ANSI/ASHRAE Standard 34-2004
`
`(Includes ANSI/ASHRAE addenda listed in Appendix C)
`
`ASHRAE STANDARD
`
`Designation and Safety
`Classification of
`
`Refrigerants
`
`See Appendix C for approval dates by the ASHHAE Standards Committee, the ASHHAE Board of Directors, and
`the American National Standards Institute.
`
`This standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the
`Standards Committee has established a documented program for regular publication of addenda or revisions,
`including procedures for timely, documented, consensus action on requests for change to any part of the stan-
`dard. The change submittal form, instructions, and deadlines may be obtained in electronic fonn from theASHFlAE
`Web site, httpJlwww.ashrae.org, or in paper form from the Managerof Standards. The latest edition of an ASHRAE
`Standard may be purchased from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305.
`E-mail: orders@ashrae.org. Fax: 404-321-5478. Telephone: 404-636-8400 (worldwide), or toll free 1-800-527-
`4723 (for orders in U.S. and Canada).
`
`© Copyright 2004 ASHRAE, Inc.
`
`ISSN 1041-2336
`
`M W80
`
`American Society of Heating, Refrigerating
`
`and Air-Conditioning Engineers, Inc.
`I791 Tullie Circle NE, Atlanta, GA 30329
`
`www.ashrae.org
`
`Arkema Exhibit 1154
`
`

`
`ASHRAE Standing Standard Project Committee 34
`Cognizant TC: TC 3.1, Refrigerants and Secondary Coolants
`SPLS Liaisons: Thomas H. Williams and Roger L. Hedrick
`
`Robert G. Doerr, Chair
`James M. Calm, Vice-Chair
`Donald B. Bivens
`Michael D. Blanford
`Denis F. Clodic
`C. James Dahn
`David A. Didion
`Paul H. Dugard
`Andrew M. Gbur
`
`Van D. Baxter, Chair
`Davor Novosel, Vice-Chair
`Donald B. Bivens
`Dean S. Borges
`Paul W. Cabot
`Charles W. Coward, Jr.
`Hugh F. Crowther
`Brian P. Dougherty
`Hakim Elmahdy
`Matt R. Hargan
`Richard D. Hermans
`John F. Hogan
`Frank E. Jakob
`
`Donald P. Grob
`H. Michael Hughes
`Gary W. Jepson
`Debra H. Kennoy
`Andrew Kusmierz
`Thomas J. Leck
`Mark O. McLinden
`Sandra Murphy
`Vikas Patnaik
`
`ASHRAE STANDARDS COMMITTEE 2003-2004
`
`Robert G. Richard
`George M. Rusch
`James R. Sand
`Mark W. Spatz
`Steven R. Szymurski
`Ganesan (Sonny) Sundaresan
`Eugene F. Troy
`Mahesh Valiya-Naduvath
`David P. Wilson
`
`Stephen D. Kennedy
`David E. Knebel
`Frederick H. Kohloss
`Merle F. McBride
`Mark P. Modera
`Cyrus H. Nasseri
`Stephen V. Santoro
`Gideon Shavit
`David R. Tree
`James E. Woods
`Ross D. Montgomery, ExO
`Kent W. Peterson, CO
`
`Claire B. Ramspeck, Manager of Standards
`
`SPECIAL NOTE
`This American National Standard (ANS) is a national voluntary consensus standard developed under the auspices of the American
`Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Consensus is defined by the American National Standards
`Institute (ANSI), of which ASHRAE is a member and which has approved this standard as an ANS, as “substantial agreement reached
`by directly and materially affected interest categories. This signifies the concurrence of more than a simple majority, but not necessarily
`unanimity. Consensus requires that all views and objections be considered, and that an effort be made toward their resolution.”
`Compliance with this standard is voluntary until and unless a legal jurisdiction makes compliance mandatory through legislation.
`ASHRAE obtains consensus through participation of its national and international members, associated societies, and public
`review.
`ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. The
`Project Committee Chair and Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAE
`members, all must be technically qualified in the subject area of the Standard. Every effort is made to balance the concerned interests
`on all Project Committees.
`The Manager of Standards of ASHRAE should be contacted for:
`a. interpretation of the contents of this Standard,
`b. participation in the next review of the Standard,
`c. offering constructive criticism for improving the Standard,
`d. permission to reprint portions of the Standard.
`DISCLAIMER
`ASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of available
`information and accepted industry practices. However, ASHRAE does not guarantee, certify, or assure the safety or
`performance of any products, components, or systems tested, installed, or operated in accordance with ASHRAE’s Standards
`or Guidelines or that any tests conducted under its Standards or Guidelines will be nonhazardous or free from risk.
`
`ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDS
`ASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of
`testing for rating purposes, by suggesting safe practices in designing and installing equipment, by providing proper definitions
`of this equipment, and by providing other information that may serve to guide the industry. The creation of ASHRAE Standards
`and Guidelines is determined by the need for them, and conformance to them is completely voluntary.
`In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, either
`stated or implied, that the product has been approved by ASHRAE.
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`Page 2 of 91
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`

`
`CONTENTS
`
`ANSI/ASHRAE Standard 34-2004
`Designation and Safety Classification of Refrigerants
`
`SECTION
`
`PAGE
`
`Foreword................................................................................................................................................................... 2
`
`1 Purpose .......................................................................................................................................................... 2
`
`2 Scope ............................................................................................................................................................. 2
`
`3 Definitions of Terms ........................................................................................................................................ 2
`
`4 Numbering of Refrigerants ............................................................................................................................. 4
`
`5 Designation..................................................................................................................................................... 5
`
`6 Safety Group Classifications........................................................................................................................... 6
`
`7 Refrigerant Classifications.............................................................................................................................. 7
`
`8 Application Instructions................................................................................................................................... 7
`
`9 References ................................................................................................................................................... 10
`
`Table 1:
`
`Refrigerant Data and Safety Classification .................................................................................. 11
`
`Table 2:
`
`Data and Safety Classification for Refrigerant Blends ................................................................. 13
`
`Appendix A:
`
`Isomer Designation Examples ..................................................................................................... 14
`
`Appendix B: Bibliography.................................................................................................................................. 14
`
`Appendix C: Addenda Description Information................................................................................................ 15
`
`When addenda, interpretations, or errata to this standard have been approved, they can be downloaded
`free of charge from the ASHRAE Web site at http://www.ashrae.org.
`
`NOTE
`
`© Copyright 2004 American Society of Heating,
`Refrigerating and Air-Conditioning Engineers, Inc.
`1791 Tullie Circle NE
`Atlanta, GA 30329
`www.ashrae.org
`
`All rights reserved.
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`Page 3 of 91
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`
`(This foreword is not part of this standard. It is merely
`informative and does not contain requirements necessary
`for conformance to the standard. It has not been pro-
`cessed according to the ANSI requirements for a stan-
`dard and may contain material that has not been subject
`to public review or a consensus process. Unresolved
`objectors on informative material are not offered the
`right to appeal at ASHRAE or ANSI.)
`
`FOREWORD
`
`ANSI/ASHRAE Standard 34-2004 is the latest edition of
`Standard 34, which describes a shorthand way of naming
`refrigerants and assigns safety classifications based on toxic-
`ity and flammability data. The 2004 edition combines Stan-
`dard 34-2001 and the twelve approved and published addenda
`to the 2001 edition, thereby providing an easy-to-use consoli-
`dated standard. More specific information on the contents of
`each addendum and its approval dates are included in an
`informative appendix at the end of this standard.
`First published in 1978, Standard 34 is now updated on a
`regular basis using ASHRAE's continuous maintenance proce-
`dures. According to these procedures, Standard 34 is continu-
`ously revised—often several times a year—by addenda that
`are publicly reviewed, approved by ASHRAE and ANSI, and
`published on the ASHRAE Web site. Because the standard
`changes as new addenda are published, users are encouraged
`to sign up for the free internet list server for the ASHRAE
`Standards Actions publication, which provides notice of all
`public reviews and approved and published addenda and
`errata. At the minimum, users should periodically review the
`ASHRAE Web site to ensure that they have all of the published
`addenda. Currently two significant proposed addenda are
`undergoing the public review and approval process and may
`be published in the near future: Addendum 34p, which adds
`flammability and fractionation test methods, and Addendum
`34u, which adds the Refrigerant Concentration Level (RCL).
`Among the key changes that were incorporated in the
`2004 edition are the following:
`
`(cid:127)
`
`(cid:127)
`
`(cid:127)
`
`(cid:127)
`
`(cid:127)
`
`Six refrigerants or refrigerant blends were added to
`Tables 1 and 2 and an A1 safety classification was
`added for R-C318.
`The term “refrigerant” as it applies to this standard was
`further defined.
`The requirements for blend compositions and tolerances
`were defined. The minimum amount of any component is
`now 0.6%, and the tolerance above or below the nomi-
`nal shall not be less than 0.1% or more than 2.0% m/m.
`The reference to ASTM E681 was updated and the con-
`version factor was deleted from the definition of lower
`flammability limit (LFL).
`Informative Appendix B, which compared previous and
`current safety classifications, was deleted. Appendix B
`is now the bibliography.
`
`Users of the standard are encouraged and invited to use
`the continuous maintenance procedure to suggest changes for
`further improvements. A form for submitting proposed
`changes to the standard is included in the back of this edition.
`The project committee for Standard 34 will take formal action
`on all proposals received.
`
`1. PURPOSE
`
`This standard is intended to establish a simple means of
`referring to common refrigerants instead of using the chemical
`name, formula, or trade name. It also establishes a uniform
`system for assigning reference numbers and safety classifica-
`tions to refrigerants. The standard identifies requirements to
`apply for designations and safety classifications for refriger-
`ants, including blends, in addenda or revisions to this standard.
`
`2. SCOPE
`
`This standard provides an unambiguous system for
`numbering refrigerants and assigning composition-designat-
`ing prefixes for refrigerants. Safety classifications based on
`toxicity and flammability data are included. This standard
`does not imply endorsement or concurrence that individual
`refrigerant blends are suitable for any particular application.
`
`3. DEFINITIONS OF TERMS
`
`acute toxicity: the adverse health effect(s) from a single,
`short-term exposure, as might occur during an accidental
`release of refrigerants.
`
`azeotropic: an azeotropic blend is one containing two or more
`refrigerants whose equilibrium vapor and liquid phase compo-
`sitions are the same at a given pressure. At this pressure, the
`slope of the temperature vs. composition curve equals zero,
`which mathematically is expressed as (dt/dx)p = 0, which, in
`turn, implies the occurrence of a maximum, minimum, or
`saddle point temperature. Azeotropic blends exhibit some
`segregation of components at other conditions. The extent of
`the segregation depends on the particular azeotrope and the
`application.
`
`azeotropic temperature: the temperature at which the liquid
`and vapor phases of a blend have the same mole fraction of
`each component at equilibrium for a specified pressure.
`
`blends: refrigerants consisting of mixtures of two or more
`different chemical compounds, often used individually as
`refrigerants for other applications.
`
`cardiac sensitization: an acute effect in which the heart is
`rendered more sensitive to the body’s own catecholamine
`compounds or administered drugs, such as epinephrine, possi-
`bly resulting in irregular heart beat (cardiac arrhythmia),
`which could be fatal.
`
`ceiling: an exposure level, permissible exposure level-ceiling
`(PEL-C) or threshold limit value-ceiling (TLV-C), that should
`not be exceeded during any part of the day.
`
`chronic toxicity: adverse health effect(s) from long-term,
`repeated exposures. This information is used, in part, to estab-
`lish a TLV-TWA, PEL, or consistent indices.
`
`committee: as used in the standard, refers to ASHRAE Stand-
`ing Standards Project Committee (SSPC) 34.
`
`2
`
`ANSI/ASHRAE STANDARD 34-2004
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`Page 4 of 91
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`compounds: substances formed by the chemical combination
`of two or more elements in definite proportions by mass.
`
`critical point: the location on a plot of thermodynamic prop-
`erties at which the liquid and vapor states of a substance meet
`and become indistinguishable. The temperature, density, and
`composition of the substance are the same for the liquid and
`vapor phases at this point. The density, pressure, specific
`volume, and temperature at the critical point are referred to as
`the critical density, critical pressure, critical volume, and crit-
`ical temperature, respectively.
`
`cyclic compound: an organic compound that contains three or
`more atoms arranged in a ring structure.
`
`fractionation: a change in composition of a blend by prefer-
`ential evaporation of the more volatile component(s) or
`condensation of the less volatile component(s).
`
`glide: the absolute value of the difference between the starting
`and ending temperatures of a phase-change process by a
`refrigerant within a component of a refrigerating system,
`exclusive of any subcooling or superheating. This term usually
`describes condensation or evaporation of a zeotrope.
`
`halocarbon (as used in this standard): a hydrocarbon deriva-
`tive containing one or more of the halogens bromine, chlorine,
`or fluorine; hydrogen also may be present.
`
`heat of combustion (HOC): the heat released when
`substances are combusted, determined as the difference in
`enthalpy between the reactants, fuel (refrigerant) and air, and
`the reaction products after combustion. The heat of combus-
`tion exceeds zero for exothermic reactions (those that give off
`heat) and is negative for endothermic reactions (those that
`require heat).
`
`hydrocarbon: a compound containing only the elements
`hydrogen and carbon.
`
`isomer: one of a group of compounds having the same chem-
`ical composition with differing molecular structures. Exam-
`ples include R-123 and R-123a, both of which contain one
`hydrogen atom and two carbon, three flourine, and two chlo-
`rine atoms; both chlorine atoms are bonded to the same carbon
`atom in R-123 (CHCl2CF3), but one is bonded to each in R-
`123a (CHClFCClF2). The methane series of refrigerants
`cannot form isomers because the single-carbon nucleus does
`not enable structural variations.
`
`maximum temperature glide: the difference between the satu-
`rated liquid temperature (bubble point) and the saturated vapor
`temperature (dew point) for the “as formulated” blend compo-
`sition at constant pressure. For a given pressure, the evaporator
`temperature glide in a direct expansion system will typically
`be 70% to 80% of the maximum temperature glide, as the
`refrigerant blend entering the evaporator is a mixture of liquid
`and vapor, and not at the saturated liquid temperature of the “as
`formulated” blend composition.
`
`near azeotropic: a zeotropic blend with a temperature glide
`sufficiently small that it may be disregarded without conse-
`quential error in analysis for a specific application.
`
`nonazeotropic: a synonym for zeotropic (defined below), the
`latter being the preferred descriptor. Both non and a are nega-
`tion prefixes, the latter from Latin, and therefore cancel one
`another (i.e., not-not-zeotropic, hence zeotropic). The double
`negative results from antecedent interest in, and the need to
`make a distinction with, azeotropic mixtures.
`
`ppm: parts per million.
`
`permissible exposure level (PEL): the time-weighted aver-
`age concentration (set by OSHA, the U.S. Occupational
`Safety and Health Administration) for a normal 8-hour work
`day and a 40-hour work week to which nearly all workers can
`be repeatedly exposed without adverse effect. Chemical
`manufacturers publish similar recommendations (e.g., accept-
`able exposure level, AEL; industrial exposure limit, IEL; or
`occupational exposure
`limit, OEL, depending on
`the
`company), generally for substances for which PEL has not
`been established.
`
`refrigerant: the fluid used for heat transfer in a refrigerating
`system; the refrigerant absorbs heat and transfers it at a higher
`temperature and a higher pressure, usually with a phase
`change. Substances added to provide other functions, such as
`lubrication, leak detection, absorption, or drying, are not
`refrigerants.
`
`relative molecular mass: the ratio of the mass of a molecule
`to 1/12 of that of carbon-12. The relative molecular mass is
`numerically equivalent to the molecular weight expressed in g/
`mol, but it is dimensionless.
`
`saturated: an organic (carbon-containing) compound in
`which each carbon atom is joined to four other atoms; all of the
`chemical bonds in a saturated compound are single.
`
`LC50: a measure of acute, inhalation toxicity representing a
`lethal concentration for 50% of exposed test animals for a
`specified time interval and species of animal.
`
`short-term exposure limit (STEL): typically a 15-minute
`time-weighted average (TWA) exposure that should not be
`exceeded at any time during a work day.
`
`lower flammability limit (LFL): the minimum concentration
`of the refrigerant that is capable of propagating a flame
`through a homogeneous mixture of the refrigerant and air
`under test conditions specified in ASTM E681.1 The LFL
`normally is expressed as refrigerant percentage by volume.
`
`temperature glide: see glide.
`
`threshold limit values (TLVs): refer to airborne concentra-
`tions of substances and represent conditions under which it is
`believed that nearly all workers may be repeatedly exposed
`
`ANSI/ASHRAE STANDARD 34-2004
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`Page 5 of 91
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`

`
`day after day without adverse health effects. Because of wide
`variation in individual susceptibility, however, a small
`percentage of workers may experience discomfort from some
`substances at concentrations at or below the threshold limit; a
`smaller percentage may be affected more seriously by aggra-
`vation of a pre-existing condition or by development of an
`occupational illness. Smoking of tobacco is harmful for
`several reasons. Smoking may act to enhance the biological
`effects of chemicals encountered in the workplace and may
`the body’s defense mechanisms against
`toxic
`reduce
`substances.
`
`Individuals may also be hypersusceptible or otherwise unusu-
`ally responsive to some industrial chemicals because of
`genetic factors, age, personal habits (smoking, use of alcohol
`or other drugs), medication, or previous exposure. Such work-
`ers may not be adequately protected from adverse health
`effects from certain chemicals at concentrations at or below
`the threshold limits. An occupational physician should evalu-
`ate the extent to which such workers require additional protec-
`tion.
`
`TLVs are based on the best available information from indus-
`trial experience, from experimental human and animal studies,
`and, when possible, from a combination of the three. The basis
`on which the values are established may differ from substance
`to substance; protection against impairment of health may be
`a guiding factor for some, whereas reasonable freedom from
`irritation, narcosis, nuisance, or other forms of stress may
`form the basis for others.2 (This definition reprinted by
`permission of ACGIH.)
`
`threshold limit value–time-weighted average (TLV-TWA):
`the time-weighted average concentration for a normal 8-hour
`workday and a 40-hour workweek, to which nearly all workers
`may be repeatedly exposed, day after day, without adverse
`effect.2 (This definition reprinted by permission of ACGIH.)
`
`toxicity: the ability of a refrigerant to be harmful or lethal due
`to acute or chronic exposure by contact, inhalation, or inges-
`tion. The effects of concern include, but are not limited to,
`those of carcinogens, poisons, reproductive toxins, irritants,
`corrosives, sensitizers, hepatoxins, nephrotoxins, neurotox-
`ins, agents that act on the hematopoietic system, and agents
`that damage the lungs, skin, eyes, or mucous membranes. For
`this standard, temporary discomfort at a level that is not
`impairing is excluded.
`
`WEEL: workplace environmental exposure level (an occupa-
`tional exposure limit set by the American Industrial Hygiene
`Association, AIHA).
`
`zeotropic: blends comprising multiple components of differ-
`ent volatilities that, when used in refrigeration cycles, change
`volumetric composition and saturation temperatures as they
`evaporate (boil) or condense at constant pressure. The word is
`derived from the Greek words zein (to boil) and tropos (to
`change).
`
`4. NUMBERING OF REFRIGERANTS
`
`An identifying number shall be assigned to each refriger-
`ant. Reference 1 in the informative Appendix B provides back-
`ground on the need for a standard refrigerant nomenclature.
`
`4.1 The identifying numbers assigned to the hydrocarbons
`and halocarbons of the methane, ethane, propane, and cyclob-
`utane series are such that the chemical composition of the
`compounds can be explicitly determined from the refrigerant
`numbers, and vice versa, without ambiguity. The molecular
`structure can be similarly determined for the methane, ethane,
`and most of the propane series.
`4.1.1 The first digit on the right is the number of fluorine
`(F) atoms in the compound.
`4.1.2 The second digit from the right is one more than the
`number of hydrogen (H) atoms in the compound.
`4.1.3 The third digit from the right is one less than the
`number of carbon (C) atoms in the compound. When this digit
`is zero, it is omitted from the number.
`4.1.4 The fourth digit from the right is equal to the number
`of unsaturated carbon-carbon bonds in the compound. When
`this digit is zero, it is omitted from the number.
`In those instances where bromine (Br) is present in
`4.1.5
`place of part or all of the chlorine, the same rules apply, except
`that the uppercase letter B after the designation for the parent
`chlorofluoro compound shows the presence of bromine. The
`number following the letter B shows the number of bromine
`atoms present.
`4.1.6 The number of chlorine (Cl) atoms in the compound
`is found by subtracting the sum of fluorine (F), bromine (Br),
`and hydrogen (H) atoms from the total number of atoms that
`can be connected to the carbon (C) atoms. For saturated
`refrigerants, this number is 2n + 2, where n is the number of
`carbon atoms. The number is 2n for mono-unsaturated and
`cyclic-saturated refrigerants.
`4.1.7 The carbon atoms shall be numbered sequentially, in
`order of appearance, with the number 1 assigned to the end
`carbon with the most number of hydrogen substituents. In the
`case where both end carbons contain the same number of (but
`different) halogen atoms, the number 1 shall be assigned to
`the first end carbon, defined as having the largest number of
`bromine, then chlorine, then fluorine, and then iodine atoms.
`In the case of isomers in the ethane series, each has
`4.1.8
`the same number, with the most symmetrical one indicated by
`the number alone. As the isomers become more and more
`unsymmetrical, successive lowercase letters (i.e., a, b, or c)
`are appended. Symmetry is determined by first summing the
`atomic mass of the halogen and hydrogen atoms attached to
`each carbon atom. One sum is subtracted from the other; the
`smaller the absolute value of the difference, the more sym-
`metrical the isomer. For an example of this system, see
`Appendix A.
`In the case of isomers in the propane series, each has
`4.1.9
`the same number, with the isomers distinguished by two
`appended lowercase letters. The first appended letter indicates
`the substitution on the central carbon atom (C2):
`
`4
`
`ANSI/ASHRAE STANDARD 34-2004
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`Page 6 of 91
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`−CCl2−
`−CClF−
`
`−CF2−
`−CClH−
`
`−CFH−
`
`a
`
`b
`
`c
`
`d
`
`e
`
`f
`
`−CH2−
`For halogenated derivatives of cyclopropane, the carbon
`atom with the largest sum of attached atomic masses shall be
`considered the central carbon atom; for these compounds, the
`first appended letter is omitted. The second appended letter
`indicates the relative symmetry of the substituents on the end
`carbon atoms (C1 and C3). Symmetry is determined by first
`summing the atomic masses of the halogen and hydrogen
`atoms attached to the C1 and C3 carbon atoms. One sum is
`subtracted from the other; the smaller the absolute value of this
`difference, the more symmetrical the isomer. In contrast to the
`ethane series, however, the most symmetrical isomer has a
`second appended letter of a (as opposed to no appended letter
`for ethane isomers); increasingly asymmetrical isomers are
`assigned successive letters. Appended letters are omitted
`when no isomers are possible, and the number alone repre-
`sents the molecular structure unequivocally; for example,
`CF3CF2CF3 is designated R-218, not R-218ca. An example of
`this system is given in Appendix A.
`4.1.10 Bromine-containing, propane-series isomers can-
`not be uniquely designated by this system.
`
`4.2 For cyclic derivatives, the letter C is used before the
`identifying refrigerant numbers.
`
`4.3 Ether-based refrigerants shall be designated with the
`prefix “E” (for “ethers”) immediately preceding the number.
`Except for the following differences, the root number
`designations for the hydrocarbon atoms shall be determined
`according to the current standard for hydrocarbon nomencla-
`ture (see 4.1).
`4.3.1 Two-carbon, dimethyl ethers require no further suf-
`fixes, as the presence of the “E” prefix provides an unambig-
`uous description.
`4.3.2 Straight chain, three-carbon ethers require the
`agreement of the hydrocarbon ordering in 4.1.7.
`4.3.2.1 The position(s) of the ether oxygen(s) shall be
`given by the carbons to which they are first encountered. An
`additional integer identifying the first carbon to which the
`ether oxygen is attached will be appended to the suffix letters.
`In the case of otherwise symmetric hydrocarbon
`4.3.2.2
`structures, the ether oxygen shall appear in the earliest
`sequential position.
`4.3.2.3 Even in those cases where only a single propane
`isomer exists for the hydrocarbon portion of the ether struc-
`ture, such as CF3-O-CF2-CF3, the suffix letters described in
`4.1.9 shall be retained. In this cited example, the correct des-
`ignation shall be R-E218ca1.
`4.3.2.4 Structures containing two interspersed oxygen
`atoms, di-ethers, shall be designated with two following inte-
`gers to designate the positions of the ether oxygens.
`
`4.3.3 For cyclic ethers carrying both the “C” and “E” pre-
`fixes, the “C” shall precede the “E,” as “CE,” to designate
`“cyclic ethers.”
`For four-membered cyclic ethers, including three carbon
`and one ether oxygen atom, the root number designations for
`the hydrocarbon atoms shall be constructed according to the
`current standard for hydrocarbon nomenclature (subsection
`4.1).
`
`4.4 Blends shall be designated by their respective refriger-
`ant numbers and mass proportions. Refrigerants shall be
`named in order of increasing normal boiling points of the
`components. Compositions shall be specified to the nearest
`0.1% m/m. No component shall be permitted at less than 0.6%
`m/m nominal. For example, a 10/90 blend by mass of Refrig-
`erants 12 and 22 shall be indicated as R-22/12 (90.0/10.0) or
`Refrigerant 22/12 (90.0/10.0). A blend of 92% m/m R-502
`(the azeotrope of R-22 and R-115) with 8% m/m R-290 (pro-
`pane) shall be indicated as R-290/22/115 (8.0/44.9/47.1).
`4.4.1 Designation. Zeotropic blends shall be assigned an
`identifying number in the 400 series. Azeotropes shall be
`assigned an identifying number in the 500 series. To differ-
`entiate among blends having the same components with dif-
`ferent proportions (% m/m), an uppercase letter shall be
`added as a suffix in serial order of assignment. An example of
`a zeotrope would be R-401A, and an example of an azeotrope
`would be R-508A.
`4.4.2 Composition Tolerances. Blends shall have toler-
`ances specified for individual components. Those tolerances
`shall be specified to the nearest 0.1% m/m. The maximum
`tolerance above or below the nominal shall not exceed
`2.0% m/m. The tolerance above or below the nominal shall
`not be less than 0.1% m/m. The difference between the high-
`est and the lowest tolerances shall not exceed one-half of the
`nominal component composition.
`
`4.5 Miscellaneous organic compounds shall be assigned
`numbers in the 600 series in decadal groups, as outlined in
`Table 1, in serial order of designation within the groups.
`
`Inorganic compounds shall be assigned numbers in the
`4.6
`700 and 7000 series.
`4.6.1 For compounds with relative molecular masses less
`than 100, the number shall be the sum of 700 and the relative
`molecular mass, rounded to the nearest integer.
`4.6.2 For compounds with relative molecular masses
`equal to or greater than 100, the number shall be the sum of
`7000 and the relative molecular mass, rounded to the nearest
`integer.
`4.6.3 When two or more inorganic refrigerants have the
`same relative molecular masses, uppercase letters (i.e., A, B,
`C, etc.) shall be added, in serial order of designation, to dis-
`tinguish among them.
`
`5. DESIGNATION
`
`5.1 General. This section provides guidance on prefixes
`for refrigerants to improve uniformity in order to promote
`understanding. Both technical and nontechnical designations
`are provided, to be selected based on the nature and audience
`of the use.
`
`ANSI/ASHRAE STANDARD 34-2004
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`Page 7 of 91
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`Identification. Refrigerants shall be identified in
`5.2
`accordance with Section 5.2.1, 5.2.2, or 5.2.3. Section 5.2.1
`shall be used in technical publications (for international uni-
`formity and to preserve archival consistency), on equipment
`nameplates, and in specifications. Section 5.2.2 can be used
`for single-component halocarbon refrigerants, where distinc-
`tion between the presence or absence of chlorine or bromine
`is pertinent. Composition designation may be appropriate for
`nontechnical, public, and
`regulatory communications
`addressing ozone-depleting compounds. Section 5.2.3 can be
`used, under the same circumstances as Section 5.2.2, for
`blends (both azeotropic and zeotropic). Section 5.2.1 shall be
`used for miscellaneous organic and inorganic compounds.
`5.2.1 Technical Prefixes. The identifying number, as
`determined by Section 4, shall be preceded by the letter R, the
`word Refrigerant (Refrigerants if more than one), or the
`manufacturer’s trademark or trade name. Examples include:
`R 12, R-12, Refrigerant 12, <Trade Name> 12, <Trade
`Name> R 12, R-500, R-22/152a/114 (36/24/40), and R-717.
`Trademarks and trade names shall not be used to identify
`refrigerants on equipment nameplates or in specifications.
`5.2.2 Composition-Designating Pr