There are many jobs that are physically demanding and where workers must lift objects of various weights throughout the day. This may cause stress to the musculoskeletal system that in its turn can lead to injury and musculoskeletal system disorders if no proper rest is taken and if no preventive and control measures are followed by the employees. (Learn more in "A Look at Lower Back Pain in the Workplace".) Along with physical demands analysis (Learn more in "Physical Demands Analysis 101".) and fit for work testing, (Learn more in "How to Set Up a Fit-for-Work Testing Program".) using an ergonomic assessment of the lifting tasks can reduce risks to workers, decrease health care costs, and increase productivity.
Why conduct an ergonomic assessment?
The factors that increase the risk of injuries in a lifting environment can be unknown or unclear to the employer and employee. An ergonomic assessment is a study to identify these ergonomic risk factors in the workplace, and classify them by risk level as well as to show what measures can be taken to prevent injuries related to lifting at work. (Learn more in "Introduction to Hazard Identification Studies".) An ergonomic risk assessment is the duty of the employer to carefully examine any potential factor that may cause harm to employees while performing lifting tasks in the workplace. (Learn more in "8 Key Areas of Ergonomics Employers Must Consider".)
Risk identification and data collection
Part of an ergonomic assessment is to identify risks and collect data. One way to identify the risks is to observe the workflow and the work environment in different departments and units looking for ergonomic hazards, and by collecting supporting pictures and videos for more detailed review. Employees may also be interviewed about their lifting practices and conditions relating to any lifting situations, such as any fatigue they experience, or how they feel the task may be made easier or safer. It is also helpful to check the safety and medical records, insurance, and other sources of information to identify repeating issues. In fact, this step will allow a first ergonomics audit that will result in a list of jobs which are the most subject to ergonomics lifting risk.
There are different measurement tools that can and should be used in this initial phase of lifting related risk assessment.
WISHA Lifting Calculator: developed by the Washington State Department of Labor and Industries It is a simplified tool to assess the risk related to "manual lifting" and "lowering tasks". Indeed, it gives the "risk", the "weight limit", and the "lifting index", an indicator of physical demands and stress; based on the "hand position", "number of lifts per minute", "daily duration" and "twisting degree".
NIOSH Lifting Equation Calculator: more elaborate than WISHA, the NIOSH tool considers more parameters for the risk assessment such as the "travel distance", the difference of values between "origin and destination" and so forth. It gives also more detailed outcomes.
Rapid Entire Body Assessment (REBA): this tool is based on the principle of "scoring postures of neck, trunk, legs, arms and wrist" according to provided scoring tables. It aims to assess the musculoskeletal disorder risk related to the entire body posture.
Rapid Upper Limb Assessment (RULA): it has the same principles and aims than the former tool but focuses only on the upper body posture.
Liberty Mutual Manual Material Lifting and Lowering Table (Snook table): gives the "maximum weight to lift" based on information about the "location of the hands", the "lifting frequency", and the "distance of the lift".
Washington State Ergonomic and MSD Risk Assessment Checklist: Uses a series of checklists in order to assess situations. The Caution Zone Checklist is first used to recognize potential ergonomic risks such as inappropriate postures, vibration, and repetitive movements. If scores on that checklist indicate a moderate to high risk, a second checklist is used to further refine the amount of risk present. The second checklist, the Hazard Zone Checklist, focuses on finding situations where urgent action is needed to be taken to reduce or eliminate risks quickly.
Factors related to injury and strain in lifting
Potential ergonomic occupational hazards related to lifting depend on several factors that should be uncovered during the lifting assessments.
The object: Although there is no standard for what is a heavy weight, most individuals will have difficulties to lift weights of 20-25Kg. In addition, lifting difficulty increases when the weight has a huge volume, has no proper grasping area, has not a stable balance or it is difficult to reach.
The task: It can be very stressful to perform when it lasts for a prolonged period or repeated over time too often, especially when there is no adequate rest and no regular breaks. Some postures and movements such as a bent trunk and a turned head also increase the risk of injuries.
The environment: The conditions under which lifting is performed is a large factor in safety. Lack of space for a proper and safe lift technique or slippery, unstable or irregular floors can cause a hazard. Extreme temperatures (hot or cold) such as heat with humidity resulting in heat exhaustion or heat stroke possibilities, or cold that could increase the chances of Raynaud's syndrome are also factors. Even a lack of ventilation or light can make the lifting tasks more hazardous.
The individual factors: Finally, factors pertaining to the individual employee must be considered. Any lack of experience and training, age, physical condition, previous injuries, (Learn more in "The Importance of Determining an Employee's Pre-Existing Injuries".) lifestyles, history of musculoskeletal disorders, and commitment to preventive measures such as the use of personal protective equipment can directly impact the risks associated with lifting.
Data analysis and evaluation
Once data is collected, it must
be reviewed by qualified individuals in the medical field, those who
understand OSHA rules, and a qualified ergonomics professional. This
step should result in the creation of a written plan and implementation of necessary preventive and control measures where necessary.
How to make lifting safer for employees
Risk elimination and technical measures
These measures aim towards eliminating lifting by employees and replacing it with automated lifting methods. Alternatively, partial automation can be implemented. It may involve lift assist devices such as vacuum lifting devices and lift tables. (Learn more in "6 Ergonomic Aids for Employees Who Work in a Standing Position".)
Administrative measures based on task reorganization to reduce risks. Measures such as allowing more frequent regular breaks and alternating lifting with other tasks to allow muscle recovery would be part of organizational measures. (Learn more in "Breaks During Work Are Necessary for Employee Well-Being and Work Performance".)
Employee information and training
Employees have the right to be informed about the risk of injuries related to the tasks they perform in the workplace and they should be educated about the correct use of preventive measures such as how to use protective equipment. (Learn more in "Why Fit Testing is Important for Workers Wearing Personal Protective Equipment (PPE)".)
These measures rely mainly on the correction of lifting techniques by being aware of the risk factors and how to avoid them by appropriate posture. Correcting the environmental factors such as increasing the light intensity, need also to be considered.
Risk monitoring and preventive measures review
Risk assessment monitoring following an ergonomic lifting review is a dynamic process and updates on a regular basis are needed not only to maintain risks at minimal levels, but also to implement better measures and catch any newly developing hazards before they become a serious problem.