Abstract 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.

Surface sampling and laboratory analysis for soot/combustion particulates was conducted following a fire at an education/research facility in the southwest United States. This provided a bank of data by which to probabilistically evaluate the behavior of soot loading (counts/mm2) and relative soot concentration (percent ratio; %R) as useful metrics for quantifying differences in soot impact across a building. Surface tape sampling and analysis via light microscopy were conducted via industry standard protocols, and resulting data from various building zones were selected to construct various comparisons. The performance of counts/mm2 and %R as metrics to identify differences in soot impact for each comparison was assessed by comparing inference generated by traditional Student’s t test, Mann Whitney U rank comparison (MW), and the directly calculated axiomatic probability associated with difference in detection (pΔfd). The fourteen (14) comparisons in which a significant difference was inferred via pΔfd was similarly indicated via Student’s t and/or MW in only four (4) instances. Further, approximately one half of the comparisons generated different inference via pΔfd for counts/mm2 and %R, with the former demonstrating better discriminatory ability. In broad view, the heuristic concept of comparing numerical “soot levels” (e.g., average) by either metric was not generally suitable for the distribution of the data. In contrast, pΔfd avoids the statistical bias imposed by traditional statistical inference, and ultimately the efficacy of post fire comparative surface sampling is as dependent upon the metric and inference model utilized as it is on the sampling and laboratory analytical protocols.

Risk-based design and assessment methods are gaining popularity in performance-based structural fire engineering. These methods usually start by defining a set of hazard scenarios to use as analysis inputs. This approach, proven highly effective for other hazard types such as earthquakes, may not be optimal for fire safety design. Indeed, the strong coupling between the fire phenomenon and structural features enables an ad-hoc design variable selection (and/or optimisation) to reduce fire intensity, making fire scenarios additional design outputs. In addition, such a coupling effect implies that fire scenarios maximising consequences are structure specific. Building on these considerations, this paper discusses the limitations that arise at different analysis steps (i.e., fire-scenario and intensity treatment, identifying fire intensity measures, probabilistic fire hazard analysis, developing fire fragility models, and risk calculation) when using conventional risk-based approaches for design purposes. Furthermore, it compares such approaches with a fire safety design methodology (the Consequence-oriented Fire intensity Optimisation, CFO, approach) that addresses the identified limitations. The potential benefits of integrating the two approaches are also discussed. Finally, the fire design of a simplified steel-girder bridge is introduced as an illustrative example, comparing the consequence metrics and design updating strategies resulting from the two approaches.

Abstract 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.

Providing NFPA 1403 compliant live-fire training can present thermal and chemical exposure risk to instructors and students. To reduce risk, training academies, fire departments, instructors, and standards setting technical committees need more information on how different training fuels used in common training structures can impact the environment in which firefighter training occurs. This study utilized a traditional concrete training structure with multiple compartments to characterize training environments with three different fuel package materials [i.e., low density wood fiberboard, oriented strand board (OSB), and wood pallets]. Exposure risks for a fire instructor located on either the first or second floor were characterized using measurements of heat flux, air temperature and airborne concentrations of several contaminants including known, probable, or possible carcinogens. It was hypothesized that utilizing a training fuel package with solid wood pallets would result in lower concentrations of these airborne contaminants [aldehydes, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs)] than wood-based sheet goods containing additional resins and/or waxes. Additionally, it was hypothesized that these concentrations would be lower than in the single compartment Fire Behavior Lab presented in a companion manuscript. For all measured compounds other than hydrochloric acid, airborne concentrations were 10 to 100 times lower than in the Fire Behavior Lab. OSB-fueled fires produced the highest median concentrations of total PAHs and VOCs such as benzene, while the pallet fuel package produced the lowest median concentrations of these compounds. These trends generally followed the qualitative visual obscuration created by each fuel. Additional tests were conducted on the OSB-fueled fires with increased ventilation and an alternate means of reducing visibility through smoldering smoke barrels. This OSB experiment with increased ventilation resulted in the highest temperatures in the fire room but the lowest impact on visibility throughout the structure, as well as the lowest overall concentrations of contaminants in this study. In contrast, the smoldering straw-filled smoke barrel created a highly obscured environment (with minimal impact on thermal environment) and some of the highest concentrations of the targeted contaminants of any test. These data may be useful in balancing obscuration for training with potential exposure to thermal stressors and contaminants.

Fires can lead to costly building damage as well as loss of lives and injuries. Installed to protect buildings from fire, or to limit the damage from such outbreaks, fire protection measures are a common feature in buildings. However, these features come at a cost. Although quite ubiquitous in buildings, the value of these features to private individuals and to society is not fully understood. To understand their value, a cost benefit analysis detailing the costs and benefits of the systems is needed. Carrying out such an analysis requires methods for computing both the cost of these fire protection measures, and losses from fires (including both direct and indirect losses). This study outlines methodologies for evaluating those costs and losses. An exhaustive collection of available data necessary for estimating both costs and losses is presented. Several limitations in current methodologies and data constraints were identified, with recommendations proposed to address these shortcomings. Relevant sections of a study by the authors that refines fire protection cost estimation at national and sub-national levels are emphasized, including updated building categories, guidance on computing multipliers, and detailed cost calculation methods for installation and maintenance costs. The calculation uses regularly updated U.S. Census Bureau construction data, ensuring timely multiplier updates. The insights and suggestions presented in this study will ultimately refine the process of selecting fire protection strategies that maximize the net benefit of fire protection measures for both private stakeholders and society at large.