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Ref. No. : ISO/R 817-1968 (E)
IS0
I N T E R N AT I O N A L ORGAN I Z AT 1 O N FOR S TA N DARD IZATl O N
IS0 RECO M M EN DATIO N
.
R 817
NUMBER DESIGNATION OF ORGANIC REFRIGERANTS
1st EDITION
September 1968
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the oniy valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 81 7, Number designation of organic refrigerants, was drawn up by
Technical Committee ISO/TC 86, Refigeration, the Secretariat of which is held by the British
Standards Institution (BSI).
Work on this question by the Technical Committee began in 1960 and led, in 1966, to the
adoption of a Draft IS0 Recommendation. I
In March 1967, this Draft IS0 Recommendation (No. 1152) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
Greece Switzerland
Argentina
Hungary Thailand
Australia
Belgium Ireland U.A.R.
Canada Israel United Kingdom
Chile Italy U.S.A.
U.S.S.R.
Czechoslovakia Japan
Yugoslavia
Denmark New Zealand
France Poland
Germany Sweden
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in September 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 817-1968 (
IS0 Recommendation R 817 September 1968
NUMBER DESIGNATION OF ORGANIC REFRIGERANTS
1. SCOPE
This IS0 Recommendation is intended to cstablish a simple svstem of referring to common organic
refrigerants instead of using the chemical name, formula or trade name. Although the use of a
number for each refrigerant covered is a concise and accurate way of designating the refrigerant, there
is no intention of precluding the use of a chemical name or formula.
2. DEFINITIONS
2.1 Refrigerant. As covered in this IS0 Recommendation, is the medium of heat transfer in a
refrigerating system which absorbs heat by evaporating at a low temperature and a low pressure,
and gives up heat on condensing at a higher temperature and pressure.
2.2 Compound. A substance formed by a union of two or more elements in definite proportions by
mass.
2.3 Iivdrocarbon. A compound containing only the elements hydrogen and carbon.
2.4 ifalocarbon. Used to define a halogenated hydrocarbon containing one or more of the following
four halogens : fluorine. chlorine, bromine, and iodine.
2.5 Isomer. One of a group of compounds having the same combination of elements, but arranged
spatially in different ways.
2.6 Mixture. A complex of two or more compounds which do not bear a fixed proportion to one
another, and which. however thoroughly mixed together, retain a separate existence.
2.7 Azeotrope. A mixture of refrigerants whose vapour and liquid phases have identical composi-
tions at a given temperature.
3. CLASSIFICATION
Refrigerants are classified as indicated in the nomenclature given in the Table, pages 6, 7 and 8. Other
refrigerants will be added through subsequent revisions.
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ISO/R 817-1968 (E)
4. NUMBERING SYSTEM
4.1 An identifying number should be assigned to each organic refrigerant within the scope of this
IS0 Recommendation.
The identifying numbers assigned to the hydrocarbons and halocarbons of the methane, ethane,
propane, and cyclobutane series are such that the structure of the compounds may be deduced
from the refrigerant numbers, and vice versa, without ambiguity. The rules of the fixed
number systems are as follows :
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 com-
pound. When this digit is zero, it is omitted from the number.
4.1.4 The number of chlorine (Ci) atoms in the compound is found by subtracting the sum of the
fluorine (F) and hydrogen (H) atoms from the total number of atoms which can be
connected to the carbon (C) atoms.
When only 1 carbon atom is present, the total number of attached atoms is 4. When 2
carbon atoms are present, the total number of attached atoms is 6, unless the compound is
unsaturated; in this case, the total number of attached atoms is 4.
For saturated hydrocarbons, the total number of attached atoms is the followirig :
For 1 C, the total number of atoms is 4
For 2 C, the total number of atoms is 6
For 3 C, the total number of atoms is 8
For 4 C, the total number of atoms is 10, etc.
For n C, the total number of atoms is 2n + 2.
For mono-unsaturated and cyclic saturated hydrocarbons, the total number of attached
atoms is the following :
For 2 C, the total number of atoms is 4
For 3 C, the total number of atoms is 6
For 4 C, the total number of atoms is 8
For 5 C, the total number of atoms is 10, etc.
For n C, the total number of atoms is 2n.
4.1.5 For cyclic derivatives the letter C is used before the identifying refrigerant number.
I
4.1.6 In those instances where bromine is present in place of part or all of the chlorine, the same
rules apply except that the letter B after the designation for the parent chloro-fluoro com-
pound shows the presence of bromine (Br). The number following the letter B shows the
number of bromine atoms present.
4.1.7 In the case of isomers of the ethane series, each has the same number and the most sym-
metrical one is indicated by the number without any letter following it. As the isomers
become more and more unsymmetrical, the letters a, b, c, etc., are appended. Symmetry is
determined by adding the atomic masses of the groups of elements attached to each carbon
atom and subtracting one sum from the other. The smaller the difference, the more
symmetrical the product.
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ISO/R 817
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