The following issues should be incorporated into all stages of the design , as an iterative process , to ensure that an offshore system operates safely and efficiently .sx - workplace layout .sx - console design .sx - control and instrumentation design .sx - VDU display design .sx - manning levels and work organisation .sx - communications .sx - environmental issues .sx - procedures .sx - training .sx - management and organisational issues .sx - evacuation system design .sx Workspace Layout and Console Design .sx Ergonomics techniques and principles can be used to specify an appropriate workplace layout , not only in relation to the platform as a whole but also within the individual work areas .sx There are a number of issues to be considered eg .sx the equipment requirements within this workplace , necessary access space for both operation and maintenance activities and the number of operators it is envisaged will work in the area .sx The workplace layout must also be considered with respect to viewing and communications requirements in relation to other work areas .sx There exist a number of design recommendations based on data , such as for example 560 mm clearance space must be allowed for body access if the person is wearing normal clothing ( obviously this will be larger if protective clothing will be worn) .sx There are in addition , other considerations based on psychological factors eg .sx performance has been shown to be better if a seated workstation is positioned at right angles to the window , if appropriate , rather than any other orientation .sx In Hardies sic !sx paper ( 4 ) he discusses the changes in perceptions of the offshore accommodation module in the 1980s .sx There was a move towards more pleasant surroundings which led to hidden benefits in terms of increased motivation , attention and a consequent reduction in accident rate .sx It is therefore an important psychological consideration within the design process .sx Anthropometric data ( data on bodily dimensions 5 ) should be used to design both control room areas and local work areas to ensure that operator access to all instrumentation and other equipment is efficient and comfortable , that displays and controls most frequently used are within easy reach and to ensure ease of maintenance .sx This latter is an important , often overlooked factor , as a greater number of accidents occur per unit of time during maintenance than during operations .sx An example of poor ergonomics is where a valve requiring frequent maintenance is located out of reach and thus necessitates the use of a ladder/scaffolding , or a situation where access is restricted to a piece of equipment , the maintenance of which demands the use of a large or intricate tool .sx Anthropometric data should also be used to design the console which houses displays and controls .sx This data will assist in the decisions regarding the location of the instrumentation on the panels to ensure that the most frequently used and important displays and controls are within the primary reach envelope and optimum viewing angle of the operators .sx The displays and controls used must be tailored to meet the information needs of the operators .sx This will have implications for the design and the layout of the instrumentation eg .sx if there is a logical sequence of use of controls and displays the layout should reflect this sequence and where possible the instruments should be functionally grouped .sx Desgin of Instrumentation .sx Task Analysis should be used to obtain the information on which to base these decisions .sx This will serve to identify individual elements of the task such as the following :sx - the goal of the particular task .sx - the subtasks needed to achieve that goal .sx - the information required in order for the operator to complete that task .sx - the action to be implemented .sx - the feedback which is required by the operator to confirm that the task has been successfully completed .sx - the relevant performance shaping factors ( NB .sx Performance shaping factors are those factors which affect human performance and may be of an external nature such as noise , lighting etc. or of an internal nature such as stress , memory overload ) .sx This technique will be used to select a design which is appropriate for the task eg .sx if the operator is required to compare two tank levels , this is likely to be displayed in the form of two vertical barcharts located next to each other .sx If a precise value is required it may need to be displayed by means of a digital indicator .sx If a simple on/off action is required during the task it will be implemented by means of a simple switch or on/off pushbuttons , whereas if continuous action is required , as in the use of a hoist or crane , than a joystick would be more appropriate .sx Ergonomics guidelines based on data and past experimentation exist to assist the designer/ergonomist/engineer .sx These guidelines also include advice about the use of colour , labelling , e.t.c. The principles used to design VDU displays , if appropriate , are similar to those for control and display design .sx It is useful to provide a layout of information on a VDU screen which is compatible with that on the hardwired control panels and which uses a consistent colour coding scheme ie .sx colours which are ascribed specific meanings on the hardwired panels should adopt the same meanings on the VDU displays .sx Environmental Issues .sx The design of the man machine interface alone however , will not ensure safe operating performance .sx Although the ergonomics techniques used to design and assess offshore systems are similar to those used in any other industry , the performance constraints and environmental conditions are very different .sx The levels of lighting will affect the visibility of the instrumentation and equipment and if inadequate may lead to hazardous situations .sx Noise levels which are too high are hazardous to health and will affect communications .sx The thermal environment is known to have an effect upon performance ( 5 ) for further details) .sx Ergonomics guidelines exist to predict the length of time people can be expected to work attentively at certain temperatures and noise levels , where prolonged periods of exposure can lead to permanent damage .sx Training and Procedures .sx The ergonomist must not work in isolation to examine the design issues relating for the workspace layout , the instrumentation and consideration of the environment .sx 'Man at work' combines these factors to produce a certain level and quality of performance .sx The task analysis mentioned earlier will allow the analyst to examine the interaction between them .sx The task analysis can be taken a stage further and a human error analysis can be performed .sx Each task step is examined to see if errors can potentially occur and the nature of these errors .sx The consequences will be identified and recovery points , if any , will be noted ; for example if it is imperative in a particular task step that a dial is read very precisely , it has been identified that potentially the dial could be misread or not read at all , there is no scope within the procedure for the operator to recover his error and the consequences lead to safety deficiencies , then a solution must be found .sx The analyst must examine the reasons why the dial could be misread ; eg .sx the operator may be experiencing performance decrement due to the stress induced by the situation .sx The solution may well be to place a flashing lamp above the dial to attract the operator's attention and make some attempt to reduce his stress levels .sx The resulting information provides a valuable input to training programmes and the writing or operational procedures as it enables the assessor to identify the following :sx - those parts of the task which may be prone to error .sx - those tasks which may be performed infrequently but it is important are performed correctly .sx - those tasks which require specialist skills .sx - any pieces of equipment which require detailed instruction .sx - the points in the task which require communication with other parts of the platform , and those communications which are critical in terms of safe operation ( this will be dealt with in more detail when the case study is discussed later up the paper) .sx The training programme will thus be designed to provide intensive training , retraining and specialist training where necessary and methods can be identified for monitoring training effectiveness .sx Procedural documents can be written using ergonomics guidelines to ensure completeness , adequacy and clarity and will be able to provide the necessary observations , cautions , precautions etc. to ensure effective and safer operation .sx In addition to training and procedures input , the task and human error analysis will contribute greatly to the quantification of risk by incorporating the human errors into fault trees .sx It can be seen that the probability of a hazardous gas release remaining undetected may be the result of an instrumentation failure but it may also be the result of a human being failing to read , or failing to read correctly , the instrumentation and thus failing to make the correct diagnosis of the circumstances .sx Workload Assessment and Job Design .sx Having discussed the ways in which design can be used to enhance human performance , assisted by correct training and procedures , it must also be mentioned that a well trained employee in a well designed environment may still find himself in a situation which he cannot deal with , for example if the operator is under stress ( the issue of stress as a performance shaping factor was touched upon earlier) .sx It is useful to perform a workload assessment of the tasks the operator is expected to perform .sx This may make use of different task analysis techniques such as observation techniques , walk/talk through exercises , simulation etc. to determine the tasks to be performed and the time taken to perform them .sx They can then be plotted on a time line graph .sx If the time line shows the operator to be overloaded at certain points in the shift there are certain manipulations which can be completed to optimise performance .sx The following are examples of corrective actions which can be taken :sx - the reallocation of some of the tasks within the shift so the operator does not have periods of intense activity or boredom .sx - the reallocation of tasks between the workers .sx -the provision of additional workers on the platform or for that particular work area .sx - the reallocation of tasks between men and machines ie .sx automate parts of the system .sx Thus this activity will not only provide useful information about the adequacy of manning levels but also about the organisation and management of the work .sx Management and Organisational Issues .sx It has been demonstrated by reference to the Piper Alpha incident that a system must not only be designed efficiently but must operate efficiently for it to be productive and the management and organisational machinery must also be well oiled .sx In order for the workers to operate in safe manner and assign safety the highest priority , the management and organisation of the company must create and maintain the environment in which these safe attitudes will be reinforced .sx Management must demonstrate their commitment to safety .sx The following are examples of organisational mechanisms which will assist in the creation of a safety culture :sx - a no-blame method of incident reporting with consequent remedial actions to prevent future accidents .sx - communications mechanisms to ensure that safety concerns are expressed both upwards and downwards through the hierarchy .sx - the practice of training needs assessment ( and reassessment when new equipment is introduced ) , to ensure the worker is aware of all job related safety concerns , and the monitoring of training effectiveness .sx - an effective permit to work system .sx - auditing systems to ensure the above systems are operating as they should .sx There are many more .sx Human Factors techniques should be used to tailor the specific safety management requirements of each offshore system .sx Evacuation System Design .sx The issues the paper has discussed in relation to ergonomics methods so far have been with respect to work activity on the platform .sx The consideration of the human and its behaviour within the surroundings are of prime importance when evacuating the work place .sx Traditionally the consideration of the human element in the design of evacuation systems has been confined to design aspects such as the width of evacuation passageways to ensure that an adequate number of people can pass and that the correct number and location of lifeboats has been provided to evacuate all employees .sx It is necessary to design the system in this way but equal weight must be given to the human behaviourial aspects of evacuation .sx