Standard-Compliant Validation of a Smart Modular Add-on for Respiratory Protective Equipment: Design, Integration, and Functional Impact Assessment

The integration of sensing technologies into respiratory protective equipment (RPE) is a key enabler for next-generation smart personal protective systems. However, to ensure their deployability in real-world contexts, it is essential to assess whether the additional sensors and electronic components compromise the primary protective functions of the device. This work presents the development and validation of a modular sensing unit designed to integrate seamlessly with standard filtering facepiece respirators FFP2 and FFP3 masks featuring a 34 mm exhalation valve by plug-in a Smart Cover Valve (SCV). Beyond design and implementation, we systematically evaluated the SCV-equipped respirator according to standard test procedures for breathing resistance (BR) (UNI EN 13274-3), fit and flammability tests (UNI EN 13274-4). Results proved the BR remained below normative thresholds in all simulated airflow conditions, with both minimum inhalation and maximum exhalation pressure drops not exceeding 0.1 mbar regardless of the presence of the SCV. Fit tests revealed a consistent trend between the bare and SCV-equipped configurations across a range of dynamic and static exercises. Flammability tests confirmed that the SCV integration did not induce any flame propagation, ignition, or structural degradation under high-temperature exposure. These findings demonstrate that the SCV can be safely deployed without compromising the core safety performance of the host equipment.