Frequently asked questions
What is the MAC?
A. The Manual Handling Assessment Charts (MAC) is a tool to help in the identification of common risk factors in lifting, carrying and team handling operations. The MAC helps the assessor to identify the tasks that need improvement first.
How does the MAC fit in with the Risk Assessment Filters and Checklists in the guidance on the Manual Handling Operations Regulations (MHOR) 1992?
A. The MAC is not appropriate for all manual handling operations, and may not comprise a fully ‘suitable and sufficient' risk assessment if relied on alone. A full risk assessment will normally need to take account of additional factors such as an individual's health problems or the need for special information and training. The guidance on the MHOR sets out in detail the requirements of an assessment.
People with knowledge and experience of the handling operations, industry specific guidance and specialist advice may also help when completing an assessment. Further information can be found at the MSD site.
What is the role of the MAC scores? What do they indicate?
A. The total scores should be used to help the assessor prioritise remedial actions. The scores provide an indication of which manual handling tasks require attention first. They should only be used for comparison purposes because the total scores do not relate to objective action levels. The scores can also be used as a way of evaluating potential improvements. The most effective improvements will bring about the highest reduction in the score.
HSE promotes an ergonomics approach to manual handling assessments by considering the task, individual, load and environment. Why is there no reference to individual or psychosocial factors?
A. HSE is aware of the importance of the role of individual and also psychosocial factors. Although not explicitly included within the flow charts, the user is prompted to consider individual and psychosocial factors in the score sheet. Due to space restrictions imposed on the MAC some risks have not been included within the flow chart, which is why it may not be a ‘suitable and sufficient’ risk assessment on its own. The role of psychosocial and individual factors is covered more thoroughly within this website.
If a manual handling task involves lifting and then carrying, what should I assess?
A. Ideally both, but after some experience of using the MAC you should be able to judge which of the task elements poses the greater risk.
Why is there no weight/frequency graph for team carrying tasks?
A. L23 provides a weight reduction factor for team handling. There has been work on team stretcher carrying but team carrying is more specialised than could be conveniently included in the MAC.
How do I interpret the load weight/frequency graph for female workers?
A. For simplicity, the load weight/frequency graphs are applicable to both males and females.
- The green zone (top of green, bottom of amber) in the graph is based on data that Snook and Ciriello (1991) found acceptable to average females.
- The amber zone (upper line) is a load and frequency acceptable to average males.
- The red zone (upper line) is acceptable to 10 percent of males (strong males), until it reaches 50 kg. The 50 kg upper limit of the red zone was selected in line with information in the risk filter (twice the 25 kg upper load level for males). See Appendix of L23.
- The purple zone was added to give an increased level of risk that was considered important by the project team, as a few industrial workers consider it acceptable to lift loads of this magnitude despite the indications of a high risk of injury.
Why do the guideline weights in Figure 20 of the MHOR (L23) differ from those in the load/frequency graph in the MAC?
A. The figures in L23 and the lifting graphs in the MAC (and V-MAC) are based on the same data set (Snook and Ciriello, 91), but have different uses. The figures in L23 are designed to identify when a more detailed assessment is required and use data that will provide a reasonable level of protection to 95% of the working population.
The MAC is designed to help the user identify high-risk manual handling operations. The load/frequency graph has been included to show how load, weight and repetition affect the degree of risk during manual handling. This is based on the lifting capabilities of the working population.
Why is there no reference to biomechanical limits in the load/frequency chart?
A. There is no reference to biomechanical limits in the MAC as calculating them is very complex. However the load/frequency data used are based on Snook and Ciriello's (1991) psychophysical studies.
Can the MAC be used to assess tasks that involve handling people?
A. Most patient-handling activities are known to pose at least some risk of MSD to workers. Although the risk assessment principles in the MAC apply to all handling situations, note that the MAC was not designed with patient handling in mind, and therefore may not be appropriate for patient-handling risk assessments. The postures assumed, direction of forces applied, and level of control by workers may differ substantially between typical patient handling and the handling of inanimate objects. In addition, patient-handling risk assessments require an additional set of patient-related factors to be considered, such as the ability of the patient to co-operate and balance, as well as tendencies towards aggressive behaviour.
Snook SH and Ciriello VM, (1991), The design of manual handling tasks: Revised tables of maximum acceptable weights and forces, Ergonomics 34, 1197-1213.