# Smart Firefighters PPE: Impact of Phase Change Materials  
[PERSON]  
1 CITEVE--Technological Center for Textile and Clothing Industries of Portugal, 4760-034 Vila Nova de Famaalicao, Portugal 1  
[PERSON]  
2 CEFT--Transport Phenomena Research Centre, Faculty of Engineering, University of Porto, [PERSON], 4200-465 Porto, Portugal; [EMAIL_ADDRESS] (S.EN.J. ; [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (J.M.J. ;); meffie.up.pt (J.B.L.M.C.) [PERSON]  
2 CEFT--Transport Phenomena Research Centre, Faculty of Engineering, University of Porto, [PERSON], 4200-465 Porto, Portugal; [EMAIL_ADDRESS] (S.EN.J. ; [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (J.M.J. ;) meffie.up.pt (J.B.L.M.C.) [PERSON]  
2 CEFT--Transport Phenomena Research Centre, Faculty of Engineering, University of Porto, [PERSON], 4200-465 Porto, Portugal; [EMAIL_ADDRESS] (S.EN.J. ; [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (J.M.J. ;) meffie.up.pt (J.B.L.M.C.) [PERSON]  
4 CeFT--Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famaalicao, Portugal; [EMAIL_ADDRESS] (J.R.); [EMAIL_ADDRESS] (A.M.); [EMAIL_ADDRESS] (P.F. ); [EMAIL_ADDRESS] (F.M.) [PERSON]  
4 CeFT--Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famaalicao, Portugal; [EMAIL_ADDRESS] (J.R.); [EMAIL_ADDRESS] (A.M.); [EMAIL_ADDRESS] (P.F. ); [EMAIL_ADDRESS] (F.M.) [PERSON]  
4 CeFT--Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famaalicao, Portugal; [EMAIL_ADDRESS] (  
while wearing task-specific equipment (e.g., a helmet and a self-contained breathing apparatus). However, current personal protective equipment (PPE) poses a significant burden, hindering heat transfer and evaporation of sweat during physical exertion [2]. In critical conditions, the body fails to regulate the temperature, leading to diminished operational capacity, potential accidents, and even heat-related illnesses (e.g., heat exhaustion and heat stroke; [3]). Thermal strain and discomfort among firefighters are prevalent issues, as revealed by surveys [3]. Typical firefighter protective clothing consists of multiple layers to ensure non-flammability, including a vapor-permeable membrane, heat insulation, and a non-flammable lining. According to firefighter surveys, enhancing clothing design and incorporating active thermal underwater are desired improvements [2; 3]. Furthermore, several approaches to improving the thermal protection of firefighter clothing have been adopted to monitor parameters in real time (e.g., wearable electronics [4]) or to react to the heat source, such as phase change materials (PCMs) [5; 6]. PCMs are materials capable of storing and releasing thermal energy during phase transitions in the form of latent heat [7; 8; 9]. Despite being commonly used for thermoregulation [10; 11; 12; 13], incorporating PCMs with higher melting points and storage capacities into firefighting clothing makes it possible to improve the overall thermal protection offered to firefighters. In practice, adding a PCM instead of a textile layer with the exact thermal properties (e.g., thermal resistance, heat capacity, etc.) has the advantage of accumulating thermal energy in its latent form, reducing the rate at which heat reaches the wearer's skin. This addition can significantly extend the time available for firefighters to operate in high-temperature environments before experiencing burns or heat-related injuries [6]. Besides the latent heat and melting temperature, the mass of PCM compromises the clothing's thermal efficiency [14]. To integrate high amounts of PCMs in firefighter protective clothing, [PERSON] et al. [6] proposed using pouches filled with microencapsulated PCMs. Using microencapsulated PCMs provides several benefits in various applications, including firefighting clothing [5; 15]. Firstly, it enhances the stability and durability of PCMs by protecting them from leakage or degradation. Further, the encapsulation shell acts as a barrier, preventing the PCM from directly contacting the environment.