Signs that your PM program is ineffective and inaccurate

A good preventive maintenance (PM) program is essential in ensuring an efficient and reliable plant, both in terms of operation and maintenance. Regardless of the industry, if your PM program is inaccurate or ineffective, it will most likely lead to increased frequency range of expected and unexpected downtime, high maintenance costs, and ultimately reduced productivity and performance. Here are 4 signs that indicate if your existing PM is ineffective: 

What is a Subjective Task 

The easiest way to identify if your PM program is inaccurate or ineffective is to look at the content of your tasks. If most of your tasks look like “check pump” or “check motors,” this is a clear sign that your PM is most likely ineffective for several reasons.

Firstly, they lack clarity, leaving room for interpretation and resulting in inconsistent execution among technicians. This inconsistency can lead to unreliable maintenance practices, with some more experienced technicians performing a full inspection of the assets while less experienced ones might only glance at the assets missing critical information.

Subjective descriptions often omit critical information about which specific components of the equipment should be checked, increasing the risk of overlooked issues. As a result, subjective tasks like “check pumps” and “check motors” often result in a relatively low number of outcomes in terms of potential failure findings compared to a risk-based inspection.  

Subjective tasks can also lead to accountability problems, as it becomes challenging to determine whether technicians followed appropriate procedures or completed tasks to a satisfactory standard during their condition assessment. Lastly, vague descriptions may inadvertently lead to the neglect of maintenance in critical maintenance activities, increasing the likelihood of equipment breakdowns. 

To mitigate these issues, it is advisable to revamp your existing PM program with a Failure Mode-Based Maintenance strategy. The process of Failure Mode Based Maintenance (FMBM) focused on identifying all possible symptoms that assets and components may experienced in the event of a failure. When doing so, you will then be able to put in place maintenance tasks that will address specific failure modes rather than generic tasks that simply inspect the equipment, without covering any specific symptoms/failure mode.  

Example of Risk Penalty Number calculation for failure modes on a gearbox and their coverage before a PM Optimization exercise 

When doing risk-based inspection with failure modes, it is advisable to make maintenance tasks as objective and detailed and developed as possible, providing technicians with specific instructions, measurements with min/max, and criteria for equipment evaluation, in a way that the integrity of tasks are as little affected as possible by the person performing the task.

For example, an asset with a task such as “check pump” should be replaced by several objective tasks such “inspect oil level – it should be within the green zone of the gauge” + “Verifiy for acoustic emission with ultrasound within the storage tank” + “perform vibration analysis on rotating equipment” + “check the pressure and flow measurements. Target flow 5 L/M, Target pressure 100 PSI”. Clear and objective task descriptions are crucial for maintaining equipment reliability, reducing downtime, and enhancing overall maintenance program effectiveness. 

What is an Intrusive tasks

Another significant red flag in a PM program is the absence of non-intrusive inspection and tasks. A good example of typical intrusive tasks are “Tear-down inspection” and “Visual inspection of couplings”. Those tasks might seem valuable in theory, but they share a common drawback: they are intrusive, requiring the equipment to be stopped, resulting directly in productivity losses. 

The primary goal of a reliability and maintenance team is to maintain equipment performance and minimize downtime. Therefore, it’s essential to prioritize non-intrusive inspection and task and reduce over-maintenance tasks in your PM program. With advancements in technology, there are often multiple non-destructive testing (NDT) alternatives that can provide similar inspection outcomes without disrupting operation efficiency. 

For example, instead of stopping equipment to inspect coupling rubber, consider a non-intrusive inspection with a strobe light. This allows you to accurately assess the coupling for cracks, deterioration, and discoloration while the equipment continues to run, therefore a similar outcome can be expected in terms of the inspection but without affecting the equipment’s production and performance. Advanced condition monitoring technologies like vibration analysis, ultrasonics, and IR thermography can offer even more insights into equipment health than visual intrusive inspections. 

Furthermore, intrusive preventive maintenance (PM) inspections often involve disassembling or physically interacting with equipment, asset or machinery to inspect and possibly repair or replace components. Often, those interventions introduce certain risks and challenges, including the potential for reinstallation issues and contamination. Here is a list of typical risks you are exposing your asset’s too when performing repairs, intrusive inspections and PMs:

Therefore, even though your PM program is full of good intention, dismantling equipment to detect potential issues carries a significant risk of introducing new problems that didn’t exist initially, potentially leaving the assets in worse condition than prior to the intrusive inspection.

Lack Predictive Maintenance and Data-Driven Insights

The absence of predictive maintenance (PdM) strategies, non-intrusive inspection and data-driven insights within a PM program can lead to over-maintenance tasks, compromising the overall effectiveness of both PM and PdM initiatives. 

Referring to what was mentioned in section #1, often the lack of predictive maintenance is due to the fact that the existing maintenance strategies where not risk based inspection or elaborated on a failure-mode based approach, meaning that the maintenance team probably didn’t identify that unusual vibration, high frequency signal, rise in temperature, rise in ultrasonics frequencies as potential symptoms during their condition assessment, therefore not creating objective tasks to address those.

Therefore, without predictive maintenance capabilities, organizations often rely solely on scheduled PM activities based on rigid calendar-based intervals. This approach can result in unnecessary maintenance on asset and equipment still operating optimally, causing excessive downtime and labor costs.  

Example of PM Optimization done with regards to Risk Penalty Number calculated at failure mode level

Additionally, making maintenance decisions without real-time data-driven insights can lead to premature component replacements or repairs, draining resources needlessly. Common examples of over-maintenance tasks include “Bearing replacement” or “Chain replacement” added to the PM program after major unplanned downtime incidents. While these tasks may seem like prudent preventive measures, they will directly lead to increased planned downtime, operation efficiency, shorten the components life which will directly lead to higher parts costs (consuming more parts within the same timeframe), and as mentioned above, the more human intervention your plant has, the higher is the potential introduction of new issues in critical asset and equipment.

In contrast, organizations in the top-performing quartile understand the importance of PdM technologies, such as condition monitoring sensors and predictive analytics. These technologies provide real-time data on asset health, enabling maintenance teams to pinpoint precisely when maintenance is needed. By detecting issues before they escalate, organizations can extend the life of their assets, reduce downtime, and optimize maintenance efforts. Failing to incorporate predictive maintenance and data-driven insights into a PM program can result in over-maintenance tasks, increasing costs and diminishing asset longevity.

Lack of Actual Findings

In essence, the primary goal of preventive maintenance (PM) is to proactively detect potential equipment issues before they escalate into costly failures. If your current PM program yields minimal results, it could be due to two reasons in your condition assessment. First, your plant may be so reliable that technicians conducting inspections struggle to find any issues on equipment, asset and components. Second, your PM program may mostly consist of subjective taks like “inspect motors”, intrusive repairs, and non-data-driven tasks. In most cases, the outcome of a few potential failure identifications is due to the second option. 

From our experience, we have detected a strange trend where some plants engage in deploying a PM program for compliance reasons rather than its true purpose. They may implement a basic preventive maintenance program just to fulfill a requirement, essentially checking a box to claim that they are running a PM program.

However, PM programs should extend beyond mere checklist completion. Their fundamental aim is to uncover actionable insights that empower organizations to plan and execute corrective actions promptly. The goal is to have maintenance personnel who are not just checking boxes but actively contributing to the identification of potential failures while minimizing downtime by prioritizing non- intrusive preventative maintenance inspection. 

Example of Data from APM tool

Technicians performing PM tasks are the eyes and ears of the organization. Their expertise enables them to detect equipment anomalies and irregularities. Shifting the focus from routine tasks to proactive problem-solving allows organizations to maximize the utility of their workforce. Skilled technicians can help prioritize maintenance efforts, allocate resources efficiently, reduce risk and downtime, while contributing directly to cost savings and operational excellence. 

What is a Non-intrusive inspection

Non-intrusive inspections (NII) are a method of examining and assessing the condition of an assets, components or piece of equipment with the use of a condition monitoring technology that allows the monitoring without disrupting operation.

NII are a safe and cost-efficient way to monitor assets health based on failure modes without disassembling equipment, assets or parts. These non-intrusive inspection uses non destructive testing (NDT) methodologies to conduct thorough condition assessment of critical assets.

NII are efficient in identifying multiple risks, need for repairs and more. They usually can detect acoustic emission, vibration frequency range, misalignment, electromagnetic waves, heat, and way more.

Conclusion

In today’s labor-constrained environment, maximizing resource utilization is imperative. When PM tasks rely on subjective assessments rather than objective data and insights, inefficiency creeps in. Technicians may end up conducting unnecessary maintenance activities, consuming valuable time and resources that could be better allocated elsewhere for a better condition assessment.

Preventive maintenance should not be a checkbox exercise. It should be a valuable tool for enhancing plant reliability, reducing costs, and optimizing resource allocation. Embracing data-driven, insight-oriented PM practices is essential and non-intrusive inspection should be prioritized. PM should be seen as a means to ensure that every minute of a technician’s time brings tangible value to the organization and operation.

Arnaud Richer, B. Eng.
Reliability solutions – Spartakus technologies
[email protected]