Office Safety (Ergonomics)
Introduction
Ergonomics involves arranging the environment to fit the person in it. An example of good ergonomic design can be as simple as a well-designed knife, screwdriver, or pliers or as elaborate as a properly-fitted computer work station. In the workplace, following ergonomic principles helps reduce stress and eliminate many potential injuries and disorders associated with overuse of muscles, bad posture, and repetitive motion. The objective of ergonomics is to accommodate workers through design of tasks, work stations, controls, displays, safety devices, tools, lighting, and equipment.
Concerns in the Workplace
Technological advances resulting in more specialized tasks, higher assembly line speeds, and increased repetition in the workplace are often major causes of current ergonomic problems. Worker's hands, wrists, arms, shoulders, backs, and legs may be subjected to thousands of repetitive twisting, forceful or flexing motions during a typical workday. Some jobs expose workers to excessive vibration and noise, eye strain, repetitive motion, and heavy lifting. Machines, tools, and the work environment may be poorly designed, placing stress on worker's tendons, muscles, and nerves. In addition, workplace temperature extremes may aggravate or increase ergonomic stress. Recognizing ergonomic hazards in the workplace is the first step in improving worker protection.
Management Commitment and Employee Involvement
Commitment and involvement are complementary and essential elements of a sound safety and health program. Commitment by management provides the organizational resources and motivating forces necessary to deal effectively with ergonomic hazards. Employee involvement and feedback, through clearly established procedures, are likewise essential, both to identify existing and potential hazards and to develop and implement an effective way to abate such hazards.
The implementation of an effective ergonomics program includes a commitment by Bentley College to provide the visible involvement of top management, so that all employees, from supervisors to contractors, fully understand that Bentley College has a serious commitment to the program. Employee involvement is also essential to the success of an ergonomics program. Employee's intimate knowledge of the jobs they perform and the special concerns they bring to the job give them a unique perspective which can be used to make the program more effective.
Disorders/Injuries Related to Ergonomic Hazards
A variety of musculo-skeletal disorders and illnesses are caused by ergonomic stresses. A musculo-skeletal disorder illness is one involving the muscles, tendons, ligaments, nerves, joints, bones, or supporting body tissue. Injuries include disorders of the back, the neck, the upper or lower extremities, or the shoulders, and involve strains, sprains, or tissue inflammation, and dislocation. Environmental hazards which cause musculo-skeletal disorders come from worker/workplace interaction. These hazards include heavy lifting, constant twisting, and repeated motions. Biological hazards are physical characteristics of the employee that vary from human to human, including size, endurance, range of motion, strength, gender, and other factors. When the job demand exceeds the physical characteristics of the worker, an injury results.
Cumulative Trauma Disorders:
Cumulative trauma disorders (CTDs) are disorders of the musculo-skeletal and nervous systems which are caused or made worse by repetitive motions, forceful exertions, vibration, hard and sharp edges, sustained or awkward postures, or by exposure to noise over extended periods of time. CTDs can affect nearly all tissues, the nerves, tendons, tendon sheaths, and muscles, with the upper extremities being the most frequently affected. These injuries develop gradually and result from repeated forceful actions, such as twisting and bending of the hands, arms, and wrists.
Today, CTDs are recognized as a major occupational health hazard and account for most occupational illnesses known as "repeated trauma disorders." In 1994, the Bureau of Labor Statistics (BLS) reported nearly 90,000 cases of occupationally-related repetitive motion disorders for 1992, accounting for four percent of all workplace injuries or illnesses. Common CTDs in the workplace are tendon disorders such as tendinitis, tenosynovitis, De Quervain's disease, trigger finger, Raynaud's syndrome, and carpal tunnel syndrome. The last CTD, carpal tunnel syndrome (CTS) is a disorder affecting the hands and wrists. It has probably received more attention in recent years than any other CTD. The 1994 BLS report stated that in 1992, 33,000 cases of CTS required the longest recuperation time: a median of 32 lost work days per incident.
Vibration along with prolonged sitting may also result in degenerative changes in the spine. For example, drivers of tractors, trucks, buses, construction machinery, and other heavy equipment may suffer from low back pain, and permanent abdominal, spinal, and bone damage. The pressure of repetitive motion causes tingling, numbness, or sever pain in the wrist and hand. The pain is often experienced at night. The pressure also results in a lack of strength in the hand and an inability to make a fist, hold objects, or perform other manual tasks. If the pressure continues, it can damage the nerve, causing permanent loss of sensation and even partial paralysis.
CTS develops in the hands and wrists when repetitive or forceful manual tasks are performed over a period of time. For example, the meatpacking industry is considered a very hazardous industry because workers can make as many as 10,000 repetitive motions per day in assembly line processes, such as deboning meats, with no variation in motion. CTS is common among meat and poultry workers, carpenters, garment workers, shoe makers, assemblers, packers, product inspectors, machine operators, keypunch operators, and cashiers. CTS also has been reported widely among many service-sector employees, including office workers and newspaper and news service employees who enter data into computers, because of the numerous repetitive motions of keystroking over long periods. Employees are often unaware of the causes of CTS and what to do about them. Often they do not associate their pain with their work because symptoms may only occur during evening or off-duty hours.
Back Disorders:
Pulled or strained muscles, ligaments, tendons, and disks are perhaps the most common back problems and may occur in almost half of the work force at least once during their lifetime. Most workplace back disorders result form chronic, or long-term injury to the back, rather than from specific incident. Back disorders are frequently caused by excessive or repetitive twisting, bending and reaching; carrying, moving, or lifting loads that are too heavy or too big; staying in one posture too long; poor physical condition; and poor posture.
Prolonged sitting stresses the body, particularly the lower back and the thighs, and may cause the lower back (lumbar) region to bow outward if there is inadequate support. This abnormal curvature (called kyphosis) can lead to painful lower back problems, a common complaint among office workers. Other factors which are contributors to back injuries include the natural degeneration of the back due to aging; inactivity both at work and at home; seasonal activity undertaken without prior physical conditioning; stress; and vibration. According to one source, truck drivers have the highest incidence of back injuries, most likely due to prolonged sitting in one position and prolonged exposure to vibration. Many other workers, however, are at risk of developing back disorders, including those in industries such as manufacturing, construction, transportation, shipbuilding, and hospital care.
Contributing Factors:
Recent studies have shown that work-related accidents increase with both higher and lower workplace temperatures. Where temperature extremes require workers to use more force in performing their jobs, ergonomic stress and risk of ergonomic disorders may also increase. Cold temperatures can affect a worker's coordination and manual dexterity, thus requiring more effort and additional manual force to perform the same task or to maintain productivity levels. Likewise, hot and humid conditions may cause excessive fatigue or reduce the employee's work capacity, resulting in increased ergonomic stress. Such conditions may also require a worker to apply more force or effort in gripping hand tools or in using other equipment, which may further increase ergonomic stress and the risk of ergonomic disorders.
One way the supervisor may uncover ergonomic hazards is by doing a worksite analysis. Possible risk factors for cumulative trauma and back disorders that may be identified during a worksite analysis include:
• Excessive repetition or prolonged activities.
• Pinch grips.
• Prolonged static postures of the body, trunk, or its extremities, either sitting/standing.
• Awkward postures of the upper body, including reaching above the shoulders or behind the back.
• Excessive bending or twisting of the wrist.
• Continued elevation of the elbow.
• Continued physical contact with work surfaces, such as contact with edges of machines.
• Forceful exertions, usually with the hands.
• Temperature extremes.
• Inappropriate or inadequate hand tools.
• Restrictive workstations and inadequate clearances.
• Vibration from power tools.
• Improper seating or support.
• Bad body mechanics such as continued bending at the waist, continued lifting below the knuckles or above the shoulders, or twisting at the waist while lifting.
• Lifting heavy or awkward objects.
• Lack of adjustable chairs, footrests, body supports, and work surfaces at work stations or slippery footing.
The combined effect of several risk factors often results in the onset of CTDs. The ergonomic approach is to make things better than they were before; even small improvements in reducing or eliminating some, if not all, risk factors within a problem area will reduce the risk and the level of physical stress for the employee.
Hazard Prevention and Control
Ergonomic hazards are prevented primarily by the effective design of a job or jobsite and the tools or equipment used in that job. Based on information gathered in the worksite analysis, procedures can be established to correct or control ergonomic hazards using the following methods.
Engineering Controls
The primary focus of fixing ergonomic problems is to make the job fit the employee, not force the employee fit the job. Engineering controls can accomplish this by ergonomically designing work stations and tools or equipment. The work station should accommodate the full range of movements the employee needs to do his/her job. Many work stations, for example, were designed for men, even though they may be also be used by women. The work station should let the employee assume several different but equally healthful and safe postures that still lets him/her do their job. For example, the employee:
• should have enough space for his/her knees and feet.
• should be able to adjust the height of worktables and chairs so that he/she has proper back and leg support (seat cushions can be used to compensate for height variations when chairs or stools are not adjustable).
• should be able to reach machine controls well whether right or left-handed.
When redesigning a workstation, the supervisor should pay attention to activities that require the employee to exert force with a particular body part without movement, the height reach at which tasks are performed, and the force requirements. Other factors the supervisor will look at include hard or sharp edges, contact with hot work surfaces, proper seating, work piece orientation, and layout of the work station. Other engineering adaptations can be made to tools and tool handles. Select ergonomically designed tools to improve productivity and prevent CTDs.
Because improper use and poor design of hand-held tools can cause damage to the employee's hand and arm, several factors should be considered when selecting a tool, including position in which it will be used, vibration, grip strength required, awkwardness, force required, and repetitive motion involved. A variety of tool sizes should be available for a variety of employees. Factors to consider include handle sizes and their adequacy for gloved hands. Tools should accommodate right and left-handed workers. The balance, center of gravity, and the weight of the tool should also be considered when evaluating a tool. Finally, the employee must use the right tool when performing a job.
Administrative Controls
Administrative controls are used to reduce the duration, frequency, and severity of exposure to ergonomic stresses. Once ergonomic problems have been identified, the supervisor may opt to train the employee on ways to avoid injury on the job, reduce the number of repetitions made, provide rest breaks, or begin cross-training so that jobs may be rotated with coworkers.
Work Practice Controls
Key elements of a good work practice program include instruction in proper work techniques, employee training and conditioning, regular monitoring, feedback, adjustments, modification, and maintenance. For example, after the employee is trained in a particular work activity, such as proper lifting or proper tool handling, the supervisor should monitor the employee to ensure he/she continues to use the proper techniques. Improper practices should be corrected to prevent injuries.
Medical Management
The employee needs to be able to recognize the signs and symptoms of CTD so that he/she can report them and start treatment if necessary, have the job evaluated to avoid further irritation, and possibly go on a modified work schedule during the treatment period. The employee can assist in this process by seeking help before injuries become more sever, and in helping the supervisor understand exactly how the employee does his/her job.
Work at Working Safely
The supervisor of his/her particular area should be aware of ergonomics and the causes of musculo-skeletal and cumulative trauma disorders. This can be accomplished by doing the following:
• Make ergonomically designed changes in the workplace where possible. Ergonomic changes to design and layout will lesson the chance of injury to the employee.
• Be aware of the signs and symptoms that may indicate a problem or injury caused by a poorly designed workplace.
• Participate in hazard control activities.
• Contact Life Safety Services x2281 for further advice on this subject.
Working Safely at the Computer
Over the long term, working at a computer can cause problems such as eyestrain, persistent fatigue, back pain, tendinitis, CTS, and more. By using ergonomics, the employee can make adjustments to improve comfort and health on the job. The following simple exercises, performed at the desk, can reduce the ergonomic stresses of working at the computer.
Legs:
• In a seated position, with one foot flat on the floor, extend other leg straight in front with toes pointed. Tense leg muscles and hold 10 seconds. Relax leg. Repeat with other leg.
Lower Back:
• Move chair back from desk. Be sure chair is stable. With feet flat on floor, bend forward slowly as far as possible, reaching for feet. Hold up to 10 seconds. Push back up with leg muscles.
Upper Back:
• Make sure chair is stable. With feet flat on floor, clasp hands behind head and slowly arch back, bending head backward. Hold up to 5 seconds.
Neck:
• Turn head slowly to the left and hold 5 seconds. Then repeat on right side. Drop chin to chest, hold, then slowly tilt head back as far as possible. Repeat sequence 5 to 10 times.
Eyes:
• Palming: cup your hands gently over closed eyes. Hold for one minute.
Shoulders:
• Let arms relax at sides. Then raise shoulders and rotate them up and back in a circular motion. Repeat up to 5 times. Then change direction.
Wrists:
• With hands held in front of body, gently rotate wrists so that the fingertips describe circles in the air. Repeat 5 times in each direction.
Hands and Fingers:
• With hands held in front of body, clench both fists and hold 5 seconds. Then spread fingers as far as possible and hold 5 seconds. Repeat 5 times.
When sitting down at the desk to work on the computer, the employee should ask him/herself the following questions:
• Is the top of the screen at eye level (slightly lower for bifocal wearers)? Is the screen approximately 15-32 inches away? Is the display sharp and steady?
• Is your field of vision free from glare and reflections?
• Do you have a document holder so that documents are close to and level with the screen?
• Are your wrists straight and horizontal to your work surface as you type? Do you have a padded wrist rest?
• Do you have enough knee clearance under the desk or table?
• Are your feet flat on the floor or on a footrest?
• Are your arms loose and comfortable at your sides, and your elbows at right angles as you type?
• Are you sitting back in your chair with your lower back well supported in its natural curve?
If there are further questions or concerns, Life Safety Services is available for advice.
