By Walter Lambertin
Decisions regarding reliability and maintenance can have a measurable impact on both maintenance costs and reliability in any plant. The following lists ten key areas that can help you achieve positive results.
Area teams consisting of Operations, Maintenance, Technical, and Inspection representatives should be assigned for each production area. These teams should be accountable for both reliability and maintenance costs. Monthly meetings with Senior Management track actual performance versus targets established for the areas.
Maintenance budgets are often developed based on past experience. Zero-based budgets should be developed based on specific tasks planned for the area. A central contingency fund should be established and be controlled by Senior Management to minimize each area building in individual contingency. Area teams should be accountable for completion of defined tasks as well as maintenance expenditures.
Equipment degradation mechanisms should be identified for all critical equipment. These mechanisms should include process (catalyst deactivation, fouling, coking, etc.), corrosion/mechanical deterioration mechanisms, as well as legal/corporate policies which limit equipment performance and could lead to shutdowns.
On-stream equipment surveillance programs designed to monitor the progress of identified degradation should be implemented. Results should be analyzed to predict expected maintenance intervention timing and allow timely planning and budgeting.
Any item of equipment which has a mean time between repair (MTBR) significantly below the average for its class of equipment should be identified as a “Bad Actor.” Senior Management should assign responsibility and provide adequate resources to analyze and attempt to resolve the root cause of these bad actors.
It is necessary to establish a cost benefit methodology which is risk-based to minimize doing low priority work at the expense of more significant activities.
Turnaround (T/A) planning requires adequate time to develop cost effective and efficient maintenance plans. To accomplish this, a multi-cycle (8 – 10 year) strategic plan establishes the timing for unit shutdowns. Each T/A should have a T/A basis memorandum defining reasons for the T/A, major work expected, oil-out and oil-in expectations, expected costs and performance expectations after start-up. Milestone charts defining scope/cost controls, pre-T/A equipment surveillance, contracting and execution activities should be developed. A detailed critical path analysis defines key milestones which can be monitored on a daily basis during the outage. For major T/As, this process should start at least 15 months in advance of oil-out.
Emergency work is disruptive to efficient planning/execution and should be limited to 5 – 10% of routine maintenance activities. Each emergency activity should be justified based on the consequences and probabilities versus executing this work on a planned basis.
Run length can be extended by understanding the limiting equipment which drives the need to shutdown. Often, T/A intervals are based on past practice rather than specific equipment limitations. A detailed analysis of equipment degradation combined with a comprehensive on-stream surveillance program can result in long runs.
Many maintenance activities are conducted at planned intervals based on past experience and have been in place for many years. Little effort is made to adjust these intervals once they have been established. A comprehensive review of these calendar based activities analyzing “condition found” and “work required” can result in interval extensions, thus reducing maintenance costs without impairing reliability.