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Temperature dependent properties of type X gypsum board: (a) Thermal conductivity; (b) specific heat; (c) density.
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Currently, green roof fire risks are not clearly defined. This is because the problem is still not well understood, which raises concerns. The possibility of plants catching fire, especially during drought periods, is one of the reasons for necessary protection measures. The potential fire hazard for roof decks covered with vegetation has not yet b...
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One of the primary functions of green roofs in urban areas is to moderate rainwater runoff, and one of the major impediments to the survival of plants on an extensive green roof (EGR) is a lack of available water during dry periods. Runoff moderation and water storage are both influenced by the composition of the growing media. Here we present a fr...
Citations
... The main criterion selected for defining the DPCs of this indicator reflects the likely heat flux radiation coming from the vegetation fire to the heritage construction under assessment. As such, the factors that are considered are the distance from the construction to the potential heat source [36,44,[92][93][94], and the number of sides/flanks of the construction that may be exposed to this effect due to nearby vegetation. The scenarios that are selected to establish the DPC levels are defined in Table 9. ...
... This study is fundamentally conducted through the relationship between HRR (Q c ) and helium release rate (q h ), allowing the investigation of smoke dispersion corresponding to different types and materials of rooftops by the correlation. Regularly, dry green roofs and wood roofs can cause fires and Refs [43,44] indicate that dry green rooftops have a maximum of 200 kW/m 2 HRR, while wood rooftops have a maximum of 300 kW/m 2 HRR, respectively. Rooftop PV fires have a larger HRR (max 500 kW/m 2 ), posing a higher risk with higher indoor non-dimensional T* (0.02) compared to wood roof fires (T* = 0.013) and green roof fires (T* = 0.009). ...
In 2022, global photovoltaic (PV) deployed capacity increased by 240 GW, reaching a cumulative capacity 1.185 of terawatts, accompanied by anticipated 34,247 PV-inducted fires. The dispersion of fire smoke from rooftops with PVs raises significant safety concerns regarding residents’ exposure. Therefore, it is essential to investigate the phenomenon of smoke dispersion generated by rooftop PV fires, particularly through rooftop openings such as skylights. However, there are limited studies on this topic in the literature. This study conducts small-scale tests in a wind tunnel to examine rooftop PV fire smoke dispersion using a novel smoke-helium similarity and scaling law. A parametric analysis is carried out, aiming to guide the fire protection design of the building. It examines the smoke dispersion generated from rooftop PV fires, considering a variety of rooftop angles, incoming wind velocities, as well as heat release rates (HRR). According to the findings, residents exposed to rooftop PV fire smoke must evacuate within 4 min. Moreover, descending to lower levels may not be a safe means of escape. The scenario with a 15° rooftop angle is deemed fatal. Conversely, rooftop angles of 45° and 60° are considered the most reliable layout for rooftop PV. As incoming wind velocity decreases from 7.75 m/s (full-scale 30 m/s) to 2.58 m/s (full-scale 10 m/s), smoke dispersion increases across the rooftop opening (e.g., skylight) as the rooftop angle increases from 0° to 30°. Smaller HRRs of rooftop PV fires correspond to more reliable fire protection.
... There was a case that happened during the summer of 2018, which was caused by the sparking of a nearby transformer and started on a poorly maintained vegetated roof with dried, overgrown plants. At the same time, another case happened on an EGR in London, possibly due to cigarette ignition [37][38][39]. Table 2 summarises the detail of GR implemented in Malaysia. Residential, commercial and institutional buildings are Malaysia's three common types of buildings with GR initiatives. ...
Urbanization and population density surges globally have triggered environmental challenges, with the construction sector notably contributing to greenhouse gas emissions and high energy consumption. Urban expansion has exacerbated issues, converting green spaces into impermeable structures and heightening flood risks. Green roofs have emerged as an eco-friendly solution, excelling in stormwater management, mitigating the urban heat island effect, enhancing air quality, reducing noise transmission, preserving biodiversity, extending roof lifespan, and augmenting aesthetics. They absorb rainwater, decreasing stormwater runoff, yet entail higher installation and maintenance costs and potential fire hazards compared to conventional roofs. In Malaysia, government policies and incentives drive green roof adoption, particularly in residential, commercial, and institutional buildings, predominantly of the intensive green roof type. Buildings undergo green rating tool evaluations for green certification. Despite progress, challenges persist, including expertise shortages, lack of design guidelines, limited research, low public awareness, and green roof component disposal issues. Addressing these demands significant government efforts, including robust policy development, increased support for local companies, expanded research initiatives, heightened public awareness, and optimized synergy with other technologies. Integrating green roofs with solar panels and utilizing greywater for irrigation can reduce energy and water consumption concurrently, showcasing potential for comprehensive and sustainable urban development.
... In 2019, one composition of the green extensive roof was tested by the company ISOVER [1], and this issue is further discussed in the Czech Republic in articles [2], [3]. Abroad, the Canadian Université Laval deals with this topic, with publications [4], [5], [6]. Due to the susceptibility of plants to ignition, green roofs may raise concerns about fire hazards. ...
The main request for roof exposed to fire is the classification Broof (t3), which prevents the transfer and spread of flame on the surface, this is not required for green roof according to Czech fire standards and regulations. A fire can spread in three ways: direct contact, flying burning particles and thermal radiation. In most cases, the spread of fire between objects occurs with the help of radiation. The article deals with the difference in flame spread over the surface of a green roof during a normal fire without the influence of radiant heat and the Broof (t3) test, where the surface is exposed to radiant heat. The aim was to determine the dependence of flame spread on a flat green roof due to the effect of radiation during a fire and the possibility of endangering neighboring buildings.
... Until now, only a few full-scale studies have focused on the fire hazard of multiple wooden houses in China. Notably, the smoke concentration and the temperature distribution during fire spread are closely related to a series of conditions [23,24], such as the fire separation between adjacent buildings [25], the combustion structure [26], the relative slope [27], the roof temperature [28], the external wind speed at the time of fire [29], the moisture content of wood [30], and the atmospheric temperature [31,32]. Therefore, the main factors influencing fire spread need to be analyzed by actual fire tests [33,34]. ...
In ancient villages, the spread of uninterrupted fires caused great damage to clustered wooden houses. Thus, the spread of fire among wooden houses should be systematically studied to explore its characteristics. Statistical analysis is a feasible way to study the characteristics and underlying mechanisms of fire in full-scale wooden houses. In this study, 4 full-scale wooden buildings were built in an ethnic village in Guizhou Province, and the fire spread test was conducted by igniting a 0.63-MW power wood crib. To investigate the fire spread, the visual characteristics were observed, and the temperatures and heat radiation at special locations were monitored with thermocouples and radiation flowmeters, respectively. The effect of relative slope, heat radiation, and wind direction on fire spread characteristics was established by mathematical statistics, and the measured temperatures were used to verify the statistics’ regularity. The results showed that in wooden houses, fire spread was mainly influenced by the slope, the distance between houses, and wind direction. When the inner wall of a wooden house is protected by a fireproof coating, the thermal radiation spread and fire spread are both slower. The slope and distance had the same influence weight (0.41) on fire spread; however, since they affect the process in different ways, they should be analyzed separately for fire risk evaluation. The findings of this study provide a theoretical foundation for understanding the fire spread process in wooden buildings.
... failure risk, complex installation) and climatic (i.e. fire risks, unavailability of suitable plants) challenges that result in the low implementation of GRs (Lee, 2013;Gerzhova et al., 2019). Thus, several strategies and actions have been proposed to overcome the barriers so that wider adoption of GRs in different countries would be possible (United States Environmental Protection Agency, n.d.; DiNardo, 2019; City of Sydney, 2014). ...
Purpose
Reportedly, green roof (GR) makes a significant contribution towards a truly sustainable-built environment; however, its implementation is yet to hit a sufficient level in developing countries. Thus, this study assesses GR implementation strategies in developing countries by providing a comparative analysis through experts in Kazakhstan, Malaysia and Turkey.
Design/methodology/approach
The study adopts a four-step methodological approach to achieve the research aim: literature review, focus group discussion, fuzzy analytical hierarchy process (FAHP) analysis and correlation analyses. First, a literature review followed by a focus group discussion is used to determine 18 (out of 25 initially) strategies for the selected context and these are classified into three categories: governmental and institutional support, knowledge and information and policy and regulation. Afterward, the identified GR strategies are evaluated using the FAHP with the data gathered from the experts in the countries studied. Finally, correlation analyses were used to observe the strength of agreement between the assessments of experts from the included countries.
Findings
The findings indicate that financial incentives, low-cost government loans and subsidies and tax rebates are the essential strategies for the wider adoption of GR. Evaluating the policy and regulations strategies also showed that mandatory GR policies and regulations and better enforcement of the developed GR policies are ranked as the most prominent strategies. The findings show a low level of agreement among respondents from Kazakhstan, while there is a high level of agreement between the experts in Malaysia and Turkey.
Research limitations/implications
The research contribution is twofold. First (research implication), the study identifies the strategies through a complete literature review. Second, the identified strategies are evaluated through the lenses of experts in three developing countries which are hoped to provide (practical contribution) a better understanding of the most effective strategies that require attention and enable the frontline stakeholders (particularly government authorities) to focus on them.
Originality/value
The study findings provide a good point of departure to explore the strategies for broader adoption of GRs in developing economic setting.
... When the numerical simulations provided by the software are timely considered, fire occurrences in buildings can be minimized, and the evacuation process is accelerated. Finally, it can be concluded that CFD modeling, FDS and CFAST are highly effective in predicting fire spreading in buildings [47,48,72]. However, it has been noted that FDS has the greatest popularity in fire simulation of the buildings as compared to other buildings. ...
In order to examine numerical simulation of fire spreading in different kinds of buildings, the present study used a systematic review of the literature. For this purpose, studies published between 2010-2022 were chosen that highlighted the numerical simulation methods and models. The present study provides key features of FDS (Fire Dynamics and Simulator), CFD (Computational Fluid Dynamics) model, and CFAST (Consolidated Model) for the fire simulation process. FDS and CFAST are effective in providing numerical simulation, thus useful in predicting fire spreading in buildings. Moreover, software accuracy, precision and increased use of the technology are the factors that can help in reducing fire occurrences in buildings. It is also found that both FDS and CFAST are effective in providing numerical simulation, thus useful in predicting fire spreading in buildings. One of the critical findings of the literature review was that the heat release rate and pyrolysis are the core factors later used in numerical simulations by both of these models. However, the use of CFAST is limited due to its inability to show high accuracy in all types of buildings and deal with a large number of variables simultaneously. Owing to the focus of study on CFD modeling, FDS, and CFAST, the research is limited as it provided a systematic review of the literature related to these models only. Hence, it has been suggested that future researchers must consider other dimensions and models related to the fire buildings and evacuation process.
... A green roof reduced the flow of heat by 70% to 90% in summer and by 10% to 30% in winter compared to a traditional roof [199]. Green roofs are also an interesting strategy to protect wood structures from igniting [200,201]. ...
The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future.
The requirements for the roof covering with a vegetation layer, from the point of view of fire safety, are not currently directly defined in the Czech Republic. According to ČSN P CEN / TS 1187: 2012, four test methods are used for the classification of roofs / roof coverings exposed to external fire. The basis for determining the fire resistance of a green roof are classification protocols prepared according to the standard (roof coverings classified in the Broof (t3) class do not spread fire and prevent ignition of flammable parts of the structure). The article deals with testing the fire resistance of a green intensive roof according to our own methodology, which is based on the Broof (t3) test. The course of temperatures in individual layers of the roof cladding was monitored. The maximum temperature under the grass was determined from the temperature sensors, followed by the maximum temperature rise of 150 mm and 300 mm below the surface. Finally, the extent of flame spread across the surface was measured. The aim was to determine the effect of external fire on the supporting structure of the roof cladding, then to classify the structure into the appropriate classification according to ČSN EN 13501-5: 2017.
We study a two-layer energy balance model of an extensive green roof. The model represents the evolution of the temperature in both the vegetation and the substrate layers. We focus on the modeling and the numerical approximation of the energy balance on the vegetation cover and the substrate. One characteristic of the model is that the vegetation layer is heterogeneous, that is, some parameters describing the vegetation are time-space-dependent. An approximate solution of the model is obtained by means of a numerical scheme based on finite volume method. This method has made possible to solve the model without any linearization. This work also includes the validation of the model with experimental data. Different scenarios have been simulated to verify how changes in some parameters affect the energy balance. Chosen parameters are: LAI, vegetation height and soil humidity. As expected, looking at the numerical results of the simulations, we can conclude that if any of these parameters increases green roof temperature is reduced.
