1,134 research outputs found

    Register of specialized sources for information on selected fuels and oxidizers

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    Thirty-eight (38) organizations are listed and described that catalog and file information in their data systems on fuel and oxidizers. The fuels include hydrogen, methane and hydrazine-type fuels; the oxidizers include oxygen, fluorine, flox, nitrogen tetroxide and ozone. The type of available information covers thermophysical properties, propellant systems, propellant fires-control-extinguishment, propellant explosions, propellant combustion, propellant safety, and fluorine chemistry. These organizations have assembled and collated their information so that it will be useful in the solution of engineering problems

    Risk analysis of LPG tanks at the wildland-urban interface

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    In areas of wildland-urban interface (WUI), especially residential developments, it is very common to see liquefied petroleum gas (LPG) tanks, particularly with a higher ratio of propane, in surface installations serving homes. The most common tanks are between 1 and 5 m3 of capacity, but smaller ones of less than 1 m3 are more frequent. In case of accident, installations may be subject to fires and explosions, especially in those circumstances where legal and normative requirements allow very close exposure to flames from vegetable fuel near LPG tanks. In this project, it is intended to do a comprehensive diagnosis of the problem, addressing the compilation of information on real risk scenarios in historical fires. First, a preliminary presentation of the properties and characteristics of liquefied petroleum gas will be exposed. Its physical and chemical properties, production methodology, pressure and temperature diagrams and important considerations will be defined when using this type of substances in a storage tank of a certain volume. Next, a review of the situation of the existence of LPG tanks in the urban forest interfaces will be exposed. In this case, the main accidents caused by problems with the storage of LPG will be analyzed taking into account the relevance of BLEVE events in this type of incidents. To do this, the main scenarios that could take place in the event of a fire will be presented. Next, the existing legislation on the storage of LPG in these environments in some Mediterranean countries will be studied. In order to develop a comprehensive analysis, the main safety measures and distances will be considered, as well as the awareness of the possibility of vegetation material in the vicinity of LPG storage tanks, which is the main problem that will arise in a possible BLEVE scenario in case of fire. To finalize and facilitate understanding, a comparative table will be included with the aim of visualizing the main advantages and legislative deficiencies between the different countries. Following, the state of the art in terms of modelling LPG accidents at the WUI will be reviewed. Trying to simulate and predict this type of scenarios, it will see the models normally chosen to obtain the tolerable values selected and the answers obtained in each case. Finally, several fire scenarios will be simulated by means of a CFD tool (FDS, Fire Dynamics Simulator). In these simulations, the wind velocity and the distance of the combustible vegetal mass to the tank will be controlled in a WUI fire in which there is a tank of fixed dimensions. The temperature and the heat flow in each of the scenarios will be obtained, and the differences among the location of the sensors and the characteristics of the scenario will be analyzed. As a conclusion, it has been observed that there is a great amount of variables that are not contemplated by the regulatory organisms and that the existing legislation does not guarantee the safety of the population in this type of environment. From the simulations results, variables as temperature should be studied for further characterizations

    Potential Terrorist Uses of Highway-Borne Hazardous Materials, MTI Report 09-03

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    The Department of Homeland Security (DHS) has requested that the Mineta Transportation Institutes National Transportation Security Center of Excellence (MTI NTSCOE) provide any research it has or insights it can provide on the security risks created by the highway transportation of hazardous materials. This request was submitted to MTI/NSTC as a National Transportation Security Center of Excellence. In response, MTI/NTSC reviewed and revised research performed in 2007 and 2008 and assembled a small team of terrorism and emergency-response experts, led by Center Director Brian Michael Jenkins, to report on the risks of terrorists using highway shipments of flammable liquids (e.g., gasoline tankers) to cause casualties anywhere, and ways to reduce those risks. This report has been provided to DHS. The teams first focus was on surface transportation targets, including highway infrastructure, and also public transportation stations. As a full understanding of these materials, and their use against various targets became revealed, the team shifted with urgency to the far more plentiful targets outside of surface transportation where people gather and can be killed or injured. However, the team is concerned to return to the top of the use of these materials against public transit stations and recommends it as a separate subject for urgent research

    The characterization and evaluation of accidental explosions

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    Accidental explosions are discussed from a number of viewpoints. First, all accidental explosions, intentional explosions and natural explosions are characterized by type. Second, the nature of the blast wave produced by an ideal (point source or HE) explosion is discussed to form a basis for describing how other explosion processes yield deviations from ideal blast wave behavior. The current status blast damage mechanism evaluation is also discussed. Third, the current status of our understanding of each different category of accidental explosions is discussed in some detail

    Assessment of institutional barriers to the use of natural gas fuel in automotive vehicle fleets

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    Institutional barriers to the use of natural gas as a fuel for motor vehicle fleets were identified. Recommendations for barrier removal were developed. Eight types of institutional barriers were assessed: (1) lack of a national standard for the safe design and certification of natural gas vehicles and refueling stations; (2) excessively conservative or misapplied state and local regulations, including bridge and tunnel restrictions, restrictions on types of vehicles that may be fueled by natural gas, zoning regulations that prohibit operation of refueling stations, parking restrictions, application of LPG standards to LNG vehicles, and unintentionally unsafe vehicle or refueling station requirements; (3) need for clarification of EPA's tampering enforcement policy; (4) the U.S. hydrocarbon standard; (5) uncertainty concerning state utility commission jurisdiction; (6) sale for resale prohibitions imposed by natural gas utility companies or state utility commissions; (7) uncertainty of the effects of conversions to natural gas on vehicle manufactures warranties; and (8) need for a natural gas to gasoline equivalent units conversion factor for use in calculation of state road use taxes

    The Recognition of Fires Originating from Photovoltaic (PV) Solar Systems

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    There has been an observable increase in the fitting of photovoltaic (PV) solar panels on the roofs of buildings in the UK over the last decade. The origin of some fires in domestic and commercial properties has been attributed to PV systems. This thesis examines the ability of fire examiners to recognise and record details of fires believed to have originated from PV systems, as well as investigating the effect of internal heating in direct current (DC) isolators to the point at which they fail. National fire data was examined along with the methods for collecting and collating these data. This clarified that national fire data cannot identify the specifics of electrical fires. Validity of these data was then tested by identifying the confidence and competence in the recognition of the origin of fire, (especially when associated with PV systems), of some fire staff responsible for collecting fire data. This suggests that some fire scenes examiners are not confident in their own ability to recognise fires originating from PV systems. Evidence for fires occurring in PV systems in Kent between 2009 and 2014 was then examined, including a cold case forensic review of the evidence. This provided an indication that a potential common point of failure, which may lead to fire originating from a PV system, was to be found within the DC section of the PV circuits and probably within the DC isolator switch itself. Experimentation revealed that internal heating of a terminal connection can lead to changes of the phase of the insulating material, causing failure of structural integrity and therefore allowing an arc to be established. Observable post fire indicators associated with this mechanism of failure have been identified as well as hydrocarbons evolved from pyrolysis of isolator insulating material. Finally, areas for further experimental research and training of fire staff are suggested as well as the modification of recording mechanisms and building regulations

    Accidental release of Liquefied Natural Gas in a processing facility: Effect of equipment congestion level on dispersion behaviour of the flammable vapour

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    An accidental leakage of Liquefied Natural Gas (LNG) can occur during processes of production, storage andtransportation. LNG has a complex dispersion characteristic after release into the atmosphere. This complexbehaviour demands a detailed description of the scientific phenomena involved in the dispersion of the releasedLNG. Moreover, a fugitive LNG leakage may remain undetected in complex geometry usually in semi-confined orconfined areas and is prone to fire and explosion events. To identify location of potential fire and/or explosionevents, resulting from accidental leakage and dispersion of LNG, a dispersion modelling of leakage is essential.This study proposes a methodology comprising of release scenarios, credible leak size, simulation, comparison ofcongestion level and mass of flammable vapour for modelling the dispersion of a small leakage of LNG and itsvapour in a typical layout using Computational Fluid Dynamics (CFD) approach. The methodology is applied to acase study considering a small leakage of LNG in three levels of equipment congestion. The potential fire and/orexplosion hazard of small leaks is assessed considering both time dependent concentration analysis and areabased model. Mass of flammable vapour is estimated in each case and effect of equipment congestion on sourceterms and dispersion characteristics are analysed. The result demonstrates that the small leak of LNG can createhazardous scenarios for a fire and/or explosion event. It is also revealed that higher degree of equipmentcongestion increases the retention time of vapour and intensifies the formation of pockets of isolated vapourcloud. This study would help in designing appropriate leak and dispersion detection systems, effective monitoring procedures and risk assessmen

    Safety Standard for Hydrogen and Hydrogen Systems: Guidelines for Hydrogen System Design, Materials Selection, Operations, Storage and Transportation

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    The NASA Safety Standard, which establishes a uniform process for hydrogen system design, materials selection, operation, storage, and transportation, is presented. The guidelines include suggestions for safely storing, handling, and using hydrogen in gaseous (GH2), liquid (LH2), or slush (SLH2) form whether used as a propellant or non-propellant. The handbook contains 9 chapters detailing properties and hazards, facility design, design of components, materials compatibility, detection, and transportation. Chapter 10 serves as a reference and the appendices contained therein include: assessment examples; scaling laws, explosions, blast effects, and fragmentation; codes, standards, and NASA directives; and relief devices along with a list of tables and figures, abbreviations, a glossary and an index for ease of use. The intent of the handbook is to provide enough information that it can be used alone, but at the same time, reference data sources that can provide much more detail if required

    CEN - CENELEC Sector Forum Energy Management/Working Group Hydrogen: Final Report

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    The main objective of the SFEM/WG Hydrogen was to perform an analysis of the state of the art of technology and standardization and a gap analysis on the main barriers including challenges and needs. A second objective was to establish contact with key stakeholders from gas sector, grids, electric supply, mobility, the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) to perform the work in the most effective way and to have broad support from the stakeholders for identifying the key challenges. Also the link to EC services, DG JRC, DG RTD, DG ENER, DG GROW was seen as important. The final objective is to set a long term collaborative framework (liaison) with major bodies for strengthening cooperation between regulatory work, standardization work and RDI programs (e.g. European Commission, JRC, FCH2 JU, IEA, ISO, IEC). The scope of the working group covered the production of hydrogen through electrolysis and the transportation, distribution and usage of that hydrogen in pure form or as a natural gas dominant mixture (H2NG). In addition, actions in cross-cutting fields such as safety and training of personnel were identified. These activities will help increase the societal acceptance of hydrogen, key to a successful market uptake.JRC.F.2-Energy Conversion and Storage Technologie

    Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems

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    Since the 1990's, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have used hydrochlorofluorocarbon-225 (HCFC-225), a Class II ozone-depleting substance, to safety clean and verify the cleanliness of large scale propulsion oxygen systems and associated test facilities. In 2012 through 2014, test laboratories at MSFC, SSC, and Johnson Space Center-White Sands Test Facility collaborated to seek out, test, and qualify an environmentally preferred replacement for HCFC-225. Candidate solvents were selected, a test plan was developed, and the products were tested for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Honewell Soltice (TradeMark) Performance Fluid (trans-1-chloro-3,3, 3-trifluoropropene) was selected to replace HCFC-225 at NASA's MSFC and SSC rocket propulsion test facilities
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