Plant assets play a key role in overall enterprise efficiency, essential today. In 2021 manufacturers are increasingly turning to Reliability Based Maintenance (RBM) as a strategy to help them maintain valuable plant assets and eliminate costly adverse impacts of performance issues, like delays and unexpected down-time. Companies today often struggle to manage preventive care and keep pace with the complexity of operational assets. Without a practical and prescriptive asset reliability process in place, companies will continue to take random hit-or-miss shots at maintenance targets, often wasting resources and experiencing disappointing results. It doesn’t have to be that way.
Evolution in technology has changed the way plant assets fail. Greater complexity of components ultimately means more complex breadth of tasks and the need for advanced warnings of failure probability. Most reliability strategies remain time-based, such as replacing bearings every six months. This has limited results, as bearings may not need to be replaced yet—or they could have been past optimal conditions months ago.
A revitalised approach to maintenance strategies is required – one which will better align with today’s digital evolution, sensor-based innovations, strict compliance mandates, and escalating customer demands. Equipment failure is not an option. Under-servicing or over-serving is not acceptable either due to the potential for equipment damage (due to overwork) and associated costs.
Fortunately, the RBM process provides a sustainable methodology with optimal results. Here is a primer on the steps to building a RBM system.
The first is to identify assets in a Master Asset List (MAL). Determine selection criteria, decide data components, and organise and group the criteria to aid in finding, maintaining and analysing data. When selecting criteria, focus on distinguishing characteristics. Remember, the definition of an asset establishes the physical scope of your programme. In establishing your definition, the criteria must speak to the things an organisation does in terms of maintenance, quality, and supply chain activity. These aspects of the business keep personnel and the environment safe, while promoting throughput of a quality operation without adverse impacts from breakdown. Be thorough.
Secondly, determine asset criticality ranking (ACR). To create a ranking of priorities, you must define the factors to be considered and the potential impact the failure would have on the enterprise. When considering the criticality of an asset or asset group, it’s important to look at all facets of how an asset’s failure can impact the business, including the cascade of secondary issues which way may launched. Typical factors for ACR calculation include operational, utilisation, quality, safety and environment. This can be customised specific to any unique drivers an operation may have. Adequately describing factors and defining impact is important to achieve consistency and consensus throughout the organization.
Once asset groups are prioritised, the next step is to develop the necessary PM schedules and task plans with proactive maintenance optimisation (PMO). The sequential steps for PMO are; identifying failure modes, understanding the risks affiliated with each, applying the appropriate proactive maintenance strategy for the risk, and, lastly, identifying what proactive tasks will be assigned for each of the respective assets.
Be sure to consider the asset criticality ranking so that the most critical asset groups are evaluated with the highest level of precision or priority. You also want to evaluate the failure modes most important to the asset or asset group. The calculation used to classify failure modes is risk priority number (RPN). The standard RPN factors are severity, likelihood, and detectability.
In addition to the PM schedule and task plan, we will also need to create a Spare Part Analysis (SPA). The sequential steps for a SPA are identical to PMO. Spare part analysis begins with the identification of failure modes, with an emphasis on ensuring all spare parts are linked to a failure mode and are identified based on risks. Similar to a PMO, the risk affiliated with each failure mode must be determined. It’s clear to see there is tremendous synergy in executing PMO and SPA in parallel as both are driven from failure mode identification and classification. Typically, all spare parts affiliated with critical failure numbers and high-risk values should have stock quantities on site.
The fifth step is to monitor the PM programme. The purpose of analytics is to measure the reliability of an asset or asset group and the effectiveness of the reliability strategy which was developed. For consistent analytic calculation, the criteria must be defined clearly, and the cross-functional engineering team should be bought into why the criteria is important and how they impact the business.
The primary means of ensuring analytics are calculated consistently is confirming the data sources and better yet, the integrity of the data within those sources. A common source for reliability data is work orders and closing code histories.
Sixth is to determine failure causes. Once the failure modes are listed for each asset group, these values can then be linked to reactive maintenance work orders. This provides the ability to effectively analyse failure data. This is the last step of RBM, because once key problems areas are identified, the root causes can be determined and remediated as a part of continuous improvement programme.
Lastly, rinse and repeat. Factual data is the key to performing an analysis that generates effective recommendations. The data-gathering step is the most time-consuming but ultimately the most important as it directly impacts the accuracy of the problem statement. Depending on the Root Cause analysis (RCA) method, analysing data can come in many shapes and sizes. The developed recommendations should be focused on further improving appropriate proactive tasks and spare parts inventory, thus providing the closed loop continuous improvement.
With this system in place, you can quickly make programme improvements where needed, as (or even before) they are needed. With a Reliability Based Maintenance system in place you will be able to manage assets, understand risk, and set priorities for preventive maintenance.