Rubber boot trapped between escalator steps
Incident Investigation
Rubber boot trapped between escalator steps
January 18, 2018
Reference Number:
II-641646-2018
Location: Burnaby, BC
Incident overview
The user was stepping up onto the escalator skirt decking and back down onto the step. The escalator users right rubber boot became entrapped between the escalator step and stationary skirt panel.
It was reported that the user was stepping up onto the stationary skirt decking and then back down on to the step at the time of the entrapment.
Site, system and components
Escalators have design features to prevent users from getting their foot wear and clothing articles from being entrapped. This entrapment mainly occurs between the moving step and stationary skirt panel on down escalators.
The escalator steps are designed and required to have a maximum running clearance of 5 mm between the step and stationary skirt panel. The skirt panels are designed to remain stiff and have adjustable brackets for support and to maintain the step to skirt running clearance. These brackets are typically spaced at 5 feet apart behind the visible skirt panels.
The escalator skirt panels are also manufactured with an anti-friction coating to help reduce fiction and lower the chances of footwear and clothing articles from being entrapped.
Failure scenario(s)
A child with soft rubber boots was unsupervised and was allowed to step up onto the escalator skirt decking.
The child stepped onto the escalator skirt decking at approximately steps 7-9 upon entering, steps 12-13 and steps 19-20. This escalator has 74 steps with approximately 33 steps visible.
As the child stepped down near the bottom end of the escalator his boot contacted the high friction step/skirt panel which was able to flex due missing skirt brackets allowing the boot to become entrapped between the moving step and the stationary skirt panel.
Facts and evidence
During the investigation the Step/skirt performance index test showed that the step gap increased when a 90 degree force of 25ft/lbs was applied to the skirt panel.
The step/skirt performance index test showed that the anti-friction coating on the skirt panels did not meet the code requirement for the co-efficient of friction.
During the investigation I found that there were only 3 skirt stiffening brackets. One bracket at top, middle and bottom for each side.
Each side was missing 10 skirt stiffening brackets for this rise of escalator.
Causes and contributing factors
Highly likely that the interaction of the soft rubber boot with the high friction step/skirt panels allowed the boot to become entrapped. Missing skirt brackets allowed the flexing of the skirt panels. This likely contributed to the entrapment.