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° 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 km 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 ∼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 industryUnderstanding (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.