ASTM E2079-19

Standard Test Methods for Limiting Oxygen (Oxidant) Concentration in Gases and Vapors

SIGNIFICANCE AND USE
5.1 Knowledge of the limiting oxygen (oxidant) concentration is needed for safe operation of some chemical processes. This information may be needed in order to start up or operate a reactor while avoiding the creation of flammable gas compositions therein, or to store or ship materials safely. NFPA 69 provides guidance for the practical use of LOC data, including the appropriate safety margin to use.  
5.2 Examples of LOC data applications can be found in references (3-5).
Note 2: The LOC values reported in references (6-8), and relied upon by a number of modern safety standards (such as NFPA 69 and NFPA 86) were obtained mostly in a 5-cm diameter flammability tube. This diameter may be too small to mitigate the flame quenching influence impeding accurate determination of the LOC of most fuels. The 4-L minimum volume specified in Section 7 would correspond to a diameter of at least 20 cm. As a result, some LOC values determined using these test methods are approximately 1.5 vol % lower than the previous values measured in the flammability tube, and are more appropriate for use in fire and explosion hazard assessment studies.  
5.3 Much of the previous literature LOC data (6-8) were measured in the flammability tube.  
5.4 Accepted LOC values (when nitrogen is the inert gas) determined for the five reference gases using these test methods in 20-L and 120-L test enclosures have been reported in Zlochower (9), and are summarized below:
Hydrogen—4.6 % in 120-L, 4.7 % in 20-L
Carbon Monoxide—5.1 % in 120-L
Methane—11.1 % in 120-L, 10.7 % in 20-L
Ethylene—8.5 % in 120-L, 8.6 % in 20-L
Propane—10.7 % in 120-L, 10.5 % in 20-L
Note 3: For carbon monoxide, results are sensitive to the humidity of the test mixture in the enclosure. Presence of a small concentration of water vapor facilitates combustion and promotes flame propagation by supplying the hydrogen (H) and hydroxyl (OH) free radicals for the chain branching reactions. For conservative results, provi...
SCOPE
1.1 These test methods cover the determination of the limiting oxygen (oxidant) concentration of mixtures of oxygen (oxidant) and inert gases with flammable gases and vapors at a specified initial pressure and initial temperature.  
1.2 These test methods may also be used to determine the limiting concentration of oxidizers other than oxygen.  
1.3 Differentiation among the different combustion regimes (such as the hot flames, cool flames, and exothermic reactions) is beyond the scope of these test methods.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 These test methods should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2019
• ICS: 75.160.30 - Gaseous fuels
• Technical Committee: E27 - Hazard Potential of Chemicals
• Drafting Committee: E27.04 - Flammability and Ignitability of Chemicals

Relations

• Refers: ASTM E1445-08(2015) - Standard Terminology Relating to Hazard Potential of Chemicals
• Effective Date: 01-Feb-2015
• Referred By: ASTM E918-19 - Standard Practice for Determining Limits of Flammability of Chemicals at Elevated Temperature and Pressure
• Effective Date: 01-Jul-2019
• Referred By: ASTM E2931-13(2019) - Standard Test Method for Limiting Oxygen (Oxidant) Concentration of Combustible Dust Clouds
• Effective Date: 01-Jul-2019
• Referred By: ASTM E681-09(2023) - Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases)
• Effective Date: 01-Jul-2019

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2079 − 19
Standard Test Methods for
Limiting Oxygen (Oxidant) Concentration in Gases and
1
Vapors
This standard is issued under the fixed designation E2079; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 These test methods cover the determination of the
E1445 Terminology Relating to Hazard Potential of Chemi-
limiting oxygen (oxidant) concentration of mixtures of oxygen
cals
(oxidant) and inert gases with flammable gases and vapors at a
3
specified initial pressure and initial temperature.
2.2 CGA Publication:
CGAP-23 Standard for Categorizing Gas Mixtures Contain-
1.2 These test methods may also be used to determine the
ing Flammable and Nonflammable Components, 2015
limiting concentration of oxidizers other than oxygen.
4
2.3 ISO Publication:
1.3 Differentiation among the different combustion regimes
ISO 10156 Gases and Gas Mixtures — Determination of
(such as the hot flames, cool flames, and exothermic reactions)
Fire Potential and Oxidizing Ability for the Selection of
is beyond the scope of these test methods.
Cylinder Valve Outlets, 2010
1.4 The values stated in SI units are to be regarded as
5
2.4 NFPA Publications:
standard. No other units of measurement are included in this
NFPA 69 Standard on Explosion Prevention Systems
standard.
NFPA 86 Standard for Ovens and Furnaces
1.5 These test methods should be used to measure and
describe the properties of materials, products, or assemblies in
3. Terminology
response to heat and flame under controlled laboratory con-
3.1 Definitions—See also Terminology E1445.
ditions and should not be used to describe or appraise the fire
3.2 Definitions of Terms Specific to This Standard:
hazard or fire risk of materials, products, or assemblies under
3.2.1 flammable, n—capable of propagating a flame.
actual fire conditions. However, results of this test may be used
as elements of a fire risk assessment which takes into account
3.2.2 ignition, n—the initiation of combustion.
all of the factors which are pertinent to an assessment of the
3.2.3 limit of flammability, n—the boundary in composition
fire hazard of a particular end use.
space dividing flammable and nonflammable regions.
1.6 This standard does not purport to address all of the
3.2.4 limiting oxygen (oxidant) concentration (LOC) of a
safety concerns, if any, associated with its use. It is the
fuel-oxidant-inert system, n—the oxygen (oxidant) concentra-
responsibility of the user of this standard to establish appro-
tion at the limit of flammability for the worst case (most
priate safety, health, and environmental practices and deter-
flammable) fuel concentration.
mine the applicability of regulatory limitations prior to use.
3.2.4.1 Discussion—Limiting oxygen (oxidant) concentra-
1.7 This international standard was developed in accor-
tion is also known as minimum oxygen (oxidant) concentration
dance with internationally recognized principles on standard-
or as critical oxygen (oxidant) concentration.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Barriers to Trade (TBT) Committee.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3
Available from Compressed Gas Association (CGA), 14501 George Carter
1
These test methods are under the jurisdiction of ASTM Committee E27 on Way, Suite 103, Chantilly, VA 20151, http://www.cganet.com.
4
Hazard Potential of Chemicals and are the direct responsibility of Subcommittee Available from International Organization for Standardization (ISO), ISO
E27.04 on Flammability and Ignitability of Chemicals. Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
Current edition approved July 1, 2019. Published July 2019. Originally approved Geneva, Switzerland, http://www.iso.org.
5
in 2000. Last previous edition approved in 2013 as E2079 – 07 (2013). DOI: Available from National Fire Protection Association (NFPA), 1 Batterymarch
10.1520/E2079-19. Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2079 − 07 (Reapproved 2013) E2079 − 19
Standard Test Methods for
Limiting Oxygen (Oxidant) Concentration in Gases and
1
Vapors
This standard is issued under the fixed designation E2079; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 These test methods cover the determination of the limiting oxygen (oxidant) concentration of mixtures of oxygen (oxidant)
and inert gases with flammable gases and vapors at a specified initial pressure and initial temperature.
1.2 These test methods may also be used to determine the limiting concentration of oxidizers other than oxygen.
1.3 Differentiation among the different combustion regimes (such as the hot flames, cool flames, and exothermic reactions) is
beyond the scope of these test methods.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 These test methods should be used to measure and describe the properties of materials, products, or assemblies in response
to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire
risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a
fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular
end use.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
E1445 Terminology Relating to Hazard Potential of Chemicals
3
2.2 CGA Publication:
CGA P-23 Standard for Categorizing Gas Mixtures Containing Flammable and Nonflammable Components, 2015
4
2.3 ISO Publication:
ISO 10156 Gases and Gas Mixtures — Determination of Fire Potential and Oxidizing Ability for the Selection of Cylinder Valve
Outlets, 2010
5
2.4 NFPA Publication:Publications:
NFPA 69 Standard on Explosion Prevention Systems
NFPA 86 Standard for Ovens and Furnaces
1
These test methods are under the jurisdiction of ASTM Committee E27 on Hazard Potential of Chemicals and are the direct responsibility of Subcommittee E27.04 on
Flammability and Ignitability of Chemicals.
Current edition approved Oct. 1, 2013July 1, 2019. Published October 2013July 2019. Originally approved in 2000. Last previous edition approved in 20072013 as
E2079 – 07.E2079 – 07 (2013). DOI: 10.1520/E2079-07R13.10.1520/E2079-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from Compressed Gas Association (CGA), 14501 George Carter Way, Suite 103, Chantilly, VA 20151, http://www.cganet.com.
4
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
5
Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E2079 − 19
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2.3 NTIS Publications:
Bulletin 503 Coward, H.F., and Jones, G.W., Bureau of Mines, “Limits of Flammability of Gases and Vapors,” NTIS AD701575,
1952
Bulletin 627 Zabetakis, M.G., Bureau of Mines, “Flammability Characteristics of Combustible Gases and Vapors,” NTIS
AD701576, 1965
Bulletin 680 Kuchta, J.M., Bureau of Mines, “Investigation of Fire and Explosion Accidents in the Chemical, Mining, and
Fuel-R
...