Modern research in thermal comfort can trace its origin from the early work of Prof. John Sheppard of Teachers' Normal College in Chicago who introduced the concept of the "comfort zone" in 1923, through the contributions of such names as Houghton, Yaglou, Drinker, Koch, Jennings, and Humphrey, to the revalidation of the Cleveland Standards in 1966 by Nevins and his associates at Kansas State University. (1) All of this work is summarized in detail by Nevins in a paper in which he traces the "criteria for thermal comfort" from the early 1900s to the present; this chronology, which is adapted from this paper is reproduced in Table.1. (2)

One of the results of this comprehensive re-evaluation of the Cleveland Standard was the development of a new baseline comfort chart which served as the basis for the 77 to 79.5 F dbt cccomfort range reported in Table.1. The "comfortable" line on this chart was determined by developing an equation by the method of least squares; however, examination of this chart together with a knowledge of the data contributing to its construction identified several points of serious concern and indeed served as the impetus for the present study.