An overt chemical protective garment reduces thermal strain compared with a covert garment in warm-wet but not hot-dry environments

© 2017 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fphys.2017.00913© 2017 Maley, Costello, Borg, Bach, Hunt and Stewart. Objectives: A commercial chemical, biological, radiological and nuclear (CBRN) protective covert garment has recently been developed with the aim of reducing thermal strain. A covert CBRN protective layer can be worn under other clothing, with equipment added for full chemical protection when needed. However, it is unknown whether the covert garment offers any alleviation to thermal strain during work compared with a traditional overt ensemble. Therefore, the aim of this study was to compare thermal strain and work tolerance times during work in an overt and covert ensemble offering the same level of CBRN protection. Methods: Eleven male participants wore an overt (OVERT) or covert (COVERT) CBRN ensemble and walked (4 km·h-1, 1% grade) for a maximum of 120 min in either a wet bulb globe temperature [WBGT] of 21, 30, or 37°C (Neutral, WarmWet and HotDry, respectively). The trials were ceased if the participants' gastrointestinal temperature reached 39°C, heart rate reached 90% of maximum, walking time reached 120 min or due to self-termination. Results: All participants completed 120 min of walking in Neutral. Work tolerance time was greater in OVERT compared with COVERT in WarmWet (P 0.05). Conclusion: Those dressed in OVERT experienced lower thermal strain and longer work tolerance times compared with COVERT in a warm-wet environment. However, COVERT may be an optimal choice in a hot-dry environment. These findings have practical implications for those making decisions on the choice of CBRN ensemble to be used during work.This project is financially supported by the Australian Government, managed by the National Security Science and Technology Centre within the Defence Science and Technology Organization, and the US Government through the Technical Support Working Group within the Combating Terrorism Technical Support Office.Published versio

The effects of protective clothing and its properties on energy consumption during different activities: literature review

There are many industrial situations where workers are required to wear personal protective clothing and equipment (PPC), for example, firefighters, chemical workers, cold store workers, army personnel and those working in the steel and forestry industries. Although this protective clothing may provide protection from the primary hazard, for example heat or chemicals, it can also create ergonomic problems. In recent years many PPC product standards have been introduced, these have helped to improve the quality of the protective clothing and so increased the safety of the workers. However, information on the effect of the clothing on the wearer and the interactions between PPC, wearer and environment are limited. Most PPC is designed for optimal protection against the hazard present, but this protection in itself can be a hazard. There are important side effects to protective clothing and typically with increasing protection requirements, the ergonomic problems increase. Often the main problem is the added load on the body in terms of weight. Also reduced mobility due to garment stiffness reduces the freedom of movement and may increase the risk of falls or getting caught in machinery. Even worse, the extra load and discomfort due to the protective clothing may tempt workers not to wear it when the primary hazard risk is low, leaving them unprotected if the hazard unexpectedly reappears or increases in strength. The problems of protective clothing can be seen as thermal, metabolic and performance issues. By creating a barrier between the wearer and the environment, clothing interferes with the process of thermoregulation, particularly reducing dry heat loss and sweat evaporation. The main metabolic effects come from the added weight of the clothing and the ‘hobbling effect’ due to garment bulk and stiffness, both of which increase metabolic cost so the worker has to expend more energy when carrying out tasks. Loss of freedom of movement and range of motion due to PPC can also lead to reduced performance. Current heat and cold stress standards consider the balance of heat production and loss but focus on environmental conditions and work rate metabolism. They also assume workers are wearing light, vapour permeable clothing. By failing to consider the metabolic effects of actual protective clothing, the standards underestimate heat production and therefore current standards cannot be accurately applied to workers wearing PPC. The effects of protective clothing on workers have been studied across a number of industries but studies have mainly concentrated on the thermal effects of clothing, such as heart rate, core temperature responses to different garments and on performance decrements caused by wearing PPC. Very few studies have considered the metabolic effects. Quantifying the effect of PPC on metabolic load based on the properties of the PPC was one of the objectives of the European Union THERMPROTECT project and the work undertaken for this thesis made up work package 4 of the EU project. The main objectives of the project were to provide data and models which allow the heat and cold stress assessment standards to be updated so that they need no longer exclude specialised protective clothing

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs

Inherent work suit buoyancy distribution:effects on lifejacket self-righting performance

Introduction: Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Methods: Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman’s test to the 0.05 alpha level. Results: All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. Discussion: LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario

The effects of protective clothing and its properties on energy consumption during different activities

There are many situations where workers are required to wear personal protective clothing (PPC), to protect against a primary hazard, such as heat or chemicals. But the PPC can also create ergonomic problems and there are important side effects which typically increase with rising protection requirements. The most extensively studied side effect is that of increased heat strain due to reduced heat and vapour transfer from the skin. Less studied is the extra weight, bulk and stiffness of PPC garments which is likely to increase the energy requirements of the worker, reduce the range of movement and lead to impaired performance. Current heat and cold stress standards assume workers are wearing light, vapour permeable clothing. By failing to consider the metabolic effects of actual PPC garments, the standards will underestimate heat production and therefore current standards cannot be accurately applied to workers wearing PPC. Information on the effect of the clothing on the wearer and the interactions between PPC, wearer and environment is limited. Data was collected to quantify the effect of PPC on metabolic load based on the properties of the PPC for the EU THERMPROTECT project (GERD-CT-2002-00846). The main objective of the project was to provide data to allow heat and cold stress assessment standards to be updated so that they need no longer exclude specialised protective clothing. The aim of this thesis was to investigate the effect of PPC and its properties on energy consumption during work. For this purpose, the effects of a range of PPC garments (Chapter 3), weight (Chapter 4), number of layers and material friction (Chapter 5) and wet layers (Chapter 6) on energy consumption whilst walking, stepping and completing an obstacle course were studied. The impact of PPC on range of movement in the lower limbs was also investigated (Chapter 7). The main findings were; a) Increased metabolic cost of 2.4 - 20.9% when walking, stepping and completing an obstacle course in PPC compared to a control condition. b) An average metabolic rate increase of 2.7% per kg increase in clothing weight, with greater increases with clothing that is heavier on the limbs and in work requiring greater ranges of movement. c) 4.5 to 7.9% increase in metabolic cost of walking and completing an obstacle course wearing 4 layers compared to a single layer control condition of the same weight. d) Changes in range of movement in PPC due to individual behavioural adaptations. e) Garment torso bulk is the strongest correlate of an increased metabolic rate when working in PPC (r=0.828, p<0.001). f) Garment leg bulk (r=0.615), lower sleeve weight (r=0.655) and weight of the garment around the crotch (r=0.638) are also all positively correlated with an increased metabolic rate. Total clothing weight and clothing insulation had r values of 0.5 and 0.35 respectively. This thesis has confirmed the major effect of clothing on metabolic rate, and the importance of including this effect in standards and models

Oral application of L-menthol in the heat: From pleasure to performance

When menthol is applied to the oral cavity it presents with a familiar refreshing sensation and cooling mint flavour. This may be deemed hedonic in some individuals, but may cause irritation in others. This variation in response is likely dependent upon trigeminal sensitivity toward cold stimuli, suggesting a need for a menthol solution that can be easily personalised. Menthol’s characteristics can also be enhanced by matching colour to qualitative outcomes; a factor which can easily be manipulated by practitioners working in athletic or occupational settings to potentially enhance intervention efficacy. This presentation will outline the efficacy of oral menthol application for improving time trial performance to date, either via swilling or via co-ingestion with other cooling strategies, with an emphasis upon how menthol can be applied in ecologically valid scenarios. Situations in which performance is not expected to be enhanced will also be discussed. An updated model by which menthol may prove hedonic, satiate thirst and affect ventilation will also be presented, with the potential performance implications of these findings discussed and modelled. Qualitative reflections from athletes that have implemented menthol mouth swilling in competition, training and maximal exercise will also be included

A Review of gaps and limitations in test methods for first responder protective clothing and equipment : a final report presented to National Personal Protection Technology Laboratory, National Institute for Occupational Safety and Health (NIOSH)

This report presents the results of a review aimed at identifying test methods for protective clothing for first responders, as well as identifying areas in which further research is required. It is intended to identify gaps and limitations in evaluation technology and to provide information on test methods research that can guide the development of new first responder protective ensembles.This project reviewed test methods specified by the National Fire Protection Association (NFPA) comprehensive standards for structural firefighters, HAZMAT response, Emergency Medical Service (EMS), technical rescue operations, response to chemical/ biological terrorism incidents and standards for selection care and maintenance of firefighting protective ensembles. Key test methods and requirements for evaluating protective clothing and equipment in the performance categories of flame and heat protection, chemical protection, biological protection, physical hazard protection, and for testing and evaluating heat stress are referenced. In addition, this project surveyed documented research on test methods for firefighter and other emergency responders.Executive summary -- I. Test methods and criterion for emergency responder protective clothing & equipment -- II. Thermal protective performance -- III. Chemical and biological protection -- IV. Heat stress and comfort -- V. In-use durability and service life -- VI. Models for predicting the performance of protective clothing -- VII. Summary of research needs for developing test methods and performance criteria -- Acknowledgement -- Appendix A: Summary of key test methods and requirements for evaluating firefighter protective clothing and equipment -- Appendix B: References.200

Preventing and monitoring work-related diseases in firefighters: a literature review on sensor-based systems and future perspectives in robotic devices.

: In recent years, the necessity to prevent work-related diseases has led to the use of sensor based systems to measure important features during working activities. This topic achieved great popularity especially in hazardous and demanding activities such as those required of firefighters. Among feasible sensor systems, wearable sensors revealed their advantages in terms of possibility to conduct measures in real conditions and without influencing the movements of workers. In addition, the advent of robotics can be also exploited in order to reduce work-related disorders. The present literature review aims at providing an overview of sensor-based systems used to monitor physiological and physical parameters in firefighters during real activities, as well as to offer ideas for understanding the potentialities of exoskeletons and assistive devices

Development of an Instrumented Dynamic Mannequin Test to Rate the Protection Provided by Protective Clothing

A dynamic mannequin testing facility has been constructed to test the thermal protective properties of Navy uniforms and protective clothing. The existing facility consists of a traversing mannequin mechanism that passes through a fire that has been spatially characterized by temperature and heat flux measurements. The fire is provided by 8 propane sand burners in a modified ISO 9705 room. The current project is a continuation of work done by WPI Students over the last 5 years. A copper disk surface heat flux transducer has been designed and calibrated in the WPI Cone Calorimeter. The mannequin has been instrumented with 40 of these transducers for the acquisition of heat flux data during fire exposures. Heat Flux data was collected with the bare mannequin and through protective clothing for a range of exposure times. A finite difference method approach is used to model the skins temperature response at the epidermis-dermis interface. This temperature is used to predict 1st and 2nd degree skin burns using Henrique\u27s burn damage integral. The percent total body area (%TBA) affected by burns can be calculated by this method. The facility is now capable of providing comparative data on the relative thermal protection provided by different clothing