Evaluating the physical demands on firefighters using hand-carried stair descent devices to evacuate mobility-limited occupants from high-rise buildings

• Evacuating people with motor disabilities from high-rise buildings produces significant physical loading of the evacuators.
• Electromyography, heart rate, and ratings of perceived exertion differentiated 3 hand-carried devices and a manual carry.
• Devices with handles that extend in the front and allow the lead evacuator to face forward reduce physical demands.

The physical demands on firefighting personnel were investigated when using different types of hand-carried stair descent devices designed for the emergency evacuation of high rise buildings as a function of staircase width and evacuation urgency. Twelve firefighters used three hand-carried stair descent devices during simulated urgent and non-urgent evacuations. The devices were evaluated under three staircase width conditions (0.91, 1.12, and 1.32 m). For comparison, an urgent manual carry was also performed on the 1.12 m wide stairs. Dependent measures included electromyographic (EMG) data, heart rates, Borg Scale ratings, task durations and descent velocities. Results indicated that the stair chair with extended front handles, which allows the front person to descend the stairs facing forward, reduced the time integrated back muscle EMG by half and showed a descent velocity that was 1.8 times faster than the other stair descent devices in the study. There were no differences across staircase widths.