Assessment of the Thermal Effectiveness of Mineral Warmers for Protective Gloves Used in Cold Environments

Abstract

The objective of the study was to assess the thermal effectiveness of mineral warmers for protective gloves used in cold environments. The study material consisted of protective gloves integrated with mineral warmers, constituting chemical heating garments (CHGs). The mineral warmers differed in terms of the amount of active mineral compounds and geometry. The warmers were applied in three protective glove that met the thermal insulation requirements stipulated in the standard EN 511:2006. The thermal effects associated with glove design and mineral warmer geometry were evaluated by recording temperature changes inside gloves placed in a climatic chamber. Continuous tests were conducted for 6 h under dynamic conditions simulating the work cycle with measurement intervals of varying length under selected ambient temperatures (-15°C,-10°C, 0°C, 5°C, 10°C) and a relative humidity of 60±5%. The results were statistically evaluated using analysis of variance (ANOVA) in order to identify differences in thermal effect between the gloves depending on the type of mineral warmers, glove design, and ambient temperature of the work environment. It was found that the use of mineral warmers significantly increased the temperature inside all the studied models of protective gloves. The smallest amount of thermoactive mixture (10 g) was insufficient to maintain thermal comfort over the adopted work period of 6 h. The optimum amount of mineral compounds ensuring a good thermal effect for periods shorter than the adopted 6 h work cycle was 20 g for the proposed warmer package design.

Modeling and Experimental Verification of the Required Power for Electrically Heated Clothing

“…Evaluation of heating performance using other methods has also been reported in the literature, albeit the approaches rarely addressed the question of thermal comfort in real-life scenarios. For example, in [16] the authors evaluated effectiveness of warmers for gloves by recording temperature changes inside gloves placed in a climatic chamber; no subjective human factor was introduced in the experiment. Some effort has also been put into determination of the most suitable placement of heating insets.…”