Breathing resistance test: dynamic (cyclic) vs constant flow

Benefits and testing equipment

Regulated methods for testing the breathing resistance of facemasks usually involve the use of constant (static) flow. However, in real-world conditions, inhaled and exhaled flow is continuous and cyclic, which places different stresses on the filter media and affects the comfort of wearing the RPE. Therefore, for a more accurate understanding of the performance of protective filtering RPE, it is important to test the breathing resistance not only on a constant flow, but also on a cyclic (pulsating or sinusoidal) flow that reflects the actual breathing conditions of the RPE user, including breathing rate and depth, i.e., lung ventilation.