Make concrete work safer and more productive

Concrete work is hard and potentially dangerous work. With every step in the process, there are heavy, repetitive jobs that must be completed with an eye on speed and safety.

Various government agencies and private companies have looked closely at how contractors complete concrete work and have come up with some ideas that can help reduce the risk of injury or death as well as make concrete jobs go faster.

The Department of Labor and Industries, through its Ergonomics Demonstration Project, worked with two concrete contractors to analyze how carpenters and laborers install rebar, forms and finish concrete.

Lifting and bending hazards
The study found that carpenters face two hazards while completing concrete work: lifting too much while moving equipment, forms and lumber, and bending the back more than 45 degrees for more than two hours at a time while installing deck form sheeting and constructing gang forms. These jobs often require lifting items greater than 90 lbs. or lifting items greater than 70 lbs. from ground level.

To minimize these hazards, the answers are straightforward: use equipment to lift heavy objects, get help from another worker, or somehow lighten the load. The study recommends limiting loads to 70 lbs. or less. If the load is heavier than 90 lbs., the researchers recommend walking a load on the ground up to standing height just as you would walk a ladder up from the ground into working position. This puts the worker in a better stance to carry the load with less chance of back strain.

To further reduce back bending, the study recommends using a screwgun or nail-gun handle extension that allows the worker to stand upright while assembling decking or forms.

Tying rebar
The study looked at more than 300 occasions where workers were tying rebar. Like carpenters, laborers involved with rebar tying often do heavy lifting. Better job planning and teamwork on heavy lifts can help reduce these lifting risks.

However, excessive back bending, awkward positions and repetitive, high hand forces that workers must use to position and tie rebar in place are harder risks to address.

The study suggests using powered rebar tying tools, especially when making repetitive mat ties.

Powered rebar tying tools offer distinct time savings and can greatly reduce the repetitive motions needed to tie rebar, says John Dominice III of Max USA Corporation.

“Tying by hand is very time consuming and can cause numerous health problems, including carpal tunnel syndrome and back pain from excessive bending over to make rebar ties. A rebar tier eliminates the repetitive action of tying,” he says.

Max USA offers a 9.6-volt Ni-MH battery-powered tool that comes in three sizes. The RB213 model can tie #3 x #3 to mesh x mesh; the RB392 can tie #6 x #5 to #3 x #3 and the RB650 uses 16-gauge wire to tie up to #10 x #10 rebar. Each tie takes less than one second, which proves to be almost six times faster than hand-tying.

“The units are also available with an extension arm that eliminates bending over while tying,” he adds.

Other job safety tips
The study also revealed other hazards that could result in worker fatigue and injury:

Hand-arm vibration: Soil compactors, chipping hammers, jackhammers and a variety of power tools used in concrete work can produce severe vibrations that, over time, can affect hands and arms.

Rotating workers into and out of these jobs can help reduce injuries. Tools that are designed to minimize vibration transmission or gloves that dampen vibration transmission to the user should be considered, the study reports.

Over-the-head work: Workers who must complete tasks with their hands over their head or elbows above their shoulders for greater than four hours a day can suffer health problems. Use scaffolds or lifts to get workers closer to overhead work, or use tool extensions that allow the user to operate the tool from below shoulder level.

Published in the July/August 2003 issue of Contractor Tools and Supplies magazine.

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