The relationship between physical attributes of beard and respirator leak rates

Abstract EN

The purpose of this study was to assess the effect of various physical attributes of beard on respirator leak rates in two ethnic groups.

Five study volunteers each of Middle Eastern and Anglo-Saxon ethnicity were selected for this study.

They were asked not to shave for a period of two weeks and subjected to a daily leak rate measurement using a Control Negative Pressure (CNP) fit tester.

At the end of the study the beard hair was collected and hair length and diameter were measured to study the association between hair charac-teristics and respirator leak rates.

A significantly higher length and diameter was observed in the Anglo-Saxon group.

However, the leak rate was not significantly different between these ethnic groups.

Independently, both hair length and diameter were not significantly correlated to leak rate but an inter-action term generated to explain the aspect ratio was inversely corre-lated with leak rate on day (r = 0.64, p-value = 0.048).

The daily respirator leak rates increased exponentially over a twelve-day period with a significant change occurring between day 4 and day 5.

A second order regression equation was plotted to accurately predict the respirator leak rate with the age of beard.

We conclude that beard hair attributes can be used to predict respirator leak rate.