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Abstract

Free-burning experimental fires were conducted in a wind tunnel to explore the role of ignition type and thus fire spread mode on the resulting emissions profile from combustion of fine (< 6 mm in diameter) Eucalyptus litter fuels. Fires were burnt spreading with the wind (heading fire), perpendicular to the wind (flanking fire) and against the wind (backing fire). Greenhouse gas compounds (i.e. CO2, CH4 and N2O) and CO were quantified using off-axis integratedcavity-output spectroscopy. Emissions factors calculated using a carbon mass balance technique (along with statistical testing) showed that most of the carbon was emitted as CO2, with heading fires emitting 17 % more CO2 than flanking and 9.5 % more CO2 than backing fires, and about twice as much CO as flanking and backing fires. Heading fires had less than half as much carbon remaining in combustion residues. Statistically significant differences in CH4 and N2O emissions factors were not found with respect to fire spread mode. Emissions factors calculated per unit of dry fuel consumed showed that combustion phase (i.e. flaming or smouldering) had a statistically significant impact, with CO and N2O emissions increasing during smouldering combustion and CO2 emissions decreasing. Findings on the equivalence of different emissions factor reporting methods are discussed along with the impact of our results for emissions accounting and potential sampling biases associated with our work. The primary implication of this study is that prescribed fire practices could be modified to mitigate greenhouse gas emissions from forests by judicial use of ignition methods to induce flanking and backing fires over heading fires.

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INTRODUCTION This report describes new full-scale compartment fire experiments, which include local measurements of temperature, heat flux and species composition, and global measurements of heat release rate and mass burning rate. The measurements are unique to the compartment fire literature. By design, the experiments provided a comprehensive and quantitative assessment of major and minor carbonaceous gaseous species and soot at two locations in the upper layer of fire in a full scale ISO 9705 room [1]. Fire protection engineers, fire researchers, regulatory authorities, fire service and law enforcement personnel use fire models (such as the NIST Fire Dynamics Simulator, FDS[2]) for design and analysis of fire safety features in buildings and for post-fire reconstruction and forensic applications. Fire field models have historically showed limited ability to accurately and reliably predict the thermal conditions and chemical species in underventilated compartment fires. Formal validation efforts have shown that for well ventilated compartment fires, with the exception perhaps of soot, field models do quite well in predicting temperature and species when experimental uncertainty is accounted for. Inaccurate predictions of incomplete burning and soot levels impact calculations of radiative heat transfer, burning rates, and estimates of human tenability. High-quality (relatively low, quantified uncertainty) measurements of fire gas species, temperature, and soot from the interior of underventilated compartment fires are needed to guide the development and validation of improved fire field models.

Introduction

This report describes new full-scale compartment fire experiments, which include localmeasurements of temperature, heat flux and species composition, and global measurements ofheat release rate and mass burning rate. The measurements are unique to the compartment fireliterature. By design, the experiments provided a comprehensive and quantitative assessment ofmajor and minor carbonaceous gaseous species and soot at two locations in the upper layer offire in a full scale ISO 9705 room [1].

Fire protection engineers, fire researchers, regulatory authorities, fire service and lawenforcement personnel use fire models (such as the NIST Fire Dynamics Simulator, FDS[2]) fordesign and analysis of fire safety features in buildings and for post-fire reconstruction andforensic applications. Fire field models have historically showed limited ability to accuratelyand reliably predict the thermal conditions and chemical species in underventilated compartmentfires. Formal validation efforts have shown that for well ventilated compartment fires, with theexception perhaps of soot, field models do quite well in predicting temperature and species whenexperimental uncertainty is accounted for. Inaccurate predictions of incomplete burning and sootlevels impact calculations of radiative heat transfer, burning rates, and estimates of humantenability. High-quality (relatively low, quantified uncertainty) measurements of fire gasspecies, temperature, and soot from the interior of underventilated compartment fires are neededto guide the development and validation of improved fire field models.

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ABSTRACT The open kitchen design in small residential units where fire load density and occupant load are very high introduces additional fire risk. One big concern is that whether flash-over can occur which may trigger a big post flashover fire, resulting in severe casualties and big property damage. It is important to understand and predict the critical conditions for flashover in this kind of units. Based on a two-layer zone model, the probability of flashover is investigated by a nonlinear dynamical model. The temperature of the smoke layer is taken as the only state variable and the evolution equation is developed in the form of a simplified energy balance equation for the hot smoke layer. Flashover is considered to occur at bifurcation points. Then the influence of the floor dimensions and the radiation feedback coefficient on flashover conditions is examined. When the dimensions of the floor vary, the resulting changes in internal surface area or size of floor area both have effect on the flashover conditions. When the radiation feedback coefficient is of small value, there is no possibility of flashover. With the increase of the radiation feedback coefficient, at first it significantly affects the conditions for flashover and then moderately when it reaches a larger value. It is proved that the flashover phenomenon can be demonstrated well by nonlinear dynamical system and it helps to understand the effect of various control parameters.

Abstract

The open kitchen design in small residential units where fire load density and occupant load are very high introduces additional fire risk. One big concern is that whether flash-over can occur which may trigger a big post flashover fire, resulting in severe casualties and big property damage. It is important to understand and predict the critical conditions for flashover in this kind of units. Based on a two-layer zone model, the probability of flashover is investigated by a nonlinear dynamical model. The temperature of the smoke layer is taken as the only state variable and the evolution equation is developed in the form of a simplified energy balance equation for the hot smoke layer. Flashover is considered to occur at bifurcation points. Then the influence of the floor dimensions and the radiation feedback coefficient on flashover conditions is examined. When the dimensions of the floor vary, the resulting changes in internal surface area or size of floor area both have effect on the flashover conditions. When the radiation feedback coefficient is of small value, there is no possibility of flashover.  With the increase of the radiation feedback coefficient, at first it significantly affects the conditions for flashover and then moderately when it reaches a larger value. It is proved that the flashover phenomenon can be demonstrated well by nonlinear dynamical system and it helps to understand the effect of various control parameters.

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1 Introduction A series of new reduced-scale compartment fire experiments were conducted, which included local measurements of temperature and species composition. The measurements are unique to the compartment fire literature. By design, the experiments provided a comprehensive and quantitative assessment of major and minor carbonaceous gaseous species and soot at two locations in the upper layer of fire in a 2/5 scale International Organization for Standards (ISO) 9705 room. The enclosure defined in the international standard ISO 9705 “Full-scale room test for surface products” [1] is an important structure in which to conduct fire research. Many dozens of research projects and journal articles have focused on this enclosure and the standard describing its use. It is a common reference point for studies of many fire-related phenomena as well as fire modeling efforts.

Introduction

A series of new reduced-scale compartment fire experiments were conducted, which includedlocal measurements of temperature and species composition. The measurements are unique tothe compartment fire literature. By design, the experiments provided a comprehensive andquantitative assessment of major and minor carbonaceous gaseous species and soot at twolocations in the upper layer of fire in a 2/5 scale International Organization for Standards (ISO)9705 room. The enclosure defined in the international standard ISO 9705 “Full-scale room testfor surface products” [1] is an important structure in which to conduct fire research. Manydozens of research projects and journal articles have focused on this enclosure and the standarddescribing its use. It is a common reference point for studies of many fire-related phenomena aswell as fire modeling efforts.

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From Out of the Abyss...

This week’s article from the past is titled Incendiary Fires Can Be Spotted and was written by Benjamin Horton, CPCU, who was President of the National Adjuster Traing School in Louisville, Kentucky..  It is taken from the Decembe 1968 Vol. XVI No.5 issue.

Incendiary Fires Can Be Spotted 

In the new issue of NFPA Journal®, President Jim Shannon said the Association will focus on the leading causes of home fires, including cooking. "We also need to continue to push hard for home fire sprinklers. That's still a large priority for NFPA, and we plan to work very aggressively in 2014 on our residential sprinkler initiative," he said.

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Governor Brown Directs State Agencies to Revise Flammability Standards

SACRAMENTO – in an effort to protect public safety by reducing the use of toxic flame retardants, Governor Edmund G. Brown Jr. today advised state agencies to revise flammability standards for upholstered furniture sold in the state.

Governor Brown has asked the Bureau of Electronic and Appliance Repair, Home Furnishings and Thermal Insulation to review the state’s four-decade-old flammability standards and recommend changes to reduce toxic flame retardants while continuing to ensure fire safety.

“Toxic flame retardants are found in everything from high chairs to couches and a growing body of evidence suggests that these chemicals harm human health and the environment,” said Governor Brown. “We must find better ways to meet fire safety standards by reducing and eliminating—wherever possible—dangerous chemicals.”
Studies show that humans are at risk from exposure to toxic chemicals used as flame retardants in upholstered furniture. A 2008 study by the Environmental Working Group found that toddlers often have three times the level of flame retardant chemicals in their bodies as their parents, and California children have some of the highest levels of toxic flame retardants in their bodies.

A peer-reviewed study by scientists at Cal/EPA found that California women have much higher levels of toxic flame retardants in their breast tissue than women in other states and countries. Researchers from the University of California, Berkeley found statistically significant associations between flame retardant levels in the blood of California women and reduced fertility. The researchers believe this link may result from alterations in thyroid hormone levels after exposure to the chemicals.

Numerous studies demonstrate that firefighters have significantly elevated rates of cancer, including non-Hodgkin’s lymphoma and brain cancer. A study published in the Journal of Occupational and Environmental Medicine concluded that firefighters have a significantly elevated risk of cancer that may be attributed to toxic chemicals they inhale, including flame retardants.

The guidelines in place now—Technical Bulletin 117 for flammability standards—will be updated to reflect modern manufacturing methods that can lower the use of harmful chemicals.

The process to change these regulations will include workshops and the opportunity for public comment as well as administrative review.


Governor Jerry Brown
State Capitol Building
Sacramento, CA 95814

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