26
2 Review of Literature: Motorcycle helmet
studied the effect of tinted helmet visors on facial warming and showed that visor
tinting reduces the actual and perceived heat load of the motorcycle rider by reducing
the transmission of solar radiation.
It is a well-known fact that 30% of the body’s heat dissipation takes place through
the head when the body is at rest. As the level of work is increased, the proportion of
heat dissipation through the head is decreased. Still, heat dissipation in this manner
has a considerable bearing on comfort. Up to now, very little research has been done
to investigate the amount by which the helmets restrict the flow of heat. Nielsen
[90] found the main cause of heat stress is a high core temperature, which affects
the functioning of motor centres and decreases muscular activity. The subsequent
response of the body to heat stress is known as heat strain, which can be evaluated by
biomechanical, physiological and psychological factors. The size of these responses
determines the degree of heat stress to which the body is subjected [91].
Heat stress due to a hot environment can lead to heat disorders from irritations
and to fatal conditions [91]. Work in hot environments, in both dry and humid conditions, causes poor motor control function and degrades mental performance well in
advance of any deterioration of physical performance [92]. Bogerd and Brühwiler
[93] investigated the heat loss variations of full face motorcycle helmets by using
head forms, which were electrically heated and placed at the exit of a wind tunnel.
They observed a large variation in heat loss among the 27 helmets they investigated.
They identified that the constructional features of helmets play an important role in
heat loss.
Fonseca [94] studied the heat transfer properties of military helmets and observed
that the evaporation of sweat increased as the standoff distance of the helmet from
the head was increased. Roszkowski [95] studied industrial helmets from different
countries and concluded that the ability to allow sweat evaporation varied with the
design of the helmets. Brühwiler studied the effect of wind on the heat loss of
motorcycle helmets and observed that the heat loss from the scalp section of a manikin
head was very low. However, it was observed that in the face there was a 20%
variation in heat loss [35]. Chinn et al. [96] suggested that wearing a motorcycle
helmet can influence the cognitive performance of a motorcyclist. The concentration
of the motorcyclist can be affected by the heat, moisture and carbon dioxide (CO 2 )
produced within a closed helmet.
It has been proven that there is considerable thermal discomfort in bicycle helmets
[26], similarly for industrial helmets [97], and the same can be expected for motorcycle helmets [89]. Kamin and Scalone [98] investigated the importance of comfort
and found that, in the United States of America, the poor standard of comfort in
industrial helmets was due to rigid suspension systems that did not fit the head properly. Proctor [99] reviewed industrial safety helmets with respect to comfort, stability,
acceptability, statistics and impact considerations. He found that the area for development of these helmets was comfort and the durability of the injection-moulded
plastics used in manufacturing the helmets. Various researchers have studied the
thermal discomfort associated with wearing a helmet [100–102].
Kim and Park [78] studied safety hats and showed that the ventilation through the
holes in the hats reduced the increase in temperature of the head. The temperature
2 Review of Literature: Motorcycle helmet
studied the effect of tinted helmet visors on facial warming and showed that visor
tinting reduces the actual and perceived heat load of the motorcycle rider by reducing
the transmission of solar radiation.
It is a well-known fact that 30% of the body’s heat dissipation takes place through
the head when the body is at rest. As the level of work is increased, the proportion of
heat dissipation through the head is decreased. Still, heat dissipation in this manner
has a considerable bearing on comfort. Up to now, very little research has been done
to investigate the amount by which the helmets restrict the flow of heat. Nielsen
[90] found the main cause of heat stress is a high core temperature, which affects
the functioning of motor centres and decreases muscular activity. The subsequent
response of the body to heat stress is known as heat strain, which can be evaluated by
biomechanical, physiological and psychological factors. The size of these responses
determines the degree of heat stress to which the body is subjected [91].
Heat stress due to a hot environment can lead to heat disorders from irritations
and to fatal conditions [91]. Work in hot environments, in both dry and humid conditions, causes poor motor control function and degrades mental performance well in
advance of any deterioration of physical performance [92]. Bogerd and Brühwiler
[93] investigated the heat loss variations of full face motorcycle helmets by using
head forms, which were electrically heated and placed at the exit of a wind tunnel.
They observed a large variation in heat loss among the 27 helmets they investigated.
They identified that the constructional features of helmets play an important role in
heat loss.
Fonseca [94] studied the heat transfer properties of military helmets and observed
that the evaporation of sweat increased as the standoff distance of the helmet from
the head was increased. Roszkowski [95] studied industrial helmets from different
countries and concluded that the ability to allow sweat evaporation varied with the
design of the helmets. Brühwiler studied the effect of wind on the heat loss of
motorcycle helmets and observed that the heat loss from the scalp section of a manikin
head was very low. However, it was observed that in the face there was a 20%
variation in heat loss [35]. Chinn et al. [96] suggested that wearing a motorcycle
helmet can influence the cognitive performance of a motorcyclist. The concentration
of the motorcyclist can be affected by the heat, moisture and carbon dioxide (CO 2 )
produced within a closed helmet.
It has been proven that there is considerable thermal discomfort in bicycle helmets
[26], similarly for industrial helmets [97], and the same can be expected for motorcycle helmets [89]. Kamin and Scalone [98] investigated the importance of comfort
and found that, in the United States of America, the poor standard of comfort in
industrial helmets was due to rigid suspension systems that did not fit the head properly. Proctor [99] reviewed industrial safety helmets with respect to comfort, stability,
acceptability, statistics and impact considerations. He found that the area for development of these helmets was comfort and the durability of the injection-moulded
plastics used in manufacturing the helmets. Various researchers have studied the
thermal discomfort associated with wearing a helmet [100–102].
Kim and Park [78] studied safety hats and showed that the ventilation through the
holes in the hats reduced the increase in temperature of the head. The temperature