Fire performance of closed-cell charring insulation materials in plasterboard insulation assemblies

This paper presents an experimental study on the fire performance of two types of plastic charring insulation materials when covered by a plasterboard lining. The specific insulation materials correspond to rigid closed-cell plastic foams, a type of polyisocyanurate (foam A) and a type of phenolic foam (foam B), whose thermal decomposition and flammability were characterised in previous studies. The assemblies were instrumented with thermocouples. The plasterboard facing was subjected to constant levels of irradiation of 15, 25, and 65\ua0kW\ua0m using the heat-transfer rate inducing system. These experiments serve as (1) an assessment of the fire behaviour of these materials studied at the assembly scale and (2) an identification of the fire hazards that these systems pose in building construction. The manifestation of the hazards occurred via initial pyrolysis reactions and release of volatiles followed by various complex behaviours including char oxidation (smouldering), cracking, and expansion of the foam. Gas-phase conditions may support ignition of the volatiles, sustained burning, and ultimately spread of the flame through the unexposed insulation face. The results presented herein are used to validate the insulation “critical temperature” concept used for a performance-based methodology focused on the selection of suitable thermal barriers for flammable insulation

An Investigation into the Effect of Exposed Timber on Thermal Load

Recent buildings and research projects have demonstrated the benefits of using engineered timber as a structural material; in addition, changes to codes around the world (including the BCA) are facilitating the use of Cross-Laminated Timber (CLT) as a construction material for medium and high rise buildings. As the material becomes more widespread, the benefits associated with careful engineering of every component of the structure become greater. The loads that a structure experiences during a fire are one such aspect of the design, and this paper presents an assessment of the thermal load that may result from using exposed CLT panels within a building. The thermal load associated with “conventional” compartment fires is already known; however, there is little data on compartments where elements of the timber structure are exposed. This paper therefore presents the results and analyses of a series of small scale tests on Cross-Laminated Timber compartment fires and seeks to give a more comprehensive study of the thermal penetration in depth of the timber structure. Comparison will be made against “conventional” compartments to analyze how a timber structure contributes to the fire by adding more fuel load, and resulting in a different thermal load that the structure has to resist

A calorimetric study of wildland fuels

The burning of two species of pine needles: Pinus halepensis and Pinus pinaster, was studied to characterize the behavior of the forest floor in wildland fires. These fuels are representative of the Mediterranean ecosystem and have very different shapes and surface-to-volume ratios. Calorimetry was performed using the FM-global fire propagation apparatus (FPA). To better understand the effects of transport in the fuel beds, the standard sample holder was replaced by a holder that allowed for the porous properties of the fuel to be studied in a systematic manner. These holders were designed with holes on the surface to allow for different air flow rates to pass through the holder and into the fuel sample. These characteristics created different internal fuel bed conditions and were the first such tests that could be identified that examined transport on this level in these types of wildland fuels. Tests were conducted under natural convection and forced flow. The test series results were analyzed with respect to the direct values of the measured variables and calculated values of heat release rate. Discrete variables of time to ignition, duration of flaming combustion and peak heat release rate were compared using an analysis of variance method. As the experiments were conducted under well-ventilated conditions, the heat release rate calculated by calorimetry was compared to mass loss rate and heat of combustion. CO concentration in time proved to be a good indicator of the combustion dynamics in the fuel bed. Heat release rate, time to ignition and time to reach peak heat release rate indicated a strong dependence on flow conditions and on fuel specie. It was shown that the transport processes in the fuel beds had a significant effect on the burning characteristics

Description of small and large-scale cross laminated timber fire tests

A large-scale fire test was conducted on a compartment constructed from cross laminated timber (CLT). The internal faces of the compartment were lined with non-combustible board, with the exception of one wall and the ceiling where the CLT was exposed directly to the fire inside the compartment. Extinction of the fire occurred without intervention. During the fire test, measurements were made of incident radiant heat flux, gas phase temperature, and in-depth temperature in the CLT. In addition, gas flow velocities and gas phase temperatures at the opening were measured, as well as incident heat fluxes at the facade due to flames and the plume leaving the opening. The fuel load was chosen to be sufficient to attain flashover, to achieve steady-state burning conditions of the exposed CLT, but to minimize the probability of uncertain behaviors induced by the specific characteristics of the CLT. Ventilation conditions were chosen to approximate maximum temperatures within a compartment. Wood cribs were used as fuel and, following decay of the cribs, self-extinction of the exposed CLT rapidly occurred. In parallel with the large-scale test, a small scale study focusing on CLT self-extinction was conducted. This study was used to establish: the range of incident heat fluxes for which self-extinction of the CLT can occur; the duration of exposure after which steady-state burning occurred; and the duration of exposure at which debonding of the CLT could occur. The large-scale test is described, and the results from both the small and large-scale tests are compared. It is found that self-extinction occurred in the large-scale compartment within the range of critical heat fluxes obtained from the small scale tests

A Review of Sociological Issues in Fire Safety Regulation

This paper presents an overview of contemporary sociological issues in fire safety. The most obviously social aspects of fire safety—those that relate to the socioeconomic distribution of fire casualties and damage—are discussed first. The means that society uses to mitigate fire risks through regulation are treated next; focusing on the shift towards fire engineered solutions and the particular challenges this poses for the social distribution and communication of fire safety knowledge and expertise. Finally, the social construction of fire safety knowledge is discussed, raising questions about whether the confidence in the application of this knowledge by the full range of participants in the fire safety design and approvals process is always justified, given the specific assumptions involved in both the production of the knowledge and its extension to applications significantly removed from the original knowledge production; and the requisite competence that is therefore needed to apply this knowledge. The overarching objective is to argue that the fire safety professions ought to be more reflexive and informed about the nature of the knowledge and expertise that they develop and apply, and to suggest that fire safety scientists and engineers ought to actively collaborate with social scientists in research designed to study the way people interact with fire safety technology

Rigorous monitoring is necessary to guide food system transformation in the countdown to the 2030 global goals

Food systems that support healthy diets in sustainable, resilient, just, and equitable ways can engender progress in eradicating poverty and malnutrition; protecting human rights; and restoring natural resources. Food system activities have contributed to great gains for humanity but have also led to significant challenges, including hunger, poor diet quality, inequity, and threats to nature. While it is recognized that food systems are central to multiple global commitments and goals, including the Sustainable Development Goals, current trajectories are not aligned to meet these objectives. As mounting crises further stress food systems, the consequences of inaction are clear. The goal of food system transformation is to generate a future where all people have access to healthy diets, which are produced in sustainable and resilient ways that restore nature and deliver just, equitable livelihoods. A rigorous, science-based monitoring framework can support evidence-based policymaking and the work of those who hold key actors accountable in this transformation process. Monitoring can illustrate current performance, facilitate comparisons across geographies and over time, and track progress. We propose a framework centered around five thematic areas related to (1) diets, nutrition, and health; (2) environment and climate; and (3) livelihoods, poverty, and equity; (4) governance; and (5) resilience and sustainability. We hope to call attention to the need to monitor food systems globally to inform decisions and support accountability for better governance of food systems as part of the transformation process. Transformation is possible in the next decade, but rigorous evidence is needed in the countdown to the 2030 SDG global goals

The state of food systems worldwide in the countdown to 2030

This Analysis presents a recently developed food system indicator framework and holistic monitoring architecture to track food system transformation towards global development, health and sustainability goals. Five themes are considered: (1) diets, nutrition and health; (2) environment, natural resources and production; (3) livelihoods, poverty and equity; (4) governance; and (5) resilience. Each theme is divided into three to five indicator domains, and indicators were selected to reflect each domain through a consultative process. In total, 50 indicators were selected, with at least one indicator available for every domain. Harmonized data of these 50 indicators provide a baseline assessment of the world’s food systems. We show that every country can claim positive outcomes in some parts of food systems, but none are among the highest ranked across all domains. Furthermore, some indicators are independent of national income, and each highlights a specific aspiration for healthy, sustainable and just food systems. The Food Systems Countdown Initiative will track food systems annually to U. Rashid Sumaila, Maximo Torero Cullen, Francesco N. Tubiello, Jose-Luis Vivero-Pol, Patrick Webb & Keith Wieb

Self-sustaining smouldering combustion of faeces as treatment and disinfection method

Smouldering combustion is a novel solution for sustainable treatment of waste. This is a low cost, off-grid and self-sustaining technology, that has been recently applied for soil remediation. Due to the high energy efficiency and the application scale, this technology is suitable for the treatment of organic waste with high moisture content (e.g. agricultural, manure, faeces). In addition, the temperatures achieved during smouldering combustion ensure pathogen destruction; therefore this technology is ideal to disinfect human waste. In this work, we present the study of the smouldering of faeces mixed with sand, at different reactor scales. Sand is used because smouldering needs a porous medium for the propagation of the reaction, enhancing oxygen diffusion. We investigated the limit of experimental parameters (moisture content, air velocity and sand-to-faeces mass ratio) that lead to the minimum faeces destruction rate in a self-sustaining process, using four different reactor sizes. It was found that there is a strong dependence on the moisture content limit with the reactor scale. On the other hand sand-to-faeces mass ratio and air velocity showed almost constant limit values. Experiments with mixed waste (faeces and agricultural) were also carried out to demonstrate the versatility and the robustness of this process towards the waste nature. Sand is clean and hot after the smouldering treatment. Part of the energy of the process can be recovered by mixing the hot sand to pre-dry a new batch of faeces. This can be repeated for at least five consecutive experiments

Investigation of self-sustaining smouldering of faeces: key parameters and scaling effects

The lack of adequate sanitation infrastructure within developing countries enables the transport of faecal matter containing harmful pathogenic compounds into the drinking water sources. The principal consequence of the pathogenic pollutant is 2.5 million preventable annual deaths. The utilisation of self-sustaining smouldering for the treatment of faecal matter mixed with sand is proposed as a solution as the high temperatures achieved ensure the destruction of the pathogens. Sand is used because it is low cost and it has been identified as an effective agent for increasing the porosity of fuels for application of smouldering treatments. Previous studies have shown the sustainability of smouldering combustion to be dependent upon experimental parameters such as moisture content, relative amount of sand and the airflow rate. In this work, we present the results of smouldering combustion experiments that were carried out to determine the sensitivity of the smouldering velocity to those experimental parameters. Experiments were conducted using four cylindrical reactors with varying size. To avoid variability, surrogate faeces which exhibits similar energetic, thermal, and mechanical properties to real faeces, are used in this study. Results showed moisture content is a critical parameter to control the sustainability of the process; however it has no effect on the smouldering velocity under robust conditions. The smouldering velocity showed a linear relationship with the air velocity and the faeces-to-sand mass ratio. Furthermore, it was demonstrated that these relationships are independent of scale. These results can be used to determine the reactor size and experimental conditions under realistic conditions

Prefab housing and the future of building products to process

As we stand on the cusp of a fundamental restructuring of the housing and building industries, this book provides timely insights into the promise of prefabricated housing. The idea of a more industrialised approach to house building is not a new one: since the 19th century, designers, inventors, engineers, builders, developers, and entrepreneurs have all been fascinated by the idea of the factory-built, modular home. But international housing affordability crises, emerging technologies, and concerns for more sustainable building practices have given a new urgency to the need to transform building construction in the 21st century. Richly illustrated and drawing on historical examples and contemporary design studies, the book takes the reader through the foundations of prefab, leading up to a discussion of contemporary problems and opportunities. It includes a broad international survey of leading companies and their products, and draws on research from an international team of experts in the field. This book suggests a future scenario for industrialised house building that will both challenge the existing industry and stimulate the public imagination