Effective temperature scale useful for hypo- and hyperbaric environments

Area of Science:

• Human physiology
• Environmental science
• Thermodynamics

Background:

• Human heat exchange involves radiation, convection, evaporation, and conduction.
• Clothing significantly impacts thermal comfort and physiological responses.
• Existing scales like Effective Temperature (ET) are limited in scope.

Purpose of the Study:

• To establish a Standard Effective Temperature (SET) scale for human thermal comfort.
• To relate sensory and physiological responses to environmental conditions.
• To validate the SET scale across a wide range of barometric pressures.

Main Methods:

• Utilized basic physics of heat exchange through clothing.
• Defined SET based on an isothermal enclosure with specific humidity and air velocity.
• Employed a 2-node model of human temperature regulation and partitional calorimetry.
• Assessed thermal equivalence using mean body temperature (Tb) across environments.

Main Results:

• The SET scale effectively relates physiological and sensory responses to environmental factors.
• Mean skin temperature (Tsk) and skin wettedness (w) are linked to thermal comfort and heat exchange.
• The model demonstrates predictable interactions between SET and environmental/clothing factors.
• The SET scale is applicable across barometric pressures from 0.33 to 30 ATA.

Conclusions:

• The Standard Effective Temperature (SET) scale provides a unified measure for human thermal responses.
• SET is a valuable tool for assessing thermal comfort and physiological strain in diverse environments.
• The findings are crucial for understanding human performance in hypo- and hyperbaric conditions.