Reconstruction of the Grenfell Tower fire – Part 4: Contribution to the understanding of fire propagation and behaviour during horizontal fire spread

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.     

Structural evolution at short and medium range distances during crystallization of a P2O5-Li2O-Al2O3-SiO2 glass

Li₂O-Al₂O₃-SiO₂ (LAS) glass-ceramics have important industrial applications and bulk nucleation is usually achieved by using nucleating agents. In particular, P₂O₅ is an efficient agent in glasses containing a low level of Al₂O₃ but its role in the first stages of nucleation is not well established. In this study, we combine structural investigations from local to mesoscales to describe the structural evolution during crystallization of LAS glass-ceramics. Local environment is probed using ²⁹Si and ³¹P MAS-NMR, indicating organization of P in poorly crystallized Li₃PO₄ species prior to any crystallization. To better understand the detailed nanoscale changes of the glass structure, ³¹P-³¹P DQ-DRENAR homonuclear correlation experiments have been carried out, revealing the gradual segregation of P atoms associated with the formation of disordered Li₃PO₄. Small-angle neutron scattering data also show the apparition of nanoscale heterogeneities associated with Li₃PO₄ species upon heating treatments and allow the determination of their average sizes. These new structural information enhance our understanding of the role of P in nucleation mechanisms. Nucleation is initiated by gradual change in P environment implying P segregation upon heating treatments, forming disordered Li₃PO₄ heterogeneities. The segregation of P atoms enables the precipitation of meta- and disilicate phases.     

Association of solid fuel use with risk of stunting in children living in China

Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = −0.21 [−0.32 to −0.09] and −0.17 [−0.31 to −0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel.     

Assessment of fly ash-aided phytostabilisation of highly contaminated soils after an 8-year field trial Part 2. Influence on plants

Aided phytostabilisation is a cost-efficient technique to manage metal-contaminated areas, particularly in the presence of extensive pollution. Plant establishment and survival in highly metal-contaminated soils are crucial for phytostabilisation success, as metal toxicity for plants is widely reported. A relevant phytostabilisation solution must limit metal transfer through the food chain. Therefore, this study aimed at evaluating the long-term efficiency of aided phytostabilisation on former agricultural soils highly contaminated by cadmium, lead, and zinc. The influence of afforestation and fly ash amendments on reducing metal phytoavailability was investigated as were their effects on plant development. Before being planted with a tree mix, the site was divided into three plots: a reference plot with no amendment, a plot amended with silico-aluminous fly ash and one with sulfo-calcic fly ash. Unlike Salix alba and Quercus robur, Alnus glutinosa, Acer pseudoplatanus and Robinia pseudoacacia grew well on the site and accumulated, overall, quite low concentrations of metals in their leaves and young twigs. This suggests that these three species have an excluder phenotype for Cd, Zn and Pb. After 8 years, metal availability to A. glutinosa, A. pseudoplatanus and R. pseudoacacia, and translocation to their above-ground parts, strongly decreased in fly ash-amended soils. Such decreases fit well together with the depletion of CaCl₂-extractable metals in amended soils. Although both fly ashes were effective to decrease Cd, Pb and Zn concentrations in above-ground parts of trees, the sulfo-calcic ash was more efficient.