All ETDs from UAB

Advisory Committee Chair

Claudiu T Lungu

Advisory Committee Members

Riedar K Oestenstad

Yasushi Ito

Alan M Shih

Uday K Vaidya

Document Type

Dissertation

Date of Award

2014

Degree Name by School

Doctor of Philosophy (PhD) School of Public Health

Abstract

For over 30 years, respirator sizing has been based on an anthropometric survey performed by LANL using the young and predominantly Caucasian US Air Force personnel. NIOSH, having observed the increase in diversity in the workplace, began a new survey in 2003 weighted to the US census. Finding that the LANL panel was no longer representative of the modern workforce, a new fit test panel recommending five sizing categories was created in 2007. Anthropometrically accurate headforms three-dimensional models for the average face in each size were designed in 2010. While these headforms are intended for use in respirator design, it has yet to be determined whether a shift to five sizes of facepieces would improve fit factors. This can be attributed to the high cost of prototyping limiting the availability of the headforms to use in testing. This collection of studies is intended to be a starting point in the assessment of any possible changes in facepiece fit resulting from shifting from the current three-size to a five-size system. An adaptive method for collecting three-dimensional facial anthropometric data using a surface laser scanner was developed and verified. A low-cost technique for cast-ing a more realistic, silicone-skinned headform prototype was developed employing silicone molds of a complete set of NIOSH headforms. The novel headform anthropometric dimensions were verified using the previously described laser scanning method. The silicone-skinned headforms were then used in initial commercial facepiece fit testing, using both controlled negative pressure and aerosol methods. Results indicated widespread fit testing failures, with visible leak sites at the bridge of the nose on the headforms. A second iteration of two low surface friction headform prototypes fit testing results indicate that facepiece-silicone surface interaction may have contributed to the widespread fit test failures previously observed. The North small facepiece yielded passing overall fit factors on both Short/Wide headforms, demonstrating a significant improvement in fit on the low surface friction headform (p = 0.0026). A novel, low-cost method combining CT scanning, rapid prototyping, and casting techniques for designing and fabricating facepiece prototypes customized to the headform facial dimensions was also developed.

Included in

Public Health Commons

Share

COinS