Manual tasks in manufacturing
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Body stressing injuries as a result of performing manual tasks is highest cause of serious and severe injury in manufacturing.
Two of sub-sectors that are at high risk of manual tasks injuries in WA include food manufacturing and metal product manufacturing.
Common hazardous manual tasks in the manufacturing industry include repetitive actions and sustained postures during assembly and processing tasks, manually handling heavy, bulky and awkward items, frequency lifting below mid-thigh and above shoulder height.
Occupations at greatest risk depend on the sub-sectors. They include occupations such as welders, process workers and metal fabricators.
The following sections provide more detailed information about manual tasks in selected high risk manufacturing sub-sectors.
Please refer to the ‘Common hazardous manual tasks’ section of this website for more detailed information about relevant manual tasks such as handling heavy, bulky and awkward loads, handling trolleys, drum handling and stacking shelves.
Manual tasks in meat processing
The term 'meat industry' means organisations involved in the manufacture of meat products, excluding poultry and small goods. It includes the slaughtering, boning, slicing and packing of meat products, and the associated tasks of processing offal and by-products and delivering meat to customers. Much of this information is also relevant to the retail meat trade and smallgoods production.
Work related injury data for Western Australia shows that the meat industry experiences a high number of lost time injuries. The most frequent type of injury in the meat industry is being struck by an object, such as a knife or carcass, resulting in cuts and bruises. However the number of serious cuts have been reduced with the introduction of safe work procedures and personal protective clothing such as mesh aprons, mesh gloves and forearm guards.
The most costly injuries are caused by overexertion or physical strain while handling loads, and are referred to here as manual handling injuries. These injuries mainly affect the back, neck and arms, but also the hands and fingers. Manual handling injuries involve extensive time off work, resulting in considerable cost to the industry and pain and suffering for the injured workers. The greatest impact on productivity and health will be achieved by targeting these injuries. These injuries cost the meat industry an estimated $1.9 million every year and the industry needs to minimise these costs to remain competitive.
Examples of risk control in meatworks
Work organisation and job design
Standing at work
Many jobs in meatworks involve continuous standing, eg. many workers in the boning room and in the offal room are standing, largely in one place, all day long. Continuous standing is a common source of discomfort and tiredness. It can cause sore feet, swelling of the legs, low back pain, and stiffness in the neck and shoulders.
To reduce discomfort, the table or station where the person is standing should have a footrest so they can rest alternate legs. This encourages good posture and relaxes the lower back muscles. The footrest should be large enough for the whole foot. Anti-fatigue matting should also be provided to reduce the effect of standing on a cold, hard floor all day and fits with the hygiene requirements as it can be lifted and hosed for cleaning.
Sitting at work
Many standing jobs in a meatworks could be done sitting down but normal office chairs are not suitable. A better idea is a sit-stand stool that allows workers to transfer about two-thirds of their body weight onto a 'butt-rest' while their feet stay on the floor. They can then alternate between sitting and standing while they work. A sit-stand stool could be used by slicers, tally clerks, carton makers and other workers where their job is largely in one place.
Where space is limited and the worker must be able to move freely, a butt-rest that folds out of the way may be appropriate. The rest can be used occasionally between carcasses and when the chain is stopped, reducing the effects of continuous standing.
There is legal requirement on employers to provide seating for workers where practicable. Occupational Safety and Health Regulation 3.19 (2) states that ' If an employee's work is done from a standing position and the employee's work allows the employee to sit from time to time then, to the extent practicable, the employer must provide and maintain seating so that the employee may sit down for the periods when the employee is not working.'
Jobs that can be done sitting in an ordinary office-type chair, such as tying strings, preparing carcass tickets and stamping boxes, need a suitable backrest that is contoured vertically and horizontally. The seat height and backrest height should both be adjustable to suit workers of different sizes.
An incentive system of work may contribute to the risk of injuries from manual tasks. Work which is machine-paced and paid by production (eg. per animal) can result in excessive demands being made on workers by the employer (to maximise production) and by other team members (to maximise earnings), leading to an increased risk of injury. High work rates with repetitive tasks may not allow adequate recovery periods for heavily loaded muscle groups, resulting in cumulative-type manual handling injuries.
This system of work also encourages workers to complete their day's work quickly and leave the meatworks at the earliest possible time. This discourages the learning of new skills that may slow the worker down at first, and discourages workers taking part in any activities that are not directly linked to production, such as training sessions or safety and health meetings. There are many alternatives to the tally system of work and ways that the work can be organised to reduce the risk of injury.
Provide sufficient supplies of materials needed for the job, such as legging paper, strings, carton liners, so that workers do not have to leave their work area and drop behind in production.
Make provisions for an operator to be able to help balance out any problems if the job demands are uneven, or individuals are not fully skilled in the task, or workers need to take a short break.
Provide adequate workers on the production line to achieve the required work speed and product quality. This should be discussed between employer and employee representatives.
Provide a variety of tasks over a work shift, by moving workers between different jobs (job rotation) or increasing the tasks that make up a job (job enlargement). This should aim to spread the load over as many muscle groups as possible and to move people from heavy to lighter jobs during the shift.
Allow adequate breaks for muscles to relax and prevent build up of fatigue. For continuous, highly repetitive work a five minute break in every hour is recommended (Eastman Kodak, 1986).
Allow new or inexperienced workers, or people returning to work after more than two weeks' off, time to gradually become accustomed to the work. This gives their muscles and joints a chance to strengthen-up for that particular job.
Provide supervision to reinforce good techniques and work practices designed to reduce the risk of injury.
Space and lay out
Allow adequate space at each work area for cuts of meat that are still to be processed to be kept until the worker is ready (referred to as a 'buffer zone'). The stored items must not interfere with the work space needed to do the job. Also allow adequate space along the chain for each worker so they can work ahead of or behind their regular work position. This provides some flexibility and variation in pace for each worker.
The work height needs to be right for the job whether it's the height of the carcass on the chain or the height of a table. the layout of the workplace should allow workers to do the majority of their tasks at about waist height and within easy reach. Tasks requiring considerable force or using the body for leverage, such as boning out shoulder blades, may need a slightly lower work height.
On the slaughter floor, the aim is to keep the section of carcass to be worked on between mid-thigh and chest height to the worker. Different rail or chain heights in different areas of the slaughter floor enable the height of the carcass to suit the task. Alternatively the floor level or platform height along the chain can be at the right height for the task. Shackle and hook length can also be varied to suit different carcass sizes. For example, baby beef can have a longer shackle length than big bulls so the carcass head remains at about waist height for workers in the head removal area. Care should be taken in adjusting hook length as longer hooks result in more pronounced movements of the carcass.
Providing the right work height can also improve product quality and productivity. For example, workers trimming fat from beef carcasses above head height are unable to see what they are doing and may leave excess fat on the carcass or trim off excess meat leading to wastage or lower product quality.
Table heights should be designed so workers can keep their arms at about normal elbow position, with the shoulders relaxed and the elbows close to the body. Workers come in all shapes and sizes, with great differences in height and reach. The employer is required to take account of the safety of each employee, and not simply design a workplace which might be safe for an average worker.
For example, many workers of different heights are doing the same task at the same boning table. The tall worker has to stoop and the short worker has to work with arms and shoulders raised. Over a period of time, these awkward postures will lead to discomfort and eventually injury. To prevent injury, workers need to be able to adjust their own work surface to suit their height. Individually adjustable work surfaces, and adjustable work stands and table tops are ways of designing the workplace to the worker.
A temporary solution may be to match workers by height and place similar height workers on the same table and raise or lower tables accordingly. This should only be a short term solution.
Position of equipment
Badly positioned controls and equipment that require frequent reaching at arm's length or reaching above head height can lead to back and shoulder injury. For example, the control lever to lower the carcass in the evisceration area of the beef rail is often placed above and behind the worker, resulting in an awkward and uncomfortable working position. Controls that are used frequently or in emergencies, such as stop buttons on the chain, should be placed in front of the worker and within easy reach.
Suspended scales on the packing table are often positioned at shoulder height in the middle of the table, resulting in frequent lifting of heavy cuts of meat at arm's length. Weighing scales should be at the same height as the wrapping and packing table and within easy reach so that meat can be slid between work areas and not lifted.
Neck problems are often associated with poorly designed and positioned displays, such as the carcass weight display. These should be positioned at a suitable height, angle and distance to reduce neck strain and with a large enough display to prevent eye strain.
Tool and equipment design
The design of the hand tools and the way in which they are used is important in reducing manual handling injuries, particularly cumulative-type injuries to the hand, wrist and forearm. Repetitive knife work is a risk factor in strain injuries to the wrist and forearm.
Reducing this risk requires a good knife sharpening facility, employee training program and supervision to ensure that knives are kept sharp. This will reduce the force needed to make a cut, reducing the strain on the worker's wrist and hand. To prevent cuts while knife sharpening, oilstones should be securely fastened to a fixed base and be adjustable to a suitable height.
The handle on all tools, including knives, should provide a good grip and be the right size for the worker's hand. Air knives in particular have a large grip and are fairly heavy which may lead to hand and wrist problems for smaller workers. People's hand sizes vary enormously and suppliers of meat knives should design handles to suit different hand sizes. They should also accommodate left and right-handed users.
The repetitive use of the trigger or push button on mechanical hock cutters, air knives and saws can be a source of muscle fatigue. A worker using a hock cutter can do as many as 19 cuts per minute and press the finger button over 8000 times during the working day. Triggers that require reasonable force and can be activated by the middle part of the finger or fingers will minimise muscle fatigue.
Hand tools should be designed to keep the hand and wrist as straight as possible, without twisting or bending. For example, a hock cutter with a pistol grip ensures a good wrist and forearm position.
Alternative knife designs are available that allow more comfortable wrist positions for various cutting tasks. A knife designed to be used with a straight wrist is recommended.
Vibration from hand tools can damage blood vessels, causing what is known as White Finger, and resulting in numbness and pain in affected fingers. Cold workplaces can make the symptoms worse. Vibration can also lead to cumulative problems in joints and tendons.
To reduce the risk of these injuries employers should ensure regular maintenance of hand tools and encourage reporting of increased vibration in any existing tool. When buying new equipment, ask the supplier for information on the vibration level of the tool and select the model with the least vibration.
Suspending power tools from a balancer reduces the force needed to operate and control the tool. For example, suspending the stun gun (concussion stunner) above the knocking box by a counter balance reduces the weight held by the operator. Lifting the gun to replace the cartridge and striking the stunner against the animal's head both require less force.
This is particularly important given that difficult positions generally adopted by this worker include frequent bending, often with arms out-stretched and feet in an unstable position. Good placement and regular maintenance of the balancer is essential.
When buying new hand tools or equipment ensure that the purchasing specifications include how the equipment will be used and the injury risks that must be minimised. Involve safety and health representatives and workers who use the equipment in selecting new tools since they are familiar with the job and the tools, and know the important features to look for.
Mechanical handling devices
Mechanical handling equipment can reduce the force needed to lift, carry or move objects. It needs to be easy to use, well designed to suit the load, properly located in relation to the work area, and readily available.
Examples of mechanical handling equipment are:
- Roller conveyors to move cartons in boning room, freezers and loading areas;
- Mechanical stackers for loading cartons into freezers;
- Screw conveyors and gravity chutes to remove trimmings and inedible products from the slaughter floor or boning room;
- Mechanical hoists to empty tubs into machines;
- Mechanical hide pullers, hock and head cutters to reduce the force needed to do these tasks; and
- Vacuum assisted lifter to lift and stack cartons on to pallets.
Changes to the work environment can reduce the risks of manual handling injuries. Blood and grease on the floor presents a serious slip hazard, especially when the job involves exerting force, such as pulling the pelt off a sheep or pushing carcasses along the rail.
Providing non-slip surfaces and ensuring regular cleaning and maintenance of floor surfaces will reduce the risk. Providing appropriate non-slip footwear and boot cleaning facilities is also important.
Inadequate lighting in meatworks can lead to postural strain injuries particularly in precision jobs and inspection tasks. Leaning and bending forward to get a good enough view of something will gradually lead to muscle discomfort or strain. The recommended minimum light levels (Australian Standard 1680.2.4:1997 Interior Lighting - Industrial Tasks and Processes) on the work surface for meatworks are:
- slaughtering — 160 lux
- boning and packing — 400 lux
- inspection — 400 lux
- general work areas — 160 lux
The Construction and Equipment Guidelines for Export Meat (DPIE 1988) recommends lighting levels of 220 lux for slaughtering and 600 lux for boning and inspection tasks. These levels can be measured using a light meter.
Manual tasks in fabricated metal product manufacturing
Body stressing injuries as a result of performing manual tasks is highest cause of severe injury in fabricated metal product manufacturing.
Common hazardous manual tasks in this industry include welding, deburring, grinding, lifting and transferring metal unloading raw materials, transport of materials on the shop floor, process and assembly work at workstations, packing stillages and loading and handling finished products and CAD design (intensive computer use).
Occupations at high risk include welders, metal fabricators, metal engineering process workers, sheetmetal trades workers, storepersons, product assemblers, forklift drivers and truck drivers.
Please refer to the ‘Common hazardous manual tasks’ section of this website for more detailed information about relevant manual tasks such as handling heavy, bulky and awkward loads, and industry specific documents produced by other organisations.
Industry specific references
- WorkSafe Victoria, A guide to safety in the metal fabrication industry, 1st edition March 2007
- WorkSafe Victoria, A guide to Handling large, bulky or awkward items, edition 2 April 2012
- WorkSafe Victoria, Manual handling in the automotive industry - A guide, March 2005
- WorkSafe Victoria, Manual handling solutions in poultry processing
- WorkSafe Victoria, A guide to manual handling in the food industry, 3rd edition April 2006
- WorkSafe Victoria, Manual handling in the red meat industry, 1st edition September 2006
- WorkSafe Victoria, Manual handling solutions in the textile industry, October 2002
- WorkSafe Victoria, Manual handling solutions in the sawmilling industry, 1st edition November 2005
- WorkSafe Victoria, A guide to safety in the wood products manufacturing industry, 1st edition March 2007
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