The perceived temperature – a versatile index for the assessment of the human thermal environment. Part A: scientific basics

Abstract

The Perceived Temperature (PT) is an equivalent temperature based on a complete heat budget model of the human body. It has proved its suitability for numerous applications across a wide variety of scales from micro to global and is successfully used both in daily forecasts and climatological studies. PT is designed for staying outdoors and is defined as the air temperature of a reference environment in which the thermal perception would be the same as in the actual environment. The calculation is performed for a reference subject with an internal heat production of 135 W m(-2) (who is walking at 4 km h(-1) on flat ground). In the reference environment, the mean radiant temperature equals the air temperature and wind velocity is reduced to a slight draught. The water vapour pressure remains unchanged. Under warm/humid conditions, however, it is implicitly related to a relative humidity of 50%. Clothing is adapted in order to achieve thermal comfort. If this is impossible, cold or heat stress will occur, respectively. The assessment of thermal perception by means of PT is based on Fanger's Predicted Mean Vote (PMV) together with additional model extensions taking account of stronger deviations from thermal neutrality. This is performed using a parameterisation based on a two-node model. In the cold, it allows the mean skin temperature to drop below the comfort value. In the heat, it assesses additionally the enthalpy of sweat-moistened skin and of wet clothes. PT has the advantages of being self-explanatory due to its deviation from air temperature and being--via PMV--directly linked to a thermo-physiologically-based scale of thermal perception that is widely used and has stood the test of time. This paper explains in detail the basic equations of the human heat budget and the coefficients of the parameterisations.

High-resolution grids of hourly meteorological variables for Germany

“…Section 4.3 describes some application examples such as the quantification of extreme years. In the final sub-section, the derived dataset is applied by way of example to derive perceived temperature (Staiger et al 2012), illustrated by the Rhine-Main area. Fig.…”

“…The RayMan bio-climate model (Matzarakis et al 2010) was run in the Rhine-Main area with the gridded climate variables air temperature, relative humidity, global radiation and cloud cover, to obtain perceived temperature (Staiger et al 2012) on 14.07.1995 at 5 UTC (Fig. Fig.…”

Adaptive Outdoor Thermal Comfort at an Urban Park in Malaysia

“…While neutrality temperature is the temperature at which people feel comfortable, preferred temperature is the temperature people want (Staiger et al, 2012). The concept of thermal comfort is closely related to thermal stress.…”

Reducing Individual Heat Stress through Path Planning

“…Staiger, Bucher and Jendritzky (1997) state that only a complete heat budget model of the human body is sufficient to make any reliable statement regarding the influence of heat on the body. The heat budget model of the human body is a simplified model that describes how the internal heat production of the human organism must be balanced with the environment by heat exchange, for instance through skin or respiration (Staiger, Laschewski, & Grätz, 2012). Some well-known indices that consider a complete human heat budget model are (1) Steadman's heat index (Steadman, 1979a;1979b), (2) the predicted mean vote (Fanger, 1973), (3) the perceived temperature (Staiger, Bucher, & Jendritzky, 1997;Jendritzky, Staiger, Bucher, Graetz, & Laschewski, 2000), and (4) the universal thermal climate index UTCI (Jendritzky, et al, 2010).…”