Research on the influence of wollastonite fibers on the stability of foam extinguishment agent and its effect on the extinguishing efficiency of pool fire

Aqueous film-forming foam (AFFF) is a frequently used foam extinguishment agent for oil fires, but the foam stability of AFFF is not perfect, which results in poor fire extinguishing performance. In order to improve the foam stability of AFFF, wollastonite fibers were explored to increase the performance of foam extinguishment agent. The influences of wollastonite fibers' concentration on foam extinguishment agent's stability are studied. When the concentration of wollastonite fibers is 30.00 g/100 mL, the drainage time is prolonged, which is the best among all the formulas. Moreover, the fire resistance and fire-fighting performances are increased significantly due to the incorporation of wollastonite fibers. In order to reveal the effect of wollastonite fibers on the stability of foam extinguishment agent, the structure of the foam and the diameter of the bubbles are investigated. The results show that the complexity and compactness of foam layer's structure are very important for foam stability, and the fire-extinguishing performance is improved due to the introduction of wollastonite fibers.     

The development of a hidden fire challenge

In accordance with the Montreal Protocol, production of all Halon fire suppressants ceased on 1 January 1994. FAR/JAR regulations require Halon 1211 or equivalent hand extinguishers to be installed on transport category aircraft. Although there is a Halon ’bank‘, a replacement agent will have to be found. The Aviation Authorities require that ’no loss of safety‘ should occur if a replacement agent is used. One proven benefit provided by Halon 1211 is the ability to extinguish hidden fires by a total flooding effect. Therefore, it is necessary to quantify the hidden fire-extinguishing ability exhibited by Halon 1211. Following an invitation for competitive tenders to develop a standard hidden fire test protocol, the Civil Aviation Authority (CAA) awarded a contract to Kidde International Research. After some range-finding work, a suitable test fixture was devised. This test fixture comprised arrays of four fires in two of five locations to establish in which regions an extinguishing concentration had been attained. A matrix of 10 tests ensured that each fire location was adequately represented. Tests have been carried out with hand extinguishers from four manufacturers. Results varied from 45% extinguishment to 60%, depending on the quantity of Halon contained in the extinguisher, and the discharge rate (a faster discharge rate creates more turbulence, aiding mixing and dispersion). In addition, tests were carried out using under- and over-filled extinguishers to examine the sensitivity of the test method. With the exception of one hand extinguisher, all results could be correlated to the mass and mass flow rate of agent used. This device extinguished a significantly higher percentage of fires than would be expected, based on its mass/mass flow rate characteristics. Limited testing was carried out with six Halon replacements: FM-200, FE-25, CEA-4.10, CEA-6.14, FE-36 and Triodide, using apparatus designed to give a constant discharge time (10±1 s). The results obtained appeared to be similar to Halon 1211 (50±5% extinguishment), provided the quantity of agent is scaled according to its n-heptane cupburner concentration. The two exceptions are agents with markedly different volatilities to Halon 1211 (b.p.−4°C): FE-25, b.p. −49° C, (65% extinguishment) and CEA-6.14, b.p.+58°C (35% extinguishment). Implications for the size and weight of a hand extinguisher, based on the results of these tests, are for the physically acting agents, a weight penalty of 1.4 to 2.6, and a volume penalty of 1.9 to 2.9. If Triodide is considered, there is a weight penalty of 1.06, and no volume penalty. However, it should be borne in mind that any hand extinguisher, before it is evaluated against hidden files, will have had to have passed the traditional ratings (currently UL 5B:C, BS 3A:34B) to be approved for aviation use. © 1997 John Wiley & Sons Ltd.     

The generation of CO in bench-scale fire tests and the prediction for real-scale fires

Carbon monoxide (CO) is the single most important factor associated with deaths in fires; thus, predictions of CO developed in fires is an essential aspect of fire quantification. It is considered crucial to have correct CO prediction methods for post-flashover fire stages, since, in the United States at least, the majority of fire deaths are associated with fires which have gone to flashover. In this paper it is shown that the yiels of CO observed in real-scale fires are generally not related to either the chemical nature of the material being burned nor to the yield observed for the same material in bench-scale testing. Instead, the generation of CO in real-scale fires is determined largely according to the oxygen available for combustion, with thermal conditions of the fire plume also playing a significant role. This behavior is in sharp contrast to many other material fire properties, including yields of gases such as CO₂ and HCI, which can be predicated for real-scale fires from bench-scale results. Finally, results from various studies completed thus far indicate how effective prediction of real-scale CO yields may be accomplished. While bench-scale measurements are not necessary to predict real-scale CO, bench-scale toxic potency measurements can be in error if the CO component in them does not reflect on the real-scale CO yield. Thus, a method is developed whereby the bench-scale toxic potency measurements can be computationally corected to better approximate the toxic potencies measured in real-scale, post-flashover room fires. These techniques will, undobtedly, be further refined as additional experimental results become available.     

Quantitative fire risk assessment of cotton storage and a criticality analysis of risk control strategies

Although fires can easily occur during cotton storage, research on cotton storage fire risk assessment is limited. This work focuses on cotton storage fire risk assessment and investigates the criticality of risk control strategies. Bow-tie and Bayesian network models are established to investigate the relationships among accident causes, safety barriers, and possible consequences. The results show that the first safety barrier (detection and extinguishment before fire brigade arrival) is more controllable and more effective than the second safety barrier (fire brigade). Based on the collected probability data, the probability and risk of a common accident are higher than those of a large accident and severe accident when safety barriers succeed; when the first safety barrier fails, the probabilities and risks of large and severe accidents increase by more than 2000 times. The criticality of safety measures is investigated by analysing their structural importance, probability importance, and critical importance. The critical events for fire occurrence are an open flame and sparks during storage, and the critical events for detection and extinguishment before fire brigade arrival are watchkeeper monitoring, regular patrolling, and automatic fire alarm systems. For cotton storage safety, this work and its outcomes are used to support the decision-making of fire risk prevention and control.     

Study on causes of the fires in rubble piles produced after the Great East Japan Earthquake, 2011

This paper seeks to determine the trigger of faint heat generation, which was one of the causes of fires in the piles of rubble produced after the 2011 Great East Japan Earthquake. The rubble piles consist of various combustible materials, such as wood, paper and plastics, as well as non‐combustible materials from destroyed buildings. Multiple rubble outdoor storage areas were temporarily set up in the disaster areas to dispose of rubble after it was piled up and separated. However, fires have been occurring in these storage areas since the summer of 2011. One cause of such fires is thought to be the heat generated by fermentation of microorganisms that easily proliferates within the piled up rubble, ultimately resulting in spontaneous ignition. In this study, we collected samples from rubble outdoor storage areas where fires have occurred. We then conducted thermal analyses to obtain basic data, and finally, we developed safety measures to prevent the recurrence of fire. The results revealed that the heat generated during fermentation of rotten tatami and wood chips most likely acts as a trigger causing the fires, given the adiabatic conditions are good. Copyright © 2014 John Wiley & Sons, Ltd.     

Specimen heat fluxes for bench-scale heat release rate testing

When a specimen is testd for its heat release rate (HRR) behaviour using a bench-scale such as ISO 5660 or equivalent, one very important test condition is not pre-standaridized and must be set: the heat flux to be imposed on the specimen by the heater. The heat flux cannot be ligitimately standardized, since the value appropriately to be used will differ according to purpose or application. The present paper sets forth the considerations which should govern the correct choice of heat flux. A discussion is given of minimum ignitiability level; statistical variability at low heat fluxes; the ranges of heat fluxes associated with small actual ignition sources; the heat fluxes associated with fires away from the ignition sources, all the way up to fully-involved room fires; the application of the product; and the needs associated with mathematical modeling of room fires. Correlational approaches are also illustrated and contrasted to physics-based ones. Finally, the empirical nature of the present situation is emphasized. Judged from first principles, it would appear that successful prediction of room fire results from bench-scale test data would require both the testing at a large number of different heat fluxes and the use of algorithms to permit time-dependent interpolation. Such algorithms have been proposed; however, some very successful predictions are noted with much simpler techniques.     

Characterization of the fire environments in central offices of the telecommunications industry

Eight free burning and two sprinklered fire tests were performed with electrical cable trays and live digital switch racks in a large enclosure to simulate telecommunications central office (TCO) fires started by electrical overheating. Very‐slow‐growing (non‐flaming), slower‐growing (partially flaming) and low‐intensity‐faster‐growing (flaming) fires releasing gray‐white, gray, and black smoke, respectively, were observed in the tests. Under quiescent conditions present in the unvented enclosure fire tests for cables, very‐slow‐growing fires were detected in about 1452 s, whereas the slower‐growing fires were detected in about 222 s by commercial fire detectors. Under ventilation conditions typical of TCOs, detection times were very similar for the five types of commercial TCOs fire detectors used in the tests. The average detection times for slower‐growing fires (cable fires) and low‐intensity‐faster‐growing fires (digital switch rack fires) were 242±17% and 249±11%s respectively. The TCO procedures to reduce smoke damage from fires (on fire detection, inlet ventilation flow is turned off and exhaust flow is turned on) were found to be beneficial. The extent of smoke damage decreased significantly with an increase in the exhaust flow rate. The chloride ion mass deposition suggested that equipment recovery would be possible in the smoke environment if the cable vapor concentration could be reduced below about 3 g/m³. The metal corrosion rate was found proportional to the 0.6th power of the smoke concentration, similar to that found for the corrosion of metal surfaces exposed to aqueous solutions of HCl and HNO₃ and for acid rain with no protective layer at the surface. Sprinkler water was found to wash down the smoke deposits on the surfaces with little indication of corrosion enhancement. Copyright © 2003 John Wiley & Sons, Ltd.     

Improving Fire Suppression of Water Mist by Chemical Additives

Although water mist fire suppression system (WMFSS) is very common, there are concerns that the system is not efficient in controlling some fires. Additives are proposed to use in a WMFSS for better fire protection. In this paper, different groups of additives for WMFSS will be briefly reviewed. Experimental studies on the surface physical and chemical characteristic of polymethylmethacrylate (PMMA) under four groups of original polymer surface without treatment, self-extinguishment, suppressed by water mist and by water mist with sodium chloride NaCl, are reviewed. The surface profiles, element constitutions, binding energies and functional groups of PMMA surfaces were analyzed with scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FTIR).

The near surface molten polymer and bubble layers in burning polymethylmethacrylate (PMMA) are found to be very complicated. The melted surface of burning PMMA is not saturated with pure MMA. Results also demonstrated that chemical reactions do occur while applying water mist. Water mist with NaCl can penetrate deeper on the burning surface of PMMA, suggesting that NaCl might be involved in the extinguishment reactions. The chloride ion from NaCl might be responsible for the interaction with the melting surface of PMMA.     

Heat release rate in fires

In this paper the definition of heat release rate in fires is given in terms of heat of combustion and mass loss rate of the fuel. Various components of the heat of combustion are defined. The dependency of heat of combustion components and mass loss rate on factors such as fire stages, oxygen to fuel ratio, heat flux received by the fuel, chemical composition of the fuel vapors and products are enumerated. Applications of heat release rate data for relative fire hazard of fuels, for various fire conditions, for human escape potential from fires and for the operation of fire-sensing devices are discussed.     

Australian fire statistics

This paper describes in some detail the sources of data on fires occurring in Australia with to their scope and reliability. Particular reference is made to the data published by the Fire Brigades Board of New South Wales for these are the most detailed and comprehensive published in Australia although limited to one State. Data are given on the number of fires, property loss, and deaths and injuries due to fires in Australia and on causes, occupancies, points of origin and extents of fires in New South Wales. Comparisons are made with United Kingdom and United States of America statistics where relevant data are available. In conclusion, some trends which indicate that better data should be available in the future are discussed.     

Furniture and furnishings in the home—some fire statistics

A statistical study of fires in the United Kingdom involving the ignition of furniture and furnishings is presented. This paper examines the data for one year (1970). The analysis shows that in fires starting in furniture and furnishings the chance of a fatality is over twice that in other domestic fires. The majority of furniture fires involve upholstery or bedding and over 90% were started by smokers' materials, electric appliances, space heating or as the result of the activities of children or suspected arsonists. Eighty-five percent of the fatalities were found in the room of origin of the fire. Eighty per cent were overcome by smoke or toxic gases. Sixty percent of the fatalities were either under 5 or over 65 years of age. Monetary values are assigned for damage, casualties and deaths in fire. These costs can be used to assess the value of fire precautions. With the values taken, the total losses in furniture fires in the home amounted to £19 million in 1970. Life loss accounted for the major part of this sum. The expected annual loss per dwelling as a result of the ignition of furniture is thus only about £1, and is only £3 for all dwelling fires. This low figure suggests an approach of either selective spending on those most at risk (the elderly and handicapped) or by government activity through publicity and education.     

Test method for characterising the thermal protective performance of fabrics exposed to flammable liquid fires

People, such as emergency service and military personnel, require protection from fires involving flammable liquids and liquefiable solids (Class B fires) in a number of situations. Fires involving flammable liquids typically reach higher temperatures sooner when compared to other types of fuel, yet there appears to be little literature that specifically investigates the protective performance of fabrics against such fires. Therefore, a new method was developed to enable the characterisation of the protective performance of fabrics when exposed to flammable liquid fires. Fabric samples were mounted on a sample plate inclined to three different angles of incidence. Known volumes of hydrocarbon fuel were pipetted into a fuel reservoir, ignited, then tipped onto fabric samples. Ten thermocouples embedded in the sample plate measured the resultant change in temperature at the technical rear of the fabric samples throughout the exposure. Significant differences were observed between fabrics for maximum temperature, time to maximum temperature, maximum heat flux, transferred energy and estimated burn risk. Therefore, this new methodology enabled discrimination among fabrics based on the protection they provide. Differences were also observed when the volume of fuel and the angle of incidence varied and, therefore, these device settings must be controlled for repeatable results. Copyright © 2016 John Wiley & Sons, Ltd.     

Ignitability Analysis of Siding Materials Using Modified Protocol for Lift Apparatus

This paper reports on the ignitability of common siding materials that could be exposed to wildland fires. When exposed to brands or fires, structures will experience piloted ignition, which is requisite for sustained ignition involving burn-through and surface flame spread in various directions. In this study, the Lateral Ignition and Flame Spread Test (LIFT) apparatus (ASTM E1321 and E1317) was used to test various siding materials (plywoods, softwoods, and vinyl), some of which were painted, humidified, or sawed. A recently developed protocol provided useful, accurate values of the following thermophysical properties: surface emissivity, surface ignition temperature, thermal conductivity, and thermal diffusivity. Full consistency was achieved with independent literature values of these properties and can be used directly in the database of fire growth models.     

The influence of emergency signage on building evacuation behavior: An experimental study

Emergency signage is important for safe escape when unexpected events (such as fires) occur. However, there are limited data on the difference in the effect of emergency signage on way finding processes between individual and group conditions. This paper aims to reveal how participants alone or in groups detect and accept the information conveyed by a signage system through an experiment in buildings. One hundred nineteen volunteers participated in the experiment, which included individual and group evacuation conditions. There were six decision points along the movement path where participants could select egress routes according to signage. Posttrial questionnaires and video recordings were used to derive the number of participants whose route choice was according to signage and to derive the decision time. Results demonstrate that both signage detection and acceptance probabilities under individual conditions are larger than those under group situations, because of social influence in groups. High‐placed signs have a positive effect on route choice, especially under individual conditions. Decision time for participants whose decisions are principally according to signs is not always smaller than that for participants whose decisions are not according to signs, eg, in group situations. These findings have implications for group evacuation modeling and signage design in buildings.     

An update to what's burning in home fires

This article is an update on the items that are first ignited in home fires and it examines the extent of their involvement in associated deaths, injuries and property loss. It will be limited to forms of material that are considered products. Trash, for example, is involved in a large portion of home fires, but is not a product in the home and therefore is not included. Also excluded are building materials such as structural components and exterior wall coverings. This exclusion is important, because many building items rank high in the overall list of materials first ignited, but are not considered consumer products. Further detail will be given to the top ten leading products associated with home fires and home fire deaths. Copyright © 2001 John Wiley & Sons, Ltd.     

A study of the fire behaviour of polypropylene letter trays

A study of the fire behaviour of polypropylene plastics trays being considered for letter handling has been carried out. Various ignition sources and configurations of trays (both empty and filled with letters) were examined. In particular, stacks of trays contained in large steel-mesh unit load devices (ULDs), protected by automatic sprinklers, were ignited and the progress of the fires, release of heat and smoke, and sprinkler activation recorded. It was found that, when examined singly or in stacks in scenarios which might be encountered in sorting areas and post offices, the trays made from fire-retardant plastics were more difficult to ignite and took longer to become involved in fire than those made from standard grade plastics. The benefits of this slower build-up fire with the retarded plastics formulation were reduced to some extent by the greater amounts of smoke released by the burning of the retarded plastics. For stacks of ULDs filled with trays, typical of a scenario in a mail exchange, the fire-retardant plastics gave significant benefits in terms of life safety and fire damage to the trays and mail.     

Highway vehicle fire data based on the experiences of US fire departments

In 2003–2007, US fire departments responded to an average of 267 600 highway vehicle fires per year. These fires caused an average of 441 civilian deaths, 1326 civilian injuries, and $1.0bn (in US dollars) in direct property damage annually. Highway vehicles include cars, trucks, and other vehicles designed for highway use; highway vehicle fires can occur anywhere, not just on a highway. While these fires and associated losses have been falling in recent years, highway vehicles fires accounted for 17% of reported US fires, 12% of US fire deaths, 8% of US civilian fire injuries, and 9% of the direct property damage from reported fires. Data from the US Fire Administration's National Fire Incident Reporting System and the National Fire Protection Association's fire department survey were used to provide details about the circumstances of highway vehicle fires. Mechanical or electrical failures caused roughly three‐quarters of the highway vehicle fires but only 11% of the deaths. Collisions and overturns were factors contributing to the ignition in only 3% of the fires, but fires resulting from these incidents caused 58% of these vehicle fire deaths. The rate of bus fires per billion miles driven was 3.5 times that for highway vehicle fires overall. Copyright © 2012 John Wiley & Sons, Ltd.     

Multi-model based process condition monitoring of offshore oil and gas production process

Offshore oil and gas production platforms are uniquely hazardous in which the operating personnel have to work in a perilous environment surrounded by extremely flammable hydrocarbons. A failure in an equipment could quickly propagate to others resulting in leaks, fires and explosions, causing loss of life, capital invested and production downtime. A method for preventing such accidents is to deploy intelligent monitoring tools which continuously supervise the process and the health of equipments to provide context-specific decision support to operators during safety-critical situations. Such an intelligent system, which is condition driven is developed and described in this paper. Since relevant process data is unavailable in the literature, a dynamic model of an offshore oil and gas production platform was developed using gPROMS and data to reflect operating conditions under normal, fault conditions and maintenance activities were simulated. The different maintenance activities and normal conditions are explicitly considered as separate states of the process. The simulated data are then used to train principal component analysis monitoring models for each of these states. Online fault detection and identification are performed by identifying the operating state in real-time and triggering the respective model. In this paper, the dynamic model and the condition monitoring system are described.