Heuristic Evaluation of Respirator Masks: Incorporating NIOSH Respirator Mask Comfort Surveying in the Product Design Process

Abstract

The SARS-CoV-2 pandemic led to world-wide global shortages in personal protective equipment (PPE) in hospitals. Acute shortages of respiratory protective devices such as N95 respirators led to highly innovative period in which new filter materials, chemical treatment, or new concepts for respirator protective equipment were proposed, which were purported as replacements for inconsistent supply of N95-type respirators. Evidence of this innovation is the vast number of new patents that were filed in the domain of filtering facepiece respirators during the first half of 2020 across North America, Europe and East Asia. Much of this product innovation focussed more on the technical mask performance, and less on user comfort of these new items of respiratory protective equipment. When designing respirator masks, technical performance is commonly used as a “decision gate” between iterative development cycles. From a product design perspective, user comfort is strongly linked to long-term market adoption, so user comfort has been an overlooked factor in the SARS-CoV-2 context. Three prototype folding-style filtering facepiece respirators (FFRs) and one commercially-available medical face mask was posted to 30 participants, who wore the masks, completed the modified R-COMFI survey for each mask. The medical face mask was included as a “control” mask which formed the baseline against which the prototype respirators were compared. The three prototype mask designs (Model A1, A2, B) were fabricated by our research group. Their R-COMFI scores were calculated from the survey data and revealed that Model A1 was the least comfortable, then the Model A2, next the Model B, and finally the medical face mask (control) was rated the most comfortable. Based on the feedback of the evaluation, a heuristic development iteration was performed on the least-comfortable respirator, Model A1, based redesigning the elastic head harness taking into the head anthropometric measurement of the users into account. A re-testing of the Model A1 respirator with a group of 12 participants showed a marked improvement in wearing comfort upon redesign of the head harness.

Appendices

Appendix 1: R-COMFI Scores

Appendix 2: R-COMFI - Model A1 Re-design