Turnout Suit Research Articles

Ergonomic Assessment of Structural Firefighter Turnout Suit Designs for Improved Mobility

The purpose of this study was to design a novel turnout suit for improved mobility based on firefighter user needs. A wear trial assessment was performed to investigate the differences in range of motion (ROM), ease of movement, and comfort of a novel structural firefighter turnout suit versus existing suit models on the market today. Ten healthy firefighters wore three different turnout suits while their ROM was measured using electro-goniometers worn against the skin in the shoulder, elbow, hip, and knee joints. Perceived ease of movement ratings were gathered for 13 static joint exercises. A subjective perception survey was administered after completing the static protocol in each suit. A dynamometer measured peak force and torque in the elbow, knee, and shoulder joints. Results indicate significant differences occurred between the suits for perceived ease of movement ratings and hip ROM.

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.

Using a physiological manikin to evaluate the effect of foam thermal reinforcement in firefighter turnout construction on heat strain

Firefighter turnout gear is a significant contributor to firefighter heat stress. This study uses a physiological manikin procedure to show how adding impermeable foam reinforcement in a firefighter suit construction can detrimentally affect firefighter heat strain. It shows that singular reliance on the THL (total heat loss) requirement called for by the NFPA (National Fire Protection Association) 1971 performance standard for firefighter gear leaves a critical gap in information needed to evaluate the heat strain contribution of reinforced turnout suit constructions. This is because THL test only measures heat loss through flat swatches of fabric used in the main body of the turnout suit construction. It does not account for the additional insulation and moisture vapor resistance of reinforcement or the overwhelming effects of garment air layers. This study demonstrates instrumented manikin testing procedures can supply the missing information in laboratory based heat strain performance testing of firefighter turnout suits.

Relationship between heat loss indexes and physiological indicators of turnout-related heat strain in mild and hot environments

A validated physiological manikin method was used to qualify environmentally dependent correlations between firefighter turnout total heat loss (THL) and intrinsic evaporative resistance (R ef) heat strain indexes and core temperature rise in stressful work conducted in mild (25 °C, 65% relative humidity [RH]) and hot (35 °C, 40% RH; 40 °C, 28% RH) conditions. Five turnout suit constructions representing a wide range of breathability were selected. The observed correlations between measured material heat loss and core temperature showed that the THL heat strain index accurately forecast thermal burden in mild environments (<25 °C); while the R ef index provided accurate prediction in hot environments (>35 °C). They showed that the THL index did not predict heat strain in hot work environments. The findings of this study support incorporating both the R ef and THL heat strain indexes as dual metrics for characterizing the heat strain performance of turnout clothing fabrics.

Effects of Outer Shell Fabric Color, Smoke Contamination, and Washing on Heat Loss through Turnout Suit Systems

Firefighters frequently have to work in direct solar radiant heat. To reduce firefighter heat stress, the influence of turnout garment properties on heat gain from solar radiation must be understood. This research studied the effects of color, texture, washing, and contamination of outer shell fabrics on heat loss through firefighter turnout fabric materials in simulated solar exposures. It showed that solar radiation could be a major factor in heat loss through turnout suits. Solar radiation equivalent to a sunny day completely reversed heat exchange through the turnout fabric systems, converting a heat loss of about 240 W/m2 to a heat gain exceeding 100 W/m2. Solar radiation caused turnout fabric systems to dry out and this decreased the performance of turnout systems that incorporated bi-component moisture barriers. Most significantly, the color of the outer shell had a major influence on lowering turnout heat loss in solar exposures. Composites with a black-dyed outer shell absorbed more solar energy than composites with lighter colored shell materials. Soot and fire-ground contaminants present on turnout outer shell fabrics also reduced heat loss under solar exposure. The findings of this study answered long-standing questions about the importance of turnout fabric color on heat exchange with the environment. The results provide additional motivation for efficient turnout cleaning practices, not only to reduce potentially toxic exposure to smoke contaminants, but to reduce turnout-gear-related heat strain on firefighters.

Identifying factors that contribute to structural firefighter heat strain in North America

This article describes results from a survey of firefighters designed to identify conditions that contribute to heat strain in structural firefighting. Based on responses from about 3000 firefighters across the USA and Canada, the article provides invaluable information about how firefighters associate environmental conditions, work tasks and other factors with heat strain. One-half of firefighters surveyed have experienced heat stress during their service. They can wear fully deployed turnout gear for 2 h or more at the fire scene, reinforcing the importance of turnout suit breathability as a factor in heat strain. Survey results are useful in weighing the comparative value of total heat loss (THL) and evaporative heat resistance (Ref) for predicting turnout-related heat strain. Survey findings support the inclusion of a performance criterion in the National Fire Protection Association 1971 standard for firefighter personal protective equipment based on limiting Ref of turnout materials along with current THL requirement.

A Survey of Structural Firefighter Station Wear in the United States

Structural turnout gear is essential for the safety of firefighters. The station wear, or clothing worn underneath the structural turnout suit, contributes to the thermal protection and performance of the overall ensemble. Depending on the fiber content and material fabrication, base layer garments may increase the risk of potential burn injuries. The purpose of this research was to evaluate National Fire Protection Association (NFPA) 1975 certified, certified flame resistant, and non-certified station wear garments in relation to firefighter burn injuries while worn under a NFPA 1971 structural firefighting ensemble. An information-gathering questionnaire was distributed nationwide with over 1800 active-duty United States firefighting personnel responding to questions regarding the selection and use of their station wear. Responses concerning the thermoplastic nature of base layer materials, the design and configuration of how base layers are worn, and the overall satisfaction with the performance of certified versus non-certified station wear were gathered. Questionnaire responses determined 80% of participants were aware of the overall risk of wearing non-certified base layer garments (i.e. synthetics that will melt or drip); however, 45% of career firefighters indicated they were not required to wear certified or flame resistant station wear. Regional analysis of the responses was performed. Findings of this research will educate the fire service and inform NFPA standards committees. Further, this study supports the need for future research to develop station wear garments with improved burn injury protection, thermal comfort, and ergonomic mobility.

Effect of structural turnout suit fit on female versus male firefighter range of motion

The purpose of this study was to assess the impact of fit on female versus male firefighter range of motion (ROM) when donning a structural turnout ensemble. Three test ensembles were evaluated: base layers (BL), turnout suit (TS), and turnout ensemble (TE). Sixteen career firefighters (10 males; 6 females) completed a user needs survey on fit and mobility restrictions, were measured in a three-dimensional body scanner, performed a static ROM protocol, and recorded ease of movement and comfort perceptions for each ensemble. Average body measurements and absolute ROM values were calculated for each test ensemble and analyzed by gender. Results demonstrated multiple significant differences in body measurements between male and female firefighters when wearing the BL and TS test ensembles. Mobility was significantly reduced when donning the TS and TE, regardless of gender. Significant differences in trunk and shoulder flexion when wearing turnout suits were identified according to participant gender.

Firefighter Turnout Suit Weight Influences Simulated Exercise Performance

PURPOSE: To investigate how structural firefighter protective ensemble weight influences rate of perceived exertion (RPE) during firefighter simulated exercise (FFSE). METHODS: 10 active firefighters (age: 33±6 years, Ht:178.2±3.1 cm, Wt:78.6±16.7 kg) were asked to wear, in random order, two ensembles: 1) a single layer (SL) outer shell (2.45 kg) and 2) a traditional turnout suit (4.57 kg). On each laboratory visit, the firefighters performed the FFSE that consisted of two rounds of a 15.24m hose advance, a 15.24m weighted (40.83 kg) carry, sledge hammer exercise, a 15.24m tire flip, a 15.24m dummy drag, rope pull, and unweighted stair climb, with a 1-minute rest period between rounds. The FFSE included a 5-minute acclimation period in the ensemble, a warm up (10 pushups, 10 squats, 20 jumping jacks). Subjects were asked to complete the FFSE as fast as possible. The traditional turnout suit consisted of an outer shell, moisture barrier, and thermal barrier typically found in most turnout suits. The Borg rating of perceived exertion scale was asked immediately at the end of each round of FFSE and ensemble weights were measured pre-FFSE. RESULTS: The SL resulted in lower average RPE for round 1 (SL: 12.8±1.7 vs. Traditional: 13.8±1.7; p=0.05) and round 2 (SL: 14.2±1.6 vs. Traditional: 16.2±2.3, p=0.01) than the traditional turnout. In addition, round 2 of the FFSE was completed significantly faster than the traditional turnout suit (SL: 262.8±55.7 vs. Traditional: 293.4±64.9 sec; p =0.02). CONCLUSIONS: The weight of the turnout suit increases RPE, which appears to influence performance for FFSE. Supported by Fire-Dex, LLC.

Relationship between novel design modifications and heat stress relief in structural firefighters’ protective clothing

The purpose of this study was to investigate design modifications in structural firefighter turnout suits for their ability to reduce heat stress during firefighting activities. A secondary aim of this research established a benchmark for the manikin heat loss value necessary to achieve significant improvements in physiological comfort. Eight professional firefighters participated in five simulated exercise sessions wearing a control turnout suit and one of four turnout prototypes: Single Layer, Vented, Stretch, and Revolutionary. Physiological responses (internal core body temperature, skin temperature, physiological strain, heart rate, and sweat loss) were measured when wearing each turnout suit prototype. Results demonstrated a significant increase in work time and significant reductions in heat stress (core temperature, skin temperature, and physiological strain) when participants wore the Single Layer, Vented, and Revolutionary prototypes. An estimated garment heat loss value of 150 W/m2 was determined in order to achieve a significant reduction in heat stress.

Impact of reinforcements on heat stress in structural firefighter turnout suits

The purpose of this research was to determine the impact of additional textile layer reinforcements on garment heat loss and the physiological comfort of the firefighter. Four structural firefighter turnouts with varying levels of ‘bulk’ were assessed. A base composite analysis was conducted and each suit was evaluated for thermal resistance, evaporative resistance, and overall total heat loss (THL) on a sweating thermal manikin. Raw resistance data were then modeled to predict the physiological responses of firefighters for each turnout suit. Base composite percentages were compared to the heat loss values and predicted physiological responses. The Light Weight suit along with the Control, demonstrated the greatest heat loss values and lowest rise in predicted core temperature. Overall, results depicted the harmful impact that bulky reinforcements may have on wearer physiological comfort as the Heavy Duty suit had significantly lower heat loss and a potentially fatal maximum predicted core temperature.

Analysis of air gap volume in structural firefighter turnout suit constructions in relation to heat loss

Air layers in multi-layer firefighter clothing ensembles resist heat transfer from the body to the environment. By reducing the volume of air between clothing layers, heat loss may be improved throughout the multi-layer firefighter turnout suit clothing system, potentially leading to reduced heat strain for the wearer. This research utilized a systems-level approach to the methodology in order to measure the effects of fabric properties and garment air gap dimensions on clothing system heat loss through specially configured turnout suit constructions. One experimental configuration incorporated a tight fitting stretchable moisture barrier garment. Another construction used thermal knit underwear to represent a closer fitting thermal liner. Air gap surface area, volume, and thickness were estimated using three-dimensional body scanning. This study showed the significant impact of fabric air permeability and clothing air gap volume on heat loss through structural firefighter suits. Tested individually, the tighter fitting moisture barrier construction permitted greater heat loss in comparison to the traditional fit moisture barrier. Heat loss differences associated with moisture barrier fit were not observed when the moisture barriers were configured in the three-layer turnout clothing system. This research showed that microclimate air gap volume is strongly correlated with total heat loss. It confirmed the significant impact of clothing air layers on heat loss through firefighter turnout systems.

Factors Affecting the Thermal Insulation and Abrasion Resistance of Heat Resistant Hydro-Entangled Nonwoven Batting Materials for Use in Firefighter Turnout Suit Thermal Liner Systems

This paper describes a study on heat resistant nonwoven batting materials used as components in the construction of thermal liners systems in firefighter turnout suits. It examines relationships between the fiber composition and construction of hydroentangled nonwoven battings and properties that can affect their performance when used in this application. Relationships between batting porosity, weight, thermal insulation, bulk and abrasion resistance are examined in hydroentangled constructions made with oxidized PAN, para-aramid and meta-aramid fibers. Correlations observed between the insulation of batting materials components and the thermal protective performance of integrated multilayered fabric systems used in firefighter turnout suits are described.

Heat Transmission and Thermal Energy Storage in Firefighter Turnout Suit Materials

This paper describes research conducted to develop a better understanding of the effects of turnout materials on heat transmission and thermal energy storage in moisture preconditioned samples exposed to low level radiant heat. It utilized a newly developed laboratory apparatus and testing procedures to generate data on a range of materials used in the construction of firefighter turnouts.

A CB Protective Firefighter Turnout Suit

This paper describes research that developed a prototype chemical and biological (CB) protective firefighter suit. It is presented as a case study demonstrating an integrated systems approach to designing, developing and evaluating a protective clothing ensemble based on end user requirements. It includes a discussion of the process that was used to gain an understanding of firefighter performance needs for a structural turnout suit that also incorporated chemical protection. It describes the design features of the turnout suit that were developed to meet these expectations as well as the program of testing and evaluation used to characterize garment performance. It discusses ensemble level performance evaluations in instrumented fire manikin tests and man-in-stimulant test procedures. It describes studies conducted to determine the impact of prototype garment design features on heat stress, wear comfort and ergonomic function in structural firefighting applications.

Manikin test for flame engulfment evaluation of protective clothing: Historical review and development of a new ISO standard

AbstractThe overall performance of a firefighter turnout suit can only be evaluated using both bench‐scale tests and an assessment based on an instrumented manikin under defined, close to real‐life conditions in a laboratory. Using manikins in rating protective clothing has already a long history which will be reflected in this paper. Efforts all over the world to reproduce a flame engulfment situation in a laboratory are currently being combined in a new draft international standard (ISO/DIS 13506.3). A round robin test showed an acceptable reproducibility for this method based on a manikin test and a gas burner system. An overview of existing measurement systems and the results of this round robin are discussed and possible improvements for the standard flame engulfment test method are proposed. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Maximal physical work performance with European standard based fire-protective clothing system and equipment in relation to individual characteristics.

Every fire fighter needs to wear fire-protective clothing and a self-contained breathing apparatus (SCBA) several times a year while carrying out various fire-fighting and rescue operations in hazardous work environments. The aim of the present study was to quantify the effects of a multilayer turnout suit designed to fulfil European standard EN 469 used over standardized (Nordic) clothing and with SCBA (total mass 25.9 kg) on maximal physical work performance, and to evaluate the relationship between individual characteristics and power output with the fire-protective clothing system and SCBA. The subjects were 12 healthy firemen aged 26-46 years. The range of their body mass, body fat and maximal oxygen consumption was 69-101 kg, 10-20% and 2.70-5.86 l.min-1, respectively. The maximal tests without (control) and with the fire-protective clothing system and SCBA were carried out on a treadmill in a thermoneutral environment. When compared to the control test, the decrease in the maximal power output in terms of maximal working time and walking speed averaged 25% (P < 0.001) varying from 18% to 34% with the fire-protective clothing system and SCBA. At maximum, no significant differences were found in pulmonary ventilation, absolute oxygen consumption, the respiratory exchange ratio, heart rate, systolic blood pressure, the rate-pressure product, mechanical efficiency, and the rating of perceived exertion between the tests with and without the fire-protective clothing system and SCBA. The reduction of the power output was related to the extra mass of the fire protective clothing and SCBA.(ABSTRACT TRUNCATED AT 250 WORDS)