2014-05-01 12:00 - Messages

Assessment of the human responses to the influence of personal liquid cooling system in the hot environment

Purpose – People working in the hot environment are constantly exposed to the overheating, that can lead to cardiovascular disorders and as a consequence result in occupational diseases. The purpose of this paper is to present developed personal liquid cooling system that is able to efficiently draw excess heat from the human organism, protecting against thermal stress.
Design/methodology/approach – The paper presents study concerning the assessment of effect of the coolant temperature in the developed liquid cooling garment (LCG) on physiological parameters of the subjects (heart rate, body temperature, skin temperature) and parameters of the undergarment microclimate, as well as subjective sensations reported by volunteers exercising in hot microclimate while wearing LCG and without LCG.
Findings – Obtained results of physiological parameters measurements, as well as undergarment physical parameters and volunteers subjective sensations, proved satisfactory level of thermal stress reduction while working in the aluminized protective clothing in hot environment by the developed personal liquid cooling system for the variant with coolant temperature 19°C and the flow rate 0.9?dm3/min.
Originality/value – This paper presents a new clothing construction intended for LCG that can efficiently support human thermoregulation processes while working in the hot environment.

Source: Grazyna Bartkowiak, Anna Dabrowska, Anna Marszalek, (2014), International Journal of Clothing Science and Technology, Vol. 26 Iss: 2, p.145 - 163.

Evaluation of two cooling systems under a firefighter coverall

Firemen often suffer from heat strain. This study investigated two chest cooling systems for use under a firefighting suit. In nine male subjects, a vest with water soaked cooling pads and a vest with water perfused tubes were compared to a control condition. Subjects performed 30 min walking and 10 min recovery in hot conditions, while physiological and perceptual parameters were measured. No differences were observed in heart rate and rectal temperature, but scapular skin temperature and fluid loss were lower using the perfused vest. Thermal sensation was cooler for the perfused vest than for the other conditions, while the cool pad vest felt initially cooler than control. However, comfort and RPE scores were similar. We conclude that the cooling effect of both tested systems, mainly providing a (temporally) cooler thermal sensation, was limited and did not meet the expectations.

Source: Teunissen LP, Wang LC, Chou SN, Huang CH, Jou GT, Daanen HA. Appl. Ergon. 2014.

Temporal changes in the required shoe-floor friction when walking following an induced slip

Biomechanical aspects of slips and falls have been widely studied to facilitate fall prevention strategies. Prior studies have shown changes in gait after an induced slipping event. As such, most researchers only slip participants one time to avoid such changes that would otherwise reduce the external validity of experimental results. The ability to slip participants more than once, after allowing gait to return to a natural baseline, would improve the experimental efficiency of such studies. Therefore, the goal of this study was to characterize the temporal changes in required shoe-floor friction when walking following an induced slip. Two experiments were completed, and each employed a different potential strategy to promote the return of gait to a natural baseline after slipping. In the first experiment, extended time away from the laboratory was used to promote the return of gait to baseline. We measured required coefficient-of-friction among 36 young adult male participants over four sessions. The first three sessions provided measurements during baseline (i.e., natural gait) both prior to slipping and immediately after slipping. The fourth session provided a measurement 1-12 weeks after slipping. In the second experiment, an extensive number of walking trials was used to promote the return of gait to baseline. We measured required coefficient-of-friction among 10 young adult male participants in a single session. Measurements were collected during 10 baseline walking trials, immediately after slipping, and during 50-55 additional trials. In both experiments, required coefficient-of-friction decreased 12-16% immediately after a single slip, increased toward baseline levels over subsequent weeks/walking trials, but remained statistically different from baseline at the end of the experiments. Based on these results, experiments involving slipping participants multiple times may not have a high level of external validity, and researchers are encouraged to continue to limit experimental protocols to a single induced slip per participant.

Source: Beringer DN, Nussbaum MA, Madigan ML. PLoS ONE 2014; 9(5).

The European, Japanese and US protective helmet, gloves and boots for firefighters

Thermoregulatory and psychological évaluations
The purpose of this study was to investigate the physiological and subjective responses of the European, Japanese (JPN) and US firefighters' helmet, gloves and boots for international standardisation. Three experimental conditions were evaluated (clothing mass: 9.4, 8.2 and 10.1 kg for the three conditions, respectively) at the air temperature of 32°C and 60% relative humidity. The results showed that there was no significant difference among the three conditions in oxygen consumption, heart rate, total sweat rate, rectal temperature and mean skin temperature, whereas peripheral temperatures and subjective perceptions were lower in the JPN condition than in the other conditions (P < 0.05). These results indicate that a 0.5-kg reduction in helmet mass and a 1.1-kg reduction in boot mass during exercise resulted in a significant decrease in head and leg temperatures and subjective perceptions, while a 1.9-kg reduction in total clothing mass had insignificant influences on the metabolic burden and overall body temperature.

Source: Lee JY, Yamamoto Y, Oe R, Son SY, Wakabayashi H, Tochihara Y. Ergonomics 2014.

Twenty years of workers' compensation costs due to falls from height among union carpenters, Washington State

BACKGROUND: Falls from height (FFH) are a longstanding, serious problem in construction.
METHODS: We report workers' compensation (WC) payments associated with FFH among a cohort (n = 24,830; 1989-2008) of carpenters. Mean/median payments, cost rates, and adjusted rate ratios based on hours worked were calculated using negative-binomial regression.
RESULTS: Over the 20-year period FFH accounted for $66.6 million in WC payments or $700 per year for each fulltime equivalent (2,000 hr of work). FFH were responsible for 5.5% of injuries but 15.1% of costs. Cost declines were observed, but not monotonically. Reductions were more pronounced for indemnity than medical care. Mean costs were 2.3 times greater among carpenters over 50 than those under 30; cost rates were only modestly higher.
CONCLUSIONS: Significant progress has been made in reducing WC payments associated with FFH in this cohort particularly through 1996; primary gains reflect reduction in frequency of falls. FFH that occur remain costly.

Source: Lipscomb HJ, Schoenfisch AL, Cameron W, Kucera KL, Adams D, Silverstein BA. Am. J. Ind. Med. 2014. 

Wearing a crotch strap on a correctly fitted lifejacket improves lifejacket performance

Wearing a lifejacket when immersed in water should support the wearer, maintaining their airway clear of the water. It is proposed that a retention system would improve airway protection by improving retention of the lifejacket around the torso. Study one (n = 10) quantified the performance of lifejackets immediately following a step into water from height when a lifejacket was worn with a crotch strap (two different tightness) and without a crotch strap. Airway freeboard was improved when wearing a crotch strap (P < 0.05) compared with no crotch strap. Study two used a manikin to examine the performance of lifejackets with and without a crotch strap during 3-h exposures to waves. During exposure to waves, the time taken to aspirate the lethal dose of seawater for drowning was doubled when wearing a crotch strap compared with the no-crotch-strap conditions (P < 0.001). Therefore, wearing a crotch strap (functioning retention system) on a correctly fitted lifejacket improves airway protection following accidental immersion and prolonged wave exposure.

Source: Lunt H, White D, Long G, Tipton M. Ergonomics 2014.

Understanding proper use and disposal of protective gowns for healthcare workers

The prevalence of infectious diseases, such as Hepatitis B, Hepatitis C, HIV, SARS and avian flu, have raised the concern of hospital personnel over the possibility of acquiring such infections. Healthcare workers (HCWs) in or outside hospitals who have contact with patients, body fluids, or specimens may easily acquire infections from or transmit infections to patients, other personnel, or loved ones. Personal protective equipment (PPE) is a critical component in the hierarchy of controls used to protect HCWs from infectious hazards. HCW PPE may include gowns, respirators, face masks, gloves, eye protection, face shields, and head and shoe coverings. Even though protective ensembles are worn to protect hospital workers and patients alike, if not used or disposed of correctly, this equipment may pose a considerable risk for the public health. Although laboratory studies have produced mixed results for the effectiveness of gown use, appropriate gowns are recommended to prevent or reduce HCW exposure to bloodborne pathogens. However, those using the gowns may have limited information on the performance of the gowns they wear every day.

Source: http://blogs.cdc.gov/niosh-science-blog/2014/05/05/gowns/

Preventing Deaths and Injuries to Fire Fighters by Establishing Collapse Zones at Structure Fires

Fire fighters are at significant risk for injury or death due to structural collapse during firefighting operations. Structural collapse often occurs without warning. The National Institute for Occupational Safety and Health (NIOSH) recommends that the Incident Commander establish defensive operations and collapse zones when there is potential for a structural collapse during fire-fighting operations.

Source: http://www.cdc.gov/niosh/docs/wp-solutions/2014-120/

Z259.2.2-14 - Self-retracting devices

This is the second edition of Z259.2.2, Self-retracting devices. It supersedes the previous edition published in 1998.
The purpose of this Standard is to specify requirements for the classification, design, testing and marking, and instructions for use with self-retracting devices. 

Source: http://shop.csa.ca/fr/canada/protection-contre-les-chutes/z25922-14/invt/27007332014

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