Thermal perception of ventilation changes in full-face motorcycle helmets: subject and manikin study.

We report the effects of full-face motorcycle helmet ventilation systems on heat, airflow, noise, and comfort perception for ventilation changes on the scalp. Eight subjects (aged 28.0 ± 5.4 years) underwent two experimental trials at ambient temperatures of 23.7 ± 0.4 °C or 27.5 ± 0.3 °C. In each trial, the thermally equilibrated subjects underwent two examination phases, during which four different helmets were assessed at wind speeds of 39.2 ± 1.9 km h(-1) and 59.3 ± 1.4 km h(-1). Vent-induced heat loss in the scalp ranged from -6.1 to 6.1 W, corresponding to vents being closed or opened, respectively. Perception of vent-induced changes was assessed immediately after the change. We find that the vent-induced heat loss, the subject, and the helmet are the most important response factors. In addition, comparison of two helmets with similar vent-induced heat loss suggests that internal airflow patterns may be important in explaining the observed perception differences.