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BS ISO 817:2014 pdf free

BS ISO 817:2014 pdf free.Refrigerants一Designation and safety classification
An identifying number shall be assigned to each refrigerant. Assigned numbers and safety classifications are shown in Tables 5, 6 and 7. Tables E.4, E.5 and E.6 provide designations for refrigerants for which insufficient data are available for safety classification or determination of an ATEL or RCL value.
The identifying numbers assigned to the hydrocarbons, halocarbons and ethers of the methane,ethane, ethene, propane, propene and cyclobutane 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, ethene and most of the propane and propene series from only the identification number.
The carbon atoms shall be numbered with the number 1 assigned to the end carbon with the greatest number of halogen atoms, and the following carbon atoms are numbered sequentially as they appear on a straight chain. In the case where both end carbons contain the same number of (but different) halogen atoms, the number 1 shall be assigned to the end carbon having the largest number of bromine then chlorine then fluorine, and then iodine atoms. If the compound is an olefin, then the end carbon nearest to the double bond will be assigned the number 1, as the presence of a double bond in the back bone of the molecule has priority over substituent groups on the molecule.
In the case of isomers in the ethane series, each shall have the same number, with the most symmetrical one indicated by the number alone. As the isomers become more and more unsymmetrical,successive lower case 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 symmetrical the isomer.BS ISO 817 pdf free download.

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