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Workload of window cleaners using ladders differing in rung separation
Marco J M Hoozemans1, Michiel P de Looze, Idsart Kingma
1Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. m.hoozemans@fbw.vu.nl
Applied Ergonomics
|April 28, 2005
Summary
A study comparing extension ladder rung separation found that while 35 cm is preferred for comfort and safety, 30 cm reduces mechanical load on lower limb joints for window cleaners.
Area of Science:
- Occupational Health
- Ergonomics
- Biomechanics
Background:
- Extension ladders are essential tools for window cleaners, but rung separation can impact user experience and physical strain.
- Optimizing ladder design, specifically rung spacing, is crucial for worker well-being and efficiency.
Purpose of the Study:
- To compare the effects of 30 cm versus 35 cm rung separation on window cleaners' energetic workload, perceived exertion, discomfort, safety, and joint mechanical load.
- To determine the optimal rung separation for extension ladder use in professional window cleaning.
Main Methods:
- Eleven male professional window cleaners of varying statures participated.
- Measurements included energetic workload, perceived exertion, discomfort, safety ratings, and lower limb joint (hip, knee, ankle) mechanical load during ladder ascent and descent.
- Two extension ladder conditions were tested: 30 cm and 35 cm rung separation.
Main Results:
- No significant differences in energetic workload were found between the two rung separations.
- Window cleaners reported higher preference for the 35 cm separation regarding perceived exertion, discomfort, and safety.
- The 30 cm separation resulted in lower mechanical load on the hip, knee, and ankle joints during climbing.
- Maintaining knees within side rails was more feasible with 35 cm separation, though this may depend on user stature.
Conclusions:
- A 35 cm rung separation is marginally favorable overall for extension ladder use by window cleaners, balancing perceived comfort and safety.
- While 35 cm enhances perceived comfort and safety, 30 cm offers biomechanical advantages by reducing joint load.
- Recommendations include considering individual cleaner stature and the feasibility of maintaining proper climbing posture, suggesting 35 cm may be preferable for enabling this posture.