bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of panel inertia effects in vented dust explosions
Authors: Tamanini Francesco
Published: June 2004

Current guidelines for sizing of vents in dust explosions deal with panel inertia effects either by suggesting that the issue be approached experimentally on a case‐by‐case basis (VDI 3673) or by recommending a maximum mass per unit area (NFPA 68). This empirical approach to the problem is surprising, given that this aspect of explosion venting should be easily amenable to analytical treatment. From this assessment, an analysis of vent panel dynamics was carried out based on a simplified explosion model, which has also been used to develop a generalized vent sizing correlation. The main result of the analysis is the identification of a dimensionless parameter which fully characterizes the effects associated with the inertia of the panel. This inertia parameter includes: the reactivity of the mixture; the volume of the enclosure; the mass of the vent per unit area; the number of equal panels on the vented volume; and a panel shape factor. The analysis has quanitified the intuitive expectation that the mass per unit area of the panel is not a property that should be considered in isolation, and that panel inertia effects are more important the more reactive the mixture and the smaller the volume. The predictions from the model have been validated by comparison with available data for both dust and gas explosions. The extensive validation work that has supported their development provides confidence that the design correlations derived from the analysis can be used reliably to account for an effect that is either neglected or referred to testing by existing guidelines.
Consequence modeling for the EPA risk management plan (RMP)
Authors: Crowl Daniel A.
Published: June 2004

The EPA Risk Management Plan (RMP) has considerable requirements for consequence modeling. This paper discusses the modeling requirements, the data required from your process to perform this modeling, and a summary of the minimal modeling procedures required to meet the RMP.
Hot work on a steam condenser ignites a titanium tube bundle fire: A case history
Authors: Mahnken Glenn E. , Rook Michael T.
Published: June 2004

The flammability of titanium chips, fines, and powders is widely recognized. Titanium alloy tubing is much more difficult to ignite. However, as this paper describes, titanium tubing in heat exchangers is subject to ignition as a result of hot work operations. Explosions can follow if water is applied to the burning titanium.

A fire consumed the titanium tube bundle of a steam turbine condenser during demolition work in a decommissioned power plant. The titanium fire is believed to have initiated by contact with hot steel slag from torch cutting which was being conducted to remove sections of the steel condenser casing above the tube bundle. The approximately 25 ft long bundle was essentially consumed end‐to‐end, including the tube sheets.

A fire watch had been stationed as part of the plant's Hot Work Permit System, but the initial phase of the fire was obscured from view. Workers reported a bright yellow flame coming from inside the south end of the tube bundle. Water application on the fire by workers and the local fire department was followed by explosions within the tube bundle and discharge pipes. Fortunately, no injuries or property damages occurred from this incident.

Loss lessons from this and two similar titanium heat exchanger fires are presented. The initiating conditions for these fires are discussed.
LFL estimates for crude oil vapors from relief tank vents
Authors: Petersen Ronald L. , Watson Kevin D. , Roehner Richard
Published: June 2004

In 1970, the Alyeska Pipeline Service Company was formed to manage the design, costruction, operation and maintenance of the Trans‐Alaska Pipeline System. The 800 mile long pipeline carries crude oil from Prudhoe Bay on the North Slope to Port Valdez on Prince William Sound. There are 11 pump stations located along the pipeline, each of which is equipped with a crude oil relief tank. Because of the potential flammable nature of the crude oil vapors being vented from the tanks, Alyeska wanted to determine the region surrounding the tanks within which the lower flammable limit (LFL) could be exceeded. Because numerical models cannot accurately model the flow near structures, especially for dense gases (as is the case here), wind tunnel modeling was conducted to provide more accurate distance to LFL estimates. The wind tunnel model simulations were also used to judge the effect of various modeling parameters (i.e., site specific configurations, release scenarios and meteorological conditions), and to assist in possible future refinements to numerical models. Field observations were also obtained at one of the pump stations for the purpose of validating the wind tunnel modeling. The project, wind tunnel scaling methods, experimental methods, concentration measurement results, distance to LFL estimates and comparison between the field and wind tunnel observations are described in this paper.
The use of a ranking matrix and recommendation prioritization system for process hazard analysis studies
Authors: Moore David A.
Published: June 2004

OSHA regulations for Process Safety Management (PSM) [1] and EPA regulations addressing risk management programs (RMP) for chemical accidental release prevention [2] require industry to identify and analyze potential process hazards. This effort, known as the Process Hazard Analysis (PHA) element of the PSM and RMP standards, involves the use of qualitative hazard identification or analysis techniques acceptable to OSHA or EPA.

While making these assessments, two issue arise; how to judge acceptable risk and how to decide on appropriate risk reduction measures where necessary. Neither regulation defines a model for making risk management decisions. In the absence of formal, sanctioned risk management criteria, it is recommended that companies adopt a standard, defensible ranking scheme to provide a common basis for decision‐making. This should be based on the company's defined safety goals. This article discusses an approach, common to many companies, that qualitatively ranks the risk of identified scenarios. In addition, this article examines the possible problems of using various ranking schemes and risk criteria.
Expansion bellows failure of synthesis loop hot heat exchanger
Authors: Anwar Zaheer , Ahmed Shahid , Kirmani Iffikhai A.
Published: June 2004

Failure of expansion bellows of a synthesis loop heat exchanger, its initial diagnosis and subsequent repair by installing sleeve with packing rings and gland arrangement to save mechanical work is discussed. The procedure resulted in a savings of approximately ten day's downtime
An application of menu design principles to an energy management system
Authors: Latta David R. , Schulze Lawrence J. H.
Published: June 2004

The organization of a menu can significantly affect user response time when selecting targets from that menu. Previous empirical studies have used laboratory tests to suggest menu design rules that can optimize user response. This study applied the design rules to a menu used for display selection on an Energy Management System. In such a study, the total number of menu targets and the relationships among them is not variable, so some compromises must be made when applying the rules. This study produced a new menu that had measurable improvement in user response time over the existing menu. Design rules regarding grouping of targets and methods of organization were successfully applied during the menu redesign.
Management of change: A pilot plant application
Authors: Wieczorek Gary M. , Basu Prabir K.
Published: June 2004

Whereas the management of change concept is a common practice for many production facilities, its application in a research and development environment is relatively new. How does one effectively manage a change control program when “change” is the normal way of doing business? Is it really necessary for pilot plants? These were the challenges facing the Searle chemical pilot plant organization in 1991 when it initiated its program.

This paper describes the Searle pilot plant equipment management of change program, its evolution, and implementation. The problems and issues faced during implementation will also be reviewed.
Safe design of a thermally unstable solid storage container: Natural convection effects on thermal ignition
Authors: Zoghlami H. , Laurent A. , Corriou J. P. , Adrian J. C. , Papp R.
Published: June 2004

A numerical simulation of the convection process in a thermally unstable solid storage container has been carried out. The obtained results show that natural convection shifts the thermal ignition to higher induction times. Beyond a critical Rayleigh number, natural convection can prevent the system against thermal ignition. Temperature and velocity fields are calculated. The influence of the dependence of Biot numbers on temperature and the radius/height ratios on the induction times for thermal ignition has been also examined.
Increased fire hazard of N‐heterocyclic compounds substituted by S‐containing group
Authors: Négyesi György , Farkas László , Rusznák István , Sallay Péter
Published: June 2004

Release of CS2 and/or H2S caused by friction is demonstrated on two N‐heterocyclic compounds carrying S‐atom containing substituents. Because of the generation of electrostatic charge and creeping discharge, simultaneously brought about by friction, ignition and possible explosion of the released gaseous products of decomposition could occur. The tested compounds proved not to be sensitive to impact. Nonetheless, fire and explosion hazard of dusts must not be judged by their sensitivity to impact only. It is necessary to test their sensitivity to friction as well.
Design practice for extinguishing barrier systems
Authors: Siwek Richard , Moore P. E.
Published: June 2004

An extinguishing barrier comprises an optical flame sensor and a HRD‐Suppressor located downstream of the detected flame front. The effectiveness of an extinguishing barrier is based on its ability to detect an explosion in a pipeline by means of an optical flame detector whose tripping signal is amplified and then very quickly actuates the detonator‐actuated valves of the pressurized HRD‐Suppressors.

Extensive practice‐related tests in pipelines, having different cross sections and length, in pipelines connected with different vessels, have shown that extinguishing barriers can be used without reservation to halt or stop an explosion in practice. The amount of suppressant agent required depends on the nature of the combustible dusts, the nominal diameter of the protected pipeline, the explosion velocity and the maximum reduced explosion overpressure in the vessel. Most significantly, the theoretical understanding of explosion propagation and extinguishing has led to computer design guidance which has simplified system design. Explosions can be combated effectively in pipelines up to diameter 2500 mm.
Vent access restriction for solids handling systems
Authors: Bernard Lionel , Brodie Frank , Ludwig Dennis , Ness Albert , Weidner Karl
Published: June 2004

A multi‐disciplinary team developed a guideline for determining access restriction zones around vented solids handling equipment. The guideline provides a method for ensuring the discharge from a vented explosion will not cause injury to personnel. The steps in this method include: calculating the extent of external hazards from vented explosions; identifying potential areas where personnel could be exposed to a hazard; identifying ways to eliminate or reduce the hazard area; and establishing and documenting any access restrictions needed. Hazard zone calculations use the latest knowledge from research into fireball size, flame length and external pressure equations in VDI 3673. The guideline provides guidance for using this information. Options for mitigating or reducing external hazards from vented explosions are also described. As part of the project, the team audited several solids handling systems to look for potential oversights in existing restricted access areas. Some of the team's learnings from these audits are reviewed.
Safety surveys—looking at key activities in depth
Authors: Kletz Trevor A.
Published: June 2004

Most audits try to look at a representative selection of the plant procedures and equipment. An alternative is a survey, a look in depth at selected procedures (such as those for testing alarms and trips, issuing permits‐to‐work, controlling modifications, taking samples or testing relief devices) or selected equipment (such as level glasses or equipment for handling LPG). If the procedure or equipment is well‐chosen, surveys may make a bigger contribution to safety, per person‐hour, than a conventional audit.
NFPA 30: An update and a look into the future
Authors: Benedetti Robert P.
Published: June 2004

In May 1996, the Flammable and Combustible Liquids Code Committee of the National Fire Protection Association (NFPA) proposed for adoption by the Association a new edition of NFPA 30, Flammable and Combustible Liquids Code. This new edition was the culmination of two and one‐half years' work by the Committee and included one of the most significant changes to that document in some twenty years: the incorporation of mandatory fire protection criteria for warehouses and other inside areas that store flammable and combustible liquids in containers and portable tanks.
Safety, health and loss prevention in AIChE
Authors: Bradford William J. , Davenport John A. , Schwab Richard F.
Published: June 2004

Safety, health and loss prevention are major areas of interst for the American Institute of Chemical Engineers (AIChE). There has been an evolution of these concerns over the years in the Institute just as it has in industry. This article chronicles this evolution.
A model for the calculation and the verification of closed cup flash points for multicomponent mixtures
Authors: Hanley Brian
Published: June 2004

Regulatory issues related to material safety have made the accurate measurement and/or prediction of flash points essential. The flash point is one of the major physical properties used to determine the fire and explosion hazards of a liquid. Flash points are used by virtually all governmental entities worldwide to define “flammable” and “combustible” materials for shipping and safety regulations.

A model is described here for the calculation of closed cup flash points for multicomponent, single liquid phase, mixtures. The model is based upon rigorous vapor/liquid equilibrium calculations supplemented with information about the lower flammable limits (LFL's) and heats of combustion (ΔHc's) for the mixture's constituent components. The closed cup flash points predicted with this model are typically within ± 5°C of the experimentally reported values. Such a model is useful as a means of verifying experimental data and as a tool for screening product formulations prior to experimental flash point determination. The model should considerably enhance the safety evaluation portion of the product development cycle, thus leading to shortened product time‐to‐market cycles. While flash points calculated with this model are in excellent agreement with experiment, experimental determination is still encouraged for critìcal safety applications.
Emergency planning: Critical evaluation of proposed AEGLs for ammonia
Authors: Michaels Robert A.
Published: June 2004

National Advisory Committee's Acute Exposure Guideline Levels (AEGLs) for ammonia are critically evaluated. The technical bases for concern about AEGL‐2 and AEGL‐3 values derived by the committee are summarized recommendations made.
Flammability hazards of lower aliphatic aldehydes at elevated pressure and temperature
Authors: Britton Laurence G.
Published: June 2004

A large and potentially hazardous decrease in aldehyde autoignition temperature (AIT) occurs with increased pressure. The AIT‐pressure curve determined in a 5 L stainless steel sphere was similar for propionaldehyde and butyraldehyde in air, falling from about 185°C at atmospheric pressure to 90°C at 140 psia. Reduction of oxygen concentration had little effect on propionaldehyde AIT. At 100°C and 140 psia, autoignitions accompanied by at least a doubling of pressure were observed above 4% oxygen. In the presence of a few grams of free liquid, propionaldehyde vapor ignited in air at initial conditions significantly below the AIT. The mechanism appears to involve rapid Fe‐catalyzed exothermic liquid‐phase oxidation leading to autoignition of the adjacent heated gas layer. An acetaldehyde vapor‐air mixture in the presence of free liquid and rust exploded at room temperature when air pressure was increased to 95 psia; this result is discussed with reference to a cylinder overpressurization that occurred while making up an ostensibly sub‐LFL calibration mixture with compressed air. Propionaldehyde's limiting oxygen concentration (LOC) was investigated in the near‐autoignition region using the same 5L apparatus; the findings are discussed with reference to an overpressurization incident in an air‐liquid partial oxidation reactor. The general results are used to illustrate the application of LOC in partial oxidation processes subject to autoignition and to discuss elements of the current ASTM draft test method for LOC, which does not address test difficulties associated with condensable and/or reactive gas systems.
Fire tests of rack storage of water miscible liquids in plastic containers
Authors: Davenport John A. , Pabich Martin J.
Published: June 2004

This article deals with fire protection for water miscible flammable liquids stored in plastic containers packaged in boxes located on pallets. A series of fire tests was conducted with palletized rack storage arrangements using in‐rack sprinkler protection at various levels. The intent of the paper is to present data from this test series for these types of commodities. The paper will identify various existing water miscible flammable liquid products stored in this fashion and provide background information for protecting this type of storage as it relates to NFPA 30 Flammable and Combustible Liquids Code. The test data indicates that further research work is needed in the area of plastic containers for use with the storage of combustible and flammable liquids. Included in the paper are discussions concerning possible protection strategies and suggestions for future research which would benefit those involved in risk management of this type of commodity.
The assignment of safety systems addressing workplace hazards
Authors: Kahn Russell , Sorel Michael , Slaven Robert , Nelson Melvin , Harlow Ronald G. , Lutz Ron
Published: June 2004

A new method is described to enhance the management of process safety risks such that the number and type of safety systems protecting against any hazard are consistently predicated upon risk. Further, that such an assignment of safety systems can be made consistent throughout an organization. This consistency is gained through standardization of qualitative risk ranking and by setting company guidelines.
Case studies of incidents in runaway reactions and emergency relief
Authors: Ho Ta‐Cheng , Duh Yih‐Shing , Chen J. R.
Published: June 2004

Case histories of 65 incidents in runaway reactions and emergency relief in Taiwan were analyzed and classified into several categories according to their causes, materials involved, equipment types, reaction types, and ignition sources. The cases in reactors and storage tanks were examined in more detail owing to the higher probability or larger potential hazard in these two types of equipments. The most common consequence of the incidents are explosions, fires, and atmospheric release of toxic chemicals. The most severe case was a thermal explosion from an organic peroxide storage area which caused the death of 33 persons. Popping and direct releasing of process chemicals to the atmosphere from relieving devices cause the greatest environmental concerns to the community close to the plants. Runaway reactions in batch type reactors occur frequently due to various operational mistakes. Heat of reaction is the most frequent ignition source of runaway reactions and emergency relief.
Evaporation enhancement through the use of sprays
Authors: Gault Terrell
Published: June 2004

One method of accommodating excess wastewater at an electric power plant is the use of sprays to enhance natural evaporation. Field testing of this concept was undertaken at the Jim Bridger plant in Wyoming.
Fire protection for cable trays in petrochemical facilities
Authors: Schultz Neil
Published: June 2004

A review of products which have been tested by different methods.
High‐tech mist elimination in multi‐stage evaporators
Authors: Lerner Bernard J. , Woinsky Samuel G.
Published: June 2004

An innovation which allows gas rates up to three times those allowable in conventional pads.
Reliability and hazards analysis of a cumene hydroperoxide plant
Authors: Arendt J. S. , Casada M. L. , Rooney J. J.
Published: June 2004

A reliability and hazards analysis of a portion of a petrochemical process plant and how the application of system reliability engineering can contribute to plant safety is demonstrated.
Multiple cracking and leakage of a hot synthesis gas pipe
Authors: Lawrence Garth M.
Published: June 2004

Leakage from multiple cracks in a synthesis gas pipe exit the ammonia converter.
The effect of oxygen and water on stress corrosion cracking of mild steel in liquid and vaporous ammonia
Authors: Lunde Liv , Nyborg Rolf
Published: June 2004

The influence of water and oxygen concentration on stress corrosion cracking of steels in liquid ammonia. Vapor phase cracking in water‐inhibited ammonia storage spheres is also discussed.
Runaway system characterization and vent sizing based on diers methodology
Authors: Leung Joseph C. , Fauske Hans K.
Published: June 2004

This article reveals the diverse nature of runaway systems as well as some general trends. In addition, it also serves to point out the usefulness of such an apparatus in characterizing virtually unknown systems.
Guidelines for vapor release mitigation
Authors: Prugh Richard W.
Published: June 2004

A new publication, developed by CCPS, which contains discussions and suggested methods of design in the area of detection, de‐inventory, isolation, counter‐measures and containment is discussed.
Shipboard polymerization of acrylic acid
Authors: Kurland J. J. , Bryant D. R.
Published: June 2004

In 1975 glacial acrylic acid polymerized in a tank of the S.S. Alchemist four days from port. Vapor and liquid vented at high pressure for three hours. Retained acid was stable. Probably steam leaking into steam coils or a deadheaded pump caused overheating that set off polymerization.
Spark ignition hazards caused by charge induction
Authors: Owens J. E.
Published: June 2004

Unexpected ignition hazards, caused by static charges on nonconductors, warrant greater attention in industrial plants and laboratories.
Experiments on the thermo‐hydraulic response of pressure liquefied gases in externally heated tanks with pressure relief
Authors: Venart James E. S. , Sumathipala U. Kuma , Steward Frank R. , Sousa Antonio C. M.
Published: June 2004

An experimental program is described and experimental results presented for the response of an externally heated horizontal cylindrical tank protected by a PRV and partially filled with a pressure liquefied gas. Measurements of tank pressure, temperatures, mass discharge and void development, along with photography of internal fluid behavior are used to demonstrate the complex thermo‐hydraulic behavior as a function of heating and valve position. The results are used to compare some of these parameters with analyses of stratification and void development.
Emergency relief system design for reactive and non‐reactive systems: Extension of the DIERS methodology
Authors: Fauske Hans K.
Published: June 2004

Simple mechanistic models for reactive and non‐reactive chemicals are summarized. The DIERS methodology has been extended as well as simplified to account for vapor disengagement and frictional effects including laminar flow conditions—both principal objectives of the DIERS program.
Developments in explosion protection
Authors: Swift Ian
Published: June 2004

Current state of testing and research programs regarding present developments relating to deflagrations of gases and dusts.
Positive pressure testing system (PPTS)
Authors: Gwynn James E.
Published: June 2004

A positive pressure testing system for primary reformers, auxiliary boilers and start‐up heaters in ammonia plants to provide a reliable, positive method of testing.
Application of health effects data to chemical process accidents
Authors: Holton Gregory A. , Montague David F.
Published: June 2004

An approach to dealing with the problem of inadequate lethal health‐effects data.
Consequences of solvent ignition during a drum filling operation
Authors: Schwab R. F.
Published: June 2004

This paper describes an incident in a pilot plant designed to make specialty chemical products based on oxime chemistry. The requirements of the process include handling fairly large amounts of flammable liquids. With this in mind the plant was built within an existing building and was provided with a properly designed sprinkler system, an adequate drainage system, ventilation system, and electrical equipment appropriate to the occupancy.
Process safety management: A U.K. approach
Authors: Hawksley J. L.
Published: June 2004

Process safety in the UK is discussed from both the legal and management standpoints. General safety legislation requires a formal statement of company policy and arrangements for managing safety, but allows freedom for an organization to decide what those arrangements should be. The basis of a company‐wide approach to process safety management that meets legal requirements is outlined. Some of the main points requiring attention for effective process hazard recognition, assessment and control on a continuing basis are discussed.
An approach to evaluate the acute impacts from simulated accidental releases of chlorine and ammonia
Authors: Gephart L. , Moses S.
Published: June 2004

The manner in which specific chemicals are used is studied in order to identify plausible release scenarios and the probability of their occurrence.
Process safety evaluation applying DIERS methodology to existing plant operations
Authors: Fauske Hans K. , Grolmes Michael A. , Clare George H.
Published: June 2004

The DIERS methodology can be used to quickly assess the relief capacity envelope for a collection of existing process vessels accounting for both vapor and gassy systems. Easy‐to‐use vent sizing nomograms and PRESS sheets are proposed that can be completed by the process engineering, the process chemistry and the process safety departments. A vessel volume‐vent size diameter relationship is also developed using the source term based on fire exposure to cover a reasonable range of credible upset scenarios. In this way the adequacy of existing relief systems can be quickly surveyed for potential trouble sources—“outliers”—warranting further evaluation and corrective action.
Investigation into an explosion that occurred during a welding operation
Authors: Nightingale P. J.
Published: June 2004

Isolation procedures and monitoring techniques for the presence of explosive mixtures proved to be inadequate to prevent an explosion which was initiated by an unexpected ignition source.
A review of models for predicting the dispersion of ammonia in the atmosphere
Authors: Kaiser Geoffrey D.
Published: June 2004

The state‐of‐the‐art of the modeling of accidental releases of anhydrous ammonia to the atmosphere.
Material verification and inspection program
Authors: Sherwood Robert J.
Published: June 2004

A Material Verification and Inspection Program was started due to the potential safety consequences of a material failure in a critical pressure service. The non‐destructive testing segment of the program was oriented toward the materials that had been in operation for a certain period of time; the material verification was relevant to both operating plants and those under construction.
Safety of exothermic reactions a UK strategy
Authors: Pantony M. F. , Scilly N. F. , Barton J. A.
Published: June 2004

The paper deals with research projects initiated by HSE to resolve certain technical issues which arose out of a study of incident histories. In addition guidance is discussed which is being published by HSE, or to which HSE is contributing. This will help industry to meet their obligations under the Health and Safety at Work etc. Act 1974 with respect to the safety of exothermic reactions having the potential for thermal‐runaway. Finally the question of to vent or not to vent' is considered.
Instructional videotapes on chemical process safety
Authors: Crowl Daniel A. , Louvar Joseph F.
Published: June 2004

This paper describes a set of videotapes on chemical process safety produced by Wayne State University and BASF Corporation. The intent of the videotapes is to provide instruction on the application of safety procedures and process safety technology in a chemical pilot plant development area and the application of proper safety procedures in a laboratory.
Procedures for preventing pilot plant runaways
Authors: Brummel Roger N.
Published: June 2004

During the nitration of a substituted benzoic acid, a runaway reaction occurred. The reaction had been run without incident many times in the laboratory and once in the pilot plant on a 50 gallon scale. As a result of the runaway, the procedures for running reactions in the pilot plant were thoroughly reviewed. The review resulted in eliminating some practices, reemphasizing some existing procedures, establishing a new review system, and formalizing a standard operating procedure for all reactions to be run in the pilot plant.
Combustion hazards of silane and its chlorides
Authors: Britton Laurence G.
Published: June 2004

This paper addresses the unusual combustion hazards of silane and its chlorides, comprising the homologous chlorosilane series SiHnCl4‐n. The literature on silane is briefly reviewed and new experimental data presented showing the effects of sudden releases into free air. New data are presented for ignition sensitivities and deflagration rates of chlorosilane mixtures with air. Specific hazardous reactions of this group of materials are described and contrasted with those of the analogous alkanes. Mechanisms for flame acceleration and transition to detonation are discussed.
An overview of exposures and exposure control in the ethylene oxide producer and ethoxylation industries
Authors: Grumbles Thomas G.
Published: June 2004

This paper presents the results of an industry survey that was sponsored by the Ethylene Oxide Industry Council (EOIC). The EOIC operates as a special program of the Chemical Manufacturers Association. The members of EOIC account for over 85 percent of domestic production of EtO and cover a broad range of EtO users, including ethoxylators and sterilizers. The survey was done to collect current information in anticipation of responding to a proposed OSHA rulemaking for a short‐term exposure limit for EtO. Specifically, the study was designed to collect information on the following:

History of the establishment of company EtO exposure guidelines.

Current EtO workplace exposure monitoring practices, capabilities and methods.

Current workplace exposure levels: Eight hour and short‐term.

Engineering control, respirator, and ancillary costs for compliance with the 1.0 Permissible Exposure Limit (PEL) and projected costs for compliance with a 5.0 ppm or 10.0 ppm Short–term Exposure Limit (STEL).
Engineering controls to minimize worker exposure to ethylene oxide at sterilization facilities
Authors: Desai Pankaj R. , Buonicore Anthony J.
Published: June 2004

Gas sterilizers, using either pure ethylene oxide (EtO) or an admixture with an inert diluent, are typically utilized for treating products which cannot withstand heat sterilization. Due to the highly toxic nature of ethylene oxide and its classification as a suspect carcinogen, special precautions must be taken to ensure safe exposure levels to human receptors. This paper discusses the various engineering controls that can be implemented at EtO sterilization facilities to minimize ethylene oxide ambient concentrations and worker exposure levels.
Responsible care
Authors: Belanger Jean M.
Published: June 2004

The following is excerpted from a speech given at the International Conference on Chemical Process Safety Management held in Toronto, Canada, May 15, through 18, 1990.
Process simulators for safety
Authors: Ferney Michael J.
Published: June 2004

Given the often dangerous nature of large‐scale chemical and petroleum‐based processes, corporations which operate plants in the hydrocarbon industry must make safety their first priority.
Guidelines for hazard evaluation procedures: Second edition
Authors: Witter Ray E.
Published: June 2004

This article presents an abstract of important additions and revisions to the Guidelines for Hazard Evaluation Procedures published by CCPS in 1985. It includes:

An outline of the background and purpose of the project

An overview of the importance of hazard identification and evaluation studies, including benefits and limitations

An overview of the new chapters

Discussion of Hazard Identification Methods and results
OSHA's interest in chemical plant safety
Authors: Seymour Thomas H.
Published: June 2004

The Occupational Safety and Health Administration (OSHA) has been required by the Clean Air Act Amendments of 1990 to promulgate a process safety management (PSM) standard for the prevention of catastrophic incidents and to protect the safety and health of employees in the covered plants. The law requires the OSHA standard to cover at least 14 areas or issues and to cover highly hazardous chemicals which include toxic, flammable, highly reactive and explosive substances. The paper will describe in detail how OSHA has responded to this statute and what we have accomplished in the rulemaking effort. Also the interface with other relevant OSHA standards, including the Hazard Communication standard, the Hazardous Waste Operations and Emergency Response standard, the Control of Hazardous Energy Sources (Lockout/Tagout) standard, and others will be discussed. In addition other recent laws that relate to and impact the OSHA PSM standard such as the Hazardous Materials Transportation Uniform Safety Act of 1990, the Oil Pollution Act of 1990, and the Superfund Amendments and Reauthorization Act (SARA) of 1986, will be explained as to their relationship to PSM. The emergency preparedness efforts required of employers under PSM and the relationship to SARA Title III efforts by local community emergency response organization will be covered, as well as the interface with the EPA Risk Management Program initiative that EPA must do under the Clean Air Act Amendments.
Dust entrainability and its effect on explosion propagation in elongated structures
Authors: Ural Erdem A.
Published: June 2004

Two apparatuses have been developed to characterize the entrainability of dust deposits. The minimum aerodynamic wall shear stress required for dust removal (Critical Shear Stress), measured by the first apparatus, is an indicator of the ease with which dust particles can be removed from a layer. The second apparatus measures the settling velocity distribution of dust clouds, which is an important factor controlling the extent of dispersion as well as the time period during which the entrained dust cloud can remain suspended.

Testing has shown that the critical shear stress depends not only on the nature of the dust, but on the way the dust deposit is formed. Therefore, a portable version of this apparatus was developed to allow field testing of dust deposits. This methodology has also been used to evaluate the effect of oil treatment sometimes used in the grain handling industry to reduce dust emission.

Simulated explosion tests have demonstrated the importance of critical shear stress on dust entrainability. A simple model calculating unsteady dust concentration in elongated structures has been developed. The model shows that flammable dust concentrations induced in a gallery by a primary explosion exist over a finite length and time period. Therefore, the probability of a secondary explosion depends not only on the dust and layer properties, but on the details of the primary explosion and of the enclosure geometry. A simple criterion for transmission of a primary explosion into an adjoining elongated structure is discussed in the paper.
Laboratory and large‐scale dust explosion research
Authors: Cashdollar Kenneth L. , Weiss Eric S. , Greninger Nevin B. , Chatrathi Kris
Published: June 2004

This paper describes dust explosibility research in full‐scale experimental mines and a 20‐L laboratory chamber at the U.S. Bureau of Mines and in a 1‐m3 laboratory chamber at Fike Corporation. The purpose of this research is to improve safety in mining and other industries that manufacture, process, or use combustible dusts. As part of this work, carbonaceous dusts with a wide range of volatilities and various particle size distributions were studied. Laboratory data on the minimum explosible concentrations of predispersed dusts were comparable to mine data for nominal dust loadings that were dispersed by the aerodynamic disturbance from a gas ignition zone. Recommendations are given on the limitations of small‐scale testing such as “overdriving” by too strong of an ignitor. The effect of dust particle size on explosibility data is illustrated for coal and aluminum dusts. For both dusts, the finest sizes were the most hazardous. The inerting requirements for preventing explosions were also measured in both laboratory and large‐scale systems. All the data show relatively good agreement between the laboratory and the large‐scale tests.
Determination of an improved set of harmonic force constants for benzene
Authors: Rashev Svetoslav
Published: June 2004

The aim of this work is to describe a specific completely symmetrized, combined local mode/symmetrized modes (LM/SM), nonperturbative vibrational calculation procedure, and computer code, designed for implementation of large‐scale calculations on the vibrational energy levels in benzene C6H6, as well as its D6h isotopomers. Using this procedure and code, calculations have been performed on the fundamental frequencies of benzene, using the harmonic force constants, as well as a very small number of anharmonic constants, as adjustable input parameters. In this way, an improved set of symmetrized harmonic force constant values for benzene C6H6 have been determined, allowing for very good reproduction of the fundamental frequencies. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Tarnen und Täuschen — Chronologie eines Cracks
Authors: Dubrawsky Ido
Published: June 2004

So schwer war das gar nicht. Jedenfalls hatte ich Schlimmeres erwartet. Also tatsächlich war es eigentlich ein Kinderspiel. Man musste sich nur ein paar Gedanken machen. Das reichte. Scheint so, dass die meisten Sicherheitsleute denken, wenn man Router und Firewalls und Intrusion Detection Systeme (IDS) einsetzt, dann haben sie ihr Netzwerk abgesichert. Aber das trifft nicht notwendigerweise zu. Es braucht nur eine klitzekleine Fehlkonfiguration irgendwo im Netzwerk oder auf einem Server, damit einer durch diese Lücke schlüpfen kann …
Risikomanagement in Energiemärkten (Teil I)
Authors: Trück Stefan , Weron Rafal
Published: June 2004

Die folgende Serie vermittelt unter Berücksichtigung des Risikomanagement‐Aspekts einen Überblick über den Stromhandel und die Modellierung von Preisen in Energiemärkten.

Der erste Teil gibt zunächst eine kurze Einführung über den Stromhandel in Deutschland. Hierbei stehen vor allem die Entwicklung des Strommarktes in der letzten Dekade sowie die entstandene Strombörse EEX in Leipzig bzw. die dort gehandelten Produkte im Vordergrund. Darüber hinaus werden die Zusammenhänge und Einflussfaktoren beim Preisbildungsprozess für Strom dargestellt, sowie Besonderheiten der Strompreise wie etwa Saisonalitäten, hohe Volatilitäten etc. verdeutlicht.

Im zweiten Teil der Serie (erscheint in der RISKNEWS 04/2004) werden dann Möglichkeiten der Modellierung von Strompreisen vorgestellt. Hier geht es vor allem um die Berücksichtigung von Saisonalitäten, der Mean‐Reversion‐Eigenschaft und die Modellierung von Preissprüngen. Ein dritter Teil (erscheint in der RISKNEWS 05/2004) erläutert schließlich verfeinerte Methoden der Modellierung sowie Ansätze des Risikomanagements in Energiemärkten.
Undergraduate students' understanding of falling bodies in idealized and real‐world situations
Authors: Cahyadi M. Veronica , Butler Philip H.
Published: June 2004

This study investigates the understanding of 18 first‐year undergraduate students when simultaneously presented with two contrasting dynamical situations: the idealized (without air resistance) and real‐world cases of balls being dropped or thrown. Previous work has shown that getting students to recognize flaws in their mental models helps them develop their understanding. Our students were better able to answer correctly the problems in idealized cases than the problems in real‐world cases. For the real‐world cases, the students understood the impact of air resistance on the object's size better than the impact of air resistance on objects of the same size but different mass. In follow‐up interviews, the students reported that using the two different situations in the same test did indeed encourage them to think more carefully. By recognizing the need to include air resistance, they activated their appropriate mental “resources” to deal with the situations. We conclude that using contrasting situations (i.e., with and without an idealization) is a useful teaching tool. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 569–583, 2004
Heat flow in the SAFOD pilot hole and implications for the strength of the San Andreas Fault
Authors: Williams Colin F. , Grubb Frederick V. , Galanis S. Peter
Published: June 2004

Detailed thermal measurements have been acquired in the 2.2‐km‐deep SAFOD pilot hole, located 1.8 km west of the SAF near Parkfield, California. Heat flow from the basement section of the borehole (770 to 2160 m) is 91 mW m−2, higher than the published 74 mW m−2 average for the Parkfield area. Within the resolution of the measurements, heat flow is constant across faults that intersect the borehole, suggesting that fluid flow does not alter the conductive thermal regime. Reanalysis of regional heat flow reveals an increase in heat flow along the SAF northwest of Parkfield. This transition corresponds to a shallowing base of seismicity and a change in fault behavior near the northern terminus of the M6 1966 Parkfield earthquake rupture. The persistence of elevated heat flow in the Coast Ranges to the west appears to rule out frictional heating on the SAF as the source of the SAFOD value.
Real‐time mud gas logging during drilling of the SAFOD Pilot Hole in Parkfield, CA
Authors: Erzinger Jörg , Wiersberg Thomas , Dahms Eckhard
Published: June 2004

The real‐time mud gas monitoring during drilling of the 2.2 km deep SAFOD Pilot Hole has proved successful. A nearly complete depth profile was obtained for methane, radon, helium, and, with limitations, for carbon dioxide. Within the sedimentary section (0–768 m) mud gas yielded the highest CH4, CO2, and 222Rn concentrations, whereas He was comparably low. Four major gas‐rich zones were identified. Methane is a mixture of microbial and thermogenic origin. Mud gas concentrations of CH4 and Rn are much lower in the underlying granitic rocks and the average background level of He is higher. In addition to several gas‐rich zones, two shear zones inferred from geophysical measurements are also indicated by increased mud gas concentrations. Gas results permit speculation that one major shear zone is hydraulically connected to the sedimentary section above. Up to 9% of the helium is of mantle origin, which is probably a lower limit.
Shear wave attenuation and dispersion in melt‐bearing olivine polycrystals: 2. Microstructural interpretation and seismological implications
Authors: Faul Ulrich H. , Fitz Gerald John D. , Jackson Ian
Published: June 2004

The torsional forced oscillation tests of melt‐bearing olivine aggregates reported by Jackson et al. [2004] consistently show a peak in attenuation that is absent from melt‐free aggregates tested under similar conditions and grain sizes. Characterization by SEM shows that the melt resides in triple junction tubules and larger pockets as previously described. TEM imaging and EDS analysis reveals that olivine‐olivine grain boundaries are characterized by a region ≤1 nm wide which is structurally and chemically distinct from olivine grain interiors. From the possible mechanisms that can produce an anelastic attenuation peak, melt squirt can be eliminated for our samples and experimental conditions. We attribute the observed attenuation peak to elastically accommodated grain boundary sliding, requiring that the grain boundaries are weak relative to olivine grain interiors but have a significantly higher viscosity than bulk melt. While the nanometer scale grain boundary structure in the melt‐bearing aggregates is essentially the same as for melt‐free aggregates studied previously, elastically accommodated sliding in the latter is apparently inhibited by tight three‐grain edge intersections. The exponentially increasing high temperature background attenuation in both types of aggregate is attributed to diffusionally accommodated grain boundary sliding. Extrapolation to mantle grain sizes shows that the broad peak may be responsible for nearly frequency independent attenuation in partially molten regions of the upper mantle.
Wave run‐up on a high‐energy dissipative beach
Authors: Ruggiero Peter , Holman R. A. , Beach R. A.
Published: June 2004

Because of highly dissipative conditions and strong alongshore gradients in foreshore beach morphology, wave run‐up data collected along the central Oregon coast during February 1996 stand in contrast to run‐up data currently available in the literature. During a single data run lasting approximately 90 min, the significant vertical run‐up elevation varied by a factor of 2 along the 1.6 km study site, ranging from 26 to 61% of the offshore significant wave height, and was found to be linearly dependent on the local foreshore beach slope that varied by a factor of 5. Run‐up motions on this high‐energy dissipative beach were dominated by infragravity (low frequency) energy with peak periods of approximately 230 s. Incident band energy levels were 2.5 to 3 orders of magnitude lower than the low‐frequency spectral peaks and typically 96% of the run‐up variance was in the infragravity band. A broad region of the run‐up spectra exhibited an f−4 roll off, typical of saturation, extending to frequencies lower than observed in previous studies. The run‐up spectra were dependent on beach slope with spectra for steeper foreshore slopes shifted toward higher frequencies than spectra for shallower foreshore slopes. At infragravity frequencies, run‐up motions were coherent over alongshore length scales in excess of 1 km, significantly greater than decorrelation length scales on moderate to reflective beaches.