Outdoor Human Comfort and Its Assessment

Prepared by the Task Committee on Outdoor Human Comfort of the Aerodynamics Committee of ASCE. This report describes state-of-the-art methods for assessing and improving outdoor human comfort. Factors affecting outdoor comfort are wind, air temperature, humidity, sun, and precipitation. Wind, in particular, is greatly affected by large buildings, and many modern developments are wind-tunnel tested to examine how wind flows around new buildings will affect pedestrians. This report discusses testing methods and criteria for assessing comfort and safety. Criteria are expressed in terms of both threshold wind speeds for discomfort and also the percentage of time that conditions should be below those thresholds. Historically, wind and its mechanical effects—such as picking up dust, impairing balance, or blowing people over—were the factors receiving the most attention. More recently, however, methods have been developed to address other factors, such as solar radiation, air temperature, and humidity. Topics include: elements of the microclimate; methods of determining wind conditions; wind criteria and control measures; and assessing thermal comfort.