Determination of Heat Transfer Coefficients for Appication of Human Heat Stress Assessment

The effective heat transfer around the segments of the human body varies depending on the dimension and orientation of the body concerned in the wind flow, the inertial and the viscous properties of the air. The physiological methods in determining heat transfer are direct calorimetry, partition calorimetry, mathematical modeling of heated wet skin, etc. These techniques have limitations as to the well-designed laboratory setup, equipment used and limitations of open field applicability. With the concept of mass transfer through naphthalene sublimation principle, direct determination of heat transfer coefficients of the human was undertaken and the mathematical aspects of heat exchange phenomena have been worked out. This allows determination of heat transfer under conditions of different types of physical activity and, therefore, the technique has field application in terms of heat stress assessment in industry. However, there is a need for extensive validation of the methodology in well-designed experimental set up. The development is primarily of theoretical in nature and an addition to the existing knowledge. A Well-designed calibration procedure allows reproducibility of results.