Dr. Hull's Publications
Failure Investigation of a Welding Regulator Fire
Newton, B. E., Hull, W. C., and Beeson, H., "Failure Investigation of a Welding Regulator Fire," Flammability and Sensitivity of Materials in Oxygen- Enriched Atmospheres: Ninth Volume, ASTM STP 1395, T. A. Steinberg, B. E. Newton, and H. D. Beeson, Eds., American Society for Testing and Materials, West Conshohocken, PA, 2000.
KEYWORDS: regulator burnout, regulator explosion, regulator fire, welding regulator, oxygen fire
ABSTRACT: This paper describes the investigation and failure analysis of a welding regulator fire that resulted in explosive energy release and injury to an operator. The failure analysis revealed that an organic contaminant in the form of an insect had entered the cylinder valve prior to attachment of the regulator. Ignition of the insect and nest materials led to an explosion-like overpressure that blew the high-pressure poppet through the nozzle and forcibly separated the regulator bonnet from the main body. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) on the residue from the fire-damaged components confirmed that insect nest material was present at the time of the fire. Autogenous Ignition Testing (AIT) on similar insect debris revealed a very low ignition temperature and probable high heat of combustion. The explosion-like energy release was felt to be related to a momentary containment of the fire in the early stages of the combustion event which led to greater involvement of the cylinder valve's nylon seat and resulted in increased reaction kinetics.
Failure Analysis of Aluminum-Bodied Medical Regulators
Newton, B. E., Hull, W. C., and Stradling, J. S., "Failure Analysis of Aluminum-Bodied Medical Regulators," Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: Ninth Volume, ASTM STP 1395, T. A. Steinberg, B. E. Newton, and H. D. Beeson, Eds., American Society for Testing and Materials, West Conshohocken, PA, 2000.
KEYWORDS: regulator burnout, regulator explosion, regulator fire, welding regulator, oxygen fire, aluminum regulator fire, aluminum combustion, explosive energy release
ABSTRACT: Over the past 5 years 16 fires have been reported to the FDA involving aluminum-bodied medical regulators. These incidents are reported to have caused severe burns to 11 health care workers and patients. Many of the incidents have occurred during emergency medical use or during routine equipment checkouts. This paper summarizes the investigation and failure analysis of several of these fires and provides the cause and origin analysis for each. Ignition with catastrophic burnout of the regulator has been observed in each of these cases. The active ignition mechanisms are felt to have included particle impact in some cases, contaminant promoted ignition in other cases, and adiabatic compression in at least one other. Several of the fires are believed to have been caused by particulate debris entrained in the oxygen flow stream from aluminum highpressure cylinders. The regulator design, pertaining to the exposure of aluminum to active ignition mechanisms, and the use of aluminum cylinders with aluminum regulators are discussed.
A Database for Metallic and Nonmetallic Materials Commonly Utilized in Oxygen Service
Newton, B., Hull, W.C., and Stradling, J., "A Database for Metallic and Nonmetallic Materials Commonly Utilized in Oxygen Service," Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: Eighth Volume, ASTM STP 1319, W.T. Royals, T.C. Chou, and T.A. Steinberg, Eds., American Society for Testing and Materials, 1997.
KEYWORDS: materials database, oxygen compatibility, relational database, hazards analysis, materials testing
ABSTRACT: This paper presents the design, structure, and use of a materials database for metallic and nonmetallic materials commonly utilized in oxygen service. Also discussed is the need for a widely accessible and easily searched database of materials compatibility test data for general use within the oxygen community. Over the last two decades, the ignition and combustion properties of metallic and nonmetallic materials exposed to oxygen-enriched environments have been widely studied by both government and commercial industry. However, to our knowledge, these data have never been compiled into a comprehensive and easily accessible database for general utilization and cross-comparison. Consequently, collecting the necessary data for hazards analyses on materials and components is difficult and time consuming, when done in accordance with the procedures advanced by ASTM Guide G-63, "Standard Guide for Evaluating Nonmetallic Materials for Oxygen Service," and ASTM Guide G-94, "Standard Guide for Evaluating Metals for Oxygen Service." This paper presents a database of materials test data and discusses the utilization of these data in a computerized hazards analysis that generally follows the guidelines of ASTM G-63 and G-94 and the "good practices" of ASTM G-88. The relational structure of the database is presented and the advantages of this type of data structure are discussed.
A 6000 psig Gaseous Oxygen Impact Test System for Materials and Components Compatibility Evaluations
Newton, B., Porter, A., Hull, W.C., Stradling, J., and Miller, R., "A 6000 psig Gaseous Oxygen Impact Test System for Materials and Components Compatibility Evaluations," Flammability and Sensitivity of Materials in Oxygen- Enriched Atmospheres: Eighth Volume, ASTM STP 1319, W.T. Royals, T.C. Chou, and T.A. Steinberg, Eds., American Society for Testing and Materials, 1997.
KEYWORDS: oxygen compatibility, component testing, pneumatic impact, materials testing
ABSTRACT: Over the last several years, the International Standards Organization (ISO) has developed standards which require pneumatic impact testing on valves, regulators, and other oxygen components used in Europe in medical, industrial, and commercial applications. The several standards involved all reference a test system designed by BAM and presented in ASTM STP 1267 by Binder, et. al. in their paper "A 500 BAR Gaseous Oxygen Impact Test Apparatus For Burn-Out Testing Of Oxygen Equipment." This paper discusses another gaseous oxygen impact test system designed to conform to the IS0 standards, and presents its performance characteristics in pneumatic impact testing. This paper also discusses the value of a component test method and considers some of the critical parameters that should be maintained in order to produce consistent test results with different test systems.
Newton, B. E., Porter, A. R., Hull, W. C., Henry, S. H., Anderson, D. S., and Randall, L. N., "Case Study of an Oxygen-Acetylene Cutting Torch Failure and Measured Overpressures Due to Flashback Reactions," Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 7th Volume, ASTM STP 1267. Dwight D. Janoff, William T. Royals and Mohan V. Gunaji, Eds., American Society for Testing and Materials, Philadelphia, 1995.
KEYWORDS: oxygen-acetylene combustion, flashback, oxygen cutting torch, welding equipment, oxygen, acetylene
ABSTRACT: A generalized case study of the failure of an oxygen-acetylene cutting torch is presented with discussion of the failure and investigation. The theory that an oxygen-acetylene flashback reaction caused the explosive failure of the torch mixing tube was investigated. The investigation led to the conclusion that abusive treatment of the torch was the primary cause of the failure. The mechanical strength of the cutting torch was determined and the dynamic overpressures due to oxygen-acetylene flashback reactions were measured by means of fast-response piezoelectric pressure transducers. The dynamic pressure measurements were compared and related to predictions of the NASA Gordon and McBride "Computer Program for Calculations of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouquet Detonations" for oxygen-acetylene combustion. Based on this investigation, a reconstruction of the accident is proposed.
Coming Soon
Failure Investigation of a Welding Regulator Fire
Failure Analysis of Aluminum-Bodied Medical Regulators
A Database for Metallic and Nonmetallic Materials Commonly Utilized in Oxygen Service
A 6000 psig Gaseous Oxygen Impact Test System for Materials and Components Compatibility Evaluations
Case Study of an Oxygen-Acetylene Cutting Torch Failure and Measured Overpressures Due to Flashback Reactions
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