bluuebunny/crossref_metadata_2025 huggingface dataset:
Cover Picture: Macromol. Mater. Eng. 4/2004
Authors: dell'Erba Ignacio E. , Fasce Diana P. , Williams Roberto J. J. , Erra‐Balsells Rosa , Fukuyama Yuko , Nonami Hiroshi
Published: April 2004

Cover: The picture on the cover shows the antiplasticization of an epoxy network, produced by the addition of a new class of oligomeric silsesquioxanes bearing multiple intramolecular rings formed through SiOC bonds.

Further details can be found in the Full Paper by I. E. dell'Erba, D. P. Fasce, R. J. J. Williams,* R. Erra‐Balsells, Y. Fukuyama, and H. Nonami on page 315.
Cover Picture: Macromol. Theory Simul. 3/2004
Authors: Semler James J. , Genzer Jan
Published: April 2004

Cover: The picture on the cover represents Monte Carlo simulation generated conformations of copolymers with alternating and diblock sequences on chemically patterned substrates with strong and week attractions between the surface active sites and the adsorbing monomers along the copolymer backbone.

Further details can be found in the Full Paper by J. J. Semler and J. Genzer* on page 219.
Developmental shift in bidirectional functions of taurine‐sensitive chloride channels during cortical circuit formation in postnatal mouse brain
Authors: Yoshida Mika , Fukuda Satoshi , Tozuka Yusuke , Miyamoto Yusei , Hisatsune Tatsuhiro
Published: April 2004

Taurine (2‐aminoethanesulfonic acid) is the most abundant free amino acid in the developing mammalian cerebral cortex, however, few studies have reported its neurobiological functions during development. In this study, by means of whole‐cell patch‐clamp recordings, we examined the effects of taurine on chloride channel receptors in neocortical neurons from early to late postnatal stages, which cover a critical period in cortical circuit formation. We show here that taurine activates chloride channels in cortical neurons throughout the postnatal stages examined (from postnatal day 2 to day 36). The physiological effects of taurine changed from excitatory to inhibitory due to variations in the intracellular Cl−concentration during development. An antagonist blocking analysis also demonstrated a developmental shift in the receptor target of taurine, from glycine receptors to GABAAreceptors. Taken together, these results may reflect genetically programmed, bidirectional functions of taurine. At the early developmental stage, taurine acting on glycine receptors would serve to promote cortical circuit formation. As cortical circuit has to be regulated in the later stages, taurine would serve as a safeguard against hyperexcitable circuit. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 166–175, 2004
Characterization of a novel molluskan tyrosine kinase receptor that inhibits neurite regeneration
Authors: Hislop Jonathan , Dyer John R. , Scott Darcy , van Kesteren Ronald E. , Sossin Wayne S.
Published: April 2004

Receptor tyrosine kinases play many important roles in neuronal signaling including regulating neurite outgrowth. We have identified a novel receptor tyrosine kinase, neurite outgrowth regulating kinase (nork) from Aplysia californica. A fragment of this kinase was also identified in another mollusk, Lymnaea. The kinase domain is equally homologous to the Ret (rearranged during transformation) and fibroblast growth factor receptor families, but the extracellular domain is entirely novel, suggesting that it binds a nonconserved ligand. Overexpression of neurite outgrowth regulating kinase, but not a kinase dead form, causes a reduction in neurite outgrowth of Aplysia sensory neurons. Thus, we have identified a novel receptor tyrosine kinase implicated in regulating neurite outgrowth. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 127–136, 2004
GABAB receptor expression and function in olfactory receptor neuron axon growth
Authors: Priest Catherine A. , Puche Adam C.
Published: April 2004

Neurotransmitters have been implicated in regulating growth cone motility and guidance in the developing nervous system. Anatomical and electrophysiological studies show the presence of functional GABAB receptors on adult olfactory receptor neuron (ORN) nerve terminals. Using antisera against the GABAB R1a/b receptor isoforms we show that developing mouse olfactory receptor neurons express GABAB receptors from embryonic day 14 through to adulthood. GABAB receptors are present on axon growth cones from both dissociated ORNs and olfactory epithelial explants. Neurons in the olfactory bulb begin to express glutamic acid decarboxylase (GAD), the synthetic enzyme for GABA, from E16 through to adulthood. When dissociated ORNs were cultured in the presence of the GABAB receptor agonists, baclofen or SKF97541, neurite outgrowth was significantly reduced. Concurrent treatment of the neurons with baclofen and the GABAB receptor antagonist CGP54626 prevented the inhibitory effects of baclofen on ORN neurite outgrowth. These results show that growing ORN axons express GABAB receptors and are sensitive to the effects of GABAB receptor activation. Thus, ORNs in vivo may detect GABA release from juxtaglomerular cells as they enter the glomerular layer and use this as a signal to limit their outgrowth and find synaptic targets in regeneration and development. © 2004 Wiley Periodicals, Inc. J Neurobiol 60:154–165, 2004
Partial atomic charges of amino acids in proteins
Authors: Thomas Annick , Milon Alain , Brasseur Robert
Published: April 2004

Using a semiempirical quantum mechanical procedure (FCPAC) we have calculated the partial atomic charges of amino acids from 494 high‐resolution protein structures. To analyze the influence of the protein's environment, we considered each residue under two conditions: either as the center of a tripeptide with PDB structure geometry (free) or as the center of 13–16 amino acid clusters extracted from the PDB structure (buried). The partial atomic charges from residues in helices and in sheets were separated. The FCPAC partial atomic charges of the Cβ and Cα of most residues correlate with their helix propensity, positively for Cβ and negatively for Cα (r2 = 0.76 and 0.6, respectively). The main consequence of burying residues in proteins is the polarization of the backbone CO bond, which is more pronounced in helices than in sheets. The average shift of the oxygen partial charges that results from burying is −0.120 in helix and −0.084 in sheet with the charge of the proton as unit. Linear correlations are found between the average NMR chemical shifts and the average FCPAC partial charges of Cα (r2 = 0.8–0.85), N (r3 = 0.67–0.72), and Cβ (r2 = 0.62) atoms. Correlations for helix and β‐sheet FCPAC partial charges show parallel regressions, suggesting that the charge variations due to burying in proteins differentiate between the dihedral angle effects and the polarization of backbone atoms. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Novel structure and nucleotide binding properties of HI1480 from Haemophilus influenzae: A protein with no known sequence homologues
Authors: Lim Kap , Sarikaya Elif , Galkin Andrey , Krajewski Wojciech , Pullalarevu Sadhana , Shin Jae‐Ho , Kelman Zvi , Howard Andrew , Herzberg Osnat
Published: April 2004

The crystal structure of the Haemophilus influenzae protein HI1480 was determined at 2.1‐Å resolution. The amino acid sequence of HI1480 is unique, having no homology with other known protein sequences. The protein adopts a novel α+β fold, and associates into a dimer of tightly associated dimers. The tight dimers are formed by intermolecular interactions that are mediated by an antiparallel β‐barrel involving both monomers. Helical regions of two dimers mediate the tetramer formation. The helical region contains a four‐helix bundle that has been seen only in the anticodon binding domains of class I tRNA synthetases. A cluster of four residues, Tyr18, Arg134, Glu26, and Lys12 is located in a depression formed at the four‐helix bundle/ β‐barrel interface. The arrangement is suggestive of an active center, possibly a catalytic site. The HI1480 gene is located within the Mu‐like prophage region of H. influenzae, has no homology to bacteriophage genes, and is flanked by transposases. Hence, this is an example of horizontal transfer from an unknown organism. Gel mobility shift assays revealed that HI1480 binds DNA and RNA molecules. Double‐stranded DNA is favored over single‐stranded DNA, and longer DNA molecules are bound better than shorter ones. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Can solvent choices enhance both process safety and efficiency?
Authors: Evon Skip E. , Chewin Sima , Bodman Glenn T. , Torres Anthony J.
Published: April 2004

Recent work has demonstrated that the decomposition characteristics of individual chemicals ae often subsrantially different from those of the same chemical when combined with a solvent. Further, different solvents alter the decomposition in significantly different ways, shifting the observed Differential Scanning Calorimeter (DSC) onset and peak temperatures and maximum rates to lower as well us higher values. Often the magnitude of these effects cannot be explained as the result of simple dilution. This prior work with energetic materials in solvents emphasizes the importance to process safety of systematically testing reaction mixtures, in addition to testing individual chemicals.

The primary focus of such testing is to ensure the hazards of the proces are well understood so that the pmcess can be modified, or additional necessary preventative and protective systems can be implemented to minimize process upsets. However, it is demonstrated here that this knowledge can also be leveraged to modify processes to substantially increase process efficiency while maintaining or enhancing safety. for example, the batch size of an existing process had been very restricted because of the potential severity of a thermal runaway.

Research on chemisty/solvent‐specific decomposition data was utilized to select candidate replacement solvents for process optimization. A cooperative effort by safety engineers and development chemists ensued, resulting in a final process that entirely eliminated the batch size restrictions while simultaneously reducing reaction time and improving quality.
The effects of explosive blast on structures and personnel
Authors: Prugh Richard W.
Published: April 2004

Data concerning the effects of explosive blast on humans, structures, windows, etc. are available in standard texts. However, the “non‐linear” relationships among the variables make it difficult to use the data in “what if” scenarios.

“Hyperbolic” equations which relate the energy of explosion (in term of TNT equivalent), distance from the explosion, blast pressure, blast impulse and degree of injury or damage to structures are developed. These relationships may be shown as straight lines on “reciprocal‐reciprocal” graph paper. Thus, correlation of blast‐effects data is simplfled, and fewer data points are required to characterize a damage‐susceptible structure. Also, this type of graph aids in presenting the results of evaluations of potential damage which could result from accidental explosions, such as detonation of “condensed” explosives, pressure‐vessel bursting, vapor‐cloud explosions, and BLEVEs. Further, such graphs are useful in evaluating plant layouts and siting.
Comparison of EPA guidelines tables with a commercial model
Authors: Woodward John L. , Worthington David R. E.
Published: April 2004

The US EPA has provided a set of guidelines to aid compliance with Risk Management Planning (RMP) regulations, one specific for ammonia releases and a generic guideline for all other materials. These guidelines were developed using specific models, the SACRUNCH and SLAB model respectively. This paper compares predictions made by a proprietay model, PHAST/SAFETI Version 5.2 with both set of guidelines. Evaporation rate predictions are shown to he highly time‐dependent. Differences with the EPA guidelines occur grimanly from the process of averaging or making discrete approximations to the time‐varying curve. Our predictions are less sensitive to storage temperature than PA guidelines because in our model the cooling effect of an evaporating pool rapidly washes out the initial pool temperature effects. PHAST/SAFETI hazard zone predictions are found to differ from the guidelines primarily by way of the averaging time adjustment applied. Hazard distances are found to depend importantly on variables not considered in the guidelines: the release direction and the actual phase of a release, whether from the liquid or vapor space. However, release height, also not considered in the guidelines, was found to be less important, at least for volatile toxic muteriuls such as chlorine.
Flammable liquid storerooms: Fire protection without halon 1301
Authors: Maranghides Alexander , Sheinson Ronald S.
Published: April 2004

Flammable Liquid Storerooms (FLSRs) pose a significant loss prevention challenge. The fire protection engineer must design the fire protection system for a very diverse fuel population. Furthermore, for military applications, provision must be made for large temperature fluctuations in the operating environment and very strict suppression system space and weight requirements.

Halon 1301 is a very effective fire suppression agent used extensively in the militay and commercial sectors for over two decades. There are more than 2200 shipboard Halon 1301 fire suppression systems. However, production of stratospheric ozone depleting halon has been banned by the Montreal Protocol and the U.S. Clean Air Act amendments since December 31, 1993.
The use of aerosol fire extinguishing generators at rotogravure fed presses
Authors: Scheuermann Klaus P. , Modigell M. , Koch Wolfgang , Roßkothen Hanns‐Jürgen , Schmidt Jochen
Published: April 2004

Comprehensive experiments have demonstrated that aerosol fire extinguishing systems with the components 'detection, fire alarm and control unit along with an extinguishing generator represent a safety component that reduces the risk of fire hazard. The new extinguishing concept based on the solid matter aerosol potassium carbonate with about 20 g of aerosol/m3, 2 s reaction time and a particle size distribution from 0.5 μn to 2 μm ensures safe extinguishing of fires in the area of ink troughs in rotogravure fed presses. Other investigations have shown that from the point of view of fire hygiene, the extinguishing aqent poses no hazard to the health of employees.
Flammability limits of dusts: Minimum inerting concentrations
Authors: Dastidar A. G. , Amyotte P. R. , Going J. , Chatrathi K.
Published: April 2004

A new flammability limit parameter has been defined as the Minimum Inerting Concentration (MIC). This is the concentration of inertant required to prevent a dust explosion regardless of fuel concentration. Previous experimental work at Fike in a 1‐m3 spherical chamber has shown this flammability limit to exist for pulverized coal dust and cornstarch. In the current work, inerting experiments with aluminum, anthraquinone and polyethylene dusts as fuels were performed, using monoammonium phosphate and sodium bicarbonate as inertants. The results show that an MIC exists only for anthraquinone inerted with sodium bicarbonate. The other combustible dust and inertant mixtures did not show a definitive MIC, although they did show a strong dependence between inerting level and suspended fuel concentration. As the fuel concentration increased, the amount ofinertant required to prevent an explosion decreased.

Even though a definitive MIC was not found for most of the dusts an effective MIC can be estimated from the data. The use of MIC data can aid in the design of explosion suppression schemes.
The constraints on inherently safer design and other innovations
Authors: Kletz Trevor A
Published: April 2004

Some of the constraints that binder or prevent the greater use of inherently safer designs are common to all innovation: lack of time for development, the fear of unforeseen problems, the influence of licensors and contractors, and the inability of the innovator to sell his or her ideas. Others are specific to intensification or particularly prone to occur there. Finally, the actions needed to overcome the constraints are discussed.
Experiences with heavy fuel‐oil firing in a steam reformer
Authors: Pequeno Catela , Severin Manfred
Published: April 2004

The primary object of this article is to report on the experience gained during 7 years of operation of a top‐fired primary reformer using heavy fuel oil. Experiences using this kind of fuel are very rare because very few installations worldwide are prepared to use it. In addition, some information on the background of the plant on the plant modifications earned out will be given.
Using constant slip ratios to model non‐flashing (frozen) two‐phase flow through nozzles
Authors: Jamerson Scott C. , Fisher Harold G.
Published: April 2004

The TPHEM computer program, supplied with the recently published AIChE / CCPS book “Guidelines for Pressure Relief and Effluent Handling Systems”, can be used to reproduce a range of two‐phase flow data through nozzles. The ability to predict data and design emergency relief systems using simple models is important to the practicing engineer.
Batch purge caused by confusing control system displays
Authors: Hendershot D. C. , Keeports G. I.
Published: April 2004

Unclear or confusing process control system displays in the control room can cause process safety incidents or near misses. An incident is described in which two very similar displays on a process control system resulted in the inadvertent operation of several valves on the wrong equipment train, causing a batch to rapidly boil over into the reactor overhead system.
Why DIERS technology should be used in risk assessment: Call for a 1999 worldwide benchmarking survey on various risk reduction methods used
Authors: Noronha John , Torres Anthony
Published: April 2004

The Design Institute for Emergency Relief Systems (DIERS) Users Group has a membership of over 130 companies worldwide. It is an affiliate of the American Institute of Chemical Engineers. Its primary mission is to advance the technology and practice in the design of emergency relief systems for runaway reactions. This proposed survey is primarily on runaway reactions while recognizing there are many other venting applications of interes.

The purpose of the survey is to benchmark various runaway risk reduction methods used from a risk and cost‐benefit basis. It will also promote the consistent use of the DIERS and other venting technologies in risk assessmen.

Since it was first proposed by DIERS in March 1997, the survey has received much interest, not only from various international process safety, chemical engineering, and chemistry associations, but also from many non‐chemical associations worldwide. The survey is expected to be sent this year.

This paper outlines the background, purpose and procedure of the proposed survey; why DIERS should be used and why it is apparently used inconsistently; the benefits of larger vents and higher vessel design pressures and the theme of the survey questions.

Many of the broader issues of risk assessment were addressed in the 1994 DIERS Report, “Risk Consideration for Runaway Reactions,” Appendix 1 entitled “Addressing Some Issues Faced in Runaway Risk Assessment” [l].
Risk analysis: An investment in engineering
Authors: Brown Anthony E. P.
Published: April 2004

Application of the process risk analysis methodology and the use of risk analysis techniques on all enterprise‐engineering phases (research, project, erection, commissioning, start‐up, operation, plant modifications and decommissioning) is presented and discussed. The respective advantages and disadvantages of the selected techniques are also examined. A technical flow to the use of the appropriated safety and risk analyses path is propose.
Flammability zone prediction using calculated adiabatic flame temperatures
Authors: Mashuga Chad V. , Crowl Daniel A.
Published: April 2004

This paper describes our work to predict the flammability zone for any mixture of fuel, oxygen and nitrogen. The method utilizes a commercially available equilibrium program to determine the calculated adiabatic flame temperature (CAFT).

The model is compared with our extensive experimental data obtained in a 20 L sphere at an initial pressure of 1 atm and 298 K. The data and model compare well over the entire flammability zone for two pure species, methane and ethylene, and not as well for a 50/50 mixture of methane/etbylene.

Our results show that a good prediction of the flammability zone is obtained using a CAFT criteron of 1200 K. Furthermore, the intermediate species and solid carbon must be included in the equilibrium calculation to fit the fuel rich part of the zone. The intermediate species were selected by the equilibrium program using a built‐in species selection criteria.

For a gas mixture of methane and ethylene, we were unable to identify, mixing rules for estimating KG and Pmax from pure component data.

This method provides a direct approach to full flammability zone prediction.
Application of pressure nutsche filtration and drying technology for toxic chemicals
Authors: Perlmutter Barry A.
Published: April 2004

Most products are filtered, washed and subsequently dried. To this extent filtration and drying are interrelated. There are many individual pieces of equipment available that can accomplish the unit operations of filtration, washing and drying. The pressure‐nutsche filter‐dryer, designed for toxic chemical production, offers the optimum solution for conducting those multiple operations in a single process vessel.

An overview of conventional drying methods is presented followed by an examination of a new approach to filtration, washing and drying in pressure nutsche filter‐dryers. The classic drying curve is used to illustrate the drying techniques. Design parameters for toxic chemical processing, equipment cleaning, automated controls, and validation are also described.

A methodology for formulating a test program to analyze filtration, washing, and drying systems is presented. The program describes the feasibility of this technology for improved product quality, reduced production cycle time, minimized worker and environmental exposures, and improved safety.
Comparison of safety integrity level selection methods and utilization of risk baed approaches
Authors: Marszal Edward M. , Fuller Brad A. , Shah Jatin N.
Published: April 2004

The method used for the selection of a Safety Integrity Level (SIL) for a Safety Instrumented System (SIS)of a hazardous process shoud we a risk based approach to evaluate potential consequences and likelihoods, as well as the effectiveness of process safeguard. Process Safty Management, under OSHA 29 CFR Part 1910, requires an assurance of mechanical integrity for all emergency shutdown systems and safty critical controls. The International Society for Measurement and Control (ISA) promulgated an industy standard S84.01, to assist in compiance with the PSM regulation in the United States, and the International Electrochemical Commission (IEC) created a similar standard for Europe. These standard specifi that all electrical electronic, and rogrammable electronic system, used in SISs, are requiread to be desiped such that they, achieve a specified SIL. These standard are perfomance baed giving guidunce on how to select and achieve an appropriate SIL for a given SIS, but are not prescriptive to any particular method or equipment. The SIL selection is critical since in many cases the SIS is the ht layer of protection for the prevention of hazardous events. The probability of failure on demand of a SIS are quantitatively categorized into discrete integrity levels (i.e. SIL) by both industry standard. Since neither standard specfies requirements for integrity level selection, the determination of a SIL for a SIS is based solely on reducing the risk of a process to a level acceptable or tolerable to each individual company.

In this paper, current industry practices for the selection of SILs are evaluated to illustrate how each method provides an estimation of risk reduction that the SIS will provide for a given process. The level of effort, required expertise, and accuracy of the methods are also compared to assist the reader in choosing the appropriate SIL selection methodology.
Risk management plans for existing control rooms
Authors: McConnell R. A.
Published: April 2004

With the advent of API RP 752 “Management of Hazards Associated with Location of Process Plant Buildings” in the U.S., and new Chemical Industry Guidance in the UK there is a need to re‐examine the vulnerability of control rooms and other occupied buildings on our existing plants. The way one part of ICI Chemicals & Polymers at Teesside, England, has approached this problem at its sites in the northeast of England is described with specific application to ammonia and similar plants.
Contribution of human factors to incidents in the petroleum refining industry
Authors: Bradley Chadwell G. , Leverenz Fred L. , Rose Susan E.
Published: April 2004

Human factors consider how effectively and safely personnel interact with processes. It can cover a variety of issues, from facility design to procedures to overall management systems. In order to minimize human factors as potential causes for incidents, the causal relationship of human factors to safety incidents must be understood. An examination of previous incidents and incident investigations can provide valuable insight into the types of human factors that most often contribute to human error and, ultimately, to loss events.

The contribution of human factors to previous incidents in the U.S. petroleum refining industy are described in this paper. First, the data collection effort, which resulted in the documentation of over 130 incidents that occurred during the past 8 years, is examined. Next, the analysis approach is discussed, including a description of the characterization scheme used to identify cause‐contribution factors with specific incidents. Lastly, the results of the analysis are presented and valuable insights into the most common contributors are discussed.
Using quantitative risk assessment to develop a cost effective spill prevention program
Authors: Davis Lloyd , Ness Albert
Published: April 2004

A manufacturing plant needed to ensure that allowable peak styrene loadings to a Publicly Owned Treatment Works (POTW) were not exceeded. To reduce the potential for spills of styrene monomer, hazdrd analysis techniques were used to identify release scenarios that could impact the POTW Recommendations were then made to reduce or eliminate the likelihood of spills. Cost estimates were done for all recommendations requiring capital outlays. A Layer of Protection Analysis (LOPA) was conducted to rank the spill scenarios by frequency. The recommendations were then asessed for their effectiveness in reducing spill frequencies using the LOPA. The analysis showed that of the 34 recommendations requiring capital outlays, 10 reduced the spill frequency by a factor of 40. The rest had a small impact on the spill frequencies. Thus, the LOPA evaluation of the recommendations saved about a half million dollars in capital outlays that would have brought little risk reduction.
Layer of protection analysis and inherently safer processes
Authors: Dowell Arthur M.
Published: April 2004

Layer of Protection Analysis (LOPA) is an effective way to determine the required Safty Integrity Level (SIL) for Safety Instrumented Systems (SIS) based on the risk of the undesired event. This paper extends the LOPA concepts presented in previous papers to show the effect of inherently safer features. Inherently safer fatures in a process design can reduce the required SIL of the SIS, or can eliminate the need for the SIS, thus reducing cost of installation and maintenance. The discussion includes how to estimate the risk reduction for some inherently safer features. Maintenance requirements and management of change issues for some inherently safer features will be included.
Application of ISA S84.01 to SIS in the chemical and petrochemical industries
Authors: Cohen Wayne
Published: April 2004

The kellogg Brown & Root Company (KBR) has created a Safety Guide for Safity Instrumented Systems (SIS). This gulde defines what must be addressed in designing a safety system, and incolporates the application of ISA S84.01. It provides a way to perform a quantitative analysis for verification of the SIL values. The life cycle process is presented. The documentation is defined and some forms are provided.

This presentation reviews each step in design of the SIS starting with management commitment. The actions that must be undertaken to apply ISA S84.01 are discussed. The components of the Safety Gulde, specific forms, safety reviews, and SIL calculations are identified.
Survey of fire hazard classification systems for liquids
Authors: Britton Laurence G.
Published: April 2004

This article discusses classification systems for describing fire hazards of flammable and combustible liquids that might need to be applied by U.S. companies in order to comply with domestic or international regulations and standards. Despite international efforts to obtain uniform terms and definitions there continues to be a number of obstacles in the way of harmonized classifcation criteria, including the signifcant dffirences that currently exist between fire hazard classification systems developed and used in the U.S.
When you cut down a tree, keep an eye on the forest
Authors: Anderson Stanley E. , Ness Albert I.
Published: April 2004

Since the EPA began mandating controls on atmospheric discharges of organic materials, there have been a number of fires, explosions and other types of incidents of varying significance involving the emissions control devices. While these kinds of repetitive incidents are common throughout the industry, this paper discusses a number of incidents in one corporation, including thermal oxidizers, flares, and charcoal beds. We then discuss the common causes that seem to rise up to catch the operators of such devices unaware in spite of the history. Reasons why these avoidable incidents keep repeating are also explored.
Process improvements from incident data
Authors: Leggett David , Singh Jasbir
Published: April 2004

This paper discusses four different chemical processing accidents that resulted from plant mal‐operations. Each incident was relatively minor yet provided valuable information about the stability and/or vulnerability of the process to upset conditions. The reaction classes involved were:

Polyester polymerization

Secondary amine formation followed by decomposition

Oxidation of poly‐alkylated aromatic hydrocarbon

Base catalyzed oligomerization

The paper describes the ‘after‐the‐fact’ data that was obtained by calorimetric hazards testing. We will discuss how the information was used, in each case to improve the process safety of the particular operation.

We also describe an incident database that may be used by chemical companies to provide an on‐going ranked and categorized record of accidents and incidents that have occurred. The value of the database information lies in the fact that the actual and potential severity of each accident is estimated from the data of the incident events. This information can be used to distinguish processes that may be responsible for the majority of the minor incidents from those processes where more severe, but infrequent, accidents occur. The information is also valuable in providing a focus with which to drive process safety improvement efforts.
Safety integrity level analysis for processes: Issues and methodologies
Authors: Bhimavarapu Kumar , Stavrianidis Paris
Published: April 2004

The performance based ANSI/ISA S84.01 and IEC 61508 standards provide overall risk based safety life cycle models for industrial processes. Among other guidance, they provide the basic methodology and guidelines for the identification of safety instrumented systems necessary for a process to meet the established target risk levels. In order to arrive at risk based solutions, many practical issues need to be addressed. Such issues include identification of target risk levels, identification of hazardous events associated with the process under consideration, establishing the existing risk associated with the process, and selection of appropriate non‐instrumented and instrumented safety systems to meet the target risk. This paper outlines the basic methodology, and discusses some of the related issues mentioned above. Further, it provides a few methodologies to establish the requirements of the safety instrumented systems and their safety integrity levels.
Evaluation of two‐phase flow models for flashing flow in nozzles
Authors: Darby Ron
Published: April 2004

A variety of methods and models have been proposed in the literature for sizing relief valves for two‐phase flow applications. A typical application involves liquids which flash during discharge as the pressure drops. The predictions from these various methods can vary greatly under such circumstances, and can also deviate as much as 300% from measured values. This paper compares predictions from several versions of the homogeneous equilibrium and non‐equilibrium models with data from the literature for flashing of initially subcooled and low quality steam‐water mixtures through nozzles of various lengths. The results indicate that the homogeneous equilibrium model gives reasonable results for nozzle lengths greater than about six inches, but non‐equilibrium effects must be taken into account for shorter nozzles. Both the Fauske model with no adjustable parameters and the TPHEM model with appropriate values of the non‐equilibrium parameter (kne) are shown to give good results for short nozzles and subcooled or low quality inlet conditions.
A natural gas feed preheater fire
Authors: Singh Jagmohan , Joshi M. D. , Desai U. R.
Published: April 2004

This paper examines an incident in an ammonia plant which began when a leakage in the radiant section tube of a natural gas preheater ignited a small fire. The small fire ultimately developed into a major blaze which caused the leaky tube to burst resulting in the plant shutdown.

A subsequent investigation revealed inadequate equipment safety procedures. These faulty measures included the bypassing of an instrument interlock system provided for the gas feed preheater. The bypass caused operational problems because two plants were operating from a single natural gas supply header. In the aftermath of the incident, the instrument interlock system of equipment was modified to handle an emergency shutdown in the affected plant safely and, in the process, avoid hampering other ammonia plants.
Was Murphy wrong? Murphy's law in operation and design of chemical plants
Authors: Hendershot Dennis C.
Published: April 2004

We've all heard of Murphy's Law. It has been stated in various forms, generally something like “If something can go wrong, it will go wrong, and at the worst possible time.” We often quote Murphy's Law often in a light‐hearted or joking context. But, do we really believe it? What effect does our belief in Murphy's Law have on how we actually operate and design chemical plants? Is our application of Murphy's Law appropriate? How should we be using Murphy's Law?
An air and refrigeration machine oil console fire
Authors: Singh P. P.
Published: April 2004

An incident due to the ignition of a fire at the top of an oil console of air and refrigeration compressors caused the shut down of an ammonia plant for five days. The cause: failure of refrigeration compressor seals resulted in the lowering of the oil level in the console. This caused cavitation in the oil pump suction resulting in high vibration in the pump discharge piping which led to the snapping of a 3/4'' diameter interconnection line weld joint. Oil splashing from the snapped joint to the nearby steam header with improper insulation caused a serious fire above the oil console.
The impact of toxicity dose‐response relationships on quantitative risk analysis results
Authors: Ferguson Jeffrey S. , Hendershot Dennis C.
Published: April 2004

The toxicity dose‐response relationship is a critical data requirement for a quantitative risk analysis of a chemical processing facility. This paper will review:

The use of toxicity dose‐response relationships in a quantitative risk analysis

The development of dose‐response relationships for use in a quantitative risk analysis from toxicity data

Examples of variation in published dose‐response relationships for some common chemicals

The impact of differences in dose‐response relationships on the results of a quantitative risk analysis

Finally, we propose the development of a standard protocol for development of toxicity dose‐response relationships for use in quantitative risk analysis, with emphasis on the benefits to the chemical industry of a standardized methodology.
A study on detonation safety of some hydrocarbon‐air mixtures
Authors: Lizhong Yang , Weicheng Fan , Xiaodong Zhou , Qingan Wang
Published: April 2004

Hazards caused by detonation of hydrocarbon‐air mixtures have been a matter of concern for a long time. In this paper, critical initiation energy of detonation of some hydrocarbon air mixtures have been measured in confined (rectangle shock tube tests) and unconfined (plastic bag tests) condition. Based on the concept of explosion length, a formula for estimating the critical initiation energy of detonation under unconfined condition is presented. Detonation safety analysis of the studied hydrocarbons is carried out using the experimental results.
Derivation of Le Chatelier's mixing rule for flammable limits
Authors: Mashuga Chad V. , Crowl Daniel A.
Published: April 2004

In 1891 Le Chatelier [6] first proposed an empirical mixing rule for predicting the flammable limit of lean fuel air mixtures ‐this method is still widely used today. This paper presents a proof to Le Chatelier's mixing rule based on thermodynamics. A number of assumptions are required to produce the proof. These assumptions are

The product heat capacities are constant.

The number of moles of gas is constant.

The combustion kinetics of the pure species are independent and unchanged by the presence of other combustible species.

The adiabatic temperature rise at the flammability limit is the same for all species.

These assumptions we re found to be reasonably valid at the lower flammability limit and less so at the upper flammability limit.

This paper also considers experimental data that support some of the assumptions made to arrive at the Le Chatelier mixing equation.
Fire protection risk assessment: A proposed methodology for oil and chemical facilities
Authors: Roe Donald L.
Published: April 2004

Fire protection is considered only part of a facility's safety and loss prevention program. Fire protection systems are designed to respond to events after they have occurred, and do not take into consideration other systems in place that prevent the event from occurring in the first place. In many instances, and especially after events have occurred, lawsuits have been filed, regulatory consent orders have been issued, and recommendations from outside experts and insurance companies have been issued, directly pressuring the company to take action. Other companies with similar risks have also felt indirect pressure to install additional protection systems. Good engineering judgment has not always been applied to assure that the money was well spent.

This paper will present a fire protection risk assessment methodology for oil and chemical facilities. In this methodology, not only are fire protection issues considered, but also select management, process safety and engineering systems are reviewed. The systematic review of these factors will assist a facility in establishing its own risk assessment criteria.

ECRC has applied and proven the benefits of this methodology at a Gulf Coast refining and petrochemical complex. I will summarize the results of this work during this presentation.
Analysis identifies deficiencies in existing pressure relief systems
Authors: Berwanger Patrick C. , Kreder Robert A. , Lee Wai‐Shan
Published: April 2004

This article presents a statistical analysis showing that the pressure relief systems on nearly half of the equipment in the oil, gas, and chemical industries lack adequate overpressure protection as defined by recognized and generally accepted good engineering practice. This analysis was based on data collected from a large number of government mandated (per OSHA 1910.119) pressure relief system design audits per‐formed by an independent contractor. The vast majority of these deviations from good practice were not identified during conventional process hazard analyses (PHA) performed on these same facilities. Most of the units had also been designed by reputable design firms.

The authors conclude that, as a practical matter, conventional PHA methods are ineffective tools for evaluating pressure relief systems. They also conclude that the pressure relief system design process could be improved. Specifically, the authors recommend that, in order to reduce this deficiency rate in the future, that the industry adopt an equipment based approach to pressure relief system design and maintenance.
Mitigation of gas explosions using water deluge
Authors: Van Wingerden Kees
Published: April 2004

The degree of congestion in petro‐chemical installations has a strong impact on the strength of possible gas explosions. Model predictions and recent full‐scale explosion tests showed that there are situations where the consequences of such gas explosions are unacceptably high. These consequences make it necessary to consider several measures including very expensive ones such as control room relocation or strengthening of control rooms. When the costs are too high other mitigation methods may also have to be assessed. One of these methods is mitigation of gas explosions using water spray systems. Such systems are already in use for this purpose offshore, water curtain systems may be applicable onshore.

An overview of recent research into the effects of water spray on the course of gas explosions in congested environments is presented in this paper. How water spray affects the course of gas explosions, under which conditions water spray will be effective as a means for explosion effects reduction is also reported. In addition, the author illustrateg how one can design a water spray system to limit the consequences of possible accidental gas explosions. Finally the potential of increase of ignition probability due to the use of water spray is discussed.
Accidental releases of two‐phase multicomponent critical flow from horizontal pipes
Authors: Verlicchi Paola , Leonelli Paolo , Spadoni Gigliola
Published: April 2004

An accident involving a two‐phase release can result in serious consequences for people as well as the environment. Consequently, tools are needed to give accurate predictions of the discharge rate, physical state, composition of released material, and chocked pressure in order to improve process safety efficiency.

This paper discusses possible approaches to the examination of two‐phase critical releases and presents a slip equilibrium model which provides critical flow rate, critical pressure, and phase fraction of the two phases emerging from an accidentally broken pipe containing a liquefied gas mixture under pressure.

Comparisons between experimental critical flow rates and model predictions are favorable in both monocomponent and multicomponent mixtures.
Design of cyclone separators for emergency relief systems
Authors: Schmidt Jürgen , Giesbrecht Hartmut
Published: April 2004

The main dimensions of cyclone separators for emergency relief systems have been optimized by measuring the gas loading capacity of geometrically similar cyclones having diameters of 290 and 1,000 mm. Experiments have been carried out with mixtures of air and water, aqueous Luviskol® (poly[vinylpyrrolidone]), having viscosities of 180 to 1,100 mPas, as well as two aqueous foams, the surfactant K8 and methylcellulose. Overall, the measurements have shown that the optimized devices are equally suitable for the separation of aqueous, viscous, and foaming media. The fluids vented during emergency reactor discharges can thus be reliably separated. Compared with design recommendations given in the literature, significantly smaller equipment is required for the same separating performance.
Overpressure protection system for ammonia storage tank
Authors: Pattabathula Venkat , McGrath John , McDonald Lew
Published: April 2004

An in‐depth hazards review and subsequent installation of overpressure protection system on a 30‐year‐old ammonia storage tank are discussed in this paper.
Cable and cabling systems in hazardous locations
Authors: Buschart Richard J.
Published: April 2004

Cabling and wiring are critical to the safety, reliability, and operability of chemical process facilities, especially in Hazardous (Classified) Locations.

The National Electrical Code (NEC), Article 500, provides the basic rules for electrical installations in locations where flammable gases or vapors may be present. There have been revolutionary changes in Article 500 in recent NEC Code Cycles. The European (or zone system) offers the option of meeting international standards, and offers significant advantages in chemical plants.

Some chemical (and petroleum) companies have been using open wiring, drip loops, cabling systems instead of conduit. Cable systems are also very flexible and offer significant maintenance advantages.
Process equipment problems caused by interaction with hydrogen—an overview
Authors: Prescott G. R. , Shannon Brian
Published: April 2004

Hydrogen damages equipment in several ways. Hydrogen attack, embrittlement, crack initiation and propagation, and other mechanisms are constant threats to equipment integrity. Ways to avoid these problems are discussed.
Lessons learned from fires, flash fires, and explosions involving hot work
Authors: Ogle Russell A. , Carpenter Andrew R.
Published: April 2004

Eight case studies of fires, flash fires and explosions involving hot work are reviewed. Each of these accidents occurred in the course of performing hot work on, or in the vicinity of, a vessel, container, or pipe. In most cases, the fuel's presence was not identified prior to the accident. Another feature of these case studies is that the accident occurred despite the fact that the hot work operators were familiar with the tools, procedures, and the equipment on which they were working.

The causal factors of these accidents are identified and compared with the applicable safety standards to show how safe work practices could have prevented the accidents. The fundamental conclusion to be drawn from these eight case studies is this: if you fail to recognize a hazard, you cannot control it.
Protecting semiconductor facilities, 2000 and beyond
Authors: Pearce Robert J.
Published: April 2004

The semiconductor industry remains one of the most rapidly changing industries, and its fate of always being on technology's cutting edge has not always been enviable. In the 1970s, the industry was concentrated in municipalities using the Uniform Building Code (UBC) [1]. None of the code's occupancy classifications were really appropriate, so semiconductor fabrication facilities (FABs) were designated as an “H” or hazardous occupancy. This vagueness reflected uneducated, arbitrary, and inconsistent interpretations of the codes that made it difficult to construct and manage facilities. To address this, many of the leading‐edge semiconductor companies dedicated staff to work with code officials to assure that any codes governing the industry could be applied uniformly, and would contain reasonable protection requirements. Continuing that practice will ensure the industry's ability to operate safe facilities despite an atmosphere of constant change.