Standard ISO 7730, which is also known as European Standard EN-ISO 7730, provides two alternative methods for the evaluation of the predicted mean vote (PMV) index: a calculation program and a set of tables. In order to use the tables, the operative temperature must be calculated beforehand. The impres sion is given from reading the standard that for a relative humidity of 50%, the two methods are equivalent, i.e. provide the same value for PMV, from the same initial values. In this paper, examples are given showing that the two methods are not equivalent. Differences between them are analysed and a proposal made to introduce an amendment in the next revision of the stan dard.
ISO: Moderate Thermal Environments: Determination of the PMV and PPD Indices and Specifications of the Conditions for Thermal Comfort. ISO Standard 7730, ed. 2. Geneva, International Standard Organization, 1992.
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CEN: Moderate Thermal Environments: Determination of the PMV and PPD Indices and Specification of the Conditions for Thermal Comfort. EN-ISO 7730. Brussels, CEN, 1995.
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Ashrae: ANSI/ASHRAE Standard 55-1992. Atlanta, American Society of Heating, Refrigerating, and Air Conditioning Engineers Inc.
