The role of head tilt, hair and wind speed on forced convective heat loss through full-face motorcycle helmets:: A thermal manikin study

A thermal manikin headform was used to examine the effect of full-face motorcycle helmets on (primarily forced) convective heat loss under the following interventions: (i) a 30 degrees forward head tilt angle (six helmets), (ii) a wig installed between the headform and helmet (six helmets), and (iii) applied wind speeds ranging from 0-80 kin h(-1) (three helmets). In all interventions measurements were carried out for open and closed vents. The average convective heat loss was obtained from a steady state period under controlled ambient conditions. It was found that: (i) for many helmets a reduction in heat loss in the face section is found when tilting the head forward, (ii) the wig reduced the heat loss by a factor of similar to 2, and (iii) heat loss is approximately linearly dependent on wind speed (0-80 km h(-1)), with some exceptions below 30 km h(-1). Relevance to industry Understanding (forced convective) heat loss of motorcycle helmets is necessary for optimization of thermal comfort, which might influence the wearer's ability to concentrate, as well as his/her desire to wear a helmet. The complexity of the problem requires the study of several parameters. (C) 2008 Elsevier B.V. All rights reserved.