ASTM G145-96(2001)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:G145–96 (Reapproved 2001)
Standard Guide for
Studying Fire Incidents in Oxygen Systems
This standard is issued under the fixed designation G 145; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 620 Practice for Reporting Opinions of Technical Ex-
perts
1.1 This guide covers procedures and material for examin-
E 678 Practice for Evaluation of Technical Data
ing fires in oxygen systems for the purposes of identifying
E 860 PracticeforExaminingandTestingItemsThatAreor
potential causes and preventing recurrence.
May Become Involved in Products Liability Litigation
1.2 This guide is not comprehensive and is not intended for
E 1020 Practice for Reporting Incidents
forensic use. The analysis of oxygen fire incidents is not a
E 1138 Terminology of Technical Aspects of Products Li-
science, and definitive causes have not been established for
ability Litigation
some events.
E 1188 Practice for Collection and Preservation of Informa-
1.3 The procedures and analyses in this guide have been
tion and Physical Items by a Technical Investigator
found useful for interpreting fire events, for helping identify
E 1459 Guide for Physical Evidence Labeling and Related
potential causes, and for excluding other potential causes. The
Documentation
inclusion or omission of any analytical strategy is not intended
E 1492 Practice for Receiving, Documenting, Storing, and
to suggest either applicability or inapplicability of that method
Retrieving Evidence in a Forensic Science Laboratory
inanyactualincidentstudy.Indeed,somematerialinthisguide
G 63 Guide for Evaluating Nonmetallic Materials for Oxy-
is considered useful, and therefore worthy of inclusion and
gen Service
consideration in a study, but not necessarily of demonstrated
G 88 Guide for Designing Systems for Oxygen Service
validity.
G 93 Practice for Cleaning Methods for Material and
NOTE 1—Although this guide has been found applicable for assisting 3
Equipment Used in Oxygen-Enriched Environments
qualified technical personnel to analyze incidents, each incident is unique
G 94 Guide for Evaluating Metals for Oxygen Service
and must be approached as a unique event. Therefore, the selection of
G 114 PracticeforAgingOxygen-ServiceMaterialsPriorto
specific tactics and the sequence of application of those tactics must be
Flammability Testing
conscious decisions of those studying the event.
G 124 Test Method for Determining the Combustion Be-
NOTE 2—The incident may require the formation of a team to provide
thenecessaryexpertiseandexperiencetoconductthestudy.Thepersonnel
havior of Metallic Materials in Oxygen-Enriched Atmo-
analyzinganincident,oratleastonememberoftheteam,shouldknowthe
spheres
process under study and the equipment installation.
G 128 Guide for Control of Hazards and Risks in Oxygen-
1.4 Warning—During combustion, gases, vapors, aerosols, Enriched Systems
fumes, or combination thereof, are evolved, which may be
2.2 ASTM Adjunct:
present and may be hazardous to people. Caution—Adequate Video: Oxygen Safety
precautions should be taken to protect those conducting a
2.3 Compressed Gas Association (CGA) Standards:
study. G-4.4 Industrial Practices for Gaseous Oxygen Transmis-
1.5 This standard does not purport to address all of the
sion and Distribution Piping Systems
safety concerns, if any, associated with its use. It is the G-4.8 Safe Use of Aluminum Structured Packing for Oxy-
responsibility of the user of this standard to establish appro-
gen Distillation
priate safety and health practices and determine the applica- 2.4 National Fire Protection Association (NFPA) Stan-
bility of regulatory limitations prior to use.
dard:
2. Referenced Documents
Annual Book of ASTM Standards, Vol 14.02.
2.1 ASTM Standards: 3
Annual Book of ASTM Standards, Vol 14.04.
Available from ASTM Customer Service, 100 Barr Harbor Drive, West
Conshohocken, PA 19428-2959. Request PCN 12-700880-31.
1 5
This guide is under the jurisdiction ofASTM Committee G4 on Compatibility Available from Compressed Gas Association, 1725 Jefferson Davis Highway,
and Sensitivity of Materials in Oxygen-Enriched Atmospheres and is the direct Suite 1004, Arlington, VA 22202.
responsibility of Subcommittee G04.02 on Practices. Available from National Fire ProtectionAssociation, 1 Batterymarch Park, Box
Current edition approved Oct. 10, 1996. Published January 1997. 9101, Quincy, MA 02269-9101.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G145
NFPA 53 Fire Hazards in Oxygen Enriched Atmospheres 7. Direct-Cause Analysis
2.5 Occupational Safety and Health Act:
7.1 In this guide, the direct cause of an incident is the
OSHA Process Safety Management Compliance Manual
mechanical or thermodynamic event (such as breakage of a
component or near-adiabatic compression), the physicochemi-
3. Terminology
cal property (such as heat of combustion), the procedure (such
3.1 Definitions—See Guides G 63, G 94, and G 128 for the
as a valve opening rate), or any departure(s) from the intended
terms listed in this section.
stateofanyoftheseitems,thatleadsdirectlytoignitionorfire,
3.1.1 oxygen compatibility, n—the ability of a substance to
or both. A fire might also be the result of a financial decision,
coexist both with oxygen and with a potential source(s) of
worker skill, or manufacturing process—all of which can be
ignition at an expected pressure and temperature with a
viewed as causes—but such factors are addressed more prop-
magnitude of risk acceptable to the user.
erly in a system hazard review. Note that some fires are
3.1.2 qualified technical personnel, n—persons such as
anticipated and the risks (whether human or economic) are
engineers and chemists who, by virtue of education, training,
addressed by such things as shielding (for example to control
or experience, know how to apply the physical and chemical
human risk) or acceptance (for example to address economic
principles involved in the reactions between oxygen and other
risk). In these cases, a fire is not an “incident” unless some
materials.
aspect of the event exceeded the initial parameters (for
3.1.3 oxygen-enriched, adj—applies to a fluid (gas or liq-
example, the shielding did not provide the expected contain-
uid) that contains more than 25 mol % oxygen.
ment, or the cost exceeded projections). This guide seeks to
3.2 Definitions of Terms Specific to This Standard:
identify the material choice, equipment design, assembly
3.2.1 incident, n—an ignition or fire, or both, that is both
procedure, or other factor that led directly to the fire—and
undesired and unanticipated or an undesired and unanticipated
more specifically, to distinguish the physical object or action
consequence of an ignition or fire that was anticipated.
that caused the fire to start, to continue, or to be injurious or
3.2.2 direct incident cause, n—the mechanical or thermo-
destructive. Remedial actions are found in other documents
dynamic event (such as breakage of a component or near-
such as Guides G 63, G 88, and G 94, and Practice G 93, as
adiabatic compression), the physicochemical property (such as
well as publications NFPA 53, CGA G-4.4, and G-4.8, OSHA
heat of combustion), the procedure (such as a valve opening
Process Safety Management Compliance Manual, and others.
rate), or any departure(s) from the intended state of any of
7.2 Example—The direct cause of an incident may be
these items, that leads directly to ignition or fire, or both.
concluded to be the use of an incompatible material, because a
3.2.3 fractional evaporation, v—thecontinuousevaporation
polyacetyl component was installed when a material such as
of a quantity of liquid that results in a progressive increase in
PTFEorCTFEwaspreferred.Thedirectcausewasnotthatthe
the concentration of a less-volatile constituent(s).
budget was inadequate to cover the cost of PTFE; nor that
specific frictional properties of polyacetyl were required for
4. Summary of Guide
mechanical purposes; nor that an incorrect part was installed in
4.1 Following a fire incident in an oxygen-enriched atmo-
error. Note that in this example, PTFE and CTFE might be
sphere, the equipment, operating procedures, and area are
needed to prevent or cope with ignition and fire, but that they
considered in light of other incidents, potential contributing
might introduce non-fire-related issues such as loss of me-
factors, suggested analytical strategies, and demonstrated labo-
chanical strength or production of toxic decomposition prod-
ratory results. The goal is to determine direct cause(s) of the
ucts when exposed to heat of compression.
incident in order to prevent a recurrence.
8. Elements of a Study
5. Significance and Use
8.1 Overview—The study of an oxygen incident typically
5.1 This guide helps those studying oxygen system inci-
begins (preferably promptly) after the event has concluded.
dents to select a direct cause hypothesis and to avoid conclu-
The fire is extinguished and any safety requirements or
sions based on hypotheses, however plausible, that have
immediate needs are addressed (treating injuries, returning
proven faulty in the past.
systems to a safe state, and so forth). Then the investigator can
begin to document the event, to preserve the artifacts, and to
6. Abstract
detect how they may have been altered or compromised by the
6.1 A series of possible causes and common scenarios are
event and follow-up activities. Although many of these steps
described to assist those seeking to understand incidents in
are itemized here, the intent of this guide is not to specify how
oxygen-enriched atmospheres. Many easily misinterpreted fac-
or in what order they should be conducted. Rather, information
tors are described to help avoid faulty conclusions. Several
is offered about certain procedures that have been effective in
suspectedbutunprovenincidentscenariosaredescribed.Select
the past, as well as some that have led to faulty conclusions.
laboratory data are presented to support assertions about direct
Typically, good scientific and laboratory skills are useful and
causes of incidents.
adequate. Forensic skills and procedures can be helpful in
many cases, but may not be practical in all. For example, the
forensic Guide E 1459 can assist with managing post-incident
artifacts, and related Practices E 1492, E 620, E 678, E 860,
Available from Occupational Safety and HealthAdministration, 1825 K Street,
NW Washington, DC 20006. E 1020, and E 1188, as well as Terminology E 1138, may have
G145
other uses. However, when a forensic approach is needed garding preventing recurrence of injury rather than fire) when
because a legal action is involved, the insights in this guide inadequate shielding or inadequate mechanical design or other
may effectively supplement it. comparable factor is identified singly or in combination as the
direct cause.
8.2 Documentation—Among the urgent post-incident ef-
8.4.3 The study is complete when the direct cause has been
forts are: photographing or videotaping the site and any
determined. Preventing the repetition of an event is the
damaged equipment; obtaining system drawings, supporting
function of a hazard review using well-established techniques,
design analysis, process hazards analysis, and any other
including the use of related standards from ASTM Committee
hazard-evaluation materials; interviewing persons knowledge-
G-4. The hazard review may be integral to the incident study
able about the system, operating procedures and the events
and may involve some or all of the same people, but it is a
before, during, and after the fire; collecting specimens, oper-
separate activity for the purpose of this guide.
ating logs, and related information; and preliminary formula-
tion and testing of hypotheses.
9. Factors Affecting an Incident Study
8.3 Analysis—The principal effort in a study will be analy-
9.1 Missing Components—Following some oxygen inci-
sis of the data and artifacts. This may require further exami-
dents, components have appeared to be absent, leading to
nation of the equipment and records, laboratory study of
speculation that the component was not installed or that its
selected items, and perhaps even laboratory simulation of the
mechanical failure and passage through the system were at
incident.
fault. Sometimes, the damage is so negligible that the possi-
8.4 Completion of Study—An incident study is completed
bility that there was no fire is considered. These conclusions
when the qualified technical personnel involved in the study
can be in error. In an oxygen-enriched atmosphere, combustion
conclude that the event is understood.
can be remarkably clean. A simple polymer may be converted
8.4.1 An incident might be understood adequately when a
totally into carbon dioxide and water, leaving no trace of its
conclusion has been drawn about the direct cause of the event.
prior presence. If the component is small or if it has a low heat
The following examples show the distinction between direct
of combustion, there may be no evidence of heat damage. For
causes and causes that are not physicochemical or thermody-
example, PTFE seats in ball valves (which are large and have
namic events.
low heat of combustion) and nylon seats in cylinder valves
8.4.1.1 Example 1—A substantial amount of hydrocarbon
(which are small and have high heat of combustion) have
oil was introduced into a system just before an incident. This
burned completely in some incidents with no melting of metal
single factor may be identified as the direct cause of the fire.
components, no appearance of residual carbon, and no remains
Any reasons for introducing the lubricant may be important to
of the polymer itself.
a new hazard review, but are not the direct cause of the fire.
9.2 Contamination:
Prevention can focus on cleanliness. Initiating Event: ignition
9.2.1 When contamination is present in an oxygen system,
of an incompatible oil. Direct Cause: contamination of the
the contaminant may serve to start the incident. Then the
system.
ensuing fire involving the polymers, metals, and contaminant
8.4.1.2 Example 2—Records may show that a component
may consume the contaminant fully, leaving no indication of
broke and produced a rub in a piece of machinery just before
its original presence.
an incident. This factor alone can ignite a fire and could be
9.2.2 When contaminant levels are large, they may produce
identified as the direct caus
...