Solution Summary: Adjustable Tower Scaffold
An adjustable tower scaffold is an engineering control that can reduce musculoskeletal disorders from overhead work, stooped postures and manual material handling by allowing workers to perform tasks between their knee and shoulder height. This type of scaffold consists of an adjustable platform(s) mounted on an independent supporting tower frame(s) equipped with a hand- or foot-operated or power winch to raise or lower the platform(s). There may be multiple, separate work-platforms. This type of scaffold may not be as fast and easy to adjust as mast climbing work platforms.
An adjustable split-level scaffold allows a brick or block mason to stoop less because the materials and work surface are both kept near waist height, which is more comfortable and stresses your body less (Figure 1). Adjustable split-level scaffolds are available for jobs ranging from small single-story residential work to large high-rise building projects. This equipment may not be appropriate for all jobs.
Figure 1. Adjustable Tower Scaffold
Overhead work can cause musculoskeletal disorders (MSDs) such as shoulder muscle strains; tendonitis, which is inflammation of the tendons; or rotator cuff tears, which is a rupture of a shoulder tendon. The adjustable tower scaffold can help reduce overhead work by adjusting to allow work to be performed at an optimal height between knee and shoulder height.
Stooped postures can cause low back disorders, such as muscle strain or a disc herniation (“slipped disc”), which is bulging of disc material possibly pressing on the spinal cord or nerves that go into the leg. The adjustable tower scaffold can help reduce stooped postures by adjusting to allow work to be performed at an optimal height between knee and shoulder height.
How Risks are Reduced:
There are several ways that adjustable height scaffolding reduces the risk of developing painful conditions in the muscles and joints.
First, compared to traditional scaffolding, the adjustable scaffold allows the work platform to be easily raised or lowered, keeping work between knee and shoulder height. A materials platform can be established at waist height. Working at waist level reduces bricklayer fatigue, and reduces the risk of back and shoulder problems associated with bending at low courses and reaching for courses above the chest.
Second, the platform may be moved vertically with the work, because the work materials do not need to be moved each time the work platform is raised. This reduces the risk of developing work-related low back pain by decreasing heavy lifting and manual material handling at work, and reduces the risk of injury from falling objects.
Third, unlike frame scaffolding, which requires constant building above the work area, adjustable tower scaffolding is assembled on the ground. This eliminates overhead work and awkward postures and reduces the risk of being struck by falling objects.
Fourth, adjustable tower scaffolding is set up once and positioned with a forklift or crane, depending on wall configurations. There is no need for laborers to repeatedly build or tear down frames or manually handle planks. Lastly, adjustable scaffolds have integral guardrails, toe boards, braking systems, and fall arrest systems to ensure jobsite safety.
Research has shown that workers who spend more time working in a stooped posture or other awkward back postures are at a higher risk for developing low back problems. Studies have reported a decrease in low back pain and stress among those working with materials kept at or near waist height.
Manufacturers also report that the ability to set the scaffold to any height allows workers to arrange materials between knee and shoulder height. Materials do not have to be moved as frequently, so there is less manual material handling of supplies and scaffolding parts. Research has shown that reduced manual materials handling decreases low back pain.
There have not been independent published studies measuring the effect of using adjustable height scaffolding on the incidence of musculoskeletal disorders. Regardless, health and safety experts are convinced that worksites that use adjustable height scaffolding may have fewer incidents of musculoskeletal disorders among their workers due to reduced exposure to known risk factors.
Effects on Productivity:
Adjustable tower scaffolding significantly increases worker productivity when compared to traditional tubular frame scaffolding. Gains in productivity result from decreased installation and dismantling time and improved mason productivity. The platform can be easily lowered to the ground for restocking, thus reducing or eliminating the cost of using heavy equipment to deliver materials to high levels of scaffolding.
Some contractors have reported more sprained wrists among laborers when using adjustable scaffolding compared to mast climbing scaffolding or traditional tubular scaffolding. Adjustable scaffolding with foot operated pump jacks may be better.
Dan Anton, PT, PhD, ATC – Eastern Washington University, and Alysha Meyers, PhD – University of Iowa
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