Heat induced delamination (HID) is a progressive loss of the not completely charred lamella in engineered wood products (EWPs) that can disrupt composite action and make structural capacity less predictable. The aim of this paper is to assess how (or whether) the choice of adhesive type and imposed mechanical loads affect HID. Bond line response is studied for cross laminated timber and glued laminated timber cantilever beams, where width & times; height & times; length = 200 & times; 90 & times; 1200 mm. Beams were manufactured using one of two adhesive types, either HB S 309 or HB X 702, both of which are one-component-polyurethane adhesives. Samples were tested at an intermediate scale under simultaneous bending and radiant panel exposure. The bond line temperatures under which HID occurred are compared against thermal degradation ranges identified through microscale thermal and smallscale dynamic thermo-mechanical analysis methods. The study shows that in both EWP products the choice of HB X adhesive, rather than HB S, results in higher flexural stiffness and strength under ambient conditions and change in burning behaviour, i.e. reduced char fall off at the bond line after HID.

This paper presents the findings of eight full-scale fire tests conducted to investigate upward vertical fire spread between balconies. The tests explored various configurations involving different deck materials, balustrade types, and the presence or absence of moveable fire loads, using a three-level balcony rig beneath a large oxygen consumption calorimeter. Key parameters measured included ignition times, heat release rates, and radiant heat fluxes. Results demonstrate that exposed combustible decking materials—particularly timber—dominate fire growth and facilitate rapid vertical spread, with flames reaching upper balconies within minutes. Laminated glass balustrades were found to marginally delay ignition of upper balcony contents but contributed minimal fuel to the fire. In contrast, high-pressure laminate (HPL) balustrades added to the fire load and accelerated vertical propagation when combined with combustible decking. A qualitative ranking based on heat release rate, ignition times, and heat flux data was developed to assess the relative fire performance of each balcony configuration. The presence of a non-combustible soffit beneath timber decking delayed fire spread but did not prevent it.

Pedestrian and crowd dynamics involves multiple disciplines, including computer science, engineering, mathematics, physics, bio-mechanics, psychology, social science and more. For effective collaboration between disciplines, researchers need a common understanding of key concepts. To address this challenge, A Glossary for Human and Crowd Dynamics was published six years ago, providing researchers with a valuable reference for cross-disciplinary communication. We now present the second version, which includes 53 new concepts and 12 revisions from the first glossary, collaboratively developed by 65 contributors from various disciplines and regions around the world through a multi-stage process. This process involved identifying new concepts not covered in the first glossary and suggesting revisions to existing entries, voting on proposed additions and modifications, writing definitions for the selected concepts, and collaboratively revising and editing the entries. By introducing new terms and refining existing definitions, this glossary aims to facilitate clearer communication, improve conceptual consistency, and support collaboration among researchers working within the field of human and crowd dynamics from diverse perspectives.

Effective evacuation simulations can be useful for assessing building safety design and optimizing emergency responses. However, configuring these simulations is often manual, time-consuming, and error-prone, especially with complex building geometries and diverse occupant characteristics. This paper introduces an automated workflow that integrates openBIM-based Occupant Movement Analysis data with fire safety regulations from the US and UK using Retrieval-Augmented Generation (RAG) methods and Large Language Models (LLMs). We benchmarked multiple parsing tools, with LlamaParse emerging as the most accurate for extracting text and tables from regulatory documents. We then tested eight RAG approaches with various LLMs across multiple question types and identified Knowledge Graph Enhanced RAG and Neo4j GraphRAG with GPT-4o as top performers in accuracy and consistency. These methods enabled on-demand interpretation of the US and UK regulatory documents for calculating occupant load from IFC-derived geometry data, generating a population input file for an Evacuation simulation as a selected evacuation software in this study. Our evaluation confirms that Knowledge Graph Enhanced RAG excelled in complex reasoning, while Neo4j GraphRAG offered higher stability. This automation enables efficient and reliable safety assessments, contributing to safer building design and emergency response planning.

In 2012, New Zealand introduced significant changes to its building code, including the fire safety clauses known as the C clauses. These changes marked a shift from qualitative assessments to strict, quantifiable legal thresholds. One clause in particular, Clause C3.4, has sparked considerable debate for its economic and legal implications. It mandates that building materials must undergo surface testing according to two specific ISO standards. These tests are designed to measure how materials perform in a fire, but they also highly restrict the means of compliance with the building code. Despite ongoing discussions and recognized challenges with these requirements, no amendments have been made to the C clauses over the past decade. This paper reviews Clause C3.4 and its implications for the construction industry regarding regulatory compliance and determines that C3.4's economic and legal constraints may not be justified under New Zealand law.

This paper investigates air leakage rates between the common corridor and the lift shaft within modern high-rise residential buildings via the lift doors. A literature review has been undertaken which indicates that leakage areas for lift doors are suggested as being between 0.047 and 0.060 m2 with only the latest version of BS EN 12101-13:2022 indicating that a reduction may be necessary to 0.020 m2 for more modern buildings. Leakage areas have been investigated for a 22 storey residential building by recording on-site flowrate and pressure measurements whilst a lift car is in operation as well as attempting to measure the gaps across a set of lift doors. The maximum instantaneous flowrate measured was -89 L/s into the shaft and +99 L/s out of the shaft. The largest pressure change recorded was a depressurisation of -22.5 Pa and the highest pressure recorded was +19.5 Pa. These values result in a maximum calculated leakage area of 0.020 m2 for this building. This value is approximately half of the lift leakage area previously quoted in BS EN 12101-6:2005, however is closer to the suggested tight lift door value of 0.020 m2 in BS EN 12101-13:2020 and would indicate that these are more appropriate for use in analyses of modern buildings.Practical application When undertaking computational fluid dynamics (CFD) modelling of smoke control systems within the common corridors of residential buildings, leakage values can be used for lift doors based on values quoted in BS EN 12101-13:2022. For a pressurisation system design, it is more onerous to use larger values, however, when designing a mechanical extract or depressurisation system, a lower leakage rate is potentially more onerous. This paper shows that the use of lower lift door leakage values from the standard as being more appropriate for use as input conditions within CFD simulations.

This paper acknowledges the influence of Dr Rita Fahy’s life’s work on a research project to evaluate fire evacuation guidance from high-rise residential buildings. It compares the application of agent-based simulations with Rita’s publications into pre-evacuation delay times. Her observed bi-modal distribution shape aligns with an approach to modelling pre-evacuation time as a series of component elements. The paper shows where Rita’s work on discrediting the notion of ‘panic’ is further supported by recent surveys and interviews of high-rise residential building residents. Similar to Rita’s findings in which an average of 61

This paper investigates the fire performance of laminated glass used in balcony balustrades under external heat flux conditions. Experiments examined ignition times and heat release rates (HRR) from laminated glass with different thicknesses of toughened glass with four inter-layer types: polyvinyl butyral (PVB), SentryGlas Plus (SGP), ethylene-vinyl acetate (EVA), and cast-in-place (CIP). Parameters included glass thickness, sample size, thermal exposure, and the condition of the glass pane (broken or unbroken). Thinner PVB samples showed a poorer reaction-to-fire performance when compared to the three other laminate types. At 75 kW/m(2) exposure conditions the 17.5 mm thick PVB samples ignited after 5.6 +/- 0.9 min versus 8.3 +/- 1.6 min for 25.5 mm think samples, faster times than equivalent samples containing SGP and EVA. When 21.5 mm thick unbroken samples were exposed to 75 kW/m(2), the peak HRR was similar to 167 kW/m(2) for PVB and SGP samples compared to similar to 85 kW/m(2) for EVA and CIP. However, the HRR from a 17.5 mm thick PVB sample peaked at 256 kW/m(2) versus 122 kW/m(2) for an equivalent SGP sample. Findings supported using 17.5 mm thick toughened laminated glass with a PVB inter-layer for a series of large-scale balcony fire spread tests in a related study.

Timber-clad facades, traditionally prevalent in North America and Scandinavia, are gaining popularity in central Europe and the UK for applications beyond low-rise buildings. Timber differs from typical cladding materials, such as masonry, due to its non-uniformity, combustibility, and moisture sensitivity, requiring unique design considerations to manage these characteristics. This paper investigates the fire hazards associated with timber cladding, particularly focusing on thermally modified timber, motivated by the 2019 Samuel Garside House fire in the UK. The study aims to address five key research questions: (1) the impact of thermal modification on external fire spread hazards, (2) the fire risk associated with slatted timber configurations, (3) the effectiveness of fire-retardant treatments, (4) the correlation between small-scale standard tests and large-scale behaviours, and (5) the adequacy of current fire safety guidance in addressing these hazards. The experimental campaign involved four timber sample variants: (i) virgin timber, (ii) new thermally modified timber, (iii) aged thermally modified timber, and (iv) fire-retardant-treated thermally modified timber. These samples were tested across four different methods, including the single-flame source test, mass loss cone test, single burning item (SBI) test, and an intermediate-scale test. Results indicated that thermal modification slightly increased the peak heat release rate (HRR) compared to virgin timber. The configuration of timber slats significantly impacted HRR, with vertically oriented slats demonstrating higher HRR than horizontally oriented flat cedar cladding. Fire-retardant treatments substantially reduced HRR, achieving Euroclass B in vertical slatted configurations. However, the long-term efficacy of these treatments under ageing and weathering conditions remains unexplored. This research underscores the need for clarifications in the guidance in timber cladding design, considering the observed fire hazards in different slat configurations and the efficacy of fire-retardant treatments.

A revised means of controlling the Fire Propagation Apparatus (FPA), enabling a constant mass loss rate (MLR), was used to assess effluent generated during the steady state pyrolysis and subsequent charring of polyisocyanurate (PIR) and phenolic insulation foams. The MLR for each foam was set (1 g s(-1) m(-2)), with char formation being investigated under three differing oxidative environments (0, 10 and 20.9 % O-2). The transition from pyrolysis into char formation was identified by the increased heat flux supplied by the FPA lamps whilst maintaining the constant MLR. Species detected in the effluent were found to be both material and process specific; hydrogen cyanide (HCN) was prominent in PIR effluent, whilst phenolic foam tended to favour carbon monoxide (CO) generation. Obtained yields of CO and HCN showed good correlation with the wide range of steady state tube furnace literature data, with an increase in the CO yield aligning with the observation of char formation. It is shown that the oxidative environment can impact the transition between differing combustion processes, thus care must be taken when generating representative effluent streams for emission sampling.

Currently there are numerous emergency evacuation simulation tools with varying levels of sophistication and differing capabilities. It is expected that investigating the same scenarios using different tools might not give the same outcome. This paper illustrates how a microscopic agent-based modelling tool (Pathfinder) and a macroscopic flow-based modelling tool (Evacuationz) can be setup to investigate high-rise residential building evacuations in comparable ways by varying configuration parameters. Both tools represent individual agents with associated characteristics (e.g., walking speed and pre-evacuation delay). These are varied in the scenarios examined to stress-test the designs or explore the impact of design/procedural changes.The two tools differ in how they deal with the building geometry and therefore have different algorithms to manage evacuee movement. In this work, assumed performance parameters (e.g., travel speeds, spacing, etc.) have been calibrated to better align the conditions represented in the tools and the outcomes produced across the scenarios examined. This then allows the tools to function at their respective levels of sophistication and granularity (providing different perspectives on performance) but adopt a more equivalent performance baseline given the calibration effort.The use of two tools increased confidence in the predictions, and also allowed for an examination of a wider range of scenario conditions such as number of stairs, stair width, and building size, given the different computational expense associated with the tools.

In this article, the performance of five radiation models is investigated, including one conventional radiation model, that is, single-point source model, as well as four recently developed models, that is, a weighted multipoint source model, a cuboid flame model, a multicuboid flame model and a multicylinder flame model. The models are assessed in terms of the height of a target above flame base, the horizontal distance of target from flame source, heat release rate and size of burner. The estimations of the theoretical models are compared with propane-based experimental data with heat release rate ranging from 100 to 300 kW and assessed through numerical and graphical analysis. From the results obtained, the single-point source model outperformed the recently developed radiation models in estimating radiant heat received by an object located at a distance from the fire source, albeit it does exhibit some sensitivity to modifications in input parameters.

Guidance issued by organisations such as fire and rescue services, insurers and governmental bodies across the UK for the fire safety design of covered car parks is changing in response to the projected rapid growth in electric vehicle (EV) use. This new guidance is impacting the provision of parking bays, particularly in residential and mixed-use buildings. This paper considers whether EVs in covered car parks pose a greater fire risk than internal combustion engine vehicles (ICEVs) using recent data on the ignition frequency and the burning characteristics of EVs. The recommended mitigating fire safety measures within the new guidance are assessed with a focus on detection, smoke ventilation, sprinkler systems and structural performance as these have the potential to have the greatest impact on a building fire safety design. The paper indicates that the recommendations may not align with available evidence which challenges a balanced approach to fire safety requirements to prevent over-specification that could affect the feasibility of building designs. This paper summarises recent fire safety guidance in the UK on the use of electric vehicles (EVs) in covered car parks. Factors that contribute to the risk posed by EVs are investigated and practical design values for heat release and fire growth are suggested. Key recommended fire safety measures proposed in the guidance have been assessed against existing evidence. The findings are useful to stakeholders involved in the design of covered car parks to allow a balanced approach to their fire safety requirements.

This short communication presents the findings of the work conducted by the human behaviour in fire permanent working group of the International Association for Fire Safety Science. Its aim is to identify determinants of research gaps in the field of human behaviour in fire. Two workshops were conducted in 2023 in which research gaps were identified and discussed by twenty experts. The workshops led experts through a series of questions to determine the reasons (or determinants) for these gaps in human behaviour in building fires and wildfires. Through the questions, the primary identified determinants were (1) researchers’ literacy in the variety of methods adopted in the field, (2) difficulties associated with recruitment of study participants, (3) multi-disciplinary barriers across different research sub-domains, and (4) issues in obtaining funding for addressing fundamental human behaviour in fire research questions. Two key issues emerged from an open discussion during the workshops, namely the difficulties in attracting and training new people in the field (given the limited educational offers around the world on the topic) and the need for more regular opportunities for the community to meet.

The adoption of timber, specifically cross-laminated timber (CLT), as a primary construction material is gaining traction due to its carbon sequestration capabilities, environmental advantages, and potential for precision manufacturing. However, the combustibility of wood raises legitimate concerns about fire safety in timber-based residential buildings. This paper investigates the fire performance of timber in a residential context, attempting to fill knowledge gaps and outline strategies for improving fire robustness in timber-built dwellings. Through comprehensive experimental studies on residential-type enclosures constructed with CLT panels, this research explores different configurations and the effects of varying degrees of non-combustible protective lining. The findings underscore the significance of considering timber surface exposure and adopting effective encapsulation strategies in CLT buildings. It has been estimated that the exposure of timber walls leads to a proportional increase in heat release rate, corresponding to the area of exposed timber surfaces and their charring rates. Consequently, the external flame has a larger projection, resulting in a much greater heat flux to the façade. Furthermore, threshold conditions for initial flaming self-extinguishment of timber defined in literature of 44.5 ± 1.2 kW/m2 have been found to be applicable to the experiments conducted in this research. Finally, it has been observed that partial encapsulation, where the protective lining will likely fall off during a fire, may hinder rather than increase the likelihood of self-extinguishment. This work contributes towards a nuanced understanding of fire dynamics in timber structures, offering insights for safer and more effective design strategies for CLT-based construction.

This paper provides further understanding of the fire performance of exposed cross-laminated timber (CLT) in large enclosures.An office-type configuration has been represented by a 3.75 by 7.6 by 2.4 m high enclosure constructed of non-combustible blockwork walls, with a large opening on one long face.Two experiments are described in which propane-fuelled burners created a line fire that impinged on CLT ceilings.The first experiment had a smooth CLT soffit, with the CLT formed from 160 mm thick panels (40-20-40-20-40 mm).The second experiment adopted the same CLT but included a 400 mm deep, 200 mm wide glulam beam half-way along the length of the enclosure.In both experiments, the lamella of each CLT were bonded using a standard polyurethane adhesive.The facing lamella of the CLT was not edge bonded.The results indicate the importance of consideration of the impact of ceiling protrusions, such as down-stand beams, with differences in both radiative heat flux to the ceiling and floor observed between the two cases.Considering large contemporary open plan office enclosures, this would likely translate to differences in spread rate within an enclosure and time to auto-extinction of flaming combustion which should be addressed by designers.

Cooking oil fires present a hazard to the occupants of residential flats with open plan kitchens where the means of escape passes fixed cooking appliances. Recent guidance has proposed a separation distance of 1.8 m from a hob/stovetop, but the basis of this advice is unclear. This paper carries out a probabilistic thermal radiation analysis using the thermal fractional effective dose (FED) methodology to assess the likelihood that the specified separation distance will be exceeded. Statistical data collected from a previous survey of cooking oil usage is used to determine reasonable worst‐case maximum heat release rate values as input to the point source model to calculate thermal radiation exposure. Occupant exposure times are assessed using walking speeds based on occupant demographics. The analysis suggests that the 1.8 m criterion equates to approximately a 99th percentile where there is no cap on the heat flux that an occupant can tolerate. This falls to the 88th percentile when the maximum tolerable heat flux is capped at 2.5 kW/m 2 to account for vulnerable occupants.

Fire loads are often used in the fire safety design of buildings as part of the assessment of the severity of potential fires. Despite recognition that balconies may contain combustible items which could contribute to fire development, there has been little research on balcony fire loads. This paper presents the results of a survey of 1020 balconies on private dwellings across England and the calculated fire loads. Consideration is also given to the influence of key parameters on the fire load energy density. It is found that balconies in England have an average fire load energy density of 64.4 MJ/m 2 , with an 80th percentile value of 110 MJ/m 2 . The influence of selected key parameters on balcony fire loads is also assessed. The results presented provide balcony fire loads which could be considered as part of building design.

Ensuring that residents of high-rise residential buildings follow fire safety guidance in emergencies is important to facilitate safe response. However, little prior research has explored how willingness to follow fire safety guidance is impacted by trust in the guidance itself and trust in the creators of the guidance. The research presented herein hypothesised that the relationship between perceived clarity of the guidance and self-reported willingness to follow the guidance in an emergency would be mediated by both trust in the guidance and trust in the creators of the guidance. An online survey (N = 769) with residents of UK high-rise residential buildings was conducted to examine the relationship between participants' perceived clarity of their building's fire safety guidance (both to stay put and evacuate) and their self-reported willingness to follow it. Specifically, we explored how this relationship was impacted by trust in the guidance itself and the providers of the guidance. Parallel mediation analyses showed that the relationship between the perceived clarity of the guidance to and willingness to follow it operated through trust in the guidance and trust in the creators of the guidance. The results replicate previous research on group processes in emergencies but highlight the importance of addressing how views of guidance, its creators, building safety as well as physical constraints may influence emergency response.

Understanding how people respond in the first moments of fire incidents is crucial for emergency planning and preparedness, and disasters such as the Grenfell Tower fire show that much work is needed to ensure safety for residents of high-rise residential buildings. This research applied the social identity approach to emergencies to explore how group dynamics impact resident behaviour in high-rise building fire incidents. We conducted 16 semi-structured focus group interviews with 40 residents of UK high-rise buildings to explore how they had responded or would respond to a fire in their building. Using reflexive thematic analysis, we found that group processes underpinned who residents looked to for information about the fire and whose views were trusted when deciding response. Collective self-organisation among residents instead of immediately following the safety guidance for the building was a recurring theme across the focus groups. Most residents reported that they would provide and expect help from other residents to evacuate, including relying on others to inform them if evacuation was needed. However, residents who felt there was little social connection among the residents anticipated they would not receive help in the event of a fire, and immediate threat to self also limited the help some felt they were able to provide. We find support for the social identity approach to emergency response in a novel context of high-rise residential buildings and foreground the importance of group processes for fire safety guidance.