Firefighter Protective Clothing Research Articles

Effect of nano silver coating on thermal protective performance of firefighter protective clothing

The main aim of this experimental work is to find out possible improvement in thermal protective performance of firefighter protective clothing when subjected to different level of radiant heat flux density. Firefighter protective clothing normally consists of three layers: outer shell, moisture barrier and thermal liner. When thermal protective performance of firefighter protective clothing is enhanced, the time of exposure against radiant heat flux is increased, which will provide extra amount of time to firefighter to carry on their work without suffering from severe skin burn injuries. In this study, the exterior side of outer shell was coated with nano-silver metallic particle through magnetron sputtering technology. Coating of outer shell with nano-silver particles was performed at three level of thickness, i.e. 1, 2 and 3 µm, respectively. All the uncoated and silver coated specimens were then characterized on air permeability tester, Permetest and radiant heat transmission machine. It was observed that coating has insignificant difference on the air and water vapor permeability of specimen and a significant decline was recorded for the value of transmitted heat flux density Qc (kW/m2) and percentage transmission factor (%TF Qo) as compared to uncoated specimen when subjected to 10 kW/m2 and 20 kW/m2 indicating improvement of thermal protective performance. These values go on further reduction with increase in thickness of coating layer of nano-silver particles.

Measurements of Range of Motion and Surface Electromyography for Analysis of Wearer Mobility with Firefighter Protective Clothing

Measurements of Range of Motion and Surface Electromyography for Analysis of Wearer Mobility with Firefighter Protective Clothing

Comparison of thermal performance of firefi ghter protective clothing at diff erent levels of radiant heat flux density

Comparison of thermal performance of firefi ghter protective clothing at diff erent levels of radiant heat flux density

Predicting Mechanical Strength of In-Use Firefighter Protective Clothing Using Near-Infrared Spectroscopy

The exact lifespan of in-use firefighter protective clothing is difficult to predict due to the large variations in use between individual garments. Furthermore, testing methods used to evaluate new protective clothing are destructive in nature and could not be applied to in-use garments. Various non-destructive techniques have been proposed for the evaluation of in-use clothing, each possessing its own advantages and disadvantages. The ability of near-infrared spectroscopy to predict the tensile strength of thermally aged fabrics used in protective clothing for wildland firefighters and other workers is investigated here. Fabrics were exposed to heat fluxes from 10 kW/m2 to 40 kW/m2 for various durations using the cone calorimeter, after which the tensile strength of the fabrics was measured. Temperatures measured during the exposures and results of thermal gravimetric analysis tests were used to interpret changes in tensile strength. Multivariate linear regression was used to develop correlations between the tensile strength and the reflectance values measured between 1500 nm and 2500 nm for new and thermally aged fabrics. It was found that models based on reflectance measurements made at as few as three wavelengths could be used to estimate the tensile strength of the thermally aged specimens.

Aerogel nonwoven as reinforcement and batting material for firefighter’s protective clothing: a comparative study

Aerogel, the most insulated solid known to modern science, is gradually expanding its field of application from space shuttle to normal clothing. So far, apparel use of aerogel nonwoven has been successfully commercialized in case of cold weather clothing. Use of aerogel in high heat protective clothing is much complex as it requires to balance comfort with protection. This paper studied the protective performance of aerogel nonwoven in a high heat protective apparel, firefighter’s protective clothing (FPC). An investigation was carried out to justify its use as reinforcement material and/or batting in thermal liner or moisture barrier of FPC. Impressive results were observed in case of reducing the risk of burn injury, increasing comfort and enhancing protection. It was observed that aerogel nonwoven can provide eight times more thermal resistance than existing commercial reinforcement material and existing thermal batting material. When the aerogel nonwoven layer was used as thermal liner, it offered five times more resistance to heat than existing thermal liner and three times more resistance than combined performance of existing thermal liner and moisture barrier. The possible burn injury under 49 N compressive load was predicted on a 200 °C heated surface. It was found that the temperature behind the commercial reinforcement material quickly raised above 70 °C within 30 s of contact, while it took more than 4 min to reach the same temperature for proposed aerogel reinforcement material. This indicates that a firefighter will receive instant burn on contact in 30 s if only the commercial reinforcement material is used. It was measured that, without any reinforcement material even when only the aerogel nonwoven is used instead of current batting material, a firefighter will have 86 s before feeling any pain, 107 s before receiving first-degree burn and will have 2 and half minutes before theoretically receiving second-degree burn at the same condition. Thus, a firefighter will gain more than 1 min of escape time to withdraw from a danger situation, where it is only 5 s for existing thermal liner and reinforcement material. Performance was also evaluated against fabric thickness and weight, air permeability, resistance to one-way liquid transfer, moisture management, moisture vapour transfer and degree of evaporative cooling. The advantages and disadvantages of proposed combination have been discussed and it was concluded that the use of aerogel reinforcement can significantly increase the protective performance of FPC. Aerogel nonwoven (A) showed superior performance over existing reinforcement material (Rinf) and thermal liner (F+B1) for firefighter’s protective clothing. In particular, aerogel nonwoven has

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

This paper presents new proposals in the evaluation and determination of the optimum materials suitable for use in the design and development of firefighter protective clothing by simultaneously addressing the conflicting factors of thermal protection [heat transfer index (HTI), radiant heat transfer index (RHTI) and thermal threshold index (TTI)] and anti-heat stress [water vapor resistance (WVR) and total heat loss (THL)]. To achieve this, this paper proposes new indices for the materials, two types of “total performance” indices, which are defined as the sum and the product of the competing factors of thermal protection and anti-heat stress. The results showed that the candidate materials of firefighter protective clothing were easily rated when the new indices were applied. Of five candidate materials viz. A, B, B1, B2 and C, the B sample, with values for HTI24 = 13.2 ± 0.2 s, RHTI24 = 18.0 ± 0.8 s, TTI = 1132 ± 33 J/m2, WVR = 17.5 ± 0.3 m2 Pa/W and THL = 266.2 ± 4.1 W/m2, was found to exhibit the best total performance. However, the methods proposed to the scientific community in this paper have so far been validated on a limited data set only, and will require further validation by a wider group of researchers and with more samples. Lastly, comments on ISO 11999-3:2015 were also made for the further improvement and development of technical standards.

Ice Slurry Ingestion and Physiological Strain During Exercise in Non-Compensable Heat Stress

Precooling with ice slurry ingestion attenuates the increase in rectal temperature (Tre) during subsequent running and cycling. It remains unclear how this cooling method affects physiological strain during work while wearing protective garments. This study investigated the effect of ice slurry ingestion on physiological strain during work in hot conditions while wearing firefighter protective clothing. In three counterbalanced trials, eight men (mean ± SD; age = 21 ± 2 yr, height = 179.5 ± 3.5 cm, mass = 79.1 ± 4.1 kg, body fat = 11.4 ± 3.7%) wore firefighter protective clothing and walked (4 km · h-1, 12% incline, ∼7 METs) for 30 min in hot conditions (35°C, 40% RH). Every 2.5 min, subjects ingested 1.25 g · kg-1 (relative total: 15 g · kg-1, absolute total: 1186.7 ± 61.3 g) of a tepid (22.4 ± 1.7°C), cold (7.1 ± 1.5°C), or ice slurry (-1.3 ± 0.2°C) beverage. Heart rates (HR) were lower with ice slurry ingestion compared to both fluid trials starting 5 min into exercise (tepid = 158 ± 14, cold = 157 ± 11, ice slurry = 146 ± 13 bpm) and persisting for the remainder of the bout (min 30: tepid = 196 ± 10, cold = 192 ± 10, ice slurry = 181 ± 13 bpm). Tre was lower with ice slurry ingestion compared to cold and tepid trials (min 5: tepid = 37.17 ± 0.38, cold = 37.17 ± 0.39, ice slurry = 37.05 ± 0.43°C; min 30: tepid = 38.15 ± 0.29, cold = 38.31 ± 0.36, ice slurry = 37.95 ± 0.32°C). The physiological strain index (PSI) was lower with ice slurry ingestion compared to fluid trials starting at min 5 (tepid = 3.8 ± 0.7, cold = 3.8 ± 0.6, ice slurry = 3.0 ± 0.5) and remained lower throughout exercise (min 30: tepid = 8.2 ± 0.6, cold = 8.3 ± 0.9, ice slurry = 6.9 ± 1.2). A large quantity of ice slurry ingested under non-compensable heat stress conditions mitigated physiological strain during exercise by blunting the rise in heart rate and rectal temperature.Ng J, Wingo JE, Bishop PA, Casey JC, Aldrich EK. Ice slurry ingestion and physiological strain during exercise in non-compensable heat stress. Aerosp Med Hum Perform. 2018; 89(5):434-441.

Effect of Air Gap Entrapped in Firefighter Protective Clothing on Thermal Resistance and Evaporative Resistance

Abstract Heat and water vapor transfer behavior of thermal protective clothing is greatly influenced by the air gap entrapped in multilayer fabric system. In this study, a sweating hot plate method was used to investigate the effect of air gap position and size on thermal resistance and evaporative resistance of firefighter clothing under a range of ambient temperature and humidity. Results indicated that the presence of air gap in multilayer fabric system decreased heat and water vapor transfer abilities under normal wear. Moreover, the air gap position slightly influenced the thermal and evaporative performances of the firefighter clothing. In this study, the multilayer fabric system obtained the highest thermal resistance, when the air space was located at position B. Furthermore, the effect of ambient temperature on heat and water vapor transfer properties of the multilayer fabric system was also investigated in the presence of a specific air gap. It was indicated that ambient temperature did not influence the evaporative resistance of thermal protective clothing. A thermographic image was used to test the surface temperature of multilayer fabric system when an air gap was incorporated. These results suggested that a certain air gap entrapped in thermal protective clothing system could affect wear comfort.

SIO2 aerogels and its application in firefighter protective clothing

This article focuses our attention on utility of silica based aerogel as insulation materials in protective clothing especially for fire fighters at higher temperature. In past, aerogels were employed for insulation of buildings, aeronautics and aerospace applications. Later on, researchers determined the utility of aerogels as insulated substrate in protective clothing. Several investigations revealed insulation properties of aerogel at elevated temperature. There are several different types of aerogel but in this article, the main emphasis is on silica based aerogel because of its excellent insulation and outstanding flame proof properties along with thermal stability at raised temperature. By applying suitable coating techniques, aerogel can be impregnated into nonwoven substrates, which can be employed as thermal barriers resulting in enhancement of the protective capability of multilayered clothing at higher temperature. All these characteristics make aerogel a potential candidate to be used as insulation material in protective clothing at elevated temperature.

Reversible thermochromic microencapsulated phase change materials for thermal energy storage application in thermal protective clothing

In this study, a series of reversible thermochromic microencapsulated phase change materials (TC-MPCMs), exhibiting excellent latent heat storage-release performance, were designed and fabricated successfully. The characterization and microstructure regulation of TC-MPCMs were conducted systematically as well. The core of TC-MPCMs was comprised of crystal violet lactone employed as thermochromic colorant, bisphenol A employed as developer and 1-tetradecanol employed as co-solvent, respectively. These influencing factors of encapsulation process such as the amount of emulsifier, stirring rate, feeding weight of core/shell ratio, acid resistance and thermal cyclic durability were carried out to clarify the effect of various experimental conditions. The surface morphology, shell thickness and core–shell structure of TC-MPCMs were characterized via optical microscope (OM), thermal field emission scanning electronic microscope (TFE-SEM), transmission electron microscope (TEM), respectively. From different scanning calorimetry (DSC) analysis, the performance of temperature of fusion and crystallization and enthalpy of TC-MPCMs under various conditions were measured as well. The results of thermogravimetric (TG) analysis illustrated the influence on thermal stability of TC-MPCMs. In addition, Lab color space obtained by colorimeter is certainly intuitive to observe the colorimetric characteristics of TC-MPCMs as well. More importantly, the reversible thermochromic property associated with phase state of the 1-tetradecanol could also provide a visual evidence of energy storage or release performance of the TC-MPCMs. Furthermore, The TC-MPCMs exhibited excellent stability even after 100th thermal cycling test without any obvious performance degradation, including the morphology, phase change properties and thermal stability. In the end, the fire fighter protective clothing containing TC-MPCMs was designed and fabricated, which could provide adequate thermal protection in the various fire environments. Thus, TC-MPCMs developed in this work showed great potential applications in thermal protective clothing and other thermal regulation fields.

Комплексная оценка качества специальной защитной одежды для пожарных

Комплексная оценка качества специальной защитной одежды для пожарных

О роли начертательной геометрии в подготовке технических специалистов

О роли начертательной геометрии в подготовке технических специалистов

The usage of phase change materials in fire fighter protective clothing: its effect on thermal protection

The thermal protective performance of the fire fighter protective clothing is of vital importance for fire fighters. In the study fabrics treated by phase change materials (PCMs) were applied in the multi-layered fabrics of the fire fighter protective clothing ensemble. The PCM fabrics were placed at the different layers of the clothing and their thermal protective performance were measured by a TPP tester. Results show that with the application of the PCM fabrics the thermal protection of the multi-layered fabrics was greatly increased. The time to reach a second degree burn was largely reduced. The location of the PCM fabrics at the different layers did not affect much on the thermal protective performance. The higher amount of the PCM adds on, the higher thermal protection was brought. The fabrics with PCMs of a higher melting temperature could contribute to higher thermal protection.

Thermal Protective Performance under Fire Conditions of Silica Aerogel Felt-bedded Firefighters’ Protective Clothing

The addition of silica aerogel felt (SAF) to firefighters’ protective clothing (FPC) is an innovation with the potential to enhance the thermal insulation capacity of FPC. In order to explore this technology, this paper describes the results of an experiment that determined the thermal protective performance of FPC with SAF under wood crib fire conditions. We also performed an experiment using FPC materials without SAF and compared the results. Finally, we compared the thermal decomposition of commercial thermal liner material and silica aerogel. The results demonstrate that the temperature at the surface of the comfort layer of the SAF-containing sample was lower than that of the commercial sample. This experiment confirms that lower overall temperatures are found on the surface of the comfort layer of the specimen with SAF than on the specimen without SAF, even when the thicknesses of the thermal liner layers are similar. The maximum temperature difference was about 20°C. The thermal protective performance of FPC with SAF increased with increasing SAF thickness, but the increase became very minor when the SAF thickness exceeded 6 mm. Additionally, the thermal stability of silica aerogel is significantly better than that of commercial thermal liner material, reducing the risk of thermal decomposition at high temperatures.DOI: http://dx.doi.org/10.5755/j01.ms.23.4.16680

Relationship between Total Heat Loss and Thermal Protective Performance of Firefighter Protective Clothing and Consequent Influence on Burn Injury Prediction via Flame-Engulfment Manikin Test

Firefighter protective clothing (FPC) provides barrier protection from hazardous materials. Two of the important performance factors tested for FPC are total heat loss (THL) and thermal protective performance (TPP). The present study evaluated the relationship between THL and TPP, and tested its subsequent influence on burn injury prediction via the flame-engulfment manikin test, using three FPC samples from the United States, Europe, and South Korea. The study results showed an inverse relationship between THL and TPP (r=-.949, p<.001). Predicted total area of second and third degree burn injury was 7.2±1.6, 19.7±4.1, and 5.0±1.0% for the United States, European, and South Korean FPC, respectively, which was significantly explained by both THL and TPP (F=34.630, p=0.001, R2=.920). The flame manikin test results showed that affected burn injury areas are not uniform over the body, but more frequent on the head and limbs.

Review: Radiation Heat Transfer Through Fire Fighter Protective Clothing

A fire fighter garment is multilayer protective clothing with an outer shell, moisture barrier and thermal barrier, respectively. Fire fighters encounter different levels of radiant heat flux while performing their duties. This review study acknowledges the importance and performance of fire fighter protective clothing when subjected to a low level of radiation heat flux as well as the influence of air gaps and their respective position on the thermal insulation behaviour of multilayer protective clothing. Thermal insulation plays a vital role in the thermal comfort and protective performance of fire fighter protective clothing (FFPC). The main emphasis of this study was to analyse the performance of FFPC under different levels of radiant heat flux and how the exposure time of fire fighters can be enhanced before acquiring burn injuries. The preliminary portion of this study deals with the modes of heat transportation within textile fabrics, the mechanism of thermal equilibrium of the human body and the thermal protective performance of firefighter protective clothing. The middle portion is concerned with thermal insulation and prediction of the physiological load of FFPC. The last section deals with numerical models of heat transmission through firefighter protective clothing assemblies and possible utility of aerogels and Phase Change Materials (PCMs) for enhancing the thermal protective performance of FFPC.

Firefighter Work Duration Influences the Extent of Acute Kidney Injury.

We tested the hypothesis that elevations in biomarkers of acute kidney injury are influenced by the magnitude of hyperthermia and dehydration elicited by two common firefighter work durations. Twenty-nine healthy adults (10 females) wearing firefighter protective clothing completed two randomized trials where they walked at 4.8 km·h, 5% grade in a 38°C, 50% RH environment. In the short trial, subjects completed two 20-min exercise bouts. In the long trial (LONG), subjects completed three 20-min exercise bouts. Each exercise bout was separated by 10 min of standing rest in an ~20°C environment. Venous blood samples were obtained before and immediately after exercise, and after 1 h recovery. Dependent variables included changes in core temperature, body weight, plasma volume, serum creatinine, and plasma neutrophil gelatinase-associated lipocalin, a marker of renal tubule injury. Changes in core temperature (+2.0°C ± 0.7°C vs +1.1°C ± 0.4°C, P < 0.01), body weight (-0.9% ± 0.6% vs -0.5% ± 0.5%, P < 0.01), and plasma volume (-11% ± 5% vs -8% ± 6%, P < 0.01) during exercise were greater in LONG. Increases in creatinine were higher in LONG postexercise (0.18 ± 0.15 vs 0.08 ± 0.07 mg·dL, P < 0.01) and after recovery (0.21 ± 0.16 vs 0.14 ± 0.10 mg·dL, P < 0.01). Increases in neutrophil gelatinase-associated lipocalin were greater in LONG postexercise (27.0 ± 20.5 vs 12.7 ± 18.0 ng·mL, P = 0.01) and after recovery (16.9 ± 15.6 vs 1.5 ± 15.1 ng·mL, P = 0.02). Biomarkers of acute kidney injury are influenced by the magnitude of hyperthermia and hypovolemia elicited by exercise in the heat.

Evaluation of a human skin surface temperature for the protective clothing – Skin system based on the protective clothing–skin imitating material results

Experimental studies used for evaluation of quality of the fire-fighters protective clothing are based on irradiation of the clothing sample by an external pulse of a given duration. The other side of the clothing sample is in contact with a material imitating the human skin, which has properties different than these of the skin. Therefore the problem considered in this paper was: what conditions should be satisfied to convert the experimental results, carried out on the stand with a skin-imitating material, to the case of the real human skin with different properties for which the experiments are not made? This will allow for better evaluation of the clothing protecting properties and estimation of the possible burns. Due to multilayer structure of the protective clothing and skin as well as complex phenomena involved in energy transfer through them the problem is very complicated. Therefore at the first attempt to solve the problem a simplified two-layer, clothing-skin system irradiated from external heat source was considered in the present paper. Temperature variation in the system was initially determined using the in-house 1D numerical code accounting for heat conduction in the skin and clothing, non-grey thermal radiation absorption, scattering and emission together with the water vapour diffusion and phase transformations of bound water to the gaseous phase in the protective clothing. Then the analytical model for temperature variation in the considered system was proposed and solved using the Laplace transform approach. In the latter model water vapour diffusion with its phase transformations were excluded and radiation emission was neglected. The analytical model allowed for deriving a formula which can be applied for converting the skin surface temperature obtained from the experiments carried out using the skin-imitating material to the material having skin properties. In order to verify the range of validity of the formula the analytical predictions were compared to the results of numerical simulations of temperature in the protective clothing-skin system considering cases in which different phenomena were included. For the majority of the cases studied good matching between analytical and numerical results was obtained for time corresponding to the heating and cooling processes of the protective clothing-skin system.

Influence of Wet Cooling Vest on Firefihters' Protective Clothing

Firefighters' Protective Clothing (FPC) is essential for protection against thermal and physical threats. FPC must be comfortable, enable heat transfer from the wearer to the environment and should not restrict motion of body parts. The application of a cooling vest under protective clothing may prevent overheating by cooling at the microenvironment level while working in a hot environment during firefighting. In this study, the effect of using a passive system, in the form of a nonwoven fleece material, was investigated. This system was distributed across the surface of a vest on the upper front chest and back. In this passive system, hydro-crystals swell on contact with cold water, lowering body temperature or holding the body temperature at a normal level. The thermal insulation of the wet and dry cooling vest was tested using a thermal manikin. Results showed that the thermal resistance of the system dropped significantly due to replacement of dry air with moist air with higher thermal conductivity. This reduction was proportional to the amount of moisture present within the system.