Protocols for improved understanding of situational awareness effects of head-borne PPE

Objective test methods were developed to quantify and assess the effects of personal protection equipment on auditory situational awareness. The tests utilize a custom head and torso simulator that is able to don personal protective equipment and employs acoustics, signal processing, and measurement techniques. The tests measure localization and speech intelligibility effects of personal protective equipment such as air purifying respirators, helmets, chemical protective jackets, and powered air purifying respirators. These methods also quantify the effects of noise generated by personal protective equipment electro/mechanical noise. Localization effects are evaluated in terms of the head-related transfer function. Speech intelligibility is evaluated using the speech transmission index. Results indicate that some types of head-borne personal protective equipment lead to significant distortions to the head-related transfer function and decreased speech transmission index scores, consequently altering auditory situational awareness.