Conclusions
A summary of the statistical analyses is presented in Table 5. Heat transmitted from the skin to the
environment through clothing consists of two parts: dry heat transfer (conduction, convection, and
radiation) and evaporative heat transfer (Celcar et al., 2008; Chen et al., 2003). Intrinsic clothing
insulation is the measurement of resistance to dry heat transfer, and intrinsic clothing evaporative
resistance is the measurement of resistance to evaporative heat transfer. Regardless of the armor
system, the results indicate that with similar protection level, the ballistic material, Dyneema, consistently
measured lower in intrinsic clothing insulation and intrinsic clothing evaporative resistance
than the ballistic material, Kevlar. This finding indicates that Dyneema would be a good choice of
ballistic material to use in future body armor systems, including the ballistic vest worn by soldiers.
When considering armor systems, QG II tended to measure lower in both intrinsic clothing insulation
and intrinsic clothing evaporative resistance as compared to QG IV Ventilated and QG IV Not
Ventilated. However, statistically, there was no significant difference between QG II and QG IV Ventilated
in Rcl and there was no significant difference between the three armor systems in Recl. SinceQG
II covers the least amount of surface area and provides the least amount of protection, it would be
expected that QG II would measure the lowest in both intrinsic clothing insulation and evaporative
resistance. Statistical comparisons in Rcl and Recl indicate that design features such as ventilation have
the potential to reduce thermal stress on the human body when protective clothing is necessary.
The ballistic material, Kevlar, retained a lower amount of moisture than Dyneema though there
were more layers of Kevlar than Dyneema for the same level of protection. One possible reason was
that Kevlar is balanced plain weave fabric while Dyneema is a nonwoven fabric. Moisture was accumulated
between the layers of Dyneema and was not able to escape due to the nonwoven structure.
The higher moisture retain in Dyneema may also contribute to the lower Rcl since water has lower
thermal insulation than air.
ConclusionsA summary of the statistical analyses is presented in Table 5. Heat transmitted from the skin to theenvironment through clothing consists of two parts: dry heat transfer (conduction, convection, andradiation) and evaporative heat transfer (Celcar et al., 2008; Chen et al., 2003). Intrinsic clothinginsulation is the measurement of resistance to dry heat transfer, and intrinsic clothing evaporativeresistance is the measurement of resistance to evaporative heat transfer. Regardless of the armorsystem, the results indicate that with similar protection level, the ballistic material, Dyneema, consistentlymeasured lower in intrinsic clothing insulation and intrinsic clothing evaporative resistancethan the ballistic material, Kevlar. This finding indicates that Dyneema would be a good choice ofballistic material to use in future body armor systems, including the ballistic vest worn by soldiers.When considering armor systems, QG II tended to measure lower in both intrinsic clothing insulationand intrinsic clothing evaporative resistance as compared to QG IV Ventilated and QG IV NotVentilated. However, statistically, there was no significant difference between QG II and QG IV Ventilatedin Rcl and there was no significant difference between the three armor systems in Recl. SinceQGII covers the least amount of surface area and provides the least amount of protection, it would beexpected that QG II would measure the lowest in both intrinsic clothing insulation and evaporative
resistance. Statistical comparisons in Rcl and Recl indicate that design features such as ventilation have
the potential to reduce thermal stress on the human body when protective clothing is necessary.
The ballistic material, Kevlar, retained a lower amount of moisture than Dyneema though there
were more layers of Kevlar than Dyneema for the same level of protection. One possible reason was
that Kevlar is balanced plain weave fabric while Dyneema is a nonwoven fabric. Moisture was accumulated
between the layers of Dyneema and was not able to escape due to the nonwoven structure.
The higher moisture retain in Dyneema may also contribute to the lower Rcl since water has lower
thermal insulation than air.
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