Firefighter daytime visibility: trim properties and conspicuity

Abstract

Abstract Conspicuity enhancing trims on turnout gear promote firefighters’ abilities to (1) reduce the possibility of struck-by accidents, (2) be located and recognized by others, and (3) coordinate their work with colleagues. Firefighting personal protective equipment (PPE) ensemble standards specify technical requirements for new visibility materials. A better understanding of the relation between laboratory measures of material properties and behavioral measures of conspicuity can be used to evaluate existing and newly developed turnout gear trim designs. The current paper examined how photometric luminance measures (%Y) of fluorescent trims on firefighter turnout gear relate to daytime conspicuity in two naturalistic field experiments (distance detection and identification, peripheral detection). The test samples consisted of lime yellow and orange-red fluorescent trims, including traditional solid trims and more recently developed segmented trims. We found overall strong relations between measured luminance and (1) observers’ detection of a firefighter from afar, and (2) observers’ identification of the color of a firefighter’s clothing in their peripheral view. A relation did not exist between %Y and peripheral detection. Additionally, the experiments demonstrated that traditional solid and newer segmented trim designs showed little conspicuity performance difference, with the only observed difference being in peripheral color identification. This suggests that the impact of luminance on conspicuity may be overestimated when evaluating a trim’s daytime performance. Our results further support that luminance measures alone are not sufficient to evaluate the conspicuity of turnout gear in naturalistic settings.