By Anthony V. Covato, PE, Reliability Management Group Inc.
Maintenance work in a power plant is prioritized to ensure that the right work is performed at the right time, resulting in the minimum impact to plant operation. When determining how to use existing resources to perform maintenance work activities, power plant personnel should follow a formal process based on the work’s priority. Anyone tasked with designing an effective prioritization process must understand that, like all work management processes, the prioritization process should be based on a system of accountability.
Planned maintenance work performed during outages does not affect the plant’s output, but some routine maintenance work must be performed while the plant is operating. This means the personnel prioritizing routine maintenance work are not necessarily driven by the same criteria as when they are planning outage maintenance work.
Routine Non-outage Maintenance Work
Given that the objective of prioritizing routine non-outage maintenance work is to minimize any negative impact to the plant’s output, one could argue that the plant’s operations group should have the largest role in determining work priorities. In reality, many things other than operation issues affect when work can be executed. Work prioritization begins with categorizing the work into one of two typescorrective or proactive.
An outage work management planning process should include an internal staffing plan.
Corrective work is typically identified by the operators and is directly related to a functional equipment failure. To determine this work’s priority (in other words, when the work should be started) personnel must know how large an effect the equipment’s functional failure will have on the plant’s output and operation. To make this determination more objective and to ensure consistency, plant personnel should develop and utilize a “critical equipment” list.
Equally important is determining when corrective work can begin. To determine this, the scheduler must know the availability of the required resources, labor, parts and material, as well as when the equipment needing repair can be made available.
Personnel must also consider the most effective way to accomplish the work. In most cases, executing planned work is more efficient than executing unplanned work. Of course, this depends on how much planning actually goes into the work. This depends upon several factors: the work’s complexity, the resource required to complete the work, and the time available to plan the work. This last factor is directly related to the work’s priority.
Proactive work is defined as work that is required to prevent an equipment functional failure. This would include work related to preventive and predictive maintenance. Proactive work is typically identified by maintenance and engineering organizations and is often planned based on results from various analyses that identify ways to improve equipment reliability. Because proactive work is usually reoccurring, it is typically well planned. “Well planned” means that plant personnel have identified all required resources needed to perform the work and those resources are available when needed to execute the work. One caution is that proactive and corrective work typically compete for the same labor resources.
Maintenance and operations organizations should work together to prioritize routine non-planned outage maintenance work. A well-designed prioritization process must address each organization’s roles and responsibilities.
Once corrective work has been identified, personnel must determine whether the work is an emergency or not. Emergency work includes work required to correct a condition that will immediately result in loss of a unit or significant impact to the unit’s capacity; injury or illness; or violation of a regulation or guideline
Plant personnel should give emergency work the highest priority and should carry it out as soon as it is identified. In some cases, this may require operations personnel to make a verbal, rather than a written, request to the maintenance organization. The maintenance organization is ultimately responsible for providing the labor resources required to perform the emergency work.
Plant personnel should prioritize all other routine maintenance work based on the required start date. The work should be conducted within a time frame that assures it will be completed before it becomes an emergency. The plant’s maintenance organization is usually responsible for planning the required work.
For activities that can rise to become an emergency in a relatively short time, (say, within seven days), plant personnel should assign the next level of priorityhighand the work should be scheduled accordingly. Because the objective of proactive work is to improve equipment reliability and avoid operating conditions that could create emergencies, most proactive work should be high priority.
Plant personnel should reserve the third priority level for those work activities that, although they may change how the equipment is operated, will likely not cause emergency conditions if not performed within a given time period. The time this work commences is directly related to the maintenance organization’s ability to plan the work and execute it with its current resources and work load.
The final priority level is reserved for those work activities not directly related to maintaining the designed capacity level, but would improve equipment operation or plant conditions in some way.
As stated previously, any change in the way non-outage maintenance work is handled should address establishing key performance indicators that measure the effectiveness of the new process and also the performance of those responsible for executing the process. This will ensure a system of accountability and also continuous improvement.
Planned Outage Work
The major difference between planned outage work and non-outage maintenance work is that all planned outage work occurs within a defined time period when the unit’s output is not an issue. An exception would be those plants with multiple units where the same internal resources are used both for simultaneous routine and outage work.
In many power plants, scheduling personnel are prioritizing planned outage work while operations and engineering personnel are developing the outage scope. Once the outage scope has been developed, the maintenance organization typically develops the work list required to complete that scope. Using outage work management tools and processes (like those used by planning and scheduling personnel) the priority in which the work activities are executed will ensure the work is completed within the defined outage period.
Well-planned work includes identifying all required resources.
An outage work management planning process should include an internal staffing plan. This plan should determine the requirements for any internal labor resources that will be needed to execute planned outage work activities. Once developed, all key individuals responsible for directing resources should review the plan and either commit to providing the resources or identify other sources for the required resources.
Where a facility has multiple units and competition for internal resources exists between outage work and routine work, outage work should have the same level of priority as proactive work. In effect, most outage work is proactive work. If appropriate plant personnel prepare, review and approve an internal staffing plan, the internal labor resource requirements for outage work should be acceptable and should not create unworkable requirements.
Prioritizing work in a power generation facility should be directed by a formal documented process that:
- Is objective and ensures work is scheduled based on equipment criticality, resource availability and the time required to plan the work.
- Is a collaborative and joint process between the plant’s operations and maintenance organizations
- Delivers the right work at the right time.
Because work management processes are interrelated and support each other, a work prioritization process can only be successful if processes are in place to support work management.
Author: Anthony V. Covato is a registered professional engineer in Pennsylvania and is currently a project manager with the Reliability Management Group.