High Fire Hazard Research Articles

Fire hazard assessment at different scales in the wildland-urban interface of semiarid areas of northern Patagonia

Wildland-urban interface (WUI) fires have increased in the last decades, putting lives and homes at risk, and fire hazard assessment is a useful tool to develop plans for prevention and fire management. In northwestern Patagonia, the WUI areas are principally located around the urbanized zones that are not only cities or towns but settlements surrounded by the natural environment. In Patagonia, there are the largest and most ancient national parks of Argentina with areas where former settlers develop their livestock activities. We assessed the fire hazard in the Laguna Blanca National Park (LBNP) located in Neuquén province (Patagonia, Argentina) dominated by steppe vegetation. We performed the study at two scales: community and species. Community scale comprised the variables vegetation cover, slope, and rock fragments, whereas species scale included flammability variables of dominant species (tussock grasses and shrubs) at leaf- and plant-level. We integrated all variables at different scales and grouped the vegetation units into three classes using multivariate analysis. Finally, we established three fire hazard categories for each vegetation unit: low, moderate, and high, to elaborate a fire hazard map. Three vegetation units, which represented 37% of the area of the park, were categorized with high fire hazard because of the high cover and horizontal continuity of dominant vegetation. The tussock grass Pappostipa speciosa and the shrubs Mulinum spinosum, Nassauvia axillaris, and Anarthorphyllum rigidum were the most flammable species and the most frequent species in the park. Land uses in the park (i.e., transhumance and tourism) would be regulated with the collaboration of settlers because increase the vulnerability to wildfires. Our fire hazard map constitutes a valuable tool because it identified the most vulnerable WUI in the LBNP. This study emphasizes the need to include flammability and fuel load studies in fire management plans to better protect human lives and natural resources in protected areas.

Interfacial gluing strategy derived closely-coupled ternary LDH@P-RGO nanohybrid towards constructing fire-safe epoxy resin

Inherently high fire hazard has been the disreputable and nerve-wracking issue of epoxy resin (EP), challenging its extended applications. Hence, we have adopted the interfacial gluing strategy to acquire closely-coupled ternary LDH@P-RGO nanohybrid as flame retardant filler. When loading 2.0 wt% LDH@P-RGO, peak heat release rate and total heat release are impaired by 36.5% and 38.4%, whilst total smoke production is lowered by 30.3%. Of note, total CO production is reduced by 37.6%. Moreover, the limited oxygen index is elevated from 22.6% to 29.1%. Flame retardation comparison with previous works also highlights the superiority of LDH@P-RGO towards impairing the fire hazard of EP. Strong evidences for the weakened emissions of toxic CO, NO and HCN gasses are also provided. Satisfactorily, the promotions in flexural strength and modulus are observable. This work can provide enlightenments for constructing closely-coupled nanohybrid via interfacial gluing strategy, mining its potencies in polymer-matrix composite aera.

Interfacially-engineered PBA based hierarchical structure with Ni(OH)2 nanocatalyst towards fire retardation of epoxy resin

The extended usage of epoxy resin (EP) has suffered from the notorious issue of high fire hazard, including the release of considerable heat and emission of abundant toxicants (smoke and toxic gasses). Hence, a prussian blue analogue (PBA) based hierarchical structure (Co@Ni(OH)2-A) with Ni(OH)2 nanocatalyst, is proposed via interfacial-engineering strategy, towards reducing the fire hazard of EP. As revealed, Co@Ni(OH)2-A shows strong interfacial catalytic strengths both in charring of decomposed volatiles and oxidizing of toxic gasses. By using 4.0 wt% Co@Ni(OH)2-A, the peak heat release rate, peak smoke production rate, total smoke production and peak CO production rate are reduced by 45.5%, 55.0%, 44.3% and 65.3%, respectively. Fire resistance comparison with previous works confirms the advantage of Co@Ni(OH)2-A in toxicants elimination. Owing to the well-generated hierarchical structure-polymer interfaces, the greatly enhanced mechanical property is obtained. Generally speaking, Co@Ni(OH)2-A holds exceptional efficacy in promoting the polymer fire safety and mechanical performance. This investigation may offer useful enlightenments for acquiring high-performance EP composites via designing PBA based flame retardants with hierarchically tailored structure.

Influence of air gap ratio of the Chinese historical wooden window on the vertical flame spread performance

The fire protection of historical buildings with wooden structures is a topic that has attracted much attention over the last few years. As one of the critical structures of ancient buildings, wooden windows have high fire hazards. This study aims to clarify the influences of air gap ratio on the fire propagation mechanism of wooden windows by experimental investigating flame characteristics such as mass loss rate (MLR), flame spread rate (FSR), total burning duration (TBD), and maximum flame length (MFL), and propose corresponding fire protection strategies. In the experiment, the typical wooden window structure in ancient buildings was selected as the research object. The wooden windows with different porosity were installed on the vertical sample rack to carry out the combustion experiment, and the area air gap ratio ranged from 32.9% to 64.2%. The experimental results show a clear relationship between MLR and the area air gap ratio. TBD, FSR and MFL are related to the vertical linear air gap ratio of the wooden window structure. FSR first increases and then decreases with the linear air gap ratio, and the peak value of FSR appears on the sample with a vertical linear air gap ratio of 69.6%.

Vulnerability Analysis of Fire Evacuation at Urban Kampong Using Space Syntax Method, Penggilingan Jakarta as a Case Study

Urban settlements including kampong at DKI Jakarta Province are vulnerable to fire hazards. The fire risk will increase along with the increase of kampong’s population, the density of housing units in the area, and spatial accessibility quality. However, the understanding of urban kampong’s spatial configuration related to the vulnerability degree of fire hazards is limited. The purpose of this study is to identify the vulnerability of urban kampong structures related to fire evacuation. Penggilingan Sub-district of East Jakarta City, DKI Jakarta, and its surrounding area were selected as a case study to represent high-density urban kampong with high fire hazards events. The space syntax analysis is utilized as a tool to analyse the main indicators of spatial vulnerability: connectivity, mean depth, and integration of the area. Connectivity affects the easiness of evacuation during a fire disaster. Meanwhile, integration and mean depth affect the level of accessibility. The correlation of connectivity and integration implies an intelligibility degree that is a supporting parameter of wayfinding. It is identified that several areas in Penggilingan Sub-district are vulnerable to fire in the aspect of evacuation because of their low connectivity and accessibility. The result of this study can be developed as a basis for evacuation planning and fire safety management in the urban dense kampong.

High-performance flame-retardant polycarbonate composites: Mechanisms investigation and fire-safety evaluation systems establishment

Polycarbonate (PC) is highly attractive for applications in high-speed railways and airplanes as engineering materials, but suffers from high fire hazards with severe melting dripping during burning. To overcome the challenge, highly effective flame retardants , such as sulfonate derivatives and silicon-based compounds have been developed. Unfortunately, there is still lacking of a systematic method to evaluate the fire risk of these flame-retardant PC composites. Herein, we propose a comprehensive and innovative approach to assess the fire safety of flame-retardant PC composites containing potassium perfluorobutane sulfonate (PPFBS) and a silicon-based flame retardant (PSR) through combining numerous combustion parameters obtained from different measurements. The pyrolysis and combustion characteristics of PC/PPFBS and PC/PSR were studied in detail and revealed that PPFBS and PSR could effectively reduce the activation energy of PC. PSR is effective at reducing the heat and smoke release due to the formation of a Si–C protective layer during combustion. In contrast, PPFBS has no obvious suppression effect on smoke generation, and even shows a combustion-supporting effect under high radiation flux. Based on the analytic hierarchy process (AHP), a comprehensive evaluation model has been established to achieve an objective and comprehensive evaluation of the fire hazards of PC and its composites. This works provides a universal guidance for evaluating fire hazards of flame-retardant polymer composite . • The pyrolysis mechanism of PC composite has been revealed. • The flame-retardant mechanism of PC composite has been revealed. • A comprehensive safety evaluation system for flame-retardant PC has been established.

RETRACTED: Design and performance evaluation of an underwater hybrid system of fuel cell and battery

• A system of hydrogen-air fuel cell and battery (FCBS) is proposed for underwater. • The coupling design issue of FCBS and the underwater vehicle is studied. • FCBS is superior to single hydrogen- oxygen fuel cell system in endurance. • A 65-min underwater experiment of FCBS is completed. At present, most underwater fuel cell power systems are fed up with pure hydrogen and pure oxygen (FC), which suffers from high capital costs and potential fire hazards. However, all commercial fuel cells are designed in an open-air environment, so it’s not available directly. To enhance the range and reduce costs of unmanned underwater vehicles, this paper proposes an underwater energy system of the hydrogen-air fuel cell and battery (FCBS), solving the problems of artificial air intake, exhaust gas treatment and energy management strategy. Employing cruise time, range and mass density as evaluation indexes, the coupling design between FCBS and the key parameters of an unmanned underwater vehicle including the length and velocity, are analyzed contrastively and optimized. The results shows that as the length expands, FCBS can be boosted by over 40 % in cruise time compared to FC, but this advantage fails in very high velocity. Moreover, the optimal velocity for the maximum range of FCBS is 1.4 m/s, and the optimal velocity of FC is 2.0 m/s. Finally, the hybrid system scheme of FCBS is verified by the underwater closed cabin experiments. The results prove the operating feasibility and dependability of the underwater hybrid system with a hydrogen-air fuel cell.

ENVIRONMENTAL IMPACT ASSESSMENT IN THE OIL AND GAS SECTOR

Oil and gas production is one of the most environmentally risky economic sectors. This field of activity is characterized by an impressive polluting capacity, as well as a high fire and explosion hazard of industrial facilities. Every year, oil and gas producing enterprises implement a wide range of measures to protect atmospheric air, land, subsoil, forests, and water resources. However, only basic and primary measures have been taken in this area to reduce the impact on the environment. Therefore, the problem of nature protection and rational use of natural resources in the country's oil and gas fields deserves special attention. Environmental assessment is a useful environmental tool that allows quantifying the consequences of human activity. Based on the data obtained, it is possible to plan and take an appropriate set of measures to prevent the consequences or reduce the negative impact, as well as to assess the magnitude of the risk. There are various types of environmental assessments, each of which has a specific purpose, orientation and an interested circle of people. This article provides an overview of the general environmental problems associated with the oil and gas industry, describes the types of environmental assessments that are widely used in the oil and gas sector. The potential problems that arise when conducting these assessments in accordance with a wide range of regulatory requirements and standards are considered.

Covalently functionalized hierarchical MnO2@LDH nanostructure as building blocks for fire-safe and mechanic-robust epoxy composites

The notorious issue of high fire hazard, including the generation of considerable heat and release of plentiful toxic volatiles, is recognized as the bottleneck of extensive use of epoxy resin (EP). Hence, a covalently functionalized hierarchical MnO2@LDH nanostructure (FA-MnO2@LDH) is rationally designed to alleviate these problems. With the incorporation of 2.0 wt% FA-MnO2@LDH, the peak heat release rate and total heat release are reduced by 44.9% and 33.1%, while the total smoke production is decreased by 50.2%, corroborating the greatly impaired heat and smoke emissions. Meanwhile, the reductions on peak CO production rate and total CO production are 46.3% and 41.3%, demonstrating the markedly impeded CO emission. Moreover, the peak CO2 production rate and total CO2 production are reduced by 46.7% and 30.0%, signifying the inhibited burning. Thermogravimetric analysis-infrared spectrometry results also confirm the impeded releases of CO and NO gases. The merit of FA-MnO2@LDH is also confirmed via the flame retardation comparison with other reported fillers. Stemming from the well-generated hierarchical nanostructure-polymer interfaces, the mechanical property is also promoted. Hence, this investigation can provide useful inspirations for fabricating fire-safe and mechanic-robust polymer composites via designing hierarchically tailored nanostructure.

Numerical Simulation Research on Cable Fire of Urban Underground Comprehensive Pipe Gallery Using Suffocating Fire Extinguishing Method

The integrated pipe corridor cable is the lifeblood of urban power transmission and has a high fire hazard. Once a fire breaks out, the electricity supply of the entire city will be paralyzed. Aiming at the cable fire in the urban underground integrated pipe gallery and combining with the Pyrosim software, this paper adopts the method of fire suffocation, to study the changes of fire smoke in the pipe gallery. The results show that in the pipe gallery of the 200m fire compartment, the open flame can be completely extinguished in 264s under the simulated working condition of the fire source power of 1MW. At 300s after the cable fire, the temperature in the pipe gallery basically maintained a stable state of 40°C. After the fire broke out, the O2 concentration dropped rapidly and plunged to 16% within 195s and it was completely consumed in 515s. Studies have shown that the use of suffocation to extinguish fires produces less fire smoke in the pipe gallery, and the visibility can be well maintained above 30m.

Predicting Wildfire Fuels and Hazard in a Central European Temperate Forest Using Active and Passive Remote Sensing

Climate change causes more extreme droughts and heat waves in Central Europe, affecting vegetative fuels and altering the local fire regime. Wildfire is projected to expand into the temperate zone, a region traditionally not concerned by fire. To mitigate this new threat, local forest management will require spatial fire hazard information. We present a holistic and comprehensible workflow for quantifying fuels and wildfire hazard through fire spread simulations. Surface and canopy fuels characteristics were sampled in a small managed temperate forest in Northern Germany. Custom fuel models were created for each dominant species (Pinus sylvestris, Fagus sylvatica, and Quercus rubra). Canopy cover, canopy height, and crown base height were directly derived from airborne LiDAR point clouds. Surface fuel types and crown bulk density (CBD) were predicted using random forest and ridge regression, respectively. Modeling was supported by 119 predictors extracted from LiDAR, Sentinel-1, and Sentinel-2 data. We simulated fire spread from random ignitions, considering eight environmental scenarios to calculate fire behavior and hazard. Fuel type classification scored an overall accuracy of 0.971 (Kappa = 0.967), whereas CBD regression performed notably weaker (RMSE = 0.069; R2 = 0.73). Higher fire hazard was identified for strong winds, low fuel moisture, and on slopes. Fires burned fastest and most frequently on slopes in large homogeneous pine stands. These should be the focus of preventive management actions.

Пожаровзрывобезопасность объектов водородной энергетики

Due to the high fire and explosion hazard of hydrogen, ensuring the safety of hydrogen energy infrastructure facilities is a very important task. The scientific basis for the development of the normative documents on fire and explosion hazard of hydrogen energy facilities was laid out in the studies of Russian and foreign researchers. This article analyzes Russian normative documents in the field under consideration. The most important among them is the Concept for the development of hydrogen energy in the Russian Federation, aimed at the production, storage, transportation, and use of hydrogen. This document defines the goals, problems, strategic initiatives, and key measures for the development of hydrogen energy with the main guidelines for the future until 2050. One of the main goals of hydrogen energy development is to combat climatic changes caused by using fossil fuels and conditioned by the greenhouse gas emissions. However, it is concluded that the Russian regulatory framework is insufficient for the development of hydrogen energy. NFPA 2 standard is considered as a normative document containing safety requirements to the installations for the production, storage, transportation, and use of hydrogen in the gaseous and liquid phase. It contains both general and specific requirements for infrastructure facilities, such as: filling stations; hydrogen storage in the gaseous and liquid phase, as well as using metal hydrides; facilities for producing hydrogen and energy using hydrogen; technological equipment containing hydrogen; laboratory premises; parking lots for cars using hydrogen as fuel, etc. Many of these requirements can be used to create a Russian regulatory framework for hydrogen energy.

Экспериментально-аналитические исследования особенностей горения масел органического происхождения в состоянии аэрозоля

The analysis of fire hazard of the technological process of vegetable oil production, which is caused by the circulation of flammable, combustible solid and li quid substances and materials in it, is carried out. Liquid oil aerosols are a high fire hazard when they are released from the process equipment under pressure and at elevated temperatures. When a combustion source occurs in them, a sequential burnout occurs (by analogy with gas combustible mixtures), creating an explosive load. The peculiarities of the combustion of oil aerosols, which are characterized by relatively light gasification (fog formation) and the absence of the need for pre-heating to flash point, are investigated. Extinguishing foams, powders, and aerosol emissions can be used as extinguishing agents for spills of organic oils.

Пожарная опасность производства и хранения растительных масел

The analysis of the fire hazard of the technological process of vegetable oil production, which is caused by the circulation of flammable, combustible solid and liquid substances and materials in it, is carried out. Liquid oil aerosols pose a high fire hazard when they are released from process equipment under pressure and at elevated temperatures. When a combustion source occurs in them, a sequential burnout occurs (by analogy with gas combustible mixtures), creating an explosive load. Extinguishing foams, powders can be used as extinguishing agents for spills of organic oils, and when aerosols are released from technological equipment, volumetric fire extinguishing agents – sprayed water, general purpose powders, carbon dioxide, nitrogen.

Constructing hierarchical structure based on LDH anchored boron-doped g-C3N4 assembled with MnO2 nanosheets towards reducing toxicants generation and fire hazard of epoxy resin

High fire hazard of releasing considerable toxicants and heat is regarded as a notorious issue for hindering the further application of epoxy resin (EP). Hence, a hierarchical structure (MLBCN) based on LDH anchored boron-doped g-C3N4 assembled with MnO2 nanosheets is rationally constructed as flame retardant additive for EP. Concretely, the incorporation of 1.0 wt% MLBCN leads to the decreases of 31.9% and 25.3% in peak heat release rate and total heat release, separately, reflecting the impeded heat release. Meanwhile, the peak smoke production rate and total smoke release are reduced by 37.1% and 33.4%, respectively, corroborating the hindered fire toxicity. The clear evidence for inhibited emissions of toxic CO and NO gases can be acquired from TG-IR spectra. These results collectively confirm the efficacy of MLBCN in reducing the toxicants generation and fire hazard of EP, deriving from its physical barrier, chemical catalyzing and charring promotion actions. Besides, the tensile and flexural strength are improved by 43.9% and 10.6%, by adding 1.0 wt% MLBCN, demonstrating the promoted mechanical performance. Overall, using MLBCN achieves the simultaneous enhancements in fire safety and mechanical capability of polymer. This work may provide valuable inspirations for constructing multicomponent hierarchical structure, optimizing their prospects in polymer-matrix composite and other areas.

Layer-by-layer self-assembled nanocoatings of Mxene and P, N-co-doped cellulose nanocrystals onto cotton fabrics for significantly reducing fire hazards and shielding electromagnetic interference

With the increasing of electromagnetic pollution, flexible electromagnetic interference (EMI) shielding textiles are of urgent demand in daily life, which have the high fire hazards. Herein, we have prepared tannic acid-modified MXene (TA-Mxene), synthesized P, N-co-doped cellulose nanocrystals (PA@PANI@CNC), and then designed an alternative deposition of TA-Mxene and PA@PANI@CNC to achieve the flame-retardant and EMI shielding nanocoatings onto cotton fabrics by the layer-by-layer self-assembled technology. In particular, the EMI shielding efficient (SE) of cotton fabric with 20 bilayers coatings (Cotton-20BL) reaches up to 21 dB over the X-band frequency range. In addition, the Cotton-20BL achieves a high limited oxygen index of 32. Most notably, the peak heat release rate and total smoke production are reduced by 63.0% and 98.3%, respectively. Therefore, this work provides a highly efficient approach for the EMI shielding textiles with high fire safety.

Designing hierarchical ternary structure based on NiAl LDH anchored phosphorus-doped g-C3N4 dotted with Fe3O4 nanoparticles towards improving the fire safety of thermoplastic polyurethane

High fire hazard of generating a great deal of heat and toxic volatiles has been deemed as notorious issue of thermoplastic polyurethane (TPU), severely impeding its practical usage. Hence, a hierarchical ternary structure (FNPCN) based on NiAl LDH anchored phosphorus-doped g-C3N4 dotted with Fe3O4 nanoparticles is rationally designed as flame retarded additive for TPU. Specifically, by adding 1.0 wt% FNPCN, the obvious reductions of 30.9% and 21.8% in peak heat release rate and total heat release are obtained, suggesting the suppressed heat release. Meanwhile, a marked decrease of 31.9% in peak smoke production rate is discovered, implying the reduced fire toxicity. Moreover, the direct evidence for hindered releases of toxic CO and HCN gases is provided by TG-IR spectra. These results jointly corroborate the efficacy of FNPCN in impairing the fire hazard of TPU, originating from its physical barrier and chemical catalyst characters. This work may shed a light on the designing of hierarchical ternary structure, optimizing their prospects in polymer-matrix composite and other areas.

Long-Term Effects of Fuel Reduction Treatments on Surface Fuel Loading in the Blue Mountains of Oregon

Fire exclusion and a lengthening fire season has resulted in an era of megafires. Fuel reduction treatments in forested ecosystems are designed to guard against future extreme wildfire behavior. Treatments create a heterogenous landscape and facilitate ecosystem function and resilience in fire-adapted forests of the western United States. Despite widespread recognition that repeated fuel treatments are needed to maintain desired stand characteristics over time, few field studies have evaluated treatment longevity. The Blue Mountains Fire and Fire Surrogate site in northeastern Oregon presented an opportunity to investigate woody fuel loading 15–17 years after four treatments: mechanical thin, prescribed burn, both thin and burn, and no treatment control. The principal findings were: (1) fine fuel load 15 years post-burn remained slightly below pre-treatment values; (2) rotten coarse fuel load was reduced post-burn, but sound coarse fuel was not altered by any active treatment; and (3) total woody fuel load 15–17 years post-treatment was similar to pre-treatment values. Understanding surface fuel loading is essential for predicting fire behavior. Overall, the effects of fuel reduction treatments on woody surface fuels were transitory in dry mixed conifer forests. Frequent maintenance treatments are recommended to protect values at risk in areas with high fire hazards. Quantifying the persistence of changes in forest conditions aids in the planning and analysis of future fuel treatments, along with scheduling maintenance of existing treated areas.

Проводные и кабельные сети пожароопасных зон

The urgency of the issue to be considered is conditioned by the high fire hazard of electric cables of the voltage up to 1000 V. As a result of fires associated with this type of products at the industrial and storage units in 2020 in Russia, the volume of direct loss exceeded 68 % comparing to the fires caused by all other types of cable lines occurred at enterprises. The high fire hazard of industrial facilities is mainly associated with numerous fire-hazardous premises containing combustible media capable of inflammation under the impact of ignition sources. In order to reduce their fire hazard, two independent and mutually reinforcing systems of fire-hazardous premise classification applied at designing such units are developed: Identification of fire-hazardous zone’s class to ensure correct selection of electric equipment and level of its fire-protection. Categorization of buildings and premises as fire-hazardous to ensure fire protection for both for buildings and attending employees. The main regulatory document where the requirements to fire-hazardous zone classification and selection of relevant fire-protected equipment were initially stipulated is the Rules for electric installations (1980). In 2008, the updated version of the Rules was incorporated into the text of the Federal Law of June 22, 2008 № 123-FZ «The technical regulation on fire safety requirements». The studies conducted by the experts of The Federal State Budgetary Establishment «All-Russian Research Institute for Fire Protection of the Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters» of Russia serves as a basis to develop normative documents regulating categorization of fire-hazardous premises and classification of fire-hazardous zones as well as the recommendations on the scope of application of some electric equipment in fire-hazardous zones. The adopted classification of fire-hazardous zones is unique and has no analogues in global practices.

Simulation of LPG Pressure Vessel under Fire Engulfment

Liquefied Petroleum Gases [LPG] are flammable mixtures of gases such as propane and butane mainly which is transported and stored in liquid phase in storage vessels under amply pressure. These industrial processes are of high fire and explosion hazard. When a vessel carrying LPG is damaged, an abrupt drop in pressure may release colossal quantities of evaporating gas and energy that has a destructive effect on the vessel itself and its surroundings. When comes in contact with ignition source, BLEVE phenomenon is developed. Elevated temperature environment outside the LPG pressure vessel can cause vessel explosion due to the pressure mount inside the tank and drop in strength of the tank walls. This catastrophic rupture will lead to BLEVE phenomenon which when ignited will again lead to a vapor cloud explosion. Most common scenario is when the pressure vessel partially filled with liquid form of LPG is exposed to a fire. The primary focus of the paper is to analyze the LPG storage pressure vessel under thermal loading condition. For this Finite element modeling approach is used and the analysis is carried out in ANSYS TM software.