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This information sheet is one of a series prepared by HSE's Docks National Interest Group
It is now generally accepted that some 80% of accidents involve human factors. One of the most important human factors is stress and one of the key factors of stress is fatigue. The causes of fatigue can include not only severe physical effort but also the effect of working at times that are contrary to the body's natural inclinations, eg at night or on some systems of shift work, intense concentration and working continuously for long periods.
Fatigue can be insidious. It may develop slowly and may not always be apparent to those concerned or to their supervisors. Nevertheless fatigue can lead to severe accidents. Fatigue may well result in failure to concentrate. This can lead to stevedores failing to ensure that they are in a safe position with the result that they are hit by a falling object or struck by a swinging load. Many stevedoring operations are team operations carried out by a number of persons in constantly changing situations which often involve heavy loads, lifting appliances and vehicles. An error by one member of the team can have serious consequences, not only for those concerned but also to others with whom they are working. This will be particularly so in the case of operators of cranes and other lifting appliances.
Regulation 3 of the Management of Health and Safety at Work (MHSW) Regulations requires all employers and self employed persons to assess the risks to the health and safety of their employees and any others who will be affected by their operations. The hazards of fatigue should be well known and it follows therefore that the consequential risks of fatigue should be assessed.
The transport industry is particularly prone to unexpected events and delays owing to matters over which it has no control such as the weather. The need for flexibility in hours of work in docks is well recognised. It is not the intention of this information sheet to specify maximum working hours. This is a matter for individual employers to determine in consultation with their workers after assessing the risks involved. Where employees of two or more employers work together, it may be necessary for the employers to liaise in accordance with regulation 9 of the MHSW Regulations. The hours of work of drivers of certain classes of road vehicles are however controlled under the Road Traffic Acts but are outside the scope of this information sheet.
The matters discussed below are some of those that should be considered when assessing the risks due to fatigue so as to be able to determine what hours can be worked safely.
Everyone is different and will be affected differently by fatigue. The guidance in this information sheet is therefore necessarily general.
In addition to physical fatigue there is also mental fatigue. This is the most dangerous type of fatigue as it can result in errors of judgement. The causes of mental fatigue include the need for concentration for long periods, excessive working hours and sleep deprivation. It is mental fatigue that is the main area of concern dealt with in this information sheet.
Some jobs need higher levels of concentration than others. An obvious example is the operation of a crane. In many cases the operator will be a member of a team. It may therefore be possible to rotate the jobs within the team to maintain the necessary level of concentration of the most demanding job throughout the working day.
Everyone needs breaks in their working day from time to time. The frequency will depend on many factors including the physical demands of the work. In some cases job rotation will again help to reduce excessive fatigue. In determining the length of working periods employers should consider not only the normal or usual working day but also whether shorter periods between intervals would be appropriate on occasions when it may be necessary to work beyond normal hours.
A number of factors may affect the transport industry over which it has no control but may lead to the need to work beyond normal hours. Such matters may include the late arrival of ships due to bad weather and the resulting need to work a ship to finish. Matters to consider in such circumstances include not only the additional hours to be worked, ie the overall length of the working day and the working week, but also the frequency of the need to work additional hours and the intervals between the end of the working day and the start of the next.
It is essential that there is an adequate interval between the end of one working day and the start of the following working day. This interval should be long enough to allow adequate time for sleep, meals, travel to and from home and, where appropriate, exercise. In considering the time necessary for travel it should be appreciated that owing to changes in industry in recent years it is less likely that employees will live close to their work. In many cases they may have to travel considerable distances each day.
The matters referred to above are equally relevant to a shift system of work. In addition particular consideration should be given to the need to cover for absences such as those due to illness or holidays. If the shift systems involve altering normal patterns of sleep the matters discussed below should also be considered. Particular attention should be given to arrangements for changing or rotating shifts, especially if a rest day is not incorporated at the time of change. In such circumstances it is preferable for the new shift to be retarded rather than advanced in time so as to ensure an adequate rest period before the next shift.
People are not naturally nocturnal animals. A person's normal body rhythm involves sleeping at night. If this rhythm is ignored, health, safety and efficiency may fall at some times of the day and particularly between about midnight and 6 am.
The ability of people to cope with changed sleep patterns varies considerably and should be considered when selecting people to work at night. Difficulty with sleeping during normal day time may be experienced resulting in less than normal periods of sleep and consequential reduction in alertness and in increased probability of falling asleep during working hours. These problems can be highlighted by the social needs and activities of workers. The problems can however be reduced by training and information on the effects of shift work and life style on fatigue. Such matters need to be understood not only by the workers themselves but also by their families. It is important therefore that such information is suitable and available to their families as well as to the workers.
One effect of shift work in general, and night work in particular, may be the taking of sedatives to aid sleep at unusual times. The effect of such sedatives may interact and lengthen reaction times thereby increasing the risk of accidents either at work or on the way to or from work. Similar effects may be produced by medication being taken for other purposes. In any cases of doubt medical advice should be obtained. Road traffic legislation and the Approved Code of Practice to regulation 11 of the Docks Regulations include provisions relating to driving under the influence of drugs.
Prolonged periods of work will increasingly lead to a build up of fatigue. When considering arrangements to cover for illness, leave or other absences, it is essential that the need for rest days at appropriate intervals is considered. This applies not only to cargo handlers but also to maintenance workers who may necessarily work at times when others do not.
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This leaflet contains notes on good practice which are not compulsory but which you may find helpful in considering what you need to do.
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Printed and published by HSE 3/94 NIS/07/04 C40
Added to the web site 5/5/98