1、Designation: G 145 08Standard Guide forStudying Fire Incidents in Oxygen Systems1This standard is issued under the fixed designation G 145; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pare
2、ntheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers procedures and material for examin-ing fires in oxygen systems for the purposes of identifyingpotential causes and preventing recur
3、rence.1.2 This guide is not comprehensive. The analysis of oxy-gen fire incidents is not a science, and definitive causes havenot been established for some events.1.3 The procedures and analyses in this guide have beenfound to be useful for interpreting fire events, for helpingidentify potential cau
4、ses, and for excluding other potentialcauses. The inclusion or omission of any analytical strategy isnot intended to suggest either applicability or inapplicability ofthat method in any actual incident study.NOTE 1Although this guide has been found applicable for assistingqualified technical personn
5、el to analyze incidents, each incident is uniqueand must be approached as a unique event. Therefore, the selection ofspecific tactics and the sequence of application of those tactics must beconscious decisions of those studying the event.NOTE 2The incident may require the formation of a team to prov
6、idethe necessary expertise and experience to conduct the study. The personnelanalyzing an incident, or at least one member of the team, should know theprocess under study and the equipment installation.1.4 WarningDuring combustion, gases, vapors, aerosols,fumes, or combinations thereof, are evolved,
7、 which may bepresent and may be hazardous to people. CautionAdequateprecautions should be taken to protect those conducting astudy.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establi
8、sh appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 620 Practice for Reporting Opinions of Scientific orTechnical ExpertsE 678 Practice for Evaluation of Scientific or TechnicalDataE 860 Prac
9、tice for Examining And Preparing Items ThatAre Or May Become Involved In Criminal or CivilLitigationE 1020 Practice for Reporting Incidents that May InvolveCriminal or Civil LitigationE 1138 Terminology for Technical Aspects of ProductsLiability LitigationE 1188 Practice for Collection and Preservat
10、ion of Informa-tion and Physical Items by a Technical InvestigatorE 1459 Guide for Physical Evidence Labeling and RelatedDocumentationE 1492 Practice for Receiving, Documenting, Storing, andRetrieving Evidence in a Forensic Science LaboratoryG63 Guide for Evaluating Nonmetallic Materials for Oxy-gen
11、 ServiceG88 Guide for Designing Systems for Oxygen ServiceG93 Practice for Cleaning Methods and Cleanliness Levelsfor Material and Equipment Used in Oxygen-EnrichedEnvironmentsG94 Guide for Evaluating Metals for Oxygen ServiceG114 Practices for Evaluating the Age Resistance of Poly-meric Materials U
12、sed in Oxygen ServiceG 124 Test Method for Determining the Combustion Be-havior of Metallic Materials in Oxygen-Enriched Atmo-spheresG 126 Terminology Relating to the Compatibility and Sen-sitivity of Materials in Oxygen Enriched AtmospheresG 128 Guide for Control of Hazards and Risks in OxygenEnric
13、hed Systems2.2 ASTM Adjunct:Video: Oxygen Safety32.3 Compressed Gas Association (CGA) Standards:4G-4.4 Industrial Practices for Gaseous Oxygen Transmis-sion and Distribution Piping Systems1This guide is under the jurisdiction ofASTM Committee G04 on Compatibilityand Sensitivity of Materials in Oxyge
14、n Enriched Atmospheres and is the directresponsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved Sept. 1, 2008. Published October 1998. Originallyapproved in 1996. Last previous edition approved in 2001 as G 14596(2001).2For referenced ASTM standards, visit the ASTM we
15、bsite, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from ASTM Customer Service, 100 Barr Harbor Drive, WestConshohocken, PA 19428-2959. Request PCN 12-
16、700880-31.4Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5thFloor, Chantilly, VA 20151-2923, http:/.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.G-4.8 Safe Use of Aluminum Structured Packing for Oxy-gen Distill
17、ation2.4 National Fire Protection Association (NFPA) Stan-dard:5NFPA 53 Fire Hazards in Oxygen Enriched AtmospheresNFPA 921 Guide for Fire and Explosion Investigations2.5 Occupational Safety and Health Act:6OSHA Process Safety Management Compliance Manual3. Terminology3.1 DefinitionsSee Guides G 63,
18、 G 94, and G 128 for theterms listed in this section.3.1.1 oxygen compatibility, (also oxidant compatibility),nthe ability of a substance to coexist with both oxygen anda potential source(s) of ignition at an expected pressure andtemperature with a magnitude of risk acceptable to the user.3.1.2 qual
19、ified technical personnel, npersons such asengineers and chemists who, by virtue of education, training,or experience, know how to apply the physical and chemicalprinciples involved in the reactions between oxygen and othermaterials.3.1.3 oxygen-enriched, adja fluid (gas or liquid) mixturecontaining
20、 more than 25 mole % oxygen.3.2 Definitions of Terms Specific to This Standard:3.2.1 incident, nan ignition or fire, or both, that is bothundesired and unanticipated or an undesired and unanticipatedconsequence of an ignition or fire that was anticipated.3.2.2 direct incident cause, nthe mechanical
21、or thermo-dynamic event (such as breakage of a component or near-adiabatic compression), the physicochemical property (such asheat of combustion), the procedure (such as a valve openingrate), or any departure(s) from the intended state of any ofthese items, that leads directly to ignition or fire, o
22、r both.3.2.3 fractional evaporation, nthe continuous evaporationof a quantity of liquid that results in a progressive increase inthe concentration of a less-volatile constituent(s).3.2.4 Contaminant, nunwanted molecular or particulatematter that could adversely affect or degrade the operation, life,
23、or reliability of the systems or components upon which itresides.3.2.5 Contamination, n(1) the amount of unwanted mo-lecular non-volatile residue (NVR) or particulate matter in asystem; (2) the process or condition of being contaminated.DiscussionContamination and cleanliness are opposingproperties:
24、 increasing cleanliness implies decreasing contami-nation.4. Summary of Guide4.1 Following a fire incident in an oxygen-enriched atmo-sphere, the equipment, operating procedures, and area areconsidered in light of other incidents, potential contributingfactors, suggested analytical strategies, and d
25、emonstrated labo-ratory results. The goal is to determine direct cause(s) of theincident in order to prevent a recurrence.5. Significance and Use5.1 This guide helps those studying oxygen system inci-dents to select a direct cause hypothesis and to avoid conclu-sions based on hypotheses, however pla
26、usible, that haveproven faulty in the past.6. Abstract6.1 A series of possible causes and common scenarios aredescribed to assist those seeking to understand incidents inoxygen-enriched atmospheres. Many easily misinterpreted fac-tors are described to help avoid faulty conclusions. Severalsuspected
27、but unproven incident scenarios are described. Selectlaboratory data are presented to support assertions about directcauses of incidents.7. Direct-Cause Analysis7.1 In this guide, the direct cause of an incident is themechanical or thermodynamic event (such as breakage of acomponent or near-adiabati
28、c compression), the physicochemi-cal property (such as heat of combustion), the procedure (suchas a valve opening rate), or any departure(s) from the intendedstate of any of these items, that leads directly to ignition or fire,or both. A fire might also be the result of a financial decision,worker s
29、kill, or manufacturing processall of which can beviewed as causesbut such factors are addressed more prop-erly in a system hazard review. It is noteworthy that some firesare anticipated and the risks (whether human or economic) areaddressed by such things as shielding (for example to controlhuman ri
30、sk) or acceptance (for example to address economicrisk). In these cases, a fire is not an “incident” unless someaspect of the event exceeded expectations the initial parameters(for example, the shielding did not provide the expectedcontainment, or the cost exceeded projections). This guideseeks to i
31、dentify the material choice, equipment design, assem-bly procedure, or other factor that led directly to the fireandmore specifically, to distinguish the physical object or actionthat caused the fire to start, to continue, or to be injurious ordestructive. Remedial actions are found in other documen
32、tssuch as Guides G 63, G 88, and G 94, and Practice G93,aswell as NFPA 53, CGA G-4.4, and G-4.8, OSHA ProcessSafety Management Compliance Manual, and others.7.2 ExampleThe direct cause of an incident may beconcluded to be the use of an incompatible material, forexample, a polyacetyl component was in
33、stalled when a mate-rial such as PTFE (polytetrafluoroethylene) or CTFE (chlorot-rifluoroethylene) was preferred. The direct cause was not thatthe budget was inadequate to cover the cost of PTFE; nor thatspecific frictional properties of polyacetyl were required formechanical purposes; nor that an i
34、ncorrect part was installed inerror. Note that in this example, PTFE and CTFE might beneeded to prevent or cope with ignition and fire, but that theymight introduce non-fire-related issues such as loss of me-chanical strength or production of toxic decomposition prod-ucts when exposed to heat of com
35、pression.8. Elements of a Study8.1 OverviewThe study of an oxygen incident typicallybegins (preferably promptly) after the event has concluded.5Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/www.nfpa.org.6Available from Occupational Safet
36、y and Health Administration (OSHA), 200Constitution Ave., NW, Washington, DC 20210, http:/www.osha.gov.G145082The fire is extinguished and any safety requirements orimmediate needs are addressed (treating injuries, returningsystems to a safe state, and so forth). Then the investigator canbegin to do
37、cument the event, to preserve the artifacts, and todetect how they may have been altered or compromised by theevent and follow-up activities. Although many of these stepsare itemized here, the intent of this guide is not to specify howor in what order they should be conducted. Rather, informationis
38、offered about certain procedures that have been effective inthe past, as well as some that have led to faulty conclusions.Typically, good scientific and laboratory skills are useful andadequate. Forensic skills and procedures can be helpful inmany cases, but may not be practical in all. For example,
39、 theforensic Guide E 1459 can assist with managing post-incidentartifacts, and related Practices E 1492, E 620, E 678, E 860,E 1020, and E 1188, as well as Terminology E 1138, may haveother uses. However, when a forensic approach is neededbecause a legal action is involved, the insights in this guid
40、emay effectively supplement it.8.2 DocumentationUrgent post-incident efforts include:photographing or videotaping the site and any damaged equip-ment; obtaining system drawings, supporting design analysis,process hazards analysis, and any other hazard-evaluationmaterials; interviewing persons knowle
41、dgeable about the sys-tem, operating procedures and the events before, during, andafter the fire; collecting specimens, operating logs, and relatedinformation; and preliminary formulation and testing of hy-potheses.8.3 AnalysisThe principal effort in a study will be analy-sis of the data and artifac
42、ts. This may require further exami-nation of the equipment and records, laboratory study ofselected items, and perhaps even laboratory simulation of theincident.8.4 Completion of StudyAn incident study is completewhen the qualified technical personnel involved in the studyconclude that the event is
43、understood.8.4.1 An incident might be understood adequately when aconclusion has been drawn about the direct cause of the event.The following examples show the distinction between directcauses and causes that are not physicochemical or thermody-namic events.8.4.1.1 Example 1A substantial amount of h
44、ydrocarbonoil was introduced into a system just before an incident. Thissingle factor may be identified as the direct cause of the fire.Any reasons for introducing the lubricant may be important toa new hazard review, but are not the direct cause of the fire.Prevention can focus on cleanliness. Init
45、iating Event: ignitionof an incompatible oil. Direct Cause: contamination of thesystem.8.4.1.2 Example 2Records may show that a componentbroke and produced a rub in a piece of machinery just beforean incident. This factor alone can ignite a fire and could beidentified as the direct cause. If the com
46、ponent broke becauseit contained a flaw, the flaw might be determined to be thedirect cause. However, if the part was selected because itoffered economy, then the direct cause is still the inadequatepartnot a misguided effort to economize. Prevention in thiscase can focus on component quality. Initi
47、ating Event: frictionduring the rub. Direct Cause: Mechanical failure.8.4.1.3 Example 3Deviation from an important operatingpractice, such as first equalizing downstream pressure with abypass valve before opening a quick-opening valve, may beestablished as the direct cause of a fire. The reasons for
48、departing from mandated practice are important, but they arenot the direct cause. Here, prevention can focus on followingstandard operating procedures. Initiating Event: approximatelyadiabatic compression. Direct Cause: incorrect operation.8.4.2 An incident might be understood adequately when aconse
49、rvative tactic has been identified that would have pre-vented or safely managed the event.8.4.2.1 Example 1If an item of machinery cannot employoxygen-compatible materials because they compromise itsoperating economy, and it becomes the site of a fire and injuressomeone, then the event may be understood adequately (re-garding preventing recurrence of injury rather than fire) wheninadequate shielding or inadequate mechanical design or someother comparable factor is identified singly or in combinationas the direct cause.8.4.3 The study is comp
