Functional Design and Evaluation of Structural Firefighter Turnout Suits for Improved Thermal Comfort

Structural firefighter prototype designs incorporating ventilation, stretch, and modularity were developed following Watkins’ functional design process. Prototypes were designed and manufactured, including single-layer, vented, stretch, and combination prototypes. Prototype garments were evaluated for improved thermal comfort and heat loss using sweating thermal manikin assessments in two conditions: static (standing still with no wind) and dynamic (walking with wind). Raw thermal and evaporative resistance data from the manikin testing were input into a thermal modeling software system (RadTherm®) and physiological responses (core temperature, skin temperature, and sweat rate) were predicted for each prototype. A significant improvement in heat loss was measured when ventilation openings and modularity were added to the design of the clothing system. The single-layer, vented, and combination prototypes also had significantly lower increases in predicted physiological responses.

Download Full-text

Comparison of clothing thermal comfort properties measured on female and male sweating manikins

Textile Research Journal ◽

10.1177/0040517516669071 ◽

2016 ◽

Vol 87 (18) ◽

pp. 2214-2223 ◽

Cited By ~ 3

Author(s):

Chao Sun ◽

Jintu Fan

Keyword(s):

Thermal Comfort ◽

Heat Loss ◽

Thermal Insulation ◽

Female Body ◽

Body Shape ◽

The Body ◽

Thermal Manikin ◽

Unit Surface Area ◽

Evaporative Resistance ◽

Evaporative Water

Thermal manikins simulating human body’s thermal regulatory system are essential tools for understanding the heat exchange between human body and the environment and also for evaluating the thermal comfort of clothing and near environment. However, most existing thermal manikins adopt a male’s body shape and no sweating female thermal manikin has been reported so far. Furthermore, it is unclear how body shape (viz. male vs female) affects the heat loss and perspiration from the body. We report on a novel female sweating thermal manikin “Wenda”. Thermal properties of the nude body and clothing ensembles measured on “Wenda” are compared with those measured on the male manikin “Walter”. It was found that, although the more curvaceous female body reduces the thermal insulation of the nude manikin, it increases the apparent evaporative resistance at the same time. This may be due to the fact that the more curvaceous female body increases the surface still air layer to add resistance to heat loss by conduction and evaporative water loss by diffusion, and significantly increases the percentage of effective radiative area and the resultant radiative heat loss per unit surface area. It was further shown that clothing thermal insulation and apparent evaporative resistance measured on Wenda are typically 0 ∼ 11% higher than those measured on the male sweating fabric manikin-Walter, probably due to the greater clothing microclimate volume on the female manikin resulting from the looser fitting of the garments on the smaller female body and the more curvaceous surface of the female body.

Download Full-text

Thermal comfort properties of bifacial fabrics

Textile Research Journal ◽

10.1177/0040517517736473 ◽

2017 ◽

Vol 89 (1) ◽

pp. 43-51 ◽

Cited By ~ 2

Author(s):

Licheng Zhu ◽

Xungai Wang ◽

Ian Blanchonette ◽

Maryam Naebe

Keyword(s):

Thermal Comfort ◽

Heat Loss ◽

Air Permeability ◽

Total Heat ◽

Loop Length ◽

Permeability Index ◽

Total Heat Loss ◽

Knitted Fabrics ◽

Evaporative Resistance ◽

Thermal Comfort Properties

Bifacial fabrics, with a single jersey on one face and a plain weave on the other, were produced on a purpose-built machine. Thermal comfort properties of bifacial fabrics were compared with conventional woven and knitted fabrics and the effect of weft density and loop length of bifacial fabrics on their thermal comfort properties was investigated. While different fabric structures were produced with the same wool, acrylic, and polyester yarns, the findings confirmed that the bifacial fabric is warmer (lower total heat loss) and more breathable (higher permeability index ( im)) than the corresponding woven and knitted fabrics. Increasing the loop length of bifacial fabrics enhanced evaporative resistance, air permeability, warm feeling, thermal resistance, and water vapor permeability index, yet reduced total heat loss. An increase in the weft density of bifacial fabrics led to higher evaporative resistance, warmer feeling, higher thermal resistance, lower air permeability, and total heat loss. However, the permeability index did not change with an increase in weft density. This study suggests that thermal comfort properties of bifacial fabrics can be optimized by modifying structural parameters to engineer high-performance textiles.

Download Full-text

The effect of garment combinations on thermal comfort of office clothing

Textile Research Journal ◽

10.1177/0040517519834609 ◽

2019 ◽

Vol 89 (21-22) ◽

pp. 4425-4437 ◽

Cited By ~ 4

Author(s):

Hande G Atasağun ◽

Ayşe Okur ◽

Agnes Psikuta ◽

René M Rossi ◽

Simon Annaheim

Keyword(s):

Thermal Comfort ◽

Heat Loss ◽

Heat Dissipation ◽

Moisture Transfer ◽

The Body ◽

Raw Material ◽

Upper Body ◽

Thermal Manikin ◽

Evaporative Heat Loss ◽

Body Regions

Clothing and the enclosed air layers highly affect heat dissipation from the body and thus, are crucial factors when it comes to thermal comfort. The heat and moisture transfer is affected by the variation of the size and the shape of air gaps between the garment and the human body. In addition, the fabric and garment design properties can affect the amount of heat loss from different body parts. In this study, we investigated the effect of fabric properties (different raw materials and weave types) and the garment fit on the heat loss through the garment combinations (undershirt and shirt) for the different parts of the upper body (trunk, chest, and back) using a sweating thermal manikin. The undershirt fit and the raw material of the shirts showed strong effects on the dry thermal resistance of the garment combinations. Moreover, the undershirt properties affected the evaporative heat loss from garment combinations, and the magnitude of these effects varied over different body regions. Whilst the undershirt fit had a significant impact on the evaporative heat loss of the back region, the influence of the undershirt raw material was more important in the chest region. The findings of this study provide fundamental knowledge to improve the thermal comfort of garment combinations for office wear.

Download Full-text

Determination of Clothing Evaporative Resistance on a Sweating Thermal Manikin in an Isothermal Condition: Heat Loss Method or Mass Loss Method?

The Annals of Occupational Hygiene ◽

10.1093/annhyg/mer034 ◽

2011 ◽

Cited By ~ 21

Keyword(s):

Mass Loss ◽

Heat Loss ◽

Isothermal Condition ◽

Thermal Manikin ◽

Evaporative Resistance ◽

Loss Method ◽

Sweating Thermal Manikin

Download Full-text

Investigation on thermal comfort of the uniform for workers in tropical monsoon climates

International Journal of Clothing Science and Technology ◽

10.1108/ijcst-07-2019-0104 ◽

2020 ◽

Vol 32 (6) ◽

pp. 849-868

Author(s):

Jingxian Xu ◽

Huijuan Liu ◽

Yunyi Wang ◽

Jun Li

Keyword(s):

Heat Transfer ◽

Thermal Comfort ◽

Dynamic Condition ◽

Thermal Manikin ◽

Content Type ◽

Wind Speeds ◽

Subjective Perceptions ◽

Tropical Monsoon ◽

Four Levels ◽

Thermal Insulations

PurposeThis study aims to investigate the heat transfer mechanism of the uniforms used by people working in hot, humid and windy environments. Furthermore, the effectiveness of an opening structure added to the armpit of the uniforms in improving thermal comfort was comparatively examined.Design/methodology/approachA set of uniforms was tested with the opening at the armpit alternatively zipped or unzipped. Thermal manikin and human tests were performed in a climatic chamber simulating the specific environmental conditions, including wind speeds at four levels (0.15, 0.5, 2, 4 m/s) and relative humidities at two levels (50 and 85%). Static and dynamic thermal insulations of clothing (IT) were examined by the thermal manikin tests. The human bodies' thermal responses, including heart rates (HR), eardrum temperatures (Te), skin temperatures (Tsk) and subjective perceptions, were given by the human tests.FindingsSpecial mechanisms of heat transfer in the specific uniforms used in tropical monsoon climates were revealed. Reductions on IT were caused by the movement of the human body and the environmental wind, and the empirical equations would underestimate this reduction. The opening at the armpit was able to prompt more heat transfer under dynamic condition, with reducing the IT by 11.8%, lowering the mean Tsk by 0.92°C, and significantly improving the subjective perceptions (p < 0.05). The heat exhaustion was alleviated with lowering the Te by 0.32°C.Originality/valueThis study managed to improve the thermal performance of uniforms for workers under unforgiving conditions. The evaluation and design methods introduced by this study provided practical guidance for similar products with strict dress codes and cost control requirements based on the findings from thorough product tests and analysis.

Download Full-text

Influence of Masks Protecting against SARS-CoV-2 on Thermal Comfort

Energies ◽

10.3390/en14113315 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3315

Author(s):

Ewa Zender-Świercz ◽

Marek Telejko ◽

Beata Galiszewska

Keyword(s):

Thermal Comfort ◽

Public Spaces ◽

Point Of View ◽

The Other ◽

Health Policies ◽

Thermal Manikin ◽

Public Health Policies ◽

Protective Shield ◽

Full Face ◽

The Impact

Due to the spread of the SARS-CoV-2 virus, most countries have tightened their public health policies. One way to limit the spread of the virus is to make mouth and nose cover compulsory in public spaces. The article presents the impact of wearing masks on the perception of thermal comfort. The following masks were analysed: FFP2, cotton, medical, PM2.5, half-face protective shield plastic and full-face protective shield plastic. The research was carried out for two scenarios of an ambient temperature: −20 and 30 °C. A thermal manikin was used for the tests. In the case of when a temperature equals 20 °C, the dry masks increase comfort, both general and local, while wet masks reduce comfort. On the other hand, at 30 °C, only wet masks do not increase discomfort. In addition, moist masks require less heat flux to achieve a certain skin temperature. However, it should be remembered that it is not advisable to wet the masks from the health point of view.

Download Full-text

Effects of environmental temperature and humidity on evaporative heat loss through firefighter suit materials made with semi-permeable and microporous moisture barriers

Textile Research Journal ◽

10.1177/00405175211026537 ◽

2021 ◽

pp. 004051752110265

Author(s):

Huipu Gao ◽

Anthoney Shawn Deaton ◽

Xiaomeng Fang ◽

Kyle Watson ◽

Emiel A DenHartog ◽

...

Keyword(s):

Heat Loss ◽

Environmental Temperature ◽

Moisture Absorption ◽

Evaporative Heat Loss ◽

Total Heat Loss ◽

Evaporative Resistance ◽

Environmental Testing ◽

Permeable Barrier ◽

Moisture Condensation ◽

Moisture Barriers

The goal of this research was to understand how firefighter protective suits perform in different operational environments. This study used a sweating guarded hotplate to examine the effect of environmental temperature (20–45°C) and relative humidity (25–85% RH) on evaporative heat loss through firefighter turnout materials. Four firefighter turnout composites containing three different bi-component (semi-permeable) and one microporous moisture barriers were selected. The results showed that the evaporative resistance of microporous moisture barrier systems was independent of environmental testing conditions. However, absorbed moisture strongly affected evaporative heat loss through semi-permeable moisture barriers coated with a layer of nonporous hydrophilic polymer. Moisture absorption in mild environment (20–25°C) tests, or when testing at high humidity (>85% RH), significantly increased water vapor transmission in semi-permeable turnout systems. It was also found that environmental conditions used in the total heat loss (THL) test (25°C and 65% RH) produced moisture condensation in bi-component barrier systems, making them appear more breathable than could be expected when worn in hotter environments. Regression models successfully qualified the relationships between moisture uptake levels in semi-permeable barrier systems and evaporative resistance and THL. These findings reveal the limitations in relying on THL, the heat strain index currently called for by the NFPA 1971 Standard for Structural Firefighter personal protective equipment, and supports the need to measure turnout evaporative resistance at 35°C (Ret), in addition to THL at 25°C.

Download Full-text