Thermal Properties of Special New Generation Personal Protective Clothing for Firefighters-Rescuers

Every day, firefighters put their health and life at risk by saving people and their property not only during fires, but by being always ready during all kinds of unfortunate events. Therefore, they need special personal protective equipment, including protective clothing. The purpose of the study was to compare thermal properties of new (PROTON and SYRIUSZ) and old (US-03) personal protective clothing for firefighters. Measurements of thermal insulation (total, effective and local) were carried out using a full body shape thermal manikin Newton consisting of 34 segments, in which temperature and heat flux were controlled independently. Results of the total thermal insulation of the entire clothing reveal differences between all three models. The lowest values were noticed for the model PROTON with light and shorter jacket and the highest values of thermal insulation for the new model SYRIUSZ, indicating that this model protect the user against heat most effectively. New models of personal protective clothing for firefighters should be recommended for use in everyday work, because they are characterized by better parameters than the previous type of protective clothing, both in terms of thermal protection and mobility.

Numerical Investigation of Bioaerosol Transport in a Compact Lavatory

The lavatory is a fertile area for the transmission of infectious disease through bioaerosols between its users. In this study, we built a generic compact lavatory model with a vacuum toilet, and computational fluid dynamics (CFD) is used to evaluate the effects of ventilation and user behaviors on the airflow patterns, and the resulting fates of bioaerosols. Fecal aerosols are readily released into the lavatory during toilet flush. Their concentration rapidly decays in the first 20 s after flushing by deposition or dilution. It takes about 315 s to 348 s for fine bioaerosols (<10 µm in diameter) to decrease to 5% of the initial concentration, while it takes 50 and 100 µm bioaerosols approximately 11 and <1 s, respectively, to completely deposit. The most contaminated surfaces by aerosol deposition include the toilet seat, the bowl, and the nearby walls. The 10 µm aerosols tend to deposit on horizontal surfaces, while the 50 and 100 µm bioaerosols almost always deposit on the bowl. In the presence of a standing thermal manikin, the rising thermal plume alters the flow field and more bioaerosols are carried out from the toilet; a large fraction of aerosols deposit on the manikin’s legs. The respiratory droplets generated by a seated coughing manikin tend to deposit on the floor, legs, and feet of the manikin. In summary, this study reveals the bioaerosol dilution time and the easily contaminated surfaces in a compact lavatory, which will aid the development of control measures against infectious diseases.

Textile Pattern Design in Thermal Vision—A Study on Human Body Camouflage

This paper reports on a new approach to the creation process in fashion design as a result of the exploitation of thermal camouflage in the conceptualization of clothing. The thermal images’ main variation factors were obtained through the analysis of their color behavior in a (diurnal and nocturnal) outdoor beach environment, with the presence and absence of a dressed human body (through the use of a thermal imaging camera), such as the analysis of textile materials in a laboratory (simulating the captured outdoor atmospheric temperatures and those of the model’s skin using the climatic chamber and the thermal manikin). The combination of different patternmaking, sewing and printing techniques in textile materials, along with the study of the camouflage environment and the human body’s variation factors, as well as the introduction of biomimetic-inspired elements (chameleon’s skin), enabled the creation of a clothing design process with innovative de-sign elements which allow us to thermally camouflage the human body and take clothing beyond the visible spectrum in a functional and artistic way.

Large-scale 3D flow investigations around a cyclically breathing thermal manikin in a 12 m³ room using HFSB and STB

Exhalation of small aerosol droplets and their transport, dispersion and (local) accumulation in closed rooms have been identified as the main pathway for indirect or airborne respiratory virus transmission from person to person, e.g. for SARS-CoV 2 or measles (Morawska and Cao 2020). Understanding airborne transport mechanisms of viruses via small bio-aerosol particles inside closed populated rooms is an important key factor for optimizing various mitigation strategies (Morawska et al. 2020), which can play an important role for damping the infection dynamics of any future and the ongoing present pandemic scenario, which unfortunately, is still threatening due to the spreading of several SARS-CoV2 variants of concern, e.g. delta (Kupferschmidt and Wadman 2021). Therefore, a large-scale 3D Lagrangian Particle Tracking experiment using up to 3 million long lived and nearly neutrally buoyant helium-filled soap bubbles (HFSB) with a mean diameter of ~ 370 µm as passive tracers in a 12 m³ generic test room has been performed, which allows to fully resolve the Lagrangian transport properties and flow field inside the whole room around a cyclically breathing thermal manikin (Lange et al. 2012) with and without mouth-nose-masks and shields applied. Six high-resolution CMOS streaming cameras, a large array of powerful pulsed LEDs have been used and the Shake-The-Box (STB) (Schanz et al. 2016) Lagrangian particle tracking algorithm has been applied in this experimental study of internal flows in order to gain insight into the complex transient and turbulent aerosol particle transport and dispersion processes around seated breathing persons.

Development and application of an integrated virtual thermal-acoustic manikin design used inside an office space

In this study an integrated virtual thermal-acoustic manikin design used inside ventilated and occupied office spaces is developed and applicated. The component of the virtual thermal manikin evaluates the internal airflow and occupants' thermal, thermo-physiology and clothing systems and calculates the thermal comfort and the indoor air quality levels. The component of the virtual binaural manikin evaluates the direct and indirect sound and calculates the reverberation time. The space geometry with complex topology is developed using a Computer Aid Design (CAD), while the occupants' geometry is made using geometric equations. The grid generation, in the surrounding space surfaces and around the external occupants' surfaces geometry, is used to calculate the radiative heat exchanges and the sound propagation. In this study, performed in an office room occupied by eight persons and equipped with personalized ventilation system, the thermal comfort level, the air quality level and the space reverberation time is evaluated and discussed. In accordance with the obtained results the values are, in general, in accordance the actual standards.

A Smart Temperature-Regulating Garment for Portable, High-Efficiency and Comfortable Cooling

In a conventional liquid cooling garment (LCG), overcooling of the water inlet temperature shortens the working time and worsens thermal comfort. Such problems have not been well solved so far. In this study, we propose a smart cooling garment with a developed temperature regulation system, effectively reducing unnecessary loss of power consumption and hence extending the work duration. Testing on a thermal manikin was conducted to evaluate the performance of temperature-regulating LCG. The results showed that, compared to the conventional LCG, the proposed system achieved the rapid and accurate adjustment of water temperature, improved the working time by more than 37% with the total weight barely increased, and ensured the thermal comfort of the wearers. The developed LCG opens the possibility for the smart control of the temperature, fitting for the user's preferences regarding the working time and thermal comfort sensations.

Design of sports-abaya and its thermal comfort evaluation

The market for sports-abaya in Saudi Arabia is growing due to an increasing participation rate of Islamic women in fitness and sports activities. As mandated by religious law, an abaya must be worn over daily clothes or sportswear by women in order to hide their body contour. The additional layer of the abaya will affect thermal comfort and performance of the wearer. Hence, a sports-abaya needs to be specifically designed to facilitate thermal comfort. This necessitates the selection and evaluation of fabrics appropriate for use in the production of sports-abaya. This study compared two fabrics (100% cotton knit and 100% polyester woven) for their air permeability, thermal resistance and evaporative resistance. The fabrics were then incorporated as sole variable into two models of sports-abaya. The thermal properties of these abayas were evaluated using a female thermal manikin in both standing and walking positions. Comparison was made with the results of a traditional abaya. The research work revealed that polyester woven fabric has a higher air permeability (44.9 mL/cm2/s) than cotton knitted fabric (24.1 mL/cm2/s). The vapor resistance of polyester fabric was lower than cotton fabric and their thermal resistant did not show any significant difference. Consequently, thermal manikin evaluation showed results favoring sports-abaya containing polyester fabric in both standing and walking positions. Furthermore, the thermal resistant and vapor resistant values of sports-abayas were lower compared with those of the traditional abaya. This leads to the conclusion that the newly designed sports-abaya containing 100% polyester woven fabric provides better thermal comfort than traditional abaya and sports-abaya containing 100% cotton fabric.

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

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.