Euskararen transmisioa / Transmisión del euskera

Based on what was said previously in this section, a turbo-compressor for refrigeration in an LNG facility, which is strategic for the plant, was studied to identify the complexity of maintenance activities. The scenario addressed was a breakdown in the compressor noticed by operators. The breakdown was reported and a request for an inspection was made. Then, the maintenance system procedure was unfolded. Twenty-eight functions were identified out of which nine functions were considered foreground functions and the others background ones. They were characterised by the six parameters of the FRAM unit (section 1.2.1) and presented in appendix 2. The consistency and completeness of the study was checked by verifying that same aspects referred to the same names or labels and that all aspects describing a function should be included in other functions as one or more of the aspects that characterised the function.

For instance, excessive vibration of the turbo-compressor (e.g. in the spacer couplings) might cause the shutdown of the equipment either automatically or manually by operators. This excessive vibration could be due to a bad grease operation, axial movement of the rotor (process), or wear in the bearings, etc. If the intolerable threshold of vibration was attained, a shutdown of the LNG train would take place, provoking variability in the system. If this situation happened during winter where the demand on LNG is very high, the pressure on all staff became critical. In the case of all functions performed as imagined, the outage would last eight to ten days; this was actually a big loss. As explained earlier in this section, this action was considered priority P1 which meant any other function was put aside by staff so that they could join the rest of the personnel to solve such an issue; two or three teams would work 24h/day to restart the LNG train in an optimum time.

The instantiation of the relations between the inputs and outputs of the functions are given in appendix 2. It can be seen that a negative variability of outputs of functions might lead to increase the duration of the shut-down of the LNG train or might generate in the future another non-planned shut-down which in fine costs a lot of money for the Company. Since the refrigeration turbo-compressor was a strategic piece of equipment that was not redundant, this variability was affected mainly by the availability of resources. Lack of spares and inadequate

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tools and equipment might lead to safety margin reduction and/or operational capability of the plant. The organisational culture affected these functions (strategy- production first, procurement procedures, etc.). The available time (time-pressure) to perform assigned tasks which was very common since the organisation is somewhat reactive (many tasks are done urgently), the supervision/coordination issues, the stress due to lack of necessary knowledge or experience to do an assigned task, and the absence of a vulnerability model were other sources of variability. The trade-off production/safety went towards satisfying production aspects. This might lead in fine to the systematic loss of safety defences. This is particularly emphasised is Chapter 7.

On the other hand, even though such variability was noticed, it is worth highlighting the positive aspects characterised by the adaptation of people to the environment as well as actions to change this environment to perform required activities despite lacks (adaptation to lack of documentation, training, spares, etc.). The organisation as a whole also adapts to maintain a certain “health” of facilities to respond to production goals and objectives.

The use of the FRAM was only for an exploratory purpose of the maintenance system. The method could allow to perform a gap analysis; consequently, the variability of functions has not been measured in this study. However, some barriers and specific performance monitoring of variability were proposed. At company level, the implementation of management systems (HSE, maintenance, etc.) and the acceleration of the introduction of the new permit to work system were judged of great importance. In addition, regulations regarding spares procurement should be evaluated and reviewed. The use of fully exploited information system for the maintenance management system could be the sought damping factors to prevent any undesirable future events stemming from maintenance activities.

The strategic objectives might be: maintenance effectiveness, maintenance activities cost- effectiveness, the improvement of equipment availability through improved maintenance materials/tools/equipment management, and the insurance of suitable training levels to fulfil the required missions. Performance indicators should be designed to follow up these objectives. Since FRAM method deals with functional resonance, the indicators should follow the same concept. Therefore, these indicators should be functional indicators. Examples of indicators include (Márquez, 2007):

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 Maintenance effectiveness (the follow-up of the number of critical assets, the number of repetitive failures for those assets, the total number of failures and the reduction in preventive maintenance tasks, percentage of preventive maintenance),

 Maintenance cost-effectiveness (compliance to maintenance planning and scheduling, quality of work and learning, etc.),

 Equipment availability (spare parts service level, spare parts turnover and urgent purchase orders released), training level per each maintenance level.

Additional strategies for improvement at both department and corporate levels are discussed in Chapter 7.