Ergonomics and Factory / Assembly Work
Why is it Important?
Factory and assembly line type work is a carryover from the industrial revolution and has evolved over the years as a result of our increasing knowledge of ergonomics. The requirements of the work are extremely varied and the resulting consequences on human health can range from repetitive or cumulative trauma disorders to death. For this reason it is essential for companies to establish ergonomic programs for ensuring the safety, efficiency, and productivity of various jobs.
It is a natural goal of these companies to minimize job related health costs and personnel turnover and to maximize productivity by workers. To this end it is important for companies to develop an overall ergonomic strategy as an integral part of their business strategy. Specifically these companies must come to understand how human performance issues contribute to production bottlenecks, problems in quality control, injury and turnover rates and how they can find solutions through production layout and tool design.
Standing vs. Sitting at Workstations
Typically in industrial settings the worker sits or stands at the workstation. Workers such as grinding machine operators whose jobs require hours of standing should be provided with sit/stand stools which allow them to relax during operations. These chairs should have pneumatically adjustable seat heights. Foot rests should be available for both standing and sitting. Prolonged standing is associated with fatigue, low back pain, and swelling in the feet and lower legs due to blood pooling. If the job requires standing for more than one hour anti-fatigue mats should be utilized. While any type of mat is preferable to standing on cement the ideal mat should be one half inch thick with a 3-4 per cent compressibility. The mat should be beveled to prevent the worker from tripping, should not slip and should cover the entire workstation. Shorter workers should be supplied with platforms. If possible sitting is desirable if a worker spends more than one continuous hour at a workstation.
A worker is certain to get neck, upper back and shoulder pain if neck flexion exceeds 20 degrees for prolonged periods of time. The optimal viewing range is between horizontal and 45 degrees. Work surfaces should be round and padded where elbows, forearms and wrists can be rested. Certain work stations aids include ladders, stools and carts with casters ergonomically designed with low rolling resistance which have shock absorbing and noise free characteristics. They should have central locking systems and be equipped with proper push/pull assists.
Any hand tools that do not accommodate the natural positioning of the hand can rapidly cause fatigue and lead to such conditions as tendonitis and tenosynovitis. Such tools include grinders, hammers, pliers, riveters, crimpers and wire cutters. Ergonomic design will accommodate natural hand/wrist positioning and the grips and handles must provide proper padding and grip support. Vibration of power tools is a concern and sufficient dampening is necessary to overcome the problem. Proper gloves are essential in order to provide padding for the hands and protection for the skin.
In most industrial applications protective ear and eyewear is vital. Earwear consists of ear plugs and ear muffs and is recommended in an environment of high noise levels caused by machinery. Eyewear consists of goggles and welding masks that fit closely around eyes and face while providing a ventilation system. Hard hats are necessary in areas that there is stacking of objects or circumstances in which objects could fall from above the worker. Other considerations for low back protection include lumbar support belts and the implementation of devices like forklifts that serve as lifting assists. Operations that involve grinding, sanding or other situations that cause particulates or chemicals to become airborne require the use of respirators or particle masks.