bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new set of blast curves from vapor cloud explosion
Authors: Tang M. J. , Baker Q. A. 
Published: April 2004

AbstractPast accidents have demonstrated that vapor cloud explosions (VCEs) are the most severe threat to refining and petrochemical industries. In order to estimate the air blast parameters at any given distance from a possible explosion source, a variety of prediction methods have been developed. A brief description of these prediction methods is first presented. Then, the focus of this paper is on an engineering method based on blast curves, which is the most frequently used prediction method.Knowledge of blast effects from vapor cloud explosions has greatly improved due to the efforts of investigators in many countries during the last three decades; however, blast curves have not been reexamined. One of the aims of this paper is to present a new set of blast curves which have been validated with available experimental results and analytical solutions. Another aim is to present a comprehensive set of blast curves including blast parameters for both positive and negative phases.The new blast curves, which are a modification of the Baker‐Strehlow curves, improve the prediction for detonations and supersonic deflagrations as well as for subsonic flames. By changing the slope of the blast pressure versus distance curve, the overly consserative blast pressure predictions by the previous Baker‐Strehlow curves at large standoff distances for detonations and supersonic deflagrations are reduced. By clarifying the labeling of the flame. Mach number for each blast curve, the overly conservative pressure and impulse preditions for subsonic flames are also avoided.The new blast curves have been validated against VCE experiments including detonations, fast deflagrations, and slow deflagrations. Particular attention was given to large scale deflagration experiments, which became available only recently. Good agreement is shown between the new blast curves and the experimental blast data for vapor cloud detonations and subsonic deflagrations. For supersonic deflagrations, the blast curve predictions are overly conservative in that blast pressure decays more rapidly with distance in experiments than the calculated curves.
Conduct of operations: A control system for your most important safety component
Authors: Haas Paul , Hager Guy 
Published: April 2004

AbstractInstrumentation and control engineers go to great lengths to ensure availability and operability of control and information display systems for process system operation, especially for safety systems. It is critically important to maintain equipment performance within the bounds of safe operation. The most crucial safety components in your facility are the human beings controlling, maintaining, monitoring, and managing the process and equipment. Have you ever given much thought to the control systems operated by humans in your facility?
Human factors: Preventing catastrophic human error in 24‐hour operations
Authors: Westfall‐Lake Peggy 
Published: April 2004

AbstractHuman factors can play havoc with quality of task performance in safety‐sensitive operations, especially those that run 24‐hours, 7‐days a week. Research across multiple industries indicates common threads of observable and preventable behaviors that can lead to catastrophic events. Fatigue, monotony, overwork and a multitude of other cultural factors and organizational policies can trigger these mental and physical human errors. With recent extensive capital investments in hardware and software to automate continuous operations, the human operating the controls may become complacent and fail to perform as anticipated.Since the chemical plant, maritime, aviation and space disasters of the mid‐1980's, there has been an increased focus on operational procedures. Operational fatigue has been on the National Transportation Safety Board's list of Most Wanted Transportation Safety Improvements since the list's inception in 1990 [1]. Today, it may be time to re‐visit human factors and focus on the human in operational settings in all modes of 24hour operations. The key is to first understand two strategies to prevent shiftwork‐related human error. The first strategy is at the organizational level where we can align human resource and safety policies, address aging needs through better shift scheduling, develop work/rest guidelines and design wellness objectives to enhance 24‐hour safety performance. The second strategy is at the operational level where employees recognize personal set‐ups for human error and take the appropriate measures. These skills are learned through “fatigue counter‐measure training.” Both strategies will be discussed throughout this article.
Safety hazards associated with air‐emission controls
Authors: Ozog Henry , Erny William J. 
Published: April 2004

AbstractAir‐emission controls have been installed in refineries since 1990 to comply with environmental regulations such as Benzene NESHAP and the Clean Air Act. Companies have experienced incidents associated with these air‐emission controls, but the extent of the problem could not be quantified. In this paper, we present the results of a survey of the member companies of API's Safety and Fire Protection Subcommittee (SFPS) to determine the number and type of air‐emission controls which have been installed, and the types of incidents which they have experienced. The survey was completed in February 1998.We obtained responses from eight SFPS member companies, including 16 refineries, 1 gas plant, 2 chemical plants and 1 marketing terminal.A total of 2,110 air‐emission controls have been installed at these facilities and 70 incidents associated with these controls have been reported. Of the 70 incidents a number involved recurring events associated with the same air‐emission control, so when these events are deleted, only 32 unique incidents remain. 15 of these unique incidents resulted in injury or significant property damage.Carbon canisters are the most common air‐emission control installed (769) and there have been 10 unique incidents associated with carbon canisters/beds, of which 5 resulted in injury or significant property damage. Given the prevalence of carbon canister installations and the associated incidents, the SFPS Emission Control Safety Work groups decided to focus mitigation/prevention efforts on carbon canisters.If carbon beds are overloaded with volatile organic compounds (VOCs) or highly reactive materials, they can overheat and catch fire, which can then provide an ignition source for VOC vapors.The industry however does not appear to be fully aware of the hazards associated with the use of carbon canisters and the limitations on their use. In many installations safeguards to prevent fires or explosions may be necessary. Typical safeguards include:

pre‐wet new canisters to prevent excessive heat buildup.
avoid applications where adsorption of highly reactive chemicals such as ketones, aldehydes and organic acids may occur.
avoid VOC concentrations in excess of 10,000 ppmv.
provide flame arrestors to pre vent flashback to VOC sources.
provide vacuum breakers directly on process equipment to prevent air ingress into hot carbon canisters.
We believe that the widespread use of carbon canisters presents the need to develop appropriate guidelines to prevent further incidents.The objective of this project was to research and evaluate the safety hazards associated with certain air‐emission control systems used in the petroleum industry and to develop recommendations to address these hazards.
Studies on the probabilities and likely impacts of chains of accident (domino effect) in a fertilizer industry
Authors: Khan Falsal I. , Abbasi S. A. 
Published: April 2004

AbstractFertilizer industries are among the chemical process industries where hazardous chemicals are handled and accidents involving heat/mass/momentum transfer can result in explosions, fires, and toxic releases. Based on experience gained from past incidents in the fertilizer industries risk assessment tools and techniques are often employed in order to identify hazards and to forecast potential disasters. These efforts have almost always focused on single events or “stand alone” accidents.The interaction of an accident with other hazardous units with the potential to cause secondary, tertiary, or higher order accidents is seldom studied. Yet, chain of accidents have been occurring in the past and the probability of a repetition in the future constantly increases because of the proximity of industrial plants and the increasing population pressure in most countries. Consequently we have developed models and computer‐automated tools to study chain of accidents or “domino effects.” In this paper we discuss the concept of domino effect in the context of our methodologies, and present an illustrative case study of a major fertilizer industry situated near the city of Chennai(Madras, India).
A methodology to evaluate industrial vapor and dust explosion hazards
Authors: Dahn C. James , Reyes Bernadette N. , Kusmierz Andrew 
Published: April 2004

AbstractA methodology was developed to evaluate the potential of vapor, dust and hybrid mixtures (combustible dusts and flammable gas in air) explosions in small to medium size industrial operations. Also, a protocol to conduct analysis and evaluation of explosion potential for industrial operations is presented.Elements for thorough site inspections are defined based on uncovering potential failures and hazards. The best ways to review applicable standards and codes pertaining to the specific operations and occupancies are also covered.The engineering hazard analysis (HA) method selection is critical to achieve the most complete evaluation of hazards in the operations. Methods and guidelines for their use will be discussed. Guidelines will also be presented for best selection of tests to evaluate the hazards. Extensive investigation to identify hazardous materials present in the industrial operations will be conducted.Criteria for successful fire and explosion hazards analysis are also identified.
Fire protection in telecommunication facilities
Authors: Robin Mark L. 
Published: April 2004

AbstractThe telecommunications industry is one of the fastest growing industries on the planet, with some analysts estimating the current annual world market to be approximately $750 billion. Telecommunications companies worldwide have spent billions of dollars to ensure that voice, data and video routes operate reliably, and of primary concern to these providers is the minimization of service disruptions. Fire is one of several possible causes of service interruption in telecommunication facilities. This paper describes the telecommunications network, its associated fire hazards, and the application of clean agent fire suppression agents, specifically HFC‐227ea, in the protection of such facilities.
Deflagration and detonation of ethylene oxide vapor in pipelines
Authors: Thibault Paul , Britton Laurence G. , Zhang Fan 
Published: April 2004

AbstractPure ethylene oxide (EO) vapor may propagate decomposition flames through pipe above certain minimum conditions of temperature, pressure and pipe diameter. Flame propagation was studied in both closed and vented 5 cm (2‐inch) pipe and closed 30 cm (12‐inch) pipe. Flame progression in closed pipe was irregular and proceeded in pulsed stages. A possible mechanism involves preferential flame propagation at the pipe roof accompanied by periodic autodecomposition of EO accumulated in hot products behind the flame front, such accumulation probably being augmented by liquid EO condensed on the pipe walls ahead of the expanding flame system. Flames propagated 15 m (50 ft) through horizontal 5 cm pipe at 70°C and initial pressures ≥ 4.3 bar (62 psia). In a series of 30 cm pipe tests employing low‐energy ignition and otherwise increasingly severe conditions, a deflagration‐to‐detonation transition (DDT) occurred, partially destroying the test equipment. A new test facility was set up to confirm the ability of EO to propagate detonations in 30 cm pipe and to further investigate the phenomenon. Two EO detonations at 2.9 bar and one at 3.5 bar were directly initiated via the strong shocks from hydrogen‐oxygen detonations. Based on a spectrum analysis of the pressure histories, the two detonations at 2.9 bar were probably marginal and propagated in a single spin detonation mode. At 3.5 bar, the pressure history suggests that the detonation propagated in a two‐head detonation mode near the end of the 24 m test section.
Dust deflagration extinction
Authors: Chatrathi Kris , Going John 
Published: April 2004

AbstractTwo basic phenomenological models for deflagration propagation in dust clouds are discussed as the basis for interpreting explosion suppression results. The first model is based on oxygen diffusion to fuel dust particles as the controlling step in explosion propagation through a dust cloud. The second model assumes explosion propagation is controlled through fuel particle volatilization followed by combustion in the gas phase.With this scientific framework as the basis, the inhibition aspects of explosion suppression are discussed to provide guidelines for industrial dust explosion mitigation. As part of the analysis, experimental results are presented for organic, inorganic and hybrid high Kmax dust explosions and dust explosion suppression.Inorganic dusts fuels included aluminum, and silicon. Organic fuels in the experiments were Pittsburgh coal, cornstarch, polyethylene, anthraquinone, calcium stearate, cadmium stearate, and cornstarch w/propane. Extinguishing agents used in the experiments were sodium bicarbonate, potassium bicarbonate, mono‐ammonium phosphate and calcium carbonate.
Safety aspects during transient and steady‐state operation of a pilot‐scale distillation column
Authors: Stark Douglas E. , Shonnard David R. , Crowl Daniel A. 
Published: April 2004

AbstractIn distillation involving flammable liquids, inert gases are used to prevent the formation of flammable or combustible gas mixtures by precluding oxygen from the equipment vapor space. In this study, a pilot‐scale distillation column for the separation of ethanol and water was used to directly measure pressure changes within the isolated column and within the inerting system during start‐up, steady‐state, and transient operation. Our results show the following:

Distillation column vacuum relief rates due to reboiler shutdown, as predicted by current literature sources, are conservative by a factor of 50 compared to measurements.
During steady‐state operation, the difference in solubility of the inert gas (N2) between the feed and distillate streams accounts for pressure changes in an isolated column. For ethanol and water, the nitrogen is more soluble in the distillate, resulting in a column vacuum. For an open system, this effect could result in air being drawn into the system, resulting in potential formation of combustible vapor mixtures.
A nitrogen balance model is presented to calculate the changes in column pressure during steady‐state column operation. The predictions are conservative by a factor of 2 to 5.
For transient operation, a simple model based on fraction‐al utilization of the condenser over‐predicts pressure changes resulting from reboiler steam duty changes to within about 30% of the measurements.
Use of propylene oxide versus nitrogen as an ethylene oxide diluent
Authors: Britton Laurence G. 
Published: April 2004

AbstractDecomposition flame propagation limits of ethylene oxide (EO) diluted either with nitrogen or propylene oxide were measured under initial conditions enveloping those commonly used in simple stirred ethoxylation reactors. Tests conducted in a 600 liter vessel at 6.5 bar (95 psia) and 165°C verified that “energetic ignition” decreases the EO propagation limit relative to the predictions of “weak ignition” models. The limit in nitrogen found using “energetic ignition” (1 gm gunpowder squib or EO decomposition flame fired into the test mixture) was about 38 mol% EO while the limit found using hot coil igniters was about 46% EO, similar to the predictions of “weak ignition” models. The rates of pressure rise due to decomposition of near‐limit mixtures were highly sensitive to low levels of turbulence but much less than values previously reported for mixtures containing 90% EO.Propylene oxide (PO) has been reported to be a more effective EO diluent than nitrogen. However, tests using “energetic ignition” in the large vessel revealed a potentially hazardous feature of PO dilution. Although the EO decomposition limit was raised from 38% in nitrogen to about 48% in PO, the latter started to decompose at greater EO concentrations, becoming a hazardous reactant rather than a diluent. Decomposition of near‐limit EO + PO mixtures generates much greater pressures than can be achieved by decomposing near‐limit EO + nitrogen mixtures. At the test conditions used in this study, decomposition of 55% EO in nitrogen produces a maximum pressure of about 34.5 bar (500 psia) while 55% EO in PO produces about 51.7 bar (750 psia). The PO decomposition phenomenon has not been previously reported. A plausible explanation involves the fate of ethylene formed during PO decomposition. In diluent mode, PO decomposes endothermically producing ethylene, CO, and hydrogen. The large heat losses and short duration of decomposition events in small test vessels allows ethylene to persist as a stable product and PO therefore appears to be an effective diluent. However, in large test vessels, the greater temperature and pressure transients developed during EO decomposition cause ethylene to decompose and the net decomposition reaction of PO becomes exothermic.
Mixture reactivity in explosions of stratified fuel/air layers
Authors: Tamanini Francesco , Chaffee Jeffrey L. 
Published: April 2004

AbstractThe paper addresses one aspect of the definition of the explosion hazard from flammable liquid spills or slow heavy vapor releases in enclosures. In this type of accidents, the explosive mixture is typically confined to a layer near the floor. No methods are currently available for the sizing of explosion vents in these partial‐volume deflagrations. Resolution of the issue was sought through tests carried out in a 63.7 m3 (2250 ft3) chamber with stratified mixtures of propane in air. The layers were formed by slowly injecting propane at the chamber floor through diffusers, at a rate of the order of the estimated rate of vaporization of a typical solvent such as acetone. The layer composition was carefully characterized through gas concentration measurements at twelve locations, using a single continuous analyzer connected to a multiplexed sampling system. Following ignition of the layers, data were obtained on the propagation velocity of the flame and on the pressure developed by the explosion in the room both with and without venting.The results of the experiments have been correlated using an existing model, modified to account for the cylindrical geometry of the system and for the dual‐mode character of the combustion process (a premixed flame is typically followed by diffusive/ convective burning of the rich portion of the fuel/air layer). While confirming the conservatism of current design recommendations, which are based on the assumption of a full‐volume explosion, the work has brought out the fact that the contributions to pressure development from the different portions of the layer must be properly taken into account.Work is currently in progress to predict the fuel distribution in the explosive layer as a function of the parameters that define the spill (or fuel release) scenario. This step is being done through modeling of the rate of vaporization of a liquid pool and the subsequent dispersion of the vapors in the surrounding area. The model, when combined with the already‐developed treatment of the explosion problem, will provide an integrated tool for predicting the protection requirements of flammable liquid process/dispensing areas.
A blasting cap test for evaluating self‐reactivity hazards
Authors: Meyers S. , Singh S. K. , Shanley E. S. 
Published: April 2004

AbstractThis paper describes a simple blasting cap test that furnishes information on sensitivity to initiation as well as rudimentary information on propagation. The design of the test provides containment of most condensed‐phase residues and explosion reaction products while minimizing noise pollution. We include comparison between test results and thermochemical hazard predictions determined by calculation of the adiabatic reaction temperature (CART).
Ignition of combustible fluids by heated surfaces
Authors: Michael Bennett J. 
Published: April 2004

AbstractIndustrial machinery fires are commonly caused by flammable operating fluids leaking onto hot machinery surfaces. This paper discusses doctoral research currently underway to identify the dominant fundamental mechanisms controlling the overall ignition process of combustible liquid stream‐fed pools impinging on heated surfaces. Experiments are now underway to characterize these processes, via modeling and the use of dimensional analysis, to be able to predict the minimum surface ignition temperature for a given set of fluid and surface properties, more accurately define safe operating boundaries of equipment to mitigate fire events, and suggest optimal designs to widen the safe operating envelope. As a result of recent analyses, a surface modification technique has been proposed to use a pattern of micro‐cavities, sized to prevent fluid seepage, on the exterior of the heated surface to reduce the heat transfer from surface to liquid (due to reduced direct contact), and inhibit the formation of superheated vapor films. This behavior could increase the temperatures necessary for ignition, permit‐ting a wider range of safe operating conditions.
Investigation of an acid spill caused by the failure of an air‐operated diaphragm pump
Authors: Ogle R. A. , Morrison D. T. 
Published: April 2004

AbstractA spill of concentrated hydrochloric acid caused considerable damage at an ion exchange resin regeneration plant. The release was caused by two independent failures: the failure of a diaphragm pump and a containment dike. An accident investigation determined the root causes of the accident and evaluated the system safety of the process. The root cause of the diaphragm pump failure was environmental stress cracking of the PTFE diaphragm in 33% HCl service. The root cause of the dike failure was insufficient steel reinforcement.Based on the accident investigation, additional safeguards were implemented to prevent a recurrence of the accident.
Multilayer protection analysis for photovoltaic manufacturing facilities
Authors: Fthenakis Vasilis M. 
Published: April 2004

AbstractThis paper gives an overview of environmental health and safety (EHS) issues related to photovoltaic (PV) technologies, and strategies for reducing EHS risks. These strategies include layers of prevention and mitigation in six sequential steps. Prevention layers are related to safer technologies, processes, and materials; safer use of materials; preventing accident‐initiating events; preventing or minimizing releases, and preventing human exposures. The mitigation options include secondary confinement, emergency scrubbers, and adsorption units. As the PV industry approaches these issues and mitigation strategies in a vigilant, systematic way, the risk to industry, workers, and the public will be minimized.
Risk analysis of a petrochemical industry using ORA (optimal risk analysis) procedure
Authors: Khan Faisal I. , Iqbal Asad , Abbasi S. A. 
Published: April 2004

AbstractRisk assessment is an essential prelude to the development of accident prevention strategies in any chemical process industry. But, the high costs and time involved in conducting risk assessment by conventional techniques often becomes a deterrent. In order to circumvent this problem, the authors have developed a risk analysis methodology based on a set of reliable rapid techniques and tools. The suitability of the methodology, named by us ORA (Optimal Risk Analysis), has been demonstrated by applying it to a real‐life situation.