of explaining the global behaviour of the fire are suggested. [ABSTRACT FROM AUTHOR]

Summary: The dramatic event of the Grenfell Tower in 2017 reminds the importance of addressing fire issues as a whole and clearly highlighted one of the major roles played by the façade as fire propagation vector. To understand and analyse this disaster, numerical simulation allows particular phenomena to be evaluated more easily. The numerical model addressed for the fire behaviour of the façade system was developed using a multiscale approach and validated at different scales. In this paper, the fire behaviour of the façade and of its window frames is addressed. A computational fluid dynamics (CFD) model is used to investigate the fire spread from the initial apartment to the overall façade with different scenarios for the fire source and ventilation. Fire propagation through windows to the façade and to upper apartments is addressed. General curves representing the re‐entry of flames into upper apartment are extracted from simulations. The numerical results are validated by comparison with observations from videos and pictures of the real fire. Numerical results show that whatever the initial fire location and ventilation conditions, even if the fire source is of hundreds kilowatts, it is enough to ignite the adjacent element early and to the appearance of external flames shortly after. [ABSTRACT FROM AUTHOR]

Summary: The dramatic event of the Grenfell Tower (June 2017), involving a combustible façade system, has raised concerns regarding the fire risk that these systems address. Indeed, as façades are complex systems, it is not straightforward to assess which part of the system is involved in the global fire behaviour. Understanding such façade fires is thus very complex as it depends on a combination of various products and system characteristics, including window frames or air gap or cavity barriers. Fire development inside the initial apartment was investigated using an appropriate CFD model with different scenarios for the fire source and ventilation conditions in a previous study. Fire propagation through the window to the external façade and to higher apartments was modelled and validated against visual observations. This paper describes CFD modelling of the complete Grenfell tower facade, and investigates vertical fire spread behaviour over the full height façade from the initial apartment. Contributions from the combustion of all the apartments' furniture, depending on window failure, and architectural details of the refurbished façade are considered in the numerical model. The modelling results are validated by comparison with photographic and video observations of the real fire. [ABSTRACT FROM AUTHOR]

Summary: The recent fire events in buildings involving combustible cladding systems have raised concerns regarding the risk that these systems can pose. Understanding such facade fires is complex as they involve a combination of various products and system. Facade fire propagation tests at ISO 13785‐1 intermediate scale were performed on different combinations of aluminium composite material (ACM) claddings and insulants. Simulations were addressed to reproduce these tests and were validated in terms of thermal conditions in the system. This allowed additional investigation and understanding of fire propagation on the facade and more accurate determination of the fire behaviour of the overall system. In this paper, the scaling influence on the fire behaviour of ACM clad systems is investigated with simulations performed to reproduce fire tests at the BS8414‐1 larger scale on three different combinations of ACM and insulants. The contributions of the cladding and insulant were numerically investigated. The fire behaviour of each component and of the overall system is validated by comparison with experiments. Simulations and tests show that the ACM cladding is the most important element driving the global fire behaviour of the systems. In particular, ACM‐PE‐based cladding systems, whatever the insulant, show extensive fire propagation while its degradation affects the integrity of the cavity. [ABSTRACT FROM AUTHOR]

Summary: Increasing the energy performance of buildings is a crucial sustainable development objective. However, building features, products, mounting, and fixing of façade components have a large impact on fire safety. Authors in previous study performed façade fire propagation tests according to ISO13785‐1 on different combinations of ACM claddings and insulants. In this paper, simulations are performed to reproduce three of these tests. The model is validated with the aforementioned experimental results, including details in terms of thermal conditions in the system. This allows better understanding of the fire propagation on the overall system. Additional information, such as the relative contribution of the cladding and the insulant, are investigated numerically. The fire behaviour of each component of the overall system is thus validated. Simulations and tests performed show that the ACM cladding is the most important element driving the global fire behaviour of façade types considered. In particular, ACM‐PE–based cladding systems show large fire propagation whatever the insulant. This series of simulations is a part of a larger study including several steps of increasing complexity. Once the model for the fire behaviour of façade system is validated at intermediate scale, larger façade systems will be investigated numerically to evaluate the influence of scaling. [ABSTRACT FROM AUTHOR]

Summary: The fire behaviour of a building façade is dependent on the overall system's performance, rather than the performance of the individual components. A façade system includes the cladding and the insulant's characteristics, but also the cavities, cavity barriers, mounting and fixings, substrate, and any singularities, such as window frames. This publication presents façade fire propagation test according to the ISO 13785‐1 standard, with additional heat release rate and gases analysis using FTIR. Tests have been performed on 9 different compositions of aluminium composite panels (ACM) with several insulants. For tested compositions, the cladding is the most important parameter driving global fire behaviour of façade mock‐ups. ACM‐PE‐based cladding systems gave very different results from the other solutions tested. This was especially visible in heat release rates, where fire intensity was very high, whatever the insulant used in the system. The contribution of the insulant was only remarkable in these tests during the decay phase. The cavity barrier was largely ineffectual in the 3 tests with ACM‐PE cladding, as the integrity of the cavity was not ensured. [ABSTRACT FROM AUTHOR]