Head and face dimensions of Black South African respirator users

Many South African workers rely on respirators for protection from airborne hazards. To our knowledge, there is no public head and face anthropometric database for Black South African respirator users to inform the design of respirators for these individuals. The objective of our study was to determine the facial dimensions of Black South African respirator users using the 13 facial dimensions recommended by the United States National Institute for Occupational Safety and Health (NIOSH).

This was a descriptive and analytical cross-sectional study of Black South African respirator users working in Gauteng. Industries and companies known to use respirators in their operations were approached, and 693 participants between the ages of 18 to 65 were enrolled. Our study followed the methodology used in a NIOSH 2005 study that conducted a head and face anthropometric survey of US respirator users. Traditional measurement tools such as a tape measure, sliding caliper, spreading caliper, and pupillometer were used. Student's t-test was used to analyze data.

The study found statistically significant differences between the facial dimensions of Black South African men and women respirator users and those of 3,000 Chinese respirator users studied in 2009 to develop a fit test panel. All the dimensions of males and females differed significantly, with the largest differences being in head circumference, neck circumference, and minimal frontal breadth. The majority of the facial dimensions of Black South Africans were also significantly different from the 3,997 American NIOSH 2007 fit test panel population, with only face width and nose protrusion not significantly different.

The mean values of Black South African facial dimensions differed significantly from those of the American and the Chinese populations. It may be that respirators designed and tested using the 2007 NIOSH and the 2009 Chinese fit test panels do not include dimensions representative of Black South Africans. Currently supplied respirators are likely to leave some Black South Africans unprotected due to poor fit.