Ergonomics
The Snook Tables gives the maximum weights and forces of handling various tasks. The Snook Tables are based on the research done by Dr Stover Snook and Dr. Vincent Ciriello at the Liberty Mutual Research Institute for Safety. The Snook tables provide the goals of design in weight or force pounds. This is achieved through making comparison of the particular manual handling tasks against the right table (Giahi et al.,2014). The Design Goal is the main Snook Tables Calculator’s output. The Design Goals tend to answer the question of whether the force or weight is too heavy or it too forceful for this task. If the actual force or the weight exceeds the design goal, there should be the implementation of control on risk reduction
A risk Index is calculated to give the relative estimate of the level of the MSD risk and the physical stress that is associated with the lifting tasks. This help answer the question of how significant is the risk
Risk Index is =Actual Weight/Force Requirement ÷ Snook Tables Design Limit
- A risk index value of 1.0 or less indicates a nominal risk to healthy employees. A risk index that is greater than 1.0 indicates a task that is of high risk. Some of the variables required when evaluating lifting tasks using Snook Tables include the following
- Weight of Object
- Force Requirement
- Lower Distance
- Hand Distance (Horizontal Hand Position)
- Hand Height
- Push/Pull/Carry Distance
- Frequency
- Lifting/Lowering Zone
When evaluating tasks, the selection should be based on the most demanding and difficult tasks. When evaluating the lifting tasks, tasks with the heaviest objects should be lifted from the most awkward positions such as above the shoulder, below the knees and farther stretch and when evaluating pulling and pushing tasks the most forceful tasks from high or low push-pull points. For the job task evaluated the evaluator would need to collect the relevant data. Data and measurement required for the assessments using the Snook Tables include weight, lift or lower distance, hand distance, hand height and frequency.
WISHA Lifting Calculator
WISHA was developed by the Washington State Department of Labor and Industries. It is a lifting calculator that is regarded as simple in application and design. The WISHA lifting calculator is an adaptation of the revised NIOSH lifting equation that is based on scientific research on the major causes of work-related injuries (Asadi et al.,2015).
WISHA Lifting equation follows the following procedures:
- Finding out the actual weight of the objects that the employee is lifting– This is given as below:
Actual Weight = ________ lbs
- Determining the unadjusted weight limit– This involves looking at the hands of the employees when they begin to lift the lower objects and marking that spot on the diagram. The number in that diagram is the unadjusted Weight Limit pound.
- Finding the Limit Reduction Modifier– This involves finding out how many times the employee lifts per minute and the total hours per day spent lifting. This information is used to look up to the Limit Reduction Modifier
- Calculating the Weight Limit-This involves copying the Unadjusted Weight Limit from step 2. If the employees twist more than 45 degrees while lifting, reduce the Unadjusted Weight Limit by multiplying by 0.85
- Comparing the Weight Limit calculated in the above procedure with the Actual Weight lifted from the first step. If the actual weight is greater than the weight limit calculated then lifting is regarded as a hazard.
Recommendations
When lifting weight it is important that a person focus on the body and not weight. A person lifting the weight should be able to align the body correctly and move smoothly through each exercise. Poor form may prompt an injury and slow gains. It is also important to concentrate with slow, smooth lifts and controlled descents while isolating the muscle group. Working at the correct tempo would help one stay in control instead of compromising strength gains through momentum. Additionally, it is important for the person lifting the weight to pay attention to breathing during the workouts by exhaling as much as they can as they work against resistance by lifting, pulling or pushing and then inhaling as they release the force or the weight of lifting.
References
Asadi, N., Choobineh, A., Keshavarzi, S., & Daneshmandi, H. (2015). A comparative assessment of manual load lifting using NIOSH equation and WISHA index methods in industrial workers of Shiraz City. Journal of Health Sciences & Surveillance System, 3(1), 8-12.
Giahi, O., Sarabi, M., Khoubi, J., & Darvishi, E. (2014). The effect of ergonomic intervention in reducing musculoskeletal disorders by Snook table method in a steel industry. Journal of Advances in Environmental Health Research, 2(2), 65-71.