In 2010, the National Institute for Occupational Safety and Health (NIOSH) published new digital head form models developed from their updated fit-test panel, which was based on the 2000 census. To better represent the modern work force, two additional sizes were created: Short/Wide and Long/Narrow. While collecting the anthropometric data that comprised the panel, additional three-dimensional data were collected on a subset of the subjects. Within each sizing category, five individuals’ three-dimensional data were used to create the new head form models. Although NIOSH has recommended a switch to a five-size system for designing respirators, little has been done in assessing the potential benefits of this change. With commercially available elastomeric facepieces available in only three or four size systems, it was necessary to develop the additional facepieces to enable testing.
Therefore, in a study led by Dr. Claudiu T. Lungu, associate professor, along with Ms. Paula Joe, doctoral student, in the department of environmental health sciences at the University of Alabama at Birmingham, a method for designing and fabricating elastomeric facepieces tailored to the new head form designs for use in fit-testing studies was developed. The novel method used computed tomography of a solid silicone facepiece and a number of computer-aided design programs (VolView, ParaView, MEGG3D, and RapidForm XOR) to develop a facepiece model to accommodate the Short/Wide head form. The generated model was given a physical form by means of three-dimensional printing, using stereolithography (SLA). The printed model was then utilized to create a silicone mold from which elastomeric prototypes can be cast. The prototype facepieces were cast in two types of silicone for use in future fit-testing.
“A Novel Method for Designing and Fabricating Low-cost Facepiece Prototypes” was published in October 2014 in the Journal of Occupational and Environmental Hygiene.