The Thermal Protective Performance of Firefighters' Clothing: The Air Gap Between the Clothing and the Body

2016 ◽  
Vol 38 (10) ◽  
pp. 975-986 ◽  
Author(s):  
Ahmed Ghazy
Keyword(s):  
Air Gap ◽  
The Body ◽  
Thermal Protective Performance ◽  
Protective Performance

scholarly journals Investigating the Thermal-Protective Performance of Fire-Retardant Fabrics Considering Garment Aperture Structures Exposed to Flames

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3579
Author(s):  
Miao Tian ◽  
Qi Wang ◽  
Yiting Xiao ◽  
Yun Su ◽  
Xianghui Zhang ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Heat Flux ◽  
Thermal Aging ◽  
Thermal Protection ◽  
Fire Retardant ◽  
Air Gap ◽  
Protective Function ◽  
Thermal Protective Performance ◽  
Positive Effects ◽  
Protective Performance

The application of fire-retardant fabrics is essential for providing thermal protective function of the garments. Appropriate clothing design are beneficial for preventing the wearers from skin burn injuries and heat strains simultaneously. The intention of this work was to investigate the effects of clothing ventilation designs on its thermal protective performance by bench-scale tests. Four boundary conditions were designed to simulate the garment aperture structures on fabric level. Tests of thermal shrinkage, mass loss and time-to-second-degree-burns were performed with and without air gap under three heat-flux levels for two kinds of inherently fire-retardant fabrics. The impacts of fabric type, heat-flux level, air gap and boundary condition were analyzed. The presence of a 6.4-mm air gap could improve thermal protective performance of the fabrics, however, the garment openings would decrease this positive effects. More severe thermal aging found for spaced test configuration indicated the importance of balancing the service life and thermal protective performance of the clothing. The findings of this study implied that the characteristics of fabric type, air gap, boundary condition, and their effects on fabric thermal aging should be considered during clothing ventilation designs, to balance the thermal protection and comfort of the protective gear.

Effects of air gap entrapped in multilayer fabrics and moisture on thermal protective performance

2012 ◽  
Vol 13 (5) ◽  
pp. 647-652 ◽  
Author(s):  
Yun-yi Wang ◽  
Ye-hu Lu ◽  
Jun Li ◽  
Jin-huan Pan
Keyword(s):  
Air Gap ◽  
Thermal Protective Performance ◽  
Protective Performance

scholarly journals Do air-gaps behind soft body armour affect protection?

2017 ◽  
Vol 164 (1) ◽  
pp. 15-18 ◽  
Author(s):  
Lee Tilsley ◽  
D J Carr ◽  
C Lankester ◽  
C Malbon
Keyword(s):  
Ceramic Composite ◽  
Air Gap ◽  
The Body ◽  
Gap Size ◽  
Soft Body ◽  
Air Gaps ◽  
Body Armour ◽  
Ballistic Protection ◽  
Back Face ◽  
Full Metal Jacket

IntroductionBody armour typically comprises a fabric garment covering the torso combined with hard armour (ceramic/composite). Some users wear only soft armour which provides protection from sharp weapons and pistol ammunition. It is usually recommended that body armour is worn against the body with no air-gaps being present between the wearer and the armour. However, air-gaps can occur in certain situations such as females around the breasts, in badly fitting armour and where manufacturers have incorporated an air-gap claiming improvements in thermophysiological burden. The effect of an air-gap on the ballistic protection and the back face signature (BFS) as a result of a non-perforating ballistic impact was determined.MethodsArmour panels representative of typical police armour (400x400 mm) were mounted on calibrated Roma Plastilina No 1 and impacted with 9 mm Luger FMJ (9×19 mm; full metal jacket; Dynamit Nobel DM11A1B2) ammunition at 365±10 m/s with a range of air-gaps (0–15 mm). Whether or not the ammunition perforated the armour was noted, the BFS was measured and the incidence of pencilling (a severe, deep and narrow BFS) was identified.ResultsFor 0° impacts, a critical air-gap size of 10 mm is detrimental to armour performance for the armour/ammunition combination assessed in this work. Specifically, the incidences of pencilling were more common with a 10 mm air-gap and resulted in BFS depth:volume ratios ≥1.0. For impacts at 30° the armour was susceptible to perforation irrespective of air-gap.ConclusionsThis work suggested that an air-gap behind police body armour might result in an increased likelihood of injury. It is recommended that body armour is worn with no air-gap underneath.

Experimental Studies on Diesel Engine with Piston Crown Modification Using an Optimum Alternative Fuel

2015 ◽  
Vol 813-814 ◽  
pp. 830-835
Author(s):  
Akkaraju H. Kiran Theja ◽  
Rayapati Subbarao
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Air Gap ◽  
The Body ◽  
Injection Timing ◽  
Positive Trend ◽  
Piston Crown ◽  
Karanja Oil

The drawbacks associated with bio-fuels can be minimized by making modifications to combustion chamber. Modification of combustion chamber is achieved by providing an air gap in between the crown and the body of the piston with the top crown made of low thermal conductivity material. Experimentation is carried on a diesel engine with brass as piston crown material and karanja as test fuel, which is found to be a better alternative fuel based on the tests carried out prior to modification. Investigations are carried out on the performance of the engine with modified combustion chamber consisting of air gap insulated piston with 2 mm air gap with brass crown when fuelled with karanja oil. Comparative studies are made between the two configurations of engine with and without modification at an injection timing of 29obTDC. Performance, heat balance and emission plots are made with respect to brake power. Fuel consumption increased with modification. The mechanical and volumetric efficiencies are similar in both the cases. Indicated and brake thermal efficiencies got reduced with modification. But, it is good to see that HC and CO emissions are showing positive trend. Thus, the present investigation hints the possibility of improvements while making piston modification and providing air gap insulation.

scholarly journals A categorization tool for fabric systems used in firefighters' clothing based on their thermal protective and thermo-physiological comfort performances

2018 ◽  
Vol 89 (16) ◽  
pp. 3244-3259 ◽  
Author(s):  
Sumit Mandal ◽  
Simon Annaheim ◽  
Andre Capt ◽  
Jemma Greve ◽  
Martin Camenzind ◽  
...  
Keyword(s):  
Performance Index ◽  
Protective Clothing ◽  
High Performance ◽  
Clustering Algorithm ◽  
Health And Safety ◽  
Thermal Protective Performance ◽  
Thermal Protective Clothing ◽  
Low Performance ◽  
Fabric System ◽  
Protective Performance

Fabric systems used in firefighters' thermal protective clothing should offer optimal thermal protective and thermo-physiological comfort performances. However, fabric systems that have very high thermal protective performance have very low thermo-physiological comfort performance. As these performances are inversely related, a categorization tool based on these two performances can help to find the best balance between them. Thus, this study is aimed at developing a tool for categorizing fabric systems used in protective clothing. For this, a set of commercially available fabric systems were evaluated and categorized. The thermal protective and thermo-physiological comfort performances were measured by standard tests and indexed into a normalized scale between 0 (low performance) and 1 (high performance). The indices dataset was first divided into three clusters by using the k-means algorithm. Here, each cluster had a centroid representing a typical Thermal Protective Performance Index (TPPI) value and a typical Thermo-physiological Comfort Performance Index (TCPI) value. By using the ISO 11612:2015 and EN 469:2014 guidelines related to the TPPI requirements, the clustered fabric systems were divided into two groups: Group 1 (high thermal protective performance-based fabric systems) and Group 2 (low thermal protective performance-based fabric systems). The fabric systems in each of these TPPI groups were further categorized based on the typical TCPI values obtained from the k-means clustering algorithm. In this study, these categorized fabric systems showed either high or low thermal protective performance with low, medium, or high thermo-physiological comfort performance. Finally, a tool for using these categorized fabric systems was prepared and presented graphically. The allocations of the fabric systems within the categorization tool have been verified based on their properties (e.g., thermal resistance, weight, evaporative resistance) and construction parameters (e.g., woven, nonwoven, layers), which significantly affect the performance. In this way, we identified key characteristics among the categorized fabric systems which can be used to upgrade or develop high-performance fabric systems. Overall, the categorization tool developed in this study could help clothing manufacturers or textile engineers select and/or develop appropriate fabric systems with maximum thermal protective performance and thermo-physiological comfort performance. Thermal protective clothing manufactured using this type of newly developed fabric system could provide better occupational health and safety for firefighters.

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