Fire Science and Technology Inc.

Issaquah, WA, United States

Fire Science and Technology Inc.

Issaquah, WA, United States
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Babrauskas V.,Fire Science and Technology Inc. | Babrauskas V.,University of California at San Diego
Fire Safety Journal | Year: 2017

When an electric arc is created, a pressure event occurs. There can be two aspects to this: the shock and sound waves propagated from the expanding arc channel, and the bulk pressurization of the enclosure, if arcing is taking place within a closed volume. The present paper is the first systematic review of the research on both these pressure phenomena. Quantitative studies on electrical arc explosion pressures date back to the 1920s, although arc pressures generated by lightning, which is a type of electric arc discharge, have been studied since the 1700s, but understanding of the phenomena is still not complete or exhaustive. Experimental data are compared to theoretical predictions. It is shown that in an enclosed volume some extremely high pressures can be generated, if the arc current is sufficient. Such pressures can destroy buildings and mechanical equipment and cause injuries or death to nearby individuals. Even without enclosures, the shock waves produced from high energy arcs can cause injuries, although arc flash injury may be of greater concern. Injury potential generally requires that high currents be available, and serious damages or injuries are not associated with low-energy arcing occurrences. © 2017 Elsevier Ltd

Babrauskas V.,Fire Science and Technology Inc. | Babrauskas V.,University of California at San Diego
Process Safety and Environmental Protection | Year: 2017

Phosphorus is a highly reactive substance and numerous accidents have been reported due to phosphorus reactions with diverse chemicals. Yet, it has generally been considered that phosphorus does not explode when O2 (or air) is the only available reaction partner. A chemical explosion requires that a bulk volume of reactant be available to react abruptly. Thus, a substance which is highly reactive is likely to participate in an explosion only if rapid, local consumption of reactant can be avoided and a sizable volume becomes capable of reacting precipitously. Since reactions of P with O2 are rapid, explosions have rarely been encountered and most chemical safety treatises warn of explosive P reactions only in connection with substances other than air. Despite this background, a series of P explosions is described which occurred in molecular beam epitaxy equipment. Earlier known incidents are also discussed. In each case, the details of the environment allowing precipitous reaction of a sizable volume of P have not been well understood, and additional research is warranted. Reference works should make clear that explosions in the system P + O2 are possible, and that neither additional reactants nor elevated temperatures are required for this. © 2017 Institution of Chemical Engineers

Babrauskas V.,Fire Science and Technology Inc. | Babrauskas V.,University of California at San Diego | Britton L.G.,Process Safety Consultant
Fire Technology | Year: 2017

Database tabulations of minimum explosion concentration MEC for dust clouds often contain data values that are extremely low, i.e., 30 g m−3, or lower. Such values invariably represent measurement or analysis errors, often due to inadequate dust uniformity in the test vessel. There are only two organic vapors with MEC values below 30 g m−3, and it is physically implausible that either stationary or randomly moving dust clouds would be more efficient in combustion than vapors. Combustion of dust clouds will have all of the types of heat losses that occur with burning of vapor clouds, but have additional sources of heat losses, particulate radiation and endothermic pyrolysis, not present for vapors (dusts of unstable chemicals are not considered in this paper). Thus, MEC values for dust clouds necessarily have to be higher than for vapors. Other sources of error for dust cloud MEC values have also been identified. These include incorrect data analysis, unrealistic pressure-rise criteria for what constitutes an explosion, and excessive igniter energies used in some apparatuses. German data based on VDI 2263-1 should be post-corrected for statistical treatment errors. But no specific correction exists for low reported MEC values due to mixture nonuniformity or inappropriate pressure criteria. It is recommended that any reported MEC values below 65 g m−3 for cellulosic agricultural dusts, below 35 g m−3 for any other organic dusts, and below 55 g m−3 for dusts of metals or non-metallic elements be expunged as likely to be incorrect. Even at higher MEC values, there is likely to be a systematic bias in the data and this needs to be considered in longer-range research. ASTM E1515 offers more reliable testing and data analysis procedures than does VDI 2263-1 and is preferred. © 2017 Springer Science+Business Media, LLC

Babrauskas V.,Fire Science and Technology Inc. | Don Russell B.,Texas A&M University
Fire and Materials | Year: 2010

For the evaluation of occupant safety in the case of building fires, the Required Safe Egress Time/Available Safe Egress Time (RSET/ASET) concept has become widespread and is now commonly used in the fire safety engineering profession. It has also become commonly used by smoke detector (smoke alarm) manufacturers in assessing whether a particular detector technology is adequate. It is shown in this paper that the concept is intrinsically flawed and its use promotes the diminishment of fire safety available to building occupants. The concept innately ignores the wide variations in capabilities and physical condition of persons involved in fire. It is based on implicitly assuming that, after a brief period where they assess the situation and mobilize themselves, occupants will proceed to the best exit in a robotic manner. This assumption completely fails to recognize that there are very few fires, especially in residential occupancies, where occupants perished or were seriously injured who had endeavored to exit in this robotic manner. Instead, in the vast majority of fire death and serious injury cases, the occupants did not move in such a manner and their evacuation took longer than anticipated on the basis of robotic movement. There is a wide variety of reasons for this, and these are well known in the profession. The concept also ignores that there can be a wide variation in fire scenarios. The same building and the same fire protection features can be evaluated, but both RSET and ASET can change drastically, depending on the scenario used. The consequence of using the RSET/ASET concept for fire safety engineering or product design purposes is that fire deaths and injuries are permitted to occur, which are preventable. © 2010 John Wiley & Sons, Ltd.

Babrauskas V.,Fire Science and Technology Inc.
Fire and Materials 2015 - 14th International Conference and Exhibition, Proceedings | Year: 2015

This study examines reasons why unfortunate individuals receive hideous, sometimes fatal burn injuries from gas-fired space heaters. The basic reasons are twofold: (1) In North America, gas-fired space heaters are tested and Listed (i.e., approved) in accordance with a series of American National Standards Institute (ANSI) product standards. These standards contain provisions for the testing of clothing ignition potential. However, the provisions are grossly inadequate and permit heaters to be Listed which can ignite fabrics in as short a time as 1 second. The defective testing procedures have persisted through numerous editions of the pertinent standards. This is likely due to imbalanced representation on the ANSI committee, which has dominant industry representation but few technical personnel representing interests of the general public. The general public is not well-served by the current inadequate standards. (2) Heater manufacturers merely submit their products for testing by Listing agencies, and fail to conduct meaningful testing which would reveal the clothing ignition hazards associated with such designs. The manufacturers involved consider that they have fulfilled their responsibility by providing product warnings. Such warnings are intrinsically ineffective in safeguarding persons from clothing ignition. Alternative designs exist which do not create the hazard of clothing ignition. Such heaters are commercially available, but do not comprise a large fraction of the products in the marketplace. The thermal design principles needed to produce a safe design are well known and do not require innovative strategies or recourse to patented schemes. CPSC should promulgate a mandatory regulation if ANSI is unable or unwilling to provide adequate protection of the public against clothing ignitions in their standards. © Interscience Communications Limited, 2015.

Babrauskas V.,Fire Science and Technology Inc.
Journal of Loss Prevention in the Process Industries | Year: 2016

The results of the UN test O.1 for oxidizing solids are shown to be incorrect when specimens contain certain inertant additives, illustrated for the case of oxidizers in the ammonium nitrate fertilizer family. Test results for three different AN-based products containing inertants show that two of the three (including calcium ammonium nitrate, CAN, a long-known safer alternative to AN) would be misranked with the O.1 test. An analogy between the heat release rate of substances containing fire retardant (FR) chemicals is established and several ways by which FR behavior can be achieved are demonstrated. It is shown that the O.1 test implicitly adopts only one model of inertant action, and that chemicals which rely on a differing mode of inertant action are liable to be incorrectly treated. It is further shown that the physical basis of the O.1 test-an intimate mixture of finely-comminuted fuel and oxidizer-misrepresents the most common type of accidents involving oxidizers, and that such test results do not correspond to scenarios of a less extreme nature. The new O.3 test improves the analysis method, but does not resolve the problem of excessive commingling of fuel into oxidizer. It is recommended that the intermediate-scale arrangement used by the Bureau of Explosives be adopted for further development and standardization, in preference to the O.1 or O.3 test arrangements. © 2015 Elsevier Ltd.

Babrauskas V.,Fire Science and Technology Inc. | Lucas D.,Lawrence Berkeley National Laboratory | Eisenberg D.,Development Center for Appropriate Technology | Singla V.,Green Science Policy Institute | And 3 more authors.
Building Research and Information | Year: 2012

US building codes balance the consideration of hazards to public safety, health and general welfare. Current codes require foam plastic insulation materials to have both protection by a thermal barrier and compliance with Steiner Tunnel test requirements. The Steiner Tunnel test is met by adding flame-retardant chemicals to the foam. Studies demonstrate that the Steiner Tunnel test does not give reliable fire safety results for foam plastic insulations. Foams that meet the Steiner Tunnel test still pose a fire hazard if used without a code-mandated thermal barrier. Insulations protected by a thermal barrier are fire safe and the use of flame retardants does not provide any additional benefit. Evidence is examined of the health and ecological impacts from the added flame-retardant chemicals. Changing the building codes could prevent health and environmental harm from the toxicity of these substances without a reduction in fire safety. Plastic foam insulations that are protected by a thermal barrier should be exempted from the Steiner Tunnel test and the need to use flame retardants. This change would align US codes with code regulations in Sweden and Norway and ensure the fire safety as well as improve health and environmental impacts. © 2012 Copyright Taylor and Francis Group, LLC.

Gann R.G.,U.S. National Institute of Standards and Technology | Babrauskas V.,Fire Science and Technology Inc. | Grayson S.J.,Interscience Communications | Marsh N.D.,U.S. National Institute of Standards and Technology
Fire and Materials | Year: 2011

The science of understanding how fires burn and how heat smoke and gases are generated and affect people has progressed substantially in the last half century. The principles of facility design for life safety in fires have reached a degree of maturity. Standards and code provisions for fire detection, suppression and control have become the norm. Real-scale (or nearly real-scale) test methods for the flammability of furnishings and interior finish have been established. In addition, some tests have been developed that measure the results of the burning of a small sample from the finished product. Yet, while there have been numerous small-scale apparatuses developed for assessing the generation of heat, toxic gases, and visible or corrosive smoke, these facets of life and property safety have not found widespread inclusion in building and fire codes. There has been an invigorated effort in ISO TC92 SC3, Fire Threat to People and the Environment, to develop a coherent and comprehensive set of fire safety standards and guidance documents for life safety. Smaller efforts are ongoing within some national and regional standards bodies. In November 2008, experts in this field gathered at The Royal Society in London to hear papers that captured the state of the art and to discuss where we might go from here. This paper summarizes the papers and the discussion from that meeting. © 2010 John Wiley & Sons, Ltd.

Babrauskas V.,Fire Science and Technology Inc.
Fire Technology | Year: 2016

The concept of noncombustibility evolved in the early days of building codes, before quantitative methods of measuring and assessing components of fire hazard were available. ‘Noncombustible’ lacks a technical definition of general scope, but in the US codes, which are the primary focus of this study, it is defined as a material which meets the criteria of the ASTM E136 test. The hazard variables underlying the noncombustibility concept are examined in this study. In view of today’s state of the art, it is shown that noncombustibility requirements, in most cases, constitute a misapplication of fire safety principles and that their use should be discontinued, in preference of using variables that express quantitative fire safety principles. Heat release rate (HRR) is the primary variable which correctly establishes the relevant hazard. In recent years, some regulations have been promulgated which use bench-scale HRR test results directly for this purpose. The ultimate hazard to be addressed, however, is the full-scale HRR behavior. When the hazard involves fires which may spread over surface linings, however, the full-scale HRR is not simply directly scaled to the bench-scale HRR. To quantify this hazard properly, additional properties of the material which govern the flame spread behavior need to be considered. A simple, easy-to-use method for this purpose are described, which is based solely on data obtainable from the Cone Calorimeter (ASTM E1354; ISO 5660) test. Validation of the concept against room-scale data is provided and is shown to be successful. © 2016 Springer Science+Business Media New York

Babrauskas V.,Fire Science and Technology Inc. | Blum A.,University of California at Berkeley | Blum A.,Green Science Policy Institute | Daley R.,Green Science Policy Institute | Birnbaum L.,U.S. National Institutes of Health
Fire Safety Science | Year: 2011

The extensive use of chemical flame retardants to meet the California Furniture Flammability Standard Technical Bulletin 117 (TB117) [1] provides an example of the need for consideration of environmental impacts of fire safety interventions before they are implemented. Flame retardants are currently being used in products with high levels of human exposure without adequate toxicological testing. For example, flame retardants commercially used to meet TB117 have been found to have negative impacts upon human, animal, and environmental health [2] and notably, the TB117 standard has not been shown to have a measurable fire safety benefit. Both the unintended adverse impacts and the lack of fire safety benefits of California TB117 are discussed in detail. © 2011 INTERNATIONAL ASSOCIATION FOR FIRE SAFETY SCIENCE.

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