Homework 1.docx

ESE133-0 Occupational Health and Safety Engr. Salvador

HAZARDS

MARILLA, JUSTINE F. 2015150118

BIOMECHANICAL

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In considering ‘biomechanical hazards’ it is important to recognise that biomechanics is relevant to more than ‘manual handling.’ As defined by Frankel and Nordin (as cited in Chaffin & Andersson, 1999, p. 1), “Biomechanics uses laws of physics and engineering concepts to describe motion undergone by the various body segments and the forces acting on these body parts during normal daily activities.” These movements and forces may enable workers to safely perform jobs or, where they over-stress the body, may cause a musculoskeletal disorder (MSD) Assessing the risk of biomechanical hazards The ultimate aim of manual-task risk management is to ensure that all tasks performed in workplaces require dynamic and varied movements of all body regions with low-tomoderate levels of force, comfortable and varied postures, no exposure to whole-body or peripheral vibration, and that breaks are taken at appropriate intervals to allow adequate recovery. Injury risk is elevated by deviations from this optimal situation, and injuries are most likely to occur when there is significant exposure to multiple risk factors. Assessing and evaluating the risk of injury associated with biomechanical hazards is complicated by the number of aspects of the task that contribute to the risks, and by the interactions between different risk factors. Controlling Biomechanical hazards Control of biomechanical hazards causing body stressing should be a workplace priority becuase such hazards. The most effective control is to eliminate the task; where this is not practical, a combination of other controls must be applied. Control options are outlined below. Elimination. Having identified the existence of a biomechanical hazard, the next step is to determine whether any, or all, of the manual tasks responsible for the hazard can be eliminated. This will be the most effective way of reducing injuries. Some manual tasks can be eliminated by adjusting the flow of materials, reducing double handling or changing to bulk-handling systems. Outsourcing hazardous manual tasks may be an appropriate way of eliminating hazards if the organisation undertaking the task has specialised equipment that reduces the risk to acceptable levels. Some nonproductive tasks such as cleaning up waste may be able to be eliminated or reduced by examining the source of the waste. Risk Prevention and Management: Designing controls: A participative approach If it is determined that a biomechanical hazard cannot be eliminated, the next step is to design controls to reduce the risks. This step is most effectively undertaken in consultation with the people who perform the work. Apart from the fact that these people know most about the tasks, the probability of success of the changes is enhanced if the people concerned have a sense of ownership of the changes.

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Also, it is important to ensure that all people affected by proposed design changes are consulted; for example, maintenance as well as operational staff may need to be involved. Work areas – height, space, reach distances, work flow, adjustability The design of work areas has a large impact on the risk associated with biomechanical hazards. For example, limited space, limited clearances and restricted access to work are common causes of awkward postures. Work should be located at an appropriate height and close to the body. Providing adjustable workstations may be an option to accommodate workers of different sizes. Workplaces should be designed to increase postural variability during work. Loads – size, shape, weight, stability, location, height Loads delivered to, handled within or produced by a workplace are common sources of biomechanical hazards. Implementing mechanised bulk-handling systems is an effective design control. Reducing the size and weight of loads is another option, but requires training and ongoing supervision to ensure multiple loads are not handled simultaneously to increase speed. Ensuring loads are easily gripped is important. Hot or cold loads should be insulated to allow them to be comfortably held close to the body. Where loads are manually handled, they should be stored at waist height rather than on the floor or above shoulder height. Tools – size, weight, handles, grips, trigger, vibration Poorly designed hand tools are a common source of awkward postures, high exertion (particularly of small muscles of the hand and arm) and peripheral vibration. Hand tools should be designed such that joint postures remain close to neutral during use, and should be as light as possible. Heavy tools may be counter-balanced to reduce exertion. While power tools reduce exertion, the vibration associated with them introduces a new risk; tools should be chosen to minimise the amplitude of the vibration as far as possible. Mechanical aids – hoists, overhead cranes, vacuum lifters, trolleys, conveyers, turntables, monorails, adjustable height pallets, forklifts, pallet movers A large range of mechanical aids is available to reduce the risk of biomechanical hazards, and these can be effective controls. However, care is required to ensure than the use of the aid does not slow down the performance of work. If it does, the probability that the control will be effective is reduced because administrative controls and ongoing supervision will be required to ensure compliance. The design of the mechanical aids requires careful consideration. For example, trolley wheels should be as large as possible to reduce rolling friction and vertical handles should be provided to allow the trolley to be gripped at different heights by different-sized people. Introducing mechanical equipment such as

BIOMECHANICAL

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forklifts also introduces new risks, which require control. Where mechanical aids are introduced to control biomechanical hazards it is important to ensure that they are maintained in working order and available when, and where, required. Administrative controls Administrative controls – relevant to maintenance, workload, job rotation and task variety, team lifting, training and personal protective equipment (PPE) – rely on human behaviour and supervision, and are more effective when used in combination with other controls. Maintenance. Maintenance of tools, equipment and mechanical aids is crucial, but requires development of a maintenance schedule and supervision to ensure compliance. Maintenance includes good housekeeping. Workoad. Reducing shift duration or the pace of work can contribute to effective biomechanicalhazard risk control. It may be possible to change the distribution of work across the day or week to avoid high peak workloads. Ensuring appropriate staff levels are maintained is important. Also, provision of adequate rest breaks can reduce injury risk. Job rotation and task variety. It may be possible to reduce risks by rotating staff between different tasks to increase task variety. This requires that the tasks are sufficiently different to ensure that different body parts are loaded in different ways. Alternatively, multiple tasks might be combined to increase task variety. Team lifting. Team lifting may be effective in reducing risk where the load is bulky, but relatively light. If team lifting is employed as a control, training and supervision are required to ensure the task is only undertaken when appropriate staff is available. Training. Training is an important administrative control regardless of the design controls employed; training in appropriate work performance and equipment use should always be provided. Implementing an effective manual-task risk-management program requires that staff are able to identify hazardous manual tasks, and are aware of the biomechanical aspects that increase the risk of injury. In the context of lifting, this might legitimately extend to principles such as ‘keep the load close’ and ‘avoid twisting;’ however, the evidence is clear that training in ‘correct’ load-handling techniques is not effective in reducing injuries associated with biomechanical hazards (Daltroy et al, 1997; Haslam, 2007; Verbeek et al., 2011). Personal protective equipment. Some forms of PPE, such as kneepads, protective aprons and gloves, may be effective in reducing the risk of injury. However, there is no evidence to support the use of ‘back belts’ or ‘abdominal belts’ and these devices should not be employed (Jellema et al., 2001).

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Risk Management Monitor and review. Managing risk associated with biomechanical hazards and manual tasks is an iterative ‘continuous improvement’ process. Following implementation of any control measures it is important to check that the controls are working as anticipated and that new risks have not been introduced. Record keeping. It is important to keep records of the steps taken in the risk-management process. This will ensure that the existence of an effective risk-management process can be demonstrated, should that be necessary. More importantly, it provides a method of tracking the improvements made and maintaining the corporate memory of the reasons changes were necessary

PSYCHOSOCIAL

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The term psychosocial hazards relate to that of psychosocial factors that have been defined by the International Labor Organization (ILO, 1986) in terms of the interactions among job content, work organization and management, and other environmental and organizational conditions, on the one hand, and the employees' competencies and needs on the other. Psychosocial hazards are relevant to imbalances in the psychosocial arena and refer to those interactions that prove to have a hazardous influence over employees' health through their perceptions and experience (ILO, 1986). A simpler definition of psychosocial hazards might be those aspects of the design and management of work, and its social and organizational contexts, that have the potential for causing psychological or physical harm. Primary prevention The management of psychosocial risks should prioritize interventions that reduce risks at source. There are a number of arguments for giving it precedence. They also can be significantly cost-effective as the focus of interventions is put on the causes and areas within the organization where change is required. Moreover, they promote organizational healthiness as they address issues relating to organizational culture and development. Interventions of this kind call for and promote social dialogue and a participative approach. Finally, in line with the risk management paradigm, actions can be tailored to different contexts and are systemic in nature. Secondary prevention The majority of interventions to manage psychosocial risks found in the relevant literatures are more focused on individuals. They have been proven to have a positive outcome in “temporarily reducing experienced stress”. These involve taking steps to improve the perception and management of psychosocial risks for groups which can be at risk of exposure. It is assumed that more training and knowledge would provide employees with the tools to cope with the difficulties they encounter at work, either taking independent action to manage the risks or using relaxation techniques to buffer their effects. The focus of these actions is on the provision of education and training. Issues that can be covered through training include interpersonal relationships (between colleagues and with supervisors), time management, relaxation techniques and communication, handling conflicts, responding to (coping with) violence, harassment and bullying, among others. Tertiary prevention In the cases where individuals have already been harmed by exposure to hazards, actions can be taken once a problem has become evident to limit its effects. The action here is on the consequences of exposure to psychosocial hazards, which can be either psychological or physical. In this sense, people who are suffering from psychosocial complaints, which include burnout, depression or strain, can be provided with counselling and therapy at the workplace and those suffering from physical symptoms can

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benefit from occupational health services provision. When affected employees have been off work because of ill health, appropriate return-to-work and rehabilitation programs can be implemented to support their effective re-integration in the workforce. Risk Management The management of psychosocial risk is about people, their (mental) health status and business and societal interests. Protecting the psychosocial health of people is not only a legal obligation, but also an ethical issue. As interests between various agents involved differ, their sphere of influence is not always clear. Shifting of consequences from enterprises to individuals or society at large may occur (externalization). Frequently there are ethical dilemmas that are easily overlooked or that (often implicitly) underlie a seemingly fully rational discussion. Managing psychosocial hazards is not a oneoff activity but part of the on-going cycle of good management of work and the effective management of health and safety. As such it demands a long-term orientation and commitment on the part of management. As with the management of many other occupational risks, psychosocial risk management should be conducted often, ideally on a yearly basis.

Figure 1.1 shows how psychosocial risk management is relevant to work processes and a number of key outcomes both within and outside the workplace. It also clarifies the key steps in the iterative risk management process. Risk Assessment Risk assessment is a central element of the risk management process. It has been defined by the European Commission as “a systematic examination of the work undertaken to consider what could

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cause injury or harm, whether the hazards could be eliminated, and if not what preventive or protective measures are, or should be, in place to control the risks”. The risk assessment provides information on the nature and severity of the problem, psychosocial hazards and the way they might affect the health of those exposed to them and the healthiness of their organization (in terms of issues such as absence, commitment to the organization, worker satisfaction and intention to leave, productivity etc.). Adequately completed, the risk assessment allows the key features of the problem (symptoms and causes, including underlying causes) to be identified. It is important to note that information generated through a well-conducted risk assessment does not only identify challenges in the work environment but also positive aspects of the work environment that should be promoted and enhanced.

In essence, psychosocial risk management is synonymous to best economic development, especially with a view on the emerging knowledge society. A healthy workforce and healthy organizations are key for the optimum use of human and social capital, and so for a vital economy. It will help for increasing productivity, fostering innovation, improving economic performance, improving public health (including reductions in health care costs), improving the functioning of the labor market (including strengthening of associated social security arrangements and social inclusion impacts). As such, best practice in relation to psychosocial risk management policies reflects best practice in terms of societal development and learning, economic development, social responsibility and the promotion of good work. Organizations have adopted at least three distinct sets of objectives in managing work-related stress and its health effects with focuses on: (a) prevention (concerned with the control of and exposure to hazards through design and worker training); (b) timely reaction (referring to management and group problem-solving to enhance the organization’s (or managers’) ability to identify and address problems

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that may arise); and (c) rehabilitation (often involving offering enhanced support (including counselling) to aid workers cope with, and recover from, problems which exist). Within this model, many authors make a distinction between those objectives which concern, or focus on, the organization (organizational stress management) and those that concern the individual (personal stress management). At the individual-level, stress management involves enhancing employees’ abilities to manage work-related psychosocial risks more effectively, and/or by alleviating symptoms of Work-related Stress (WRS); whilst at the organizational level, stress management involves reducing or eliminating job-related or environmental psychosocial risks that cause WRS and its associated health effects. The basis in the management of work-related violence is zero tolerance to all kinds of physical and psychological violence both from inside and from outside the workplace. Policies and codes of conduct can be built in organizations to prevent and deal with bullying and third-party violence. In relation to third party violence some organizations, e.g. public transport, also have policies for customers that stipulate how a customer/client must behave. A core component of any work-related violence prevention strategy is the designing-out of risk; the roots, causes, antecedents and risks of bullying and third-party violence. Strategies include recording and reporting systems of violent incidents or acts, risk assessment tools as well as activities to redesign the work environment. Risk assessment tools for third party violence include: for example, the physical work environment, lay out, environmental planning, and alarm systems, access limitations and escape routes. Also, trauma risk assessment has been undertaken. Studies have shown that psychosocial factors, e.g. conflicting demands, poor possibilities to influence decisions in the workplace, poor collaboration between co-workers, and poor flow of information, are connected with violent incidents by third parties. Therefore, psychosocial work environment risks and the functioning of the work unit should also be taken into account in the prevention of third-party violence. Evidently only one risk assessment tool for bullying at work has so far been developed. The Negative Acts Questionnaire is the most widely used method to measure forms of negative behavior in research. Initiatives focusing on personality and personality characteristics in relation to bullying are seen as unlikely to succeed. Various types of training for managers and workers are widely used in primary and secondary interventions both to combat bullying as well as third party violence at work. As concerns, tertiary level interventions, rehabilitation is based on the recognition that violence is part of work, but it is not part of the job description. Problems are seen as related to violence at work not as personal problems or caused by personal history. In addition to possible physical consequences, threatening and violent attacks by third parties evoke also psychological reactions which need to be handled. Rehabilitation programs include, for example, education that helps the individual to understand the phenomenon of violence, psychological counselling as well as physiotherapy and physical exercise.

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Counselling after a threatening or violent incident by a third party, or after a person has been subjected to long lasting bullying can help employees to cope with violence or bullying, to recognize aggressive impulses in their present behavior or reactions, and to change their conduct and attitude. Counselling models can include debriefing, individual or group therapy on the basis of different theories (e.g. cognitive behavioral therapy). When dealing with bullying it is helpful to be able to integrate a number of counselling models and interventions. Traditional counselling as a means of tertiary intervention has, however, limitations in dealing with workplace bullying. Whilst it is helpful in dealing with employee reactions, it is not particularly effective in dealing with the organizational aspects of bullying

ERGONOMICS

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Ergonomics is an applied science concerned with the design of workplaces, tools, and tasks to match the physiologic, anatomic, and psychological characteristics and capabilities of the worker. More simply put, ergonomics involves adapting the work environment to be within the worker's capabilities and to prevent injury, illness, and strain. Ergonomics originated in response to recognition of occupational hazards. Occupational hazards are believed to induce microtrauma, which may result in cumulative trauma disorders (CTD) Cumulative Trauma Disorders Cumulative trauma disorders primarily affect the hands, wrists, arms, elbows, shoulders, lower back, and cervical spine area. Involved structures include tendons, muscles, bones, nerves, and blood vessels. Causative factors associated with CTD include: • Susceptibility • Localized contact areas • Pre-existing medical conditions • Lack of training and experience • Excessive force • Prolonged static posture Looking at each of the body parts involved, along with the causative factors, can assist in understanding the ergonomic hazards. Back injuries due to poor workplace design and improper lifting techniques make up a large portion of workers' compensation settlements and result in significant disabilities and loss of productivity. "The majority of workplace back disorders result from chronic, or long term, injury to the back rather than from one specific incident" (U.S. Dept. of Labor, 1991). Gradual, cumulative back trauma is experienced by employees who twist at the waist; lift with straight legs; bend and reach repetitively; maintain awkward postures for long periods; carry, push, pull, lift, or move heavy objects below the knees or above the shoulders; or lift weight beyond their capabilities (NIOSH,1981). Repeated trauma leads to scarring and weakening of ligaments, disks, muscles, and tendons. As these structures become damaged, the worker is at greater risk of additional injuries and irreversible damage which may result in chronic back problems and often total disability. Even sitting combined with vibration, experienced by truck drivers and heavy equipment operators, can lead to back injuries. Preexisting or underlying back conditions also can increase the likelihood of a work-related back injury. Another common site for CTD is the hand and wrist. Hand and wrist problems are not new, as illustrated by such terms as Gamekeeper's Thumb, Cotton Twister's Hand, and Stitcher's Wrist. Risk Prevention and Management The ideal solution for abatement of ergonomic hazards involves a proactive approach to safety. Positive action is promoted by health, safety, and management personnel who are interested in employee

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welfare and in controlling workers' compensation costs. If any of the risk factors are present or ifCTD appear as workers' compensation cases, an ergonomics program may be the answer. The cornerstone of an ergonomics program is management commitment. A program is doomed to failure unless management makes a commitment that includes financial backing and visible support. Information provided to management needs to include a thorough evaluation of the frequency and severity of the current CTD cases, including the number of cases for the past several years as well as the number of lost workdays. Document the current costs of existing cases, their projected cost at closure, and an estimate of anticipated new cases and their projected costs and impact on the company. A number of companies document successful ergonomic programs. Milton Bradley experienced a 90% increase in quality after implementing ergonomic changes in the packing area. Engineering controls consisting of repositioning the conveyor, installing a packing table, and decreasing the tilt of shipping cartons led not only to a decrease in CTD but to increased quality and productivity. General Motors and Ford Motor Company also are among companies that have established a proactive program (OSHA, 1991). A well written, accountable plan should focus on cost containment projections. Prepare a proposed budget and indicate the projected savings of an ergonomics program. Suggest accountability and set objectives. Stress that this program is not only for employee welfare, but that it will have a positive impact on corporate profit projections. One also may want to emphasize the improved employee morale, healthier work force, and decreased absenteeism that can occur. Statistics should be monitored for the program. Compensation, frequency (the number of lost time case occurrences), severity rates (the number of lost work days per 100 workers), and absenteeism need to be evaluated quarterly. Finally, stress that an active, focused commitment from the management level and throughout the entire organization is essential for success. The OSHA general duty clause, which requires employers to provide a safe and healthy workplace, and proposed regulatory standards may be cited as added incentives to have a program well underway before compliance is mandatory or a fine is imposed. Along with the proposed budget, a well written plan must be presented to management. Identify those who will be the active players in the program and form an ergonomic task force of engineers, health and safety professionals, supervisors, and other employees. Train this in-house task force in anthropometric and ergonomic principles, using outside professionals, ergonomists, or training programs. Initial efforts should focus on already identified at risk positions. Evaluate work station design, tools, posture (or static posture), positions during task performance, lifting techniques, vibration (torque), temperature, task intensity and duration, number of repetitions per minute or shift, and mechanical risk factors. Videotaping or a checklist can assist in risk factor identification.

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Talk with employees. Find out if they are experiencing difficulties in performing their job or if they are experiencing pain. Is the position and posture comfortable? Is the hand tool heavy or does it fit the hand properly? A number of resources have been developed to assist in identifying ergonomic hazards and solutions; for example, the AAOHN video and accompanying manual "Ergonomics: Creating a Healthier Workplace for a Healthier Bottom Line" (AAOHN, 1993) or National Safety Council series (Brough, 1991). Collect observations, employee complaints, medical data, and quantitative data (such as amount of weight lifted or number of repetitions), and have the task force conduct an analysis of the position. Take into consideration the natural resistance to change on the part of the worker and reinforce positive change with teaching and support as modifications are introduced. Modification will vary with each position. Modification of tools or tool handles may promote a more neutral hand position or decrease vibration. Padded handles or padding the edge of tables may decrease direct pressure and stress to the hands and forearms. Suspending air drivers from the ceiling will decrease weight. The solution may be very simple, as in the case of a worker with hand complaints who was actually hitting a bracket with her hand. Listening to the employee, evaluating the station, and supplying a rubber mallet for hitting the bracket eliminated the impact forces to the palm and the employee's pain quickly disappeared. Solutions for VDT hazards can include platforms or adjustable chairs; engineering modification of the job station; adjusting VDTs, hanging papers from suspended hooks for typists so their necks are not flexed throughout the day; ensuring that work tables are at appropriate heights; and providing slanted desks for drafters to improve posture. Avoid static posture with regular stretch breaks. To prevent back injuries, lifts should be only above the knees and never above shoulder level. Refer to the revised NIOSH (1991) work practice guide lifting formula for calculating acceptable weight limits for lifting (DeClercy, 1993). Limit unassisted lifts to 50 lbs. Train employees in proper lifting techniques. Provide a mechanical lift if necessary and feasible. Develop written guidelines for lifting. Train employees to follow the guidelines and post the guidelines in appropriate work areas. Solutions may be simple. In one case a worker was leaning over a bezel to place a strip on the other side, and simply having the bezel placed facing the employee completely eliminated the awkward posture. If repetitive movements are a problem, consider job expansion to provide varying movements and muscle recovery time. Promote rest breaks or exercises. Identify whether measures such as job modification, rotation to another position periodically, or institution of robotics could help. Re-evaluate as changes are instituted, since changes may fail to solve a problem or can create new problems. Set a schedule for re-evaluation of the station and to speak with the employee. Finally,

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continue to document occurrence and costs of CTD. Document the efforts and successes of the program and report the impact to management. Companies should evaluate their position and recommend the formation of an ergonomic program for hazard abatement if problems exist. Providing a work environment free of ergonomic hazards will prevent or reduce costly injuries and have a positive impact on the profit objectives of the company. Productivity and employee morale will improve. Having an ergonomics program in place also lessens concern about negative sanctions that could be instituted by OSHA should an ergonomic problem be identified at the company (currently under the general duty clause). Not only will the company be a better place to work, but the programs should show a quantifiable positive impact on the bottom line which will promote health and safety goals. Musculoskeletal disorders (MSDs) Musculoskeletal disorders (MSDs) affect the muscles, nerves, blood vessels, ligaments and tendons. Workers in many different industries and occupations can be exposed to risk factors at work, such as lifting heavy items, bending, reaching overhead, pushing and pulling heavy loads, working in awkward body postures and performing the same or similar tasks repetitively. Exposure to these known risk factors for MSDs increases a worker's risk of injury. Work-related MSDs can be prevented. Ergonomics, fitting a job to a person, helps lessen muscle fatigue, increases productivity and reduces the number and severity of work-related MSDs. Examples of Musculoskeletal Disorders (MSDs)      

Carpal tunnel syndrome Tendinitis Rotator cuff injuries (affects the shoulder) Epicondylitis (affects the elbow) Trigger finger Muscle strains and low back injuries

Impact of MSDs in the Workplace Work related MSDs are among the most frequently reported causes of lost or restricted work time.According to the Bureau of Labor Statistics (BLS) in 2013, MSD1cases accounted for 33% of all worker injury and illness cases. A Process for Protecting Workers

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Employers are responsible for providing a safe and healthful workplace for their workers. In the workplace, the number and severity of MSDs resulting from physical overexertion, and their associated costs, can be substantially reduced by applying ergonomic principles. Implementing an ergonomic process is effective in reducing the risk of developing MSDs in highrisk industries as diverse as construction, food processing, firefighting, office jobs, healthcare, transportation and warehousing. The following are important elements of an ergonomic process: Provide Management Support - A strong commitment by management is critical to the overall success of an ergonomic process. Management should define clear goals and objectives for the ergonomic process, discuss them with their workers, assign responsibilities to designated staff members, and communicate clearly with the workforce. Involve Workers - A participatory ergonomic approach, where workers are directly involved in worksite assessments, solution development and implementation is the essence of a successful ergonomic process. Workers can: o o

Identify and provide important information about hazards in their workplaces. Assist in the ergonomic process by voicing their concerns and suggestions for reducing exposure to risk factors and by evaluating the changes made as a result of an ergonomic assessment.

Provide Training - Training is an important element in the ergonomic process. It ensures that workers are aware of ergonomics and its benefits, become informed about ergonomics related concerns in the workplace, and understand the importance of reporting early symptoms of MSDs. Identify Problems - An important step in the ergonomic process is to identify and assess ergonomic problems in the workplace before they result in MSDs. Encourage Early Reporting of MSD Symptoms - Early reporting can accelerate the job assessment and improvement process, helping to prevent or reduce the progression of symptoms, the development of serious injuries, and subsequent lost-time claims. Implement Solutions to Control Hazards - There are many possible solutions that can be implemented to reduce, control or eliminate workplace MSDs. Evaluate Progress - Established evaluation and corrective action procedures are required to periodically assess the effectiveness of the ergonomic process and to ensure its continuous improvement and long-term success. As an ergonomic process is first developing, assessments should include determining whether goals set for the ergonomic process have been met and determining the success of the implemented ergonomic solutions.

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Heavy work Scope and prevalence Heavy work includes the type of work that is characterized by high external forces on the body. These may result from:    

lifting of heavy loads, carrying of heavy loads, pushing of loads, pulling of loads.

Despite the increased mechanization and automation in many sectors of industry, the proportion of workers exposed to heavy work have remained relatively stable over the past decennia. In the Netherlands the percentage of workers exposed to heavy work is about 20%. Across Europe, carrying or moving heavy loads is part of the work of 25-40% of the workers (Eurofound, data can be found for each country. In industrially developing countries that percentage may be much higher. Sectors with high incidences of heavy work are: nursing, construction, metal, agriculture, transport and logistics. Risk There is strong evidence that the frequent lifting of heavy loads is related to the occurrence of lower back pain. Many epidemiological studies have investigated this relationship. Estimates for the relative risk associated with occupational lifting and lower back injury ranges from 1.3 to 4.2. It was also established that the risk of developing injury increases with the frequency of lifting. However, there is no evidence that the frequent pushing and pulling of loads is related to the occurrence of lower back pain. Some studies suggest a relationship of pulling/pushing with shoulder complains, but the number of these studies is quite limited. Risk assessment method The risk associated with the lifting of loads depends on several factors, among others the weight of the load, the vertical travel distance, the horizontal distance between the load and the body, and the frequency of lifting. These risk factors are addressed in the so-called NIOSH equation which can be considered as the most complete and applied risk assessment method for lifting. The method is relatively simple to use, but one needs to follow the manual carefully (CDC website). The primary product of the NIOSH lifting equation is the Recommended Weight Limit (RWL), which defines the maximum acceptable weight (load) that nearly all healthy employees could lift over

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the course of an 8-hour shift, without increasing the risk of musculoskeletal disorders (MSD) to the lower back. In the NIOSH equation: RWL (kg) = 23 x HM x VM x DM x AM x FM x CM, where 23 reflects the number of kgs considered to be safe in ideal lifting conditions, and HM up to CM represent the multipliers M associated with the following risk factors:      

H = Horizontal location of the object relative to the body V = Vertical location of the object relative to the floor D = Distance the object is moved vertically A = Asymmetry angle or twisting requirement F = Frequency and duration of lifting activity C = Coupling or quality of the workers grip on the object.

Another method for risk assessment is the KIM method [12]. This method not only addresses lifting, but also holding, carrying, pushing and pulling. The method was developed by the Federal Institute for Occupational Safety and Health (BAuA) and Committee of the Laender for Occupational Safety and Health (LASI) (European Agency for Safety and Health at Work website). Prevention The NIOSH calculation allows identification of the factor(s) that are the most promising for intervention. As loads are usually not easy to change, in many cases workplace improvements are the best option. Reducing the horizontal distance is important, and can be attained by both workplace design and good work instruction. Repetitive work Scope and prevalence Repetitive work is the type of work that involves repetitive movements of the arms and hands. This type of work is prevalent in many occupations, like assembly, packing, computer work, hair dressing, etc. For the Dutch population of workers, it has been established that 35% are exposed to ‘repetitive movements of the arms and hands’. Computer work is a specific form of repetitive work involving repetitive movements mainly of the hands and fingers. Obviously, the prevalence of this type of work has increased dramatically over the past decennia. The Euro found website provides detailed information for European countries about the percentage of workers that are involved in computer work. In many countries about 40% of the employees work (almost) all the time with computers.

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Risk The type of musculoskeletal disorders associated with repetitive work mainly concern neck, shoulder, elbow and wrist complaints. Several terms are used to group these types of disorders, for instance Repetive Strain Injury or Cumulative Trauma Disorder or Complaints or Arms, neck and Shoulders (CANS). Epidemiological evidence for the association between repetitive work and repetitive strain injury has been provided: relative risks ratios have been estimated in a range from 2,3 to 8,8 Typical computer work with keyboard and mouse is characterized by a combination of small repetitive movements of fingers, precise hand operations and static muscles in the neck-shoulder region. It has been reported that the task duration is a main determinant of risk in this kind of work. The risk of developing health complaints particularly increases at a task duration above 6 hours per day. Other extra risk factors are:    

too little recovery time (minimum 5 minutes per hour), no option to take micro breaks (minimum 20 seconds every 10 minutes), no individual control of work pace, mental work strain.

Risk assessment method The OCRA method can be used for the assessment of the risk of repetitive movements of elbows, wrists and hands in cases where:   

one or both upper extremities moves in cycles of less than 30 seconds, these or similar cycles are performed for more than 50% of the working time, the cycles are frequent and are identical or similar in nature.

As with the NIOSH formula, the OCRA method calculates the risk with the Recommended Technical Actions, the maximum permissible number of actions per minute: RTA = 30 x Pf x Rf x Af x Ff x (Rc x Dc) where the risk factors are:     

Constant of Frequency” of technical actions per min = 30 Posture (Pf) Repetition (Rf) Additional factors (Af): cold, vibrations, noise, gloves Force (Ff)

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 

Recovery options (Rc) Duration (Dc)

The OCRA index = real number of movements / RTA and is judged according to the following traffic light model: Green <2,2 no risk Orange 2,3 – 3,5 low risk Red >3,5 risk, action must be taken. Prevention The OCRA calculation allows identification of the most promising factor(s) for intervention. Static work Static work is the type of work that involves prolonged standing and prolonged postures of the back, neck and arms. Prolonged standing Prolonged standing (more than 4 hours a day) without regular intermittent walking is prevalent in many occupational sectors like healthcare, catering, retail and security. The type of musculoskeletal disorders associated with prolonged standing mainly concern chronic venous insufficiency and musculoskeletal pain of the lower back and feet. Prolonged postures As for repetitive work, prolonged postures (holding times longer than 4 seconds) are prevalent in many occupations like assembly, packing, computer work, hair dressing, etc. Exposure and risk are much the same as for repetitive work, and the risk assessment methods for upper body movements and postures are similar Sedentary work Scope and prevalence Many workers perform their work seated for prolonged periods. In the Netherlands the mean worker sits 5,8 hours per day at work plus 3,5 hours in private life [9]. Jobs with high incidence of sedentary work are: office work, security (control rooms), transport (drivers), services, cashier work. Risk

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ERGONOMICS

Sedentary work is related to overweight, lack of physical activity and poor and prolonged postures. In addition to MSDs, it has been linked to CVD, digestive cancers, reproductive disorders and reduced mental health. Prevention A good workplace design and frequent changes in postures are required in order to prevent strains. Some desks allow alternate sitting and standing, and if one does not have such a desk, one should walk regularly. As a minimum it is advised to move semi-intensively during 30 minutes per day. Mini breaks will contribute to the reduction of overloads. Walking during lunch breaks is an option for office workers. The newest designs in ergonomic seating allow for more dynamic seating, with postural changes. However, even the best furniture cannot overcome the strains on the body from excessive periods of sitting. Good instruction on how to use adjustable furniture is also important.