2007, Piran, Slovenia

Personal protective equipment
THERMAL COMFORT RANGE OF A MILITARY COLD
PROTECTION GLOVE – DATABASE BY THERMOPHYSIOLOGICAL
SIMULATION
Carsten Zimmermann 1 , Wolfgang H. Uedelhoven 1 , Bernhard Kurz 2 , Karl Jochen Glitz 3
1 Bundeswehr Research Institute for Materials, Explosives and Lubricants, Erding, Germany
2 Institute for Applied Ergonomics, Munich, Germany
3 Central Institute of the Federal Armed Forces Medical Services, Koblenz, Germany
Contact person: carsten1zimmermann@bundeswehr.org
INTRODUCTION
The European Standard EN342 describes the requirements for cold protective clothing.
Handwear, however, is excluded because of the special sensitivity of hands against cooling
and frostbite. Basic requirements (e.g. thermal isolation values) and testing procedures for
protective gloves against cold are summarized in the European Standard EN511. Based on the
standards, it was the aim of this study to create a more detailed database for the thermal
comfort range of a special military glove by thermophysiological simulation, comparable to
the procedure known from the evaluation of the cold protective properties of sleeping bags.
METHODS
The human-physiological simulation device CYBOR (Cybernetic Body Regulation) is
equipped with a control feature, that is intended to give reliable predictions of the thermal
comfort range of handwear systems. The heat flow into the hand phantom is controlled as a
function of the skin temperature of the phantom between 31°C to 15°C (Zimmermann et. al.,
2006). It was shown in wear trials, that the skin temperature is a nearly linear function of the
perfusion of the fingers, due to vasoconstriction, hand blood flow is reduced down to about
30% at 15 o C, compared to the value at 31°C (Glitz et. al., 2005). A mean temperature of 15°C
is said to be the lowest acceptable skin temperature for sufficient manual skill and thermal
self-perceived comfort (Heus et al., 1995). The lower limit Tmin of the predicted thermal
comfort range of the cold protective glove can, therefore, be taken from plots of skin
temperature Tskin as a function of outside temperature at the point where Tskin equals 15°C of
the phantom, in dependence on the metabolic rate. In a second step, a maximum time period
for wearing the cold protective gloves within the thermal comfort range under various
boundary conditions was estimated. Assuming different metabolic rates and a given
environmental temperature, the criterion that defines this maximum period of the thermal
comfort range is the time duration during which an average skin temperature of at least 15 o C
can be maintained. Similar to that procedure, the maximum period of the thermal comfort
range was estimated for a selected metabolic rate and various environmental temperatures as
well. The special military glove for wet and cold protection under investigation is equipped
with a 3-layer laminate, Primaloft ® wadding and a X-static ® lining.
RESULTS AND DISCUSSION
As the hands are extremities with only little muscle, and a very low intrinsic heat production,
it is important that they have a continuous heat (blood) supply from the body core. Due to the
strong dependence of the thermal heat balance of hands (and feet as well) on the arterial blood
flow (perfusion) as the main heat source, it is very complicated to make reliable predictions of
the thermal comfort range of handwear under certain climatic conditions. Equipping military
personnel for out of area operations under extreme climatic conditions, however, requires an
evaluation of the performance of the clothing to be worn to make a preselection of garments.
Taking into account different boundary conditions like metabolic rate, environmental
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