Thermal radiation is a significant factor affecting comfort microclimatic conditions of different man-made environments. Mean radiant temperature (Tmrt) is a major indicator for prediction of comfort conditions in an enclosure with different surface temperatures.

Calculation of the mean radiant temperature within an enclosure is based on a manual method, developed by P.O. Fanger, for generating the angle factor of a person and a surface within a rectilinear enclosure, only. However, simple rectilinear enclosures are not truly indicative of modern architecture. Geometric reduction of complex enclosures to simple rectilinear shapes is time consuming and inaccurate.

This paper describes a method for developing angle factors from a person to an inclined surface in front of and above his center and to the rear and below his center. The method of solution parallels that used by Fanger to generate angle factors for horizontal and vertical surfaces. The determination of angle factors from a person to an inclined surface is necessary for determining thermal comfort within complex enclosures.