Firefighter Protective Clothing Research Articles

Revisiting 30 years of advances in firefighter protective clothing: a quantitative assessment and bibliometric analysis

Firefighter protective clothing research has undergone rapid development and garnered extensive attention over the past three decades. However, its trajectory lacks quantitative evaluation due to the complex relationship among humans, clothing, and the environment. Here, we aimed to (1) develop an objective and reproducible evaluation index system for the quantitative assessment of firefighter protective clothing research, (2) delineate the developmental stages and their analytical characteristics over the past three decades through bibliometric analysis, and (3) scrutinize the current status, research hotspots, gaps, and future concerns. Our review of 314 publications from the Web of Science Core database (1994–2023) led to the creation of an evaluation index system that integrates the catastrophe progression method with bibliometric analysis, incorporating 10 indicators across 4 dimensions: productivity, influence, development, and innovation. The bibliometric analysis was conducted using the Bibliometrix R package. The results reveal a rapid increase in firefighter protective clothing studies from 1994 to 2023, comprising two stages: the start-up phase (1994–2009) and the rapid development phase (2010–2023). Thematic evolution over three decades indicates a shift from single specific to composite domains, with emerging themes such as achieving a balance in the interaction between the human body, clothing, and environment signaling future research directions. In addition, we visualized the most relevant countries, institutions, journals, authors, articles, and potential challenges during the last 30 years. This review provides an overview of current evidence and minimizes subjectivity bias compared to traditional manual reviews, thus presenting specific future research questions advancing firefighter protective clothing research.

Moisture barriers used in firefighters' protective clothing: Effect of accelerated ultraviolet radiation aging on their mechanical and barrier performance

AbstractFirefighters rely on their protective clothing as a second skin to perform their job. In the middle of this multilayered protective garment, the moisture barrier plays a vital role in preventing liquids to enter while allowing perspiration to escape. This research delves into the impact of accelerated ultraviolet (UV) aging on the performance of firefighter protective clothing moisture barriers, focusing on tear force retention, water vapor transmission rate (WVTR), and wetting via apparent contact angle. Changes in the tearing behavior and reductions in the tear force and tearing distance were observed after aging. Additionally, a reduction in WVTR was found for all the moisture barriers, due to pore closure in the ePTFE/FR PU membrane. In terms of water repellency, the base fabric side of one moisture barrier experienced a transition from hydrophobic to superhydrophilic potentially due to the degradation of the water‐repellent finish. The investigation also revealed that, due to the screening effect by the outer shell fabric, only a low percentage of UV radiation received by the turnout gear, less than 2% in the UVA range, may reach the moisture barrier. These results indicate the need to consider realistic exposure scenarios when assessing moisture barrier service life.

Performance assessment of firefighter protective clothing under different thermal environments: Impact of the variation of thickness in inter-layer airgap and microclimate

Personal protective equipment for firefighters can effectively prevent skin burns and ensure firefighters' safety. Considering a variety of fire environments faced by a firefighter, the present study is devoted to showing the role of the inter-layer fabric airgap and its variation in thickness on skin burns under high intensity heat flux. The present numerical model is formulated by considering a coupled conduction and radiation heat interaction in the porous fabric medium and the Pennes bioheat transfer model for the multi-layered skin. The study considers the effect of variation in airgap thickness, variation in heat transfer coefficient, and duration of exposure on the thermal damage of the firefighter's skin subjected to different harsh thermal environments. The results found that increasing the thickness of AG1 and AG2 does not yield a significant impact during the exposure time. Conversely, AG3 and AG4 lead to considerable temperature reductions at the basal layer, with AG3 causing a decrease of 2.6 °C to 2.9 °C and AG4 causing a decrease of 11.9 °C to 17.0 °C under all exposure conditions. Additionally, when the heat transfer coefficient increases during post-exposure, temperature drops of 9.17 °C to 10.72 °C, 9.81 °C to 11.46 °C, 10.0 °C to 11.64 °C, and 8.68 °C to 10.07 °C are observed for AG1, AG2, AG3, and AG4, respectively, across all exposure conditions. However, both the airgaps have a substantial effect on thermal protection during the post exposure period. In addition, the nature of the variation of stored and transmitted energy in fabric assembly shows an opposite trend during both the exposure and post exposure period in contrast to the third and fourth airgaps for all the considered thermal environments.

Moisture barriers used in firefighters' protective clothing: Effect of accelerated hydrothermal aging on their mechanical and barrier performance

AbstractFirefighters' protective clothing rely on moisture barriers to safeguard against liquid ingress while enabling sweat evaporation for comfort and safety. However, these moisture barriers can degrade over time, jeopardizing firefighters' safety. Existing evaluation methods, primarily visual inspection, are inadequate for assessing moisture barrier integrity in service. This study examines the effect of accelerated hydrothermal aging on the tear force, water vapor transmission rate (WVTR), and apparent contact angle in three moisture barrier models used in firefighter protective clothing. The moisture barriers studied varied in composition, structure, and base fabric fiber content. Results revealed that moisture barriers' responses to aging are influenced by factors, such as fabric structure, adhesive configuration, finish, and the presence of additional coatings. The hardening of the adhesive layer between the ePTFE membrane and the base fabric was observed in two of the moisture barriers, leading to a slight tear force reduction. Two of the moisture barriers also experienced crack and pit formation on the membrane side, which affected the WVTR. The water‐repellent finish on the fabric side degraded in one moisture barrier. Understanding these complex behaviors is essential for predicting the long‐term moisture barrier performance and enhancing firefighter safety.

Objective multi-criteria decision-making for optimal firefighter protective clothing size selection

Objectives. Addressing the prevalent issue of size misfits in large-scale issued firefighter uniforms due to diverse and complex body morphologies, this article presents an objective method for intelligent garment sizing matching without subjective weighting. Methods. The method employs criteria importance through inter-criteria correlation (CRITIC) and the catastrophe progression method (CPM) for more accurate and reliable sizing. Traditional methods, reliant on limited indicators such as height and chest girth and often subjectively determined by experts, are prone to reliability concerns. Matching decisions made based on our approach are evidence-based, transparent and reproducible, thus minimizing subjectivity and expert intervention. Results. A case study of 388 cases validates the method’s efficacy in providing garment size recommendations, surpassing traditional experience-based approaches by reducing subjective bias. Conclusion. Despite some differences, the optimal alternatives for examinees are almost consistent across the different methods. Compared with traditional subjective weighting methods, this method has potential advantages in situations such as large-scale matching of firefighter protective clothing where individual customization or direct try-on is not feasible.

Relationship between firefighter protective clothing design ease and heat stress

PurposeClothing fit, including garment ease and drape, impacts the volume of air between clothing layers and the body, directly affecting the amount of heat that can be transferred through a multi-layer clothing system. As most acute firefighting fatalities are caused by overexertion and heat strain, the purpose of this research was to determine the impact of ease allowances on air gaps in structural firefighting turnout suits and their subsequent effect on total heat loss (THL) when worn on a three-dimensional form.Design/methodology/approachFour turnout suits with chest ease allowances of 6″, 8″, 10″ and 12″ were evaluated using an ANDI dynamic sweating thermal manikin. The average predicted manikin THL of each ensemble was calculated from the thermal and evaporative resistance measurements. A three-dimensional (3D) body scanner was utilized to calculate the distance and volume of clothing air gaps between the base layer and each turnout suit.FindingsResults demonstrate that reductions in upper body ease measurements trend towards statistically significant increases in THL, to a point, with fit limitations being reached before benefits can be significantly realized. An increase in standard chest ease measurements significantly decreased heat loss, even when forced convection from movement was considered.Originality/valueThis is the first article of its kind to explore the relationship between garment ease and predicted manikin THL, especially for fire service protective clothing. Findings indicate a valid recommendation for turnout gear designers and manufacturers to optimize clothing fit to improve breathability and potentially reduce incidents of heat strain in the fire service.

Implementation of Numerical Model for Prediction of Temperature Distribution for Metallic-Coated Firefighter Protective Clothing

The aim of this study is to predict the distribution of temperature at various positions on silver-coated firefighter protective clothing when subjected to external radiant heat flux. This will be helpful in the determination of thermal protective performance. Firefighter clothing consists of three layers, i.e., the outer shell, moisture barrier and thermal liner. The outer shell is the exposed surface, which was coated with silver particles through a physical vapor deposition process called magnetron sputtering. Afterwards, these uncoated and silver-coated samples were exposed to radiant heat transmission equipment at 10 kW/m2 as per the ISO 6942 standard. Silver-coated samples displayed better thermal protective performance as the rate of temperature rise in silver-coated samples slowed. Later, a numerical approach was employed, contemplating the impact of metallic coating on the exterior shell. The finite difference method was utilized for solving partial differential equations and the implicit method was employed to discretize the partial differential equations. The numerical model displayed a good prediction of the distribution of temperature at different nodes with respect to time. The comparison of time vs. temperature graphs at different nodes for uncoated and silver-coated samples acquired from numerical solutions showed similar patterns, as witnessed in the experimental results.

The heat and moisture transfer model of firefighter protective clothing

This paper presents a model of heat and moisture transfer through multilayer firefighter protective clothing, which for the first time has taken into account all the major heat and moisture transport mechanisms including conductive and convective heat transfer, two-flux radiative heat transfer, moisture bulk flow, moisture absorption/desorption by fibers, moisture diffusion and phase change. The model was solved by Crank–Nicolson scheme of the finite difference method. Numerical analysis showed that our model can accurately predict the second-degree burn time with an error ranging from 0.37% to 3.55% for different types of clothing assemblies. With this model, the distributions of heat and moisture within the protective clothing system are elucidated and the relative importance of key clothing parameters on thermal protection better understood. It revealed that the thickness of the moisture barrier layer has the greatest influence on the skin burn time. This study is significant in providing a theoretical framework for optimizing the design of thermal protective clothing.

Enhancing heat protection performance of firefighters’ protective clothing: A comparative analysis of fabric and knit structure in the lining of multi-layered construction

A firefighting protective clothing item is an important piece of equipment that can protect firefighters from the risk of burns during firefighting and rescue activities. In this study, a method to improve the heat protection performance of firefighter protective clothing lining was proposed, while consulting with textile experts. The protective performance effects of flame and radiant heat were investigated according to the quilting spacing (25.4, 50.8, and 76.2 mm) of the lining and weaving method (fabric or knitted) used for the multi-layered structure of the protective clothing. The experiments conducted to evaluate the impact of different weaving methods on the protective performance of firefighter clothing against flame, radiant heat, and combined flame/radiant heat revealed that the knitted lining exhibited excellent protection performance. Specifically, the knitted lining demonstrated a delayed effect in temperature increase, with maximum delays ranging from approximately 2.2–4.0 s for flame protection experiments, and 5.7–7.4 s for radiant heat protection experiments. For knitted lining, one thread is woven in an interlocking manner; thus, the heat resistance is higher and thermal conductivity is lower owing to the formation of a space compared that for a fabric lining. The results suggest that the weaving method affects the heat transfer according to the formation of space and change in the thickness of the clothing. The findings of this study could be useful for many purposes, such as cost effective and quick analysis of the expected performance of a design or weaving method.

Impact of conventional and advanced cleaning techniques on the durability of firefighter turnout ensembles

The concern for firefighters’ occupational exposure to harmful contaminants is growing due to the increase in health issues in the firefighting community. At such times, effective decontamination of personnel and equipment is an essential component of a hazard mitigation strategy. The current decontamination practices used for firefighter protective clothing have been shown to not be very effective. Hence, the scientific community is looking for several alternatives to conventional washing procedures. Liquid carbon dioxide (CO2) has been used in laundering and has distinct advantages over conventional dry-cleaning solvents such as perchloroethylene. The following study is aimed to assess how different washing procedures affect the durability of the turnout material. The study includes using three washing procedures on different samples: 1) conventional washing procedure, 2) liquid CO2 washing procedure, and 3) a high-temperature washing procedure. Samples for durability testing were constructed from a common aramid fabric used in firefighter turnout ensembles. These swatches were subjected to different washing techniques. The durability assessment was performed for physical testing of the samples, visual inspection, water repellency, and quantifying color changes using spectrophotometric analysis. The conventional wash and high-temperature washing affected the durability of the outer shell material in a significant manner. The liquid CO2 process did not affect the samples’ water repellency or physical strength. In contrast, conventional and high-temperature washing significantly affected the durability of the outer shell material. However, all samples met the criteria for tearing strength outlined in the NFPA 1971 standard subsection 7.1.11.

An Extended Model for Analyzing the Heat Transfer in the Skin-Microenvironment-Fabric System during Firefighting.

This study proposed an extended multi-layer heat transfer model to simulate skin burns of firefighters during firefighting. The proposed model takes into account the effect of fabric movement frequencies, fabric movement amplitudes and human body movement speeds on the heat transfer between the skin and the heat source under low-level radiative exposure. The simulation performance was validated against the simulations in the published literature in terms of the heat transfer in the multi-layer fabric system, skin temperature and skin burns. The results indicated that the fabric periodic movement caused by human body movement decreased the time to skin burns and the skin temperature increased with increasing fabric movement amplitude. During firefighting, the time to 2nd degree burn was 33.3-35.2% shorter at medium human body movement speed than at low and high movement speeds. Furthermore, at low movement speeds, the time to 2nd degree burn was negatively associated with fabric movement amplitude, whereas it was delayed by 12.9-29.8% at the fabric movement amplitude of 2.5 mm at medium and high human body movement speeds. This research provides foundational knowledge for the development of a new generation of firefighters' protective clothing (FPC) and the assessment of skin burns in firefighters.

A Database of Static Thermal Insulation and Evaporative Resistance Values of Dutch Firefighter Clothing Items and Ensembles.

The rescue operations' environment can impair firefighters' performance and increase the risk of injuries, e.g., burns and hyperthermia. The bulk and carried weight of heavy protection contributes to lower physical performance, higher metabolic load and internal body heat production. For recommending optimal protection for the tasks and incident scenarios, knowledge of clothing thermal properties is needed. However, detailed data on firefighter protective clothing systems are not available. The aim of the study was to provide scientific background and a dataset that would allow for validation of thermo-physiological models for task-specific conditions of rescue work. Thermal insulation of 37 single items and their variations and 25 realistic protective clothing ensembles were measured on a thermal manikin. Twelve (12) ensembles that evenly covered the whole insulation range were selected for evaporative resistance testing. The equations for summing up individual item's insulation to ensemble insulation and calculating clothing area factor were derived from the dataset. The database of a firefighter clothing system was created. In addition, the local and regional thermal properties of the clothing ensembles were provided for use in future validation of advanced thermo-physiological models for rescue worker exposure predictions and for designing decision aid tools.

Effect of cooling on static postural balance while wearing firefighter’s protective clothing in a hot environment

Objectives. Postural imbalance can result from hyperthermia-mediated muscular fatigue and is a major factor contributing to injuries from falling. The objective of this study was to investigate the effect of exercise-induced hyperthermia and the impact of cooling on postural balance while wearing firefighters’ protective clothing (FPC) in a hot environment. Methods. A portable force platform measured postural balance characterized by postural sway patterns using center of pressure metrics. Twelve healthy, physically fit males were recruited to stand on the force platform once with eyes open and once with eyes closed before and after treadmill exercise (40% V ˙ O 2 max ) inside an environmental chamber under hot and humid conditions (30 °C and 70% relative humidity) while wearing FPC. Subjects participated in two randomly assigned experimental phases: control and cooling intervention. Results. A significant increase in physiological responses and postural balance metrics was observed after exercising in the heat chamber while wearing FPC. Cooling resulted in a significant effect only on postural sway speed after exercise-induced hyperthermia. Conclusions. Hyperthermia can negatively alter postural balance metrics, which may lead to an increased likelihood of falling. The utilization of body cooling reduced the thermal strain but had limited impact on postural balance stability.

Effects of personal protective clothing on firefighters’ gait analyzed using a three-dimensional motion capture system

Objectives. The effects of personal protective clothing (PPC) on firefighters’ gait were investigated to develop high-performance PPC. Methods. Thirteen participants participated in human trials with three types of PPC (firefighter protective clothing [FPC], semi-enclosed chemical protective clothing [CPC_semi] and fully enclosed chemical protective clothing [CPC_full]) and a T-shirt (control clothing [CON]). A three-dimensional (3D) motion capture system was used to obtain gait parameters (step length, step width, stride frequency, gait speed and toe-out angle) and the range of motion (ROM) of the joints (hip, knee and ankle). Results. PPC produced an increase in step width (23.4%, p > 0.05), but the gait speed (9.1%) and stride frequency (6.4%) decreased compared with the CON results. ROM is affected by the PPC type and joint. FPC and CPC_semi had no significant effect in terms of ROM of the hip and knee besides the landing angle of the knee. However, CPC_full had a significant effect on the maximum extension angle of the hip and maximum flexion angle of the knee, which reached up to 27.2%. Conclusion. The ROM of the firefighter’s lower limbs was limited by PPC. This study offers insights into next-generation PPC design and development, as well as guidelines for training and firefighting.

Firefighting: Challenges of Smart PPE

The continuous research and development regarding firefighters’ personal protective equipment (PPE) has led to significant improvements in recent decades. Despite the evolution of firefighters’ PPE, every year an undesirable number of firefighters are seriously burned during firefighting operations, with some of them eventually losing their lives. The protection given by firefighters’ PPE can be further increased with the incorporation of smart textiles in the personal protective equipment, namely, wearable electronics (i.e., integrated sensors to monitor diverse parameters: heart rate, oxygen saturation, carbon dioxide detector, and setting real-time communication with a command post) and advanced materials such as phase change materials (PCMs). The evolution of firefighters’ PPE has been followed by an evolution and update in the international and national standards that specify performance requirements for firefighters’ protective clothing for structural and wildland firefighting as well as technical rescue. This study will focus on the analysis of firefighters protective clothing evolution regarding the use and integration of advanced smart materials, namely, phase change materials, taking into consideration the evolution and requirements of international and European standards as well as national legislation for firefighters’ protective clothing.

Impact of repeated radiative heat exposure on protective performance of firefighter’s protective clothing

Firefighters rely heavily on their firefighter’s protective clothing (FPC) for their safety. The effectiveness of an appropriately engineered turnout suit decreases over time when repeatedly exposed to radiative heat and flame. A measure of durability is the radiative protective performance (RPP) rating, which is influenced by properties like thickness, surface area, and areal density (mass per unit area) of outer shell fabric in multilayered ensembles. Four independent variables were considered: fabric material, pick density, exposure cycles and heat flux intensity. In addition to RPP, changes in the thickness, shrinkage, and mass loss was also tracked. An evaluation of properties was conducted at the end of each cycle to determine the effects of the heat flux (21, 42 and 63 kW/m2), number of exposure cycles (from one to five) and effects of each attribute. Two types of fabrics were used in this study, one made with meta aramid (Nomex® IIIA) yarns in both warp and weft (type-A fabric), and the other made with Nomex® IIIA (warp) and para aramid (Kevlar®) (weft) (type-B fabric). Type-A fabrics displayed a greater degree of differentiation in their properties than type-B fabrics. With the same exposure conditions, the thickness, shrinkage, mass loss and RPP gradually increased. A regression analysis conclusively established that pick density significantly affects the performance of the outer-shell fabric used in FPCs. Textile designers may find the results useful for creating more thermo-stable and durable turnout suits in the future.

Contamination and removal of polycyclic aromatic hydrocarbons in multilayered assemblies of firefighting protective clothing

Contaminants deposited on the firefighter protective clothing increase the risk of carcinogenesis by transdermal absorption. The effects of the inclination angle, waterproof grade, and fabric structure of the flame retardant outer layer of firefighting protective clothing on polycyclic aromatic hydrocarbon (PAH) contamination and laundering were studied by simulating smoking exposure. The permeation and transmission process of PAHs in multilayered assemblies were investigated. Results showed that the adsorption capacity of soot and PAH contamination on fabric with a water repellent finish relatively increased, and outer layer absorbed more PAHs at 180° compared to other inclination angles. The fabric structure with single layer had a strong adsorption capacity and low removal capacity for PAHs. The highest amount of PAH contaminant was found in the moisture barrier layer, and the removal rate (44.7%) was much lower than that of the outer layer cleaned through conventional laundering (91.3%). The research can better provide scientific support for pollution control and clothing cleaning in the actual firefight.

Durability of metallic coating for improvement of thermal protective performance of firefighter protective clothing

The objective of this study is to investigate the durability of metallic coating for firefighter protective clothing when subjected to different washing cycles. Firefighter clothing ensemble consists of three layers, i.e. outer shell, moisture barrier, and thermal liner. The exposed surface of the outer shell was coated with silver particles through the physical vapor deposition process also called Magnetron sputtering. Afterwards, these specimens were exposed to radiant heat transmission machine at 30 kW/m2 and 40 kW/m2, respectively. It was found that specimens coated with silver particles showed improved thermal protective performance as compared to uncoated specimens. Later on, silver-coated specimens undergo five cycles of washing and their thermal protective performance in terms of transmitted heat flux density Qc (kW/m2) and radiant heat transmission index (RHTI 24 and RHTI 12) was measured. It was found that after five washing cycles, there was a negligible decline in thermal protective performance when exposed to 40 kW/m2. Afterwards, bending moment and water vapor resistance properties were measured before and after five washing cycles. It was inferred that there was no considerable difference in bending moment and water vapor resistance after different washing cycles, which confirmed stability of silver coating layers. However, when silver-coated outer shells were evaluated for abrasion resistance, there was a substantial decline in thermal protective performance on exposure to 40 kW/m2 after one hundred to five hundred cycles of abrasion.

PAH contamination of firefighter protective clothing and cleaning effectiveness

The objective of this study was to determine the concentration of polycyclic aromatic hydrocarbons (PAHs) in firefighter protective clothing used under different conditions (fire suppression operations and live-fire enclosure simulations). Ultra-high performance liquid chromatography with fluorescence detection (UHPLC/FL) was applied to determine PAH content in the outer shell, moisture barrier (membrane), and thermal barrier layers of protective clothing. Analysis involved eight PAHs, with the total PAH concentration being strongly dependent on use conditions and clothing layer. The PAH concentration in clothing worn during fire suppression (43 ± 16–63 ± 26 μg g−1) was approx. 10–12 times higher as compared to that in clothing worn during live-fire simulation (4.0 ± 1.1–5.4 ± 1.4 μg g−1). The highest total PAH content (84 ± 41 μg g−1) was found in the membrane of clothing worn during fire suppression (approx. 50 times greater than in the case of live-fire simulation – 1.6 ± 0.99 μg g−1). Cleaning with the use of machine washing removed a considerable part of PAH contamination, with cleaning effectiveness ranging from 79 ± 14% for the outer shell, 63 ± 25% for the membrane to 58 ± 14% for the thermal barrier. Furthermore, in firefighter protective clothing worn during fire suppression operations higher PAH concentrations were detected in samples from the knee region as compared to those from the sleeves.

Smart coating in protective clothing for firefighters: An overview and recent improvements

Recently, new developments in the design and performance optimization of smart mechanisms associated with natural and man-made hazards have progressed considerably. This is mainly owing to advances in smart sensing mechanisms including communication and data technologies. This work provides a detailed overview of existing improvements on smart hazard monitoring equipment and materials applied in textile sensing systems. Given that fire is one of the most common disasters in many countries such as Australia, and every year many firefighters are affected by these unfortunate incidents, the focus of this study is on firefighters' protective clothing Fire Fighter Protective clothing. This review provides a unique opportunity to study smart sensing systems in coating technologies, potentially provides more effective techniques for training and better safety protocols of fire fighters. It aims to revisit the existing advances and address recent challenges and opportunities for improvement in the domain of smart coating and fire protective wearables. The goal of this review is to provide information about smart coating in protective clothing for firefighters. The capability of some of these clothing in managing thermal stresses, responding to humid environment, monitoring some critical parameters and adapting to the size of the wearers (clothes fabricated with phase change and shape memory substances) made them attractive choice in adjusting specific design features of industrial textiles. Various types of phase change and shape memory substances are defined and a combination of these substances within the structure of fabrics are presented. This paper also provides a detailed review on the heat exposure and capability of the shape memory substances (SMM) and phase change materials (PCM) to delay the heat transfer through fire fighter protective clothing. Referring to the former research, several issues have been detected using such substances. For instance, combination of phase change and shape memory materials needs fundamental improvements with regards to assessment techniques and testing criteria. Additionally, recent improvements in the domain of PCM and SMM including modifying mechanical features, functionality, and durability under different conditions have been informed. It has been suggested that the major problem in developing fabric-Phase Change Materials (PCMs) and Shape memory material (SMM) systems is their usage methods. At last recent developments on wearable monitoring systems applied in the firefighters’ protective gear. Wearable sensors are usually used directly on the body or located on wearable items to monitor information related to firefighters’ safety.