Dynamic Breathing Headform Assessment of Mask Performance and Face Seal

Animatronic headform with neck gaiter and face maskRenowned for more than 25 years’ experience in personal protective equipment (PPE) testing as well as extensive lab capabilities, TPACC stands ready to help in the COVID-19 pandemic. We now offer an animatronic breathing headform to test and evaluate face mask fit and seal for particle filtration performance. As cases related to COVID-19 rise, communities worldwide are advising that face coverings be used in public places to reduce coronavirus spread and safeguard others. Shortages in certified medical-grade masks have resulted in creative solutions for face protection including producing various cloth-based designed masks in private residences for personal use and public distribution, wearing a bandana or t-shirt in alternative ways so it covers the nose and mouth, and exploring the use of different fabrications as a viable option compared to the nonwoven fabrication base standard.

Our dynamic, breathing headform assessment method utilizes TPACC’s animatronic headform with a compressible silicone skin layer to provide a realistic seal to the face. The test procedure mimics respirator fit testing protocols. Over a 7 minute test duration, it runs through programmable motions that simulate normal breathing and head shake as well as head wobble, nodding and speaking motions (up and down jaw movements). Particles in 0.3 μm size are measured on the outside and inside of the mask in ambient air conditions. The testing data illustrates the % Particulate Filtration Efficiency (%PFE) of face masks worn on the headform by minute and motion during testing. The figure below shows examples of %PFE of different face masks benchmarked against N95 mask filtration performance. It shows that a cloth mask provides 55-60% PFE, while neck gaiters offer little (<15%) particle filtration, though filtration performance can be improved with extra layers or by inserting a paper towel. These findings demonstrate the responsiveness of the breathing headform to test filter material. It also highlights the importance of assessing face coverings of different designs, layers and materials which impact the face seal and mask performance when worn.

Chart - One Minute Headform Motions

This methodology was created as an accessible screening tool to characterize the performance and effectiveness of particulate filtration of masks, neck gaiters, or any other designed protection intended for the head and face.

For more information on TPACC testing capabilities related to COVID-19 response, contact
Mr. Shawn Deaton, Special Projects Director
asdeaton@ncsu.edu 919.749.6384
textiles.ncsu.edu/tpacc