Performance Evaluations of Micro-Climate Cooling Products (original) (raw)
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Evaluating the Effectiveness of Cooling Vest in a Hot and Humid Environment
Annals of work exposures and health, 2017
This study aims to evaluate the effectiveness of a newly designed hybrid cooling vest for construction workers in alleviating heat stress. Two types of cooling vests, namely, a commonly worn Vest A and a newly designed Vest B, were tested in a climatic chamber environment (34.0°C temperature, 60% relative humidity, and 0.4 m s-1 air velocity) using a sweating thermal manikin. Four test scenarios were included: fan off with no phase change materials (PCMs) (Fan-off), fan on with no PCMs (Fan-on), fan off with completely solidified PCMs (PCM + Fan-off), and fan on with completely solidified PCMs (PCM + Fan-on). Test results showed that Vests A and B provided a continuous cooling effect during the 3-h test. The average cooling power for the torso region of Vest B was 67 W, which was higher than that of Vest A (56 W). The addition of PCMs offered a cooling effect of approximately 60 min. Ventilation fans considerably improved the evaporative heat loss compared with the Fan-off condition...
Cooling efficiency of vests with different cooling concepts over 8-hour trials
Ergonomics
As frequency and severity of heat waves are increasing, personal cooling systems are being considered as a tool to mitigate heat strain in workers in various occupational settings. This study assessed cooling capacities (C; WÁhÁm À2) of various commercially available vests using different cooling concepts. Measurements were conducted over 8 h in a climatic chamber (Ta: 35 C, RH: 35 %) using a thermal manikin (Ts: 35 C). Cooling power (P) and duration of efficient cooling (t c) determined the C value of each vest. Among the cooling concepts the active cooling vests were the most efficient, extracting 331 WÁhÁm À2 , followed by the vests with phase change material (PCM) inserts, hybrid and evaporative vests, extracting a maximum of 164 WÁhÁm À2 , 146 WÁhÁm À2 and 113 WÁhÁm À2 , respectively. While some vests with PCM inserts provided intense but shorter cooling, evaporative vests provided mild but longer cooling throughout.
International journal of occupational safety and ergonomics : JOSE, 2004
The aim of the study was to examine the effects of wearing an ice-vest (ca 1 kg) on physiological and subjective responses in fire fighters. The experiments were carried out on a treadmill in a hot-dry environment. The physical cooling effect of the ice-vest was measured with a thermal manikin. The ice-vest effectively reduced skin temperatures under the vest. On average, heart rate was 10 beats/min lower, the amount of sweating was reduced by 13%, and subjective sensations of effort and warmth were lower during work with the ice-vest compared to work without it. Thermal manikin tests indicated that the useful energy available from the vest for body cooling was rather high (58%). In conclusion, the ice-vest reduces physiological and subjective strain responses during heavy work in the heat, and may promote efficient work time by 10%.
Prehospital Emergency Care, 2010
Background-Thermal protective clothing (TPC) worn by firefighters provides considerable protection from the external environment during structural fire suppression. However, TPC is associated with physiological derangements that may have adverse cardiovascular consequences. These derangements should be treated during on-scene rehabilitation periods. Objective-The present study examined heart rate and core temperature responses during the application of four active cooling devices, currently being marketed to the fire service for on-scene rehab, and compared them to passive cooling in a moderate temperature (approximately 24°C) and to an infusion of cold (4°C) saline. Methods-Subjects exercised in TPC in a heated room. Following an initial exercise period (BOUT 1) the subjects exited the room, removed TPC, and for 20 minutes cooled passively at room temperature, received an infusion of cold normal saline, or were cooled by one of four devices (fan, forearm immersion in water, hand cooling, water perfused cooling vest). After cooling, subjects donned TPC and entered the heated room for another 50-minute exercise period (BOUT 2). Results-Subjects were not able to fully recover core temperature during a 20-minute rehab period when provided rehydration and the opportunity to completely remove TPC. Exercise duration was shorter during BOUT 2 when compared to BOUT 1 but did not differ by cooling intervention. The overall magnitude and rate of cooling and heart rate recovery did not differ by intervention. Conclusions-No clear advantage was identified when active cooling devices and cold intravenous saline were compared to passive cooling in a moderate temperature after treadmill exercise in TPC.
The physiological impact of body armor cooling devices in hot environments: a systematic review
Military medicine, 2014
Heat-related illness is a primary threat to unit readiness, and individual body armor (IBA) cooling devices represent one potential solution. To quantify research findings of active and passive cooling devices designed to reduce physiological strain while wearing IBA during strenuous tasks using a systematic review approach. Literature searches were performed in multiple databases using the key words "physiological," "body armor," "military," "cooling," and "thermal." Two independent reviewers appraised methodological quality using a modified Downs and Black Quality Index. Physiological outcomes were tabulated and effect sizes were calculated when appropriate. The search yielded 733 citations, with nine articles fitting our inclusion criteria: six articles with active and three articles with passive cooling devices. Results reveal a moderate level of methodological quality. On average, all six active IBA cooling device studies compar...
Reduction of physiological strain under a hot and humid environment by a hybrid cooling vest
Journal of strength and conditioning research, 2017
Cooling treatment is regarded as one of good practices to provide safe training conditions to athletic trainers in the hot environment. The present study aimed to investigate whether wearing a commercial lightweight and portable hybrid cooling vest that combines air ventilation fans with frozen gel packs was an effective means to reduce participants' body heat strain. In this within-subject repeated measures study, 10 male volunteers participated in two heat-stress trials (one with the cooling vest - COOL condition, and another without - CON condition, in a randomized order) inside a climatic chamber with a controlled ambient temperature 33 °C and relative humidity (RH) 75% on an experimental day. Each trial included a progressively incremental running test, followed by a 40 min post-exercise recovery. Core temperature (Tc), heart rate (HR), sweat rate, rating of perceived exertion (RPE), exercise duration, running distance, power output, and sweat rate were measured. When compa...
Prehospital Emergency Care, 2013
Most duties performed by firefighters require the use of personal protective equipment, which inhibits normal thermoregulation during exertion, creating an uncompensable heat stress. Structured rest periods are required to correct the effects of uncompensable heat stress and ensure that firefighter safety is maintained and that operations can be continued until their conclusion. While considerable work has been done to optimize firefighter cooling during fireground operations, there is little consensus on when or how cooling should be deployed. A systematic review of cooling techniques and practices among firefighters and hazardous materials operators was conducted to describe the state of the science and provide recommendations for deploying resources for fireground rehab (i.e., structured rest periods during an incident). Five electronic databases were searched using a selected combination of key words. One hundred forty publications were found in the initial search, with 27 meeting all the inclusion criteria. Two independent reviewers performed a qualitative assessment of each article based on nine specific questions. From the selected literature, the efficacy of multiple cooling strategies was compared during exertion and immediately following exertion under varying environmental conditions. When considering the literature available for cooling firefighters and hazardous materials technicians during emergency incident rehabilitation, widespread use of cooling devices does not appear to be warranted if ambient temperature and humidity approximate room temperature and protective garments can be removed. When emergency incident rehabilitation must be conducted in hot or humid conditions, active cooling devices are needed. Hand/forearm immersion is likely the best modality for cooling during rehab under hot, humid conditions; however, this therapy has a number of limitations. Cooling during work thus far has been limited primarily to cooling vests and liquid-or air-cooled suits. In general, liquid-perfused suits appear to be superior to air-cooled garments, but both add weight to the firefighter, making current iterations less desirable. There is still considerable work to be done to determine the optimal cooling strategies for firefighters and hazardous materials operators during work.
Extremity cooling for heat stress mitigation in military and occupational settings
Journal of Thermal Biology, 2013
Physical work, high ambient temperature and wearing protective clothing can elevate body temperature and cardiovascular strain sufficiently to degrade performance and induce heat-related illnesses. We have recently developed an Arm Immersion Cooling System (AICS) for use in military training environments and this paper will review literature supporting such an approach and provide details regarding its construction. Extremity cooling in cool or cold water can accelerate body (core temperature) cooling from 0.2 to 1.0 1C/10 min vs. control conditions, depending on the size/surface area of the extremity immersed. Arm immersion up to the elbow results in greater heat loss than hand-or foot-only immersion and may reduce cardiovascular strain by lowering heart rate by 10-25 beats/min and increase work tolerance time by up to 60%. The findings from studies in this paper support the use of AICS prototypes, which have been incorporated as part of the heat stress mitigation procedures employed in US Army Ranger Training and may have great application for sports and occupational use.