ASTM G145-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: G 145 – 96
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 2. Referenced Documents
1.1 This guide covers procedures and material for examin- 2.1 ASTM Standards:
ing fires in oxygen systems for the purposes of identifying E 620 Practice for Reporting Opinions of Technical Ex-
potential causes and preventing recurrence. perts
1.2 This guide is not comprehensive and is not intended for E 678 Practice for Evaluation of Technical Data
forensic use. The analysis of oxygen fire incidents is not a E 860 Practice for Examining and Testing Items That Are or
science, and definitive causes have not been established for May Become Involved in Products Liability Litigation
some events. E 1020 Practice for Reporting Incidents
1.3 The procedures and analyses in this guide have been E 1138 Terminology of Technical Aspects of Products Li-
found useful for interpreting fire events, for helping identify ability Litigation
potential causes, and for excluding other potential causes. The E 1188 Practice for Collection and Preservation of Informa-
inclusion or omission of any analytical strategy is not intended tion and Physical Items by a Technical Investigator
to suggest either applicability or inapplicability of that method E 1459 Guide for Physical Evidence Labeling and Related
in any actual incident study. Indeed, some material in this guide Documentation
is considered useful, and therefore worthy of inclusion and E 1492 Practice for Receiving, Documenting, Storing, and
consideration in a study, but not necessarily of demonstrated Retrieving Evidence in a Forensic Science Laboratory
validity. G 63 Guide for Evaluating Nonmetallic Materials for Oxy-
gen Service
NOTE 1—Although this guide has been found applicable for assisting
G 88 Guide for Designing Systems for Oxygen Service
qualified technical personnel to analyze incidents, each incident is unique
G 93 Practice for Cleaning Methods for Material and
and must be approached as a unique event. Therefore, the selection of
specific tactics and the sequence of application of those tactics must be Equipment Used in Oxygen-Enriched Environments
conscious decisions of those studying the event.
G 94 Guide for Evaluating Metals for Oxygen Service
NOTE 2—The incident may require the formation of a team to provide
G 114 Practice for Aging Oxygen-Service Materials Prior to
the necessary expertise and experience to conduct the study. The personnel 2
Flammability Testing
analyzing an incident, or at least one member of the team, should know the
G 124 Test Method for Determining the Combustion Be-
process under study and the equipment installation.
havior of Metallic Materials in Oxygen-Enriched Atmo-
1.4 Warning—During combustion, gases, vapors, aerosols, 2
spheres
fumes, or combination thereof, are evolved, which may be
G 128 Guide for Control of Hazards and Risks in Oxygen-
present and may be hazardous to people. Caution—Adequate 2
Enriched Systems
precautions should be taken to protect those conducting a
2.2 ASTM Adjunct:
study. 3
Video: Oxygen Safety
1.5 This standard does not purport to address all of the 4
2.3 Compressed Gas Association (CGA) Standards:
safety concerns, if any, associated with its use. It is the
G-4.4 Industrial Practices for Gaseous Oxygen Transmis-
responsibility of the user of this standard to establish appro-
sion and Distribution Piping Systems
priate safety and health practices and determine the applica-
G-4.8 Safe Use of Aluminum Structured Packing for Oxy-
bility of regulatory limitations prior to use.
gen Distillation
Annual Book of ASTM Standards, Vol 14.02.
1 3
This guide is under the jurisdiction of ASTM Committee G-4 on Compatibility Available from ASTM Customer Service, 100 Barr Harbor Drive, West
and Sensitivity of Materials in Oxygen-Enriched Atmospheres and is the direct Conshohocken, PA 19428-2959. Request PCN 12-700880-31.
responsibility of Subcommittee G04.02 on Practices. Available from Compressed Gas Association, 1725 Jefferson Davis Highway,
Current edition approved Oct. 10, 1996. Published January 1997. Suite 1004, Arlington, VA 22202.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G 145
2.4 National Fire Protection Association (NFPA) Stan- suspected but unproven incident scenarios are described. Select
dard: laboratory data are presented to support assertions about direct
NFPA 53 Fire Hazards in Oxygen Enriched Atmospheres causes of incidents.
2.5 Occupational Safety and Health Act:
7. Direct-Cause Analysis
OSHA Process Safety Management Compliance Manual
7.1 In this guide, the direct cause of an incident is the
3. Terminology
mechanical or thermodynamic event (such as breakage of a
component or near-adiabatic compression), the physicochemi-
3.1 Definitions—See Guides G 63, G 94, and G 128 for the
cal property (such as heat of combustion), the procedure (such
terms listed in this section.
as a valve opening rate), or any departure(s) from the intended
3.1.1 oxygen compatibility, n—the ability of a substance to
state of any of these items, that leads directly to ignition or fire,
coexist both with oxygen and with a potential source(s) of
or both. A fire might also be the result of a financial decision,
ignition at an expected pressure and temperature with a
worker skill, or manufacturing process—all of which can be
magnitude of risk acceptable to the user.
viewed as causes—but such factors are addressed more prop-
3.1.2 qualified technical personnel, n—persons such as
erly in a system hazard review. Note that some fires are
engineers and chemists who, by virtue of education, training,
anticipated and the risks (whether human or economic) are
or experience, know how to apply the physical and chemical
addressed by such things as shielding (for example to control
principles involved in the reactions between oxygen and other
human risk) or acceptance (for example to address economic
materials.
risk). In these cases, a fire is not an “incident” unless some
3.1.3 oxygen-enriched, adj—applies to a fluid (gas or liq-
aspect of the event exceeded the initial parameters (for
uid) that contains more than 25 mol % oxygen.
example, the shielding did not provide the expected contain-
3.2 Definitions of Terms Specific to This Standard:
ment, or the cost exceeded projections). This guide seeks to
3.2.1 incident, n—an ignition or fire, or both, that is both
identify the material choice, equipment design, assembly
undesired and unanticipated or an undesired and unanticipated
procedure, or other factor that led directly to the fire—and
consequence of an ignition or fire that was anticipated.
more specifically, to distinguish the physical object or action
3.2.2 direct incident cause, n—the mechanical or thermo-
that caused the fire to start, to continue, or to be injurious or
dynamic event (such as breakage of a component or near-
destructive. Remedial actions are found in other documents
adiabatic compression), the physicochemical property (such as
such as Guides G 63, G 88, and G 94, and Practice G 93, as
heat of combustion), the procedure (such as a valve opening
well as publications NFPA 53, CGA G-4.4, and G-4.8, OSHA
rate), or any departure(s) from the intended state of any of
Process Safety Management Compliance Manual, and others.
these items, that leads directly to ignition or fire, or both.
7.2 Example—The direct cause of an incident may be
3.2.3 fractional evaporation, v—the continuous evaporation
concluded to be the use of an incompatible material, because a
of a quantity of liquid that results in a progressive increase in
polyacetyl component was installed when a material such as
the concentration of a less-volatile constituent(s).
PTFE or CTFE was preferred. The direct cause was not that the
4. Summary of Guide budget was inadequate to cover the cost of PTFE; nor that
specific frictional properties of polyacetyl were required for
4.1 Following a fire incident in an oxygen-enriched atmo-
mechanical purposes; nor that an incorrect part was installed in
sphere, the equipment, operating procedures, and area are
error. Note that in this example, PTFE and CTFE might be
considered in light of other incidents, potential contributing
needed to prevent or cope with ignition and fire, but that they
factors, suggested analytical strategies, and demonstrated labo-
might introduce non-fire-related issues such as loss of me-
ratory results. The goal is to determine direct cause(s) of the
chanical strength or production of toxic decomposition prod-
incident in order to prevent a recurrence.
ucts when exposed to heat of compression.
5. Significance and Use
8. Elements of a Study
5.1 This guide helps those studying oxygen system inci-
8.1 Overview—The study of an oxygen incident typically
dents to select a direct cause hypothesis and to avoid conclu-
begins (preferably promptly) after the event has concluded.
sions based on hypotheses, however plausible, that have
The fire is extinguished and any safety requirements or
proven faulty in the past.
immediate needs are addressed (treating injuries, returning
systems to a safe state, and so forth). Then the investigator can
6. Abstract
begin to document the event, to preserve the artifacts, and to
6.1 A series of possible causes and common scenarios are
detect how they may have been altered or compromised by the
described to assist those seeking to understand incidents in
event and follow-up activities. Although many of these steps
oxygen-enriched atmospheres. Many easily misinterpreted fac-
are itemized here, the intent of this guide is not to specify how
tors are described to help avoid faulty conclusions. Several
or in what order they should be conducted. Rather, information
is offered about certain procedures that have been effective in
the past, as well as some that have led to faulty conclusions.
Available from National Fire Protection Association, 1 Batterymarch Park, Box
Typically, good scientific and laboratory skills are useful and
9101, Quincy, MA 02269-9101.
adequate. Forensic skills and procedures can be helpful in
Available from Occupational Safety and Health Administration, 1825 K Street,
NW Washington, DC 20006. many cases, but may not be practical in all. For example, the
G 145
forensic Guide E 1459 can assist with managing post-incident oxygen-compatible materials because they compromise its
artifacts, and related Practices E 1492, E 620, E 678, E 860, operating economy, and it becomes the site of a fire and injures
E 1020, and E 1188, as well as Terminology E 1138, may have someone, then the event may be understood adequately (re-
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
...