Sweating Thermal Hand
The sweating thermal hand instrumentation is designed to evaluate heat and moisture management properties of glove systems. This instrument simulates heat and sweat production making it possible to assess the influence of gloves on the thermal comfort process for a given environment. Simultaneous heat and moisture transport through the glove system, and variations in these properties over different areas of the hand can be quantified.
The hand manikin operates on the same principles as the sweating manikin system. It consists of several features designed to work together to evaluate glove comfort and / or heat stress. Housed in a climate-controlled chamber, the hand manikin surface is divided into 8 separate sections, each of which has its own sweating, heating, and temperature measuring system. Using a pump, preheated water is supplied from a reservoir located outside of the environmental chamber. An internal sweat control system distributes moisture to “sweat glands” distributed across the surface of the manikin. Water supplied to the simulated sweat glands is controlled by operator entry of the desired sweat rate. Each sweat gland is individually calibrated and the calibration values are used by the control software to maintain the sweat rate of each body section.
Continuous temperature control for the 8 hand segments is accomplished by a process control unit that uses analog signal inputs from separate Resistance Temperature Detectors (RTDs). These evenly distributed RTDs are used instead of point sensors because they provide temperature measurements in a manner such that all areas are equally weighted. Distributed over an entire section, each RTD is embedded just below the surface and provides an average temperature for each section. Software establishes any discrepancy between temperature set point and the input signal, and adjusts power to section heaters as needed.
Insulation and breathability of glove systems are measured following procedures for sweating thermal manikin testing adapted for testing of gloves on a hand manikin (ASTM F 1291 Standard Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin and ASTM F 2370 Standard Test Method for Measuring the Evaporative Resistance of Clothing Using a Sweating Manikin, respectively).
Heat Loss Potential (W/m2) is calculated for a standard environment by combining both the dry and sweating components of heat loss measured in their respective states.