ASTM D7327-21

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of the standard as published by ASTM is to be considered the official document.
Designation: D7327 − 17 D7327 − 21
Standard Specification for
HFC Blend B (CH FCF , CHF CF , and CO )
2 3 2 3 2
This standard is issued under the fixed designation D7327; 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 This specification covers requirements for HFC Blend B as a fire-fighting medium.
1.2 This specification does not address the fire-fighting equipment or hardware that employs HFC Blend B or the conditions of
employing such equipment (for example, handhelds, fixed installations, etc.).
1.3 This specification does not address the storage or transportation of HFC Blend B. Storage, handling, and transportation issues
are addressed in Practice D7326.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard
1.5 The following safety hazards caveat pertains only to the test methods portion, Section 6, of this specification: 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. Specific cautionaryhazards statements are given in Section 4.
1.6 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.
This specification is under the jurisdiction of ASTM Committee D26 on Halogenated Organic Solvents and Fire Extinguishing Agents and is the direct responsibility
of Subcommittee D26.09 on Fire Extinguishing Agents.
Current edition approved Feb. 1, 2017June 1, 2021. Published February 2017June 2021. Originally approved in 2007. Last previous edition approved in 20122017 as
D7327-12.-17. DOI: 10.1520/D7327-17.10.1520/D7327-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7327 − 21
2. Referenced Documents
2.1 ASTM Standards:
D7326 Practice for Handling, Transportation, and Storage of HFC Blend B (CH FCF , CHF CF , and CO )
2 3 2 3 2
D6806 Practice for Analysis of Halogenated Organic Solvents and Their Admixtures by Gas Chromatography
2.2 ISO Standard:
ISO 3427 Gaseous Halogenated Hydrocarbons (Liquefied Gases)–Taking of a Sample
2.3 ASHRAE Standard:
ASHRAE 34 Designation and Safety Classification of Refrigerants
2.2 U.S. Government Standards:
49 CFR Title 49,Part 172 Part 172, Subpart D, U.S. Department of Transportation (DOT), Marking Requirements of Packaging
for TransportationHazardous Materials Table, Special Provisions, Hazardous Materials Communications, Emergency
Response Information, Training Requirements and Security Plans
49 CFR Title 49, Part 172.101 Tables Purpose and Use of Hazardous Materials and Special ProvisionsTable
2.3 AHRI Standard:
2008 Appendix C for Analytical Procedures for AHRI Standard 700-2014
2.4 ASHRAE Standard:
ASHRAE Standard 34 Designation and Safety Classification of Refrigerants
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 HFC—HFC, n—hydrofluorocarbon; a chemical compound in which the compound molecule is comprised exclusively of
hydrogen, chlorine, fluorine and carbon atoms.
3.1.2 HFC Blend B—B, n—tertiary blend comprised of HFC-134a (1,1,1,2-tetrafluoroethane), HFC-125 (pentafluoroethane), and
carbon dioxide (CO ); a compound used to inert, extinguish, or suppress a fire or explosion hazard.
3.1.2.1 Discussion—
The terminology system for fluorine-containing compounds (described in detail in ASHRAE Standard 34) provides a convenient
means to reference the structure of individual compounds. By definition, the first digit of the numbering system represents one less
than the number of carbon atoms in the compound molecule; the second digit, one more than the number of hydrogen atoms in
the compound molecule; and the third digit, the number of fluorine atoms in the compound molecule. Unaccounted for valence
requirements are assumed to be chlorine atoms. For example, the designation HFC-123 indicates two carbon atoms (1 + 1), two
hydrogen atoms (3-1), and four fluorine atoms (4). The “a” designation at the end of the naming convention relates to the symmetry
of the molecule.
Example: CH FCF = HFC-134a
2 3
4. Material Requirements
4.1 Type I – Mixtures of HFC Blend B and Nitrogen:
4.1.1 The nitrogen (N ) partial pressure shall be such that the safe working pressure of the receiving vessel is not exceeded. To
prevent excessive pressure, the fill density of HFC Blend B within a container should not exceed that needed to achieve complete
filling of the container at the maximum envisaged storage temperature. For example, for the U.S. DOT Department of
Transportation (DOT) 4BA500 cylinder, the nitrogen partial pressure shall not exceed 316 psig at 70 °F (21.8 bar at 21 °C) for a
3 3
58 lb/ft (930 kg/m ) fill density (yielding a total pressure of 360 psig at 70 °F (25.8 bar at 21 °C). For this example, the safe
working pressure of the 4BA500 cylinder is not exceeded for temperatures below 130 °F (54 °C).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA 30329,
http://www.ashrae.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.
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