Results of Applying the RCM Process

The use of risk-oriented approaches to maintenance and repair (hereinafter referred to as O&M) by large industrial companies that operate a large number of production equipment — physical assets — has become widespread in recent years. This is due to the fact that the classic approach to maintenance and repair, taking into account regulatory deadlines, requires significant costs and is often ineffective, does not take into account the real causes of equipment failures and their consequences.

One of the most widely known risk-oriented approaches is "Reliability-centered Maintenance," or RCM. Applying this approach, according to [1], gives three main results:

• Maintenance schedules for performance by the relevant departments;
• Revised production procedures for process personnel;
• A list of areas where changes to the asset’s design or operation should be made.

How can an O&M schedule be obtained from the RCM process if, formally, the application of the RCM process ends with filling out tables with recommended solutions (actions)[1] ? What information should these solutions or recommendations contain? What information should an O&M strategy contain? These questions will be addressed in this article.

Existing sources of information on O&M and reliability management contain a large number of different terms and definitions that do not always clearly give an understanding of what is hidden behind them.

For example, "maintenance strategy" in [3] is defined as: "The overall approach to ensuring maintenance and its support, based on the goals and policies of owners, users, and customers." What "overall approach" means in this formulation is unclear; no further explanations are given in the document.

Ramesh Gulati [4] defines PM*, RCM, and CBM — Preventive maintenance, Reliability-centered maintenance, and Condition-based maintenance, respectively, as O&M strategies, which translates to Preventive Maintenance, Reliability-centered Maintenance, and Condition-based Maintenance. Each strategy should include regular O&M tasks:

• Time-scheduled — preventive maintenance according to calendar or operating hours;
• Condition monitoring tasks (CBM/PdM);
• Tasks for finding hidden failures;
• Run-to-failure.

Another definition, which we find more interesting, is: strategy is an approach to O&M (or their combination) and tasks for execution. O&M planning is carried out based on the formulated strategy.

As for planning, the same R. Gulati divides it into independent processes — planning and scheduling. The planning process determines what will be done and how, schedule formation determines when the work will be done and who will do it. A completely reasonable approach — a large process is broken down into smaller ones: it is easier to perform, control, and monitor.

D. Mowbray defines one of the main results of the RCM process as O&M schedules, pays a lot of attention to describing functions and functional failures, analyzing the types and consequences of failures, while not using the concepts of "maintenance strategy" or "O&M strategy." In his understanding, the RCM process ends with the selection of O&M tasks (or actions): planned replacement or restoration, condition monitoring, failure finding, their combination, or redesign if other tasks are not applicable or impractical.

Summarizing the above, we can draw the following conclusions:

1. The maintenance strategy as an intermediate result of the RCM process should clearly answer the questions:

• Which approach to O&M or their combination should be applied: preventive, corrective, condition-based (or predictive**), reliability-based, risk-based, etc.;
• What specific tasks should be performed, what is their cost, and what is the cost of failure if no tasks are performed.

2. The tasks in the strategy should be formulated in such a way that they can be unambiguously matched to operations (diagnostics, maintenance, repair, modernization, and equipment replacement), which can be planned and performed in such a way as to achieve the expected effect.

Many companies, applying the RCM approach in practice, use specialized software, usually APM class — Asset Performance Management. One of the world leaders in the field of digitalization of asset management processes in its software product defines the result of applying RCM as follows: "Asset maintenance strategies that allow you to identify ways in which equipment can fail and the actions you want to take to prevent these failures and reduce their consequences." [2]. In other words, the maintenance strategy (hereinafter referred to as the O&M strategy) is a set of actions to prevent failures and their consequences. For each of the actions, its cost is determined, the risks that are planned to be reduced by performing these very actions, and the degree of risk reduction — the difference between the "reduced" and "unreduced" risk.

The next step used in practice is to "transform" actions into specific types of O&M activities and operations that can already be planned with the necessary resources and on specific dates, using their tool, and perform these operations.

We get the following sequence of results of the RCM process: recommended actions — operations for planning — work schedule.

Rephrasing in more formalized terms, we get the sequence of results of the RCM process:

• O&M Strategy — what needs to be done to prevent failure or reduce its consequences;
• O&M Plan — what will be done and how;
• O&M Schedule — when and who will do it.

There are some nuances in the "transformation" of the O&M strategy into the O&M plan.

First, the tasks in the strategy and the operations in the plan are formed by different people. Classically, the RCM process should be carried out by a special group, which should include a production foreman, an O&M foreman, an operator who monitors the operation of the equipment or system under consideration, a repair mechanic and / or electrician, and a facilitator, whose responsibility is to ensure the achievement of a common understanding of the process within the group and document the results.

In practice, all these functions are often performed by the company’s "reliability engineer" appointed by management, as a rule, appointed from specialists in divisions that perform the functions of ensuring operation or O&M. Specific operations and the resources needed to perform them are formed by the planner — a specialist with the function of planning work assignments.

With this approach, there is a high risk that the O&M programs formed as a result will be too general, insufficient, and will not produce the expected effect.

Second, often the actions formulated by the reliability specialist do not always take into account the company’s real capabilities for its implementation. The reasons can be different: the inability to determine unambiguous operations for recommended actions, technical limitations on performing operations with a recommended frequency, or the inability to provide the required technical conditions for performing the operation.

Thus, when forming an O&M strategy, all tasks should be assessed according to several criteria:

• Applicability — each task: prevents or mitigates a failure or identifies the onset of a failure or detects a hidden failure;
• Feasibility — all tasks should be technically, organizationally, and physically feasible;
• Efficiency — the total cost of performing the task will be less than the total damage from failure.

As mentioned in the previously published article ["Asset Management: From General to Particular and Back", Pivovarov K.L.] when developing a recommendation in the process of conducting an RCM analysis to form an O&M strategy for a specific piece of equipment, it is necessary to clarify the technological map and standards for performing O&M operations. From these recommendations, the planner should clearly understand the company’s readiness to implement the proposed measures.

A number of industry regulations and equipment manufacturer’s manuals contain sufficiently comprehensive information on the types of O&M and operations that need to be carried out in certain cases, controlled parameters that give an idea of the asset’s "health." Based on this information, individual enterprises form full-fledged standard technological maps (TTC), which contain the necessary and sufficient information for forming O&M plans and schedules.

The process of forming such TTC is long and laborious, but having them available, a reliability engineer or RCM group facilitator has the opportunity to form O&M strategy tasks by selecting the necessary operations from the composition of the TTC, thus forming an individual technological map that will fully meet the requirements of the results of RCM analysis. This method will reduce the time for forming the O&M strategy and plan, minimize the risk that the resulting O&M program will not be too general, insufficient, and will not be able to produce the expected effect.

To create a detailed and comprehensive work plan, the planner will only need to determine the operation packages with planning rules, the correct sequence of operations, if necessary, remove redundant or repetitive operations, add auxiliary or supporting operations (such as, for example, personnel delivery, permit issuance, etc.), determine the necessary resources and materials.

When implementing the RCM process, or in other words, conducting an RCM analysis, another important factor is the classification and standardization of systems and the assets (equipment) that are part of them, their functions, functional failures, and tasks for restoring function operation. This collection of information can be called a "Reliability Model." This is discussed in more detail in the article "Asset Management: From General to Particular and Back".

Forming an O&M schedule, having a detailed O&M plan as a basis, is a more understandable and familiar task for a planner or schedule creator. To form such a schedule that can be followed 80−90% of the time, it is first necessary to determine the priority of each work package, obtain information about the availability of necessary resources and budget constraints. But this information is not enough to assign each operation a correct date for its execution; there are many other factors that need to be considered! But more on that in the next article.

This article is the result of an analytical review of existing sources of information and applied reliability management practices, without any claims to ultimate truth.