Handrail Speed and Landing Defects on a Mall Escalator
A shopping mall has two 1995 escalators side by side, 30 degree inclination, 18 ft (5.5 m) rise. Riders report that the left unit's handrail seemed to lag and one rider lost balance. A mechanic measures step speed at 100 ft/min (0.51 m/s) on both units; handrail speed is 96 ft/min on the left unit and 101 ft/min on the right. On the left unit, the handrail return side has visible slack, and the drive wheel was replaced two years ago. At the lower landing of the left unit, the step-to-skirt clearance at one location looks larger than elsewhere, two comb teeth are missing, and the skirt panel shows a dent. The mall wants the left unit kept running until the weekend because of a scheduled sale.
1. Evaluate the handrail speed readings and the required action.
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The handrail speed must be at least equal to the step speed and no more than 2 percent faster. The right unit at 101 ft/min is about 1 percent faster and is within the allowance. The left unit at 96 ft/min is about 4 percent slower than its steps, which is out of tolerance and is a real fall hazard, because a rider holding the handrail is pulled backward relative to the steps. The rider report is consistent with the measurement, so this is not a nuisance complaint.
A slow handrail usually comes from slip or wear in the drive: a glazed or worn drive wheel or tire, oil or dirt on the drive surface, a loose or stretched handrail, worn chain or sprocket, or excessive drag from guides and rollers. The visible slack on the return side points to tension and drive condition. Correct it per the manufacturer's procedure, which typically means replacing the drive tire or wheel as needed, setting handrail tension to specification, and inspecting the drive chain and rollers. Do not overtighten the handrail to regain speed; that increases drag and damages the rail.
After repair, re-measure both handrails and steps at more than one point on the incline, and confirm the speeds are within the 0 to +2 percent band before the unit carries riders.
2. What do the missing comb teeth and the skirt condition require?
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They require the unit to be taken out of service now, not after the weekend. Missing comb teeth, an enlarged step-to-skirt clearance, and a dented skirt panel are all conditions that can cause entrapment or a stumble at the landing, and they are visible defects that the mall has now been told about. Keeping the unit running until the sale creates a known hazard and a documentation problem for both the contractor and the owner.
Inspect and correct:
- Replace the damaged comb sections; do not run with missing teeth.
- Check the step-to-comb clearance and step levelness at the landing, and check whether step chain elongation or a damaged step is holding the step out of alignment.
- Measure the step-to-skirt clearance against the adopted code and the manufacturer's values; a dented skirt or a shifted step can open a gap that exceeds the limit.
- Inspect the skirt panels, skirt deflectors, and the step treads for damage, and check the handrail entry guards at both landings.
Repair to the code and manufacturer's dimensions, then have the unit re-inspected. Record the measurements, photographs, and code references used so the decision is defensible.
3. How should the contractor handle the owner's request and the documentation?
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Put the refusal and the reason in writing the same day. State the measured handrail speed against the requirement, the defects found, and that the unit is out of service until corrected. The owner can be given a repair schedule, but the contractor should not agree to operate a unit with a known handrail-speed defect, missing comb teeth, and skirt damage because of a sales event. The decision to remove an escalator from service for a hazard is a safety judgment the contractor is expected to make and defend.
Documentation should include:
- Step and handrail speeds with the measuring method and points used.
- The comb and skirt measurements, photographs, and the code or manufacturer's limit each is compared against.
- The repair performed, parts replaced, post-repair measurements, and who verified them.
- Notification to the owner and, where required, the AHJ, plus the permit status and reinspection before return to service.
Also confirm the unit's maintenance records are current, since a drive wheel replaced two years ago and a handrail that has now stretched may indicate a tension or alignment problem that was never corrected.