Lifting and Handling, a Risk Assessor s Guide

Transcription

1 Lifting and Handling, a Risk Assessor s Guide 1 Introduction Unfortunately manual handling accidents are all too common, and can lead to life-long problems with bad backs. While they do not have the same drama as fire, electrocution, etc, they deserve careful consideration as they represent an enormous cost to both the individual and to the employer. Choosing the right lifting method, and executing it correctly can remove most of the risk. Injuries from manual handling include bad backs a whole range of musculo-skeletal injuries, but the hands, arms and feet are also vulnerable. Manual handling accounts for 37% of accidents at work, and a back injury usually results in an average of 20 days off work. Other injuries are sprains and strains, hernia, cuts, abrasions and bruising, crushing and injuries due to repetitive movements. Manual handling includes any transporting or supporting of a load by hand or by bodily force, applied directly or indirectly. It includes lifting, putting down, pushing, pulling, carrying or moving. Employers should avoid the need for employees to undertake manual handling operations that involve a risk of their being injured. If such manual handling cannot be avoided, then you shall Make a suitable and sufficient assessment of the manual handling task Take steps to reduce the risk of injury to the lowest level reasonably practicable. Thus, there is an explicit requirement to undertake risk assessment for some manual handling operations. Summary: Having identified that a manual handling operation carries a risk of injury, a risk assessment is required and the hierarchy of control measures is to Avoid manual handling so far as is reasonably practicable Assess any manual handling operation that cannot be avoided Reduce the risk of injury by mechanical assistance, or by improving the task, the load or the environment. Equally important, the people doing the manual handling need to be aware of the risks and need to know how to apply correct technique to their lifting operations. Mechanised lifting is not without hazard. Suitable equipment must be chosen and used correctly. Lifting equipment must be made to good engineering standards, tested before use, and also be periodically examined. Fork lift trucks have poor stability and may only be driven by trained personnel. 2 Anatomy The spine has 33 bones, which support the upper body, protect the spinal cord and allow movement. The nerves serving the limbs and the rest of the body branch out from the spinal cord and the spine itself is supported by ligaments, muscles and tendons. Manual handling Page 1 of 9 August 2006

2 Figure 1: Disc Pressures Manual handling Page 2 of 9 August 2006

3 Between the top 24 vertebrae lie discs, which act as shock absorbers and allow movement between the vertebrae. Discs are roughly circular and consist of an outer rim of elastic fibres and an inner core of jelly-like fluid. Disc injuries account for 90% of back problems. When the spine is upright in its natural curves the discs are symmetrical, but as the person bends over the discs become pinched. Worst of all, if the person then twists the outer rim of the disc can be damaged. The disc has few nerves so we are usually unaware that damage is taking place - it doesn t hurt. Once damaged, healing is slow because the disc also has a poor blood supply. A damaged disc may leak fluid and this is extremely irritating to the surrounding tissue, giving rise to the extreme pain of a slipped disc. It is thought that most, if not all, disc lesions are a result of cumulative damage, and it is very important to stress to your colleagues that bad handling techniques, although not painful now, may lead to a very painful injury later. The final load that may cause the disc to fail may be a sneeze, lifting a cup of coffee, trying to stand up after bending forwards or any other seemingly trivial event. Figure 1 shows the variation in the load on a disc with posture, normalised to a 16 stone individual standing up. Notice how sitting down is 40% more stressful for the lower back. The mechanics of lifting also present problems for the muscles in the back as shown in Figure 2. Figure 2: A simplified model of the forces exerted by muscles during lifting Arms length = approx 500 mm from the pivot point Muscles 20 mm from pivot point Load 10 kg Muscles are exerting 25 times as much force as the force of gravity on the load The spine acts as the pivot about which the lift takes place. The muscles are approximately 20 mm from the pivot. Suppose the person chooses to lift something at arm s length that weighs 10 kg, this may be 500 mm away from the pivot point. Since the load is 25 times further from the pivot point than the muscles it follows that the muscles must exert 25 times as much force as the force of gravity on the load. In the example given, this would be equivalent to the force sufficient to lift 250 kg! This muscular effort exerts stresses on the discs. It follows that the closer the load is to the body, the smaller the lever arm on the left hand side of Figure 2, and the smaller the stress placed on the back muscles and the discs in the spine. Manual handling Page 3 of 9 August 2006

4 3 Deciding Whether a Formal Risk Assessment is Required It is not possible to set hard and fast rules on the weight that a human being can lift unaided, but the diagram below is reproduced from the HSE guidance. It represents weight limits that are within the capabilities of the majority of the adult population. The underlying message from the regulations is that exceeding these limits would warrant risk assessment, but it is not illegal to lift weights that are heavier than this by hand. It is suggested that these weights are used as the filter for a formal risk assessment. Restriction of tasks to the weights shown in Figure 3 gives a reasonable level of protection to around 95% of working men and women. For those at special risk, individual capability should always be taken into account. Figure 3: Relative lifting capability, taking into account the zones around the body Even within these limits, it is still perfectly possible to injure oneself, unless correct lifting technique is used. This technique has to be learnt, and this is why training is so important. Some guidance is given in section 4. If the operation involves twisting reduce these limits, e.g. by 10% if the angle of twist exceeds 45 o, and by 20% if it exceeds 90 o. When seated the basic guideline figures are 3 kg for women and 5 kg for men, and these are confined to situations where the arms are close to the body. Reaching further away for a lifting operation when seated deserves a more detailed assessment. For pushing and pulling operations, where the force is to be applied between knuckle and shoulder height, the guideline figure for stopping or starting a load is 20 kg for men and 15 kg for women. For keeping a load in motion the guideline figures are 10 kg for men and 7 kg for women. Summary table: Suggested filter to be used for risk assessment Operation Guideline for men Guideline for women Lifting standing See diagram above Lifting seated, close to the body 5 kg 3 kg Pushing or pulling a load, setting it in motion or stopping it 20 kg 15 kg Pushing or pulling a load, keeping in motion 10 kg 7 kg Manual handling Page 4 of 9 August 2006

5 If the operation is to be done frequently, or involves twisting, stooping, or handling in a confined or awkward area, the guideline figures should be reduced. For example, librarians are at risk of injury from repetitive movements, even though the loads that they handle may be well below the guideline figures above. This is because they may be stooping, twisting and reaching awkwardly. For them, training should be targeted towards the correct design of their tasks to avoid injury. 4 Risk Assessment and the Safe System of Work 4.1 Assessing the risk Risk assessment for manual handling will need to address the following questions: The Task Does it involve The Loads Are they Loading or moving loads at a distance from the trunk? Unsatisfactory bodily movement or posture, especially twisting the trunk, stooping, reaching upwards? Excessive movement of loads especially excessive lifting, lowering, carrying, pushing or pulling distances? Risk of sudden movement of loads? Insufficient rest or recovery periods? A rate of work imposed by a process? Heavy? Bulky or unwieldy? Difficult to grasp? Unstable, or with contents likely to shift? Sharp, hot, or otherwise potentially damaging? The Working Environment Are there Space constraints preventing good posture? Uneven, slippery or unstable floors? Variations in level of floors or work surfaces? Extremes of temperature, humidity, or air movement? Poor lighting conditions? Individual Capability Does the job Other Factors Require unusual strength, height, etc? Create a hazard to those who are pregnant or have a health problem? Require special knowledge or training for its safe performance? Is movement or posture hindered by personal protective equipment or by clothing? A form for undertaking this exercise is at the end of this document. 4.2 Risk Reduction Measures Can you reduce the risk by: Improving the workplace layout? Reducing the amount of twisting and stooping? Avoiding lifting from floor level to above shoulder height? Reducing carrying distances? Avoiding repetitive handling? Manual handling Page 5 of 9 August 2006

6 Varying the work, allowing one set of muscles to rest while another is used? Can you: Reduce the bulk or weight of the load? Make it easier to grasp? Make it more stable? Make it less damaging to hold? To assist the workforce in approaching their tasks, you should provide general indications of the weight of a load and the heaviest side (if it is not symmetrical). Can you: Remove the obstructions to free movement? Provide better flooring? Avoid steps and steep ramps? Prevent extremes of hot and cold? Improve lighting? Consider less restrictive clothing or personal protective equipment? Can you: Take better care of those who have a physical weakness or are pregnant? Give the employees more information, e.g. about the tasks to be done? 4.3 Training Training in manual handling technique is very important. It does not, however, overcome failing to use a lifting aid where needed, or bad working conditions. Training should cover How to recognise harmful manual handling Systems of work appropriate to the kinds of situation in the Department How to choose and use mechanical aids Good manual handling techniques. 4.4 Good Lifting Technique The instructions below should be followed to ensure that you reduce the level of risk in lifting. Stop and think. Plan the lift where is the load going? Use handling aids if possible. Do you need help? Remove obstructions on the route you intend to use. Position the feet Place your feet apart to give a balanced and stable base. Put the leading leg as far forward as is comfortable, pointing in the direction you want to go. Manual handling Page 6 of 9 August 2006

7 Adopt a good posture When lifting from a low level, bend the knees. Do not kneel or overflex the knees. Keep your back straight, maintaining its natural curve. Lean forward a little over the load, if necessary, to get a good grip. Keep your shoulders level and facing in the same direction as the hips. Lift smoothly, raising the chin as the lift begins. Keep control of the load. Don t jerk. Avoid flexing your back further by straightening your legs before starting to raise the load. Move the feet Don t twist your trunk when turning to the side move your feet first. Don t lean sideways, especially while your back is bent. Put it down, then adjust If you need to place the load precisely, put it down first, then adjust its position. Get a firm grip. Try to keep the arms within the boundary formed by the legs. Make sure your grip is secure. A palm grip is preferred. Keep close to the load Keep the load close to your trunk for as long as possible. If the load is unbalanced, keep the heaviest side of the load close to your trunk. Source of advice and accompanying drawings: The Health and Safety Executive. 4.5 Coordination of Two or More People Lifting a load in cooperation with others is quite difficult as the load will shift from one to another in a complex way it is rarely equally shared! In consequence, two people should not attempt to lift a load that represents their combined capability. HSE Guidance is that two people should only attempt to lift two thirds of their combined capability, and three people may lift half of their combined capability. Decide who will be in charge BEFORE you begin the lift, and what commands will be used (watch any medical drama series and notice how they lift patients in co-operation). Lack of coordination of such a lift can easily lead to injury for one or more members of the team plan your work carefully. Manual handling Page 7 of 9 August 2006

8 5 Manual Handling and Lifting Aids As already stressed, there are no weight limits, but the table below gives some general guidelines for lifting and transporting which may be found helpful. THEY ARE NOT DEFINITIVE GUIDANCE. kg lb Lift by hand Transport by hand Lift by hand Transport by sack barrow or trolley Lift by hand - with assistance if the load is awkward or at the heavier end of this zone (note the need for risk assessment for weights >25 kg). Transport by sack barrow or trolley Lifting by hand in this zone would normally be with the assistance of others, see section 4.5 Use a fork-lift truck, hoist, or other lifting aid Practice can generally be adopted but in the case of manual handling you must take account of the zone of the body where the lift is taking place, the posture and the individual s capability. Weights over those defined by the HSE filters should be the subject of risk assessment. Practice may be adopted, with care, if personnel are suitably fit and trained, and the load is easily manipulated. Note the capability for lifting in the various zones around the body detailed in the diagram in section 4. The weight limit for lifting by hand can be exceeded IF the person is capable and competent, and it is not reasonably practicable to lift by another means. 6 Further Reading Free guide from the HSE: Getting to grips with Manual Handling The full document: L23 Manual Handling. Manual Handling Operations Regulations 1992 (as amended). Guidance on the Regulations, ISBN X Manual handling Page 8 of 9 August 2006

9 Risk Assessment for Manual Handling Assessor Date Description of the task: Who is to do it? To move From How many loads? The Task Tick if any of the following apply The load must be held away from the body Twisting Approximate weight To Strenuous pushing or pulling Unpredictable movement of the load Stooping Reaching up above chest height Travelling a long distance (>10 m) The Individual Tick if any of the following apply Does the person have impaired lifting capability (e.g. through illness or injury)? (Female only!) Could the person be pregnant? The Load Tick if any of the following apply Is it bulky or unwieldy Is it difficult to grasp? Working environment Tick if any of the following apply Lack of space, interfering with posture or making it difficult to manoeuvre Poor floors, uneven, slippery Repetitive handling Insufficient rest or recovery time Handling while seated Does the task call for special capabilities? Is it unstable or unpredictable? Is it harmful (e.g. hot, sharp)? Hot/cold/rain/ice/humid conditions Strong air movement Variations in level Recommendations for the lift No of people to share the task Method of working to minimise the risks identified above to the lowest level reasonably practicable. Poor lighting Lifting aids (if any) Manual handling Page 9 of 9 August 2006