There is a number that most industrial asset managers are familiar with, yet it rarely takes centre stage in budget decisions: the cost of an unplanned shutdown. In medium and large-scale industrial facilities — refineries, gas plants, chemical production units — that cost can easily exceed €100,000 per hour.
And yet, many companies continue to delay or underinvest in predictive maintenance for their rotating equipment. This article explains why this is a strategic mistake — and what to do about it.
What is Predictive Maintenance?
Predictive maintenance (or condition-based maintenance) consists of continuously monitoring the actual condition of equipment — through vibration, temperature, pressure and other sensors — in order to detect signs of degradation before they turn into failures.
Unlike preventive maintenance (which intervenes according to a fixed schedule) or corrective maintenance (which reacts after failures have already occurred), predictive maintenance allows intervention at the right moment: when it is needed, neither too early nor too late.
Definition: Predictive maintenance is an industrial maintenance strategy that uses real-time data to predict equipment failures before they occur, reducing unplanned downtime and unnecessary maintenance costs.
The Hidden Costs of Not Monitoring Equipment
1. Unplanned Shutdowns: The Most Visible Cost
A failure in a centrifugal compressor or a critical fan can bring an entire production line to a halt. The direct costs of an unplanned shutdown include:
- Production losses: potentially representing tens or hundreds of thousands of euros per hour in continuous-process facilities
- Emergency repair costs: urgent spare parts typically cost 2 to 5 times more than scheduled orders
- Overtime and urgent mobilisation of external technical teams
- Accelerated logistics and shipping costs for components
2. Damage to Secondary Equipment
A compressor or fan failure rarely occurs in isolation. Excessive vibration prior to failure can damage seals, adjacent bearings, couplings and even the equipment support structure.
What starts as a problem in one component can, if not detected in time, evolve into a complete machine overhaul — or even full replacement.
Example: An imbalance in a centrifugal compressor impeller, if not detected through vibration analysis, can progress into bearing and seal damage within weeks, multiplying the initial intervention cost by 3 to 10 times.
3. Safety Impact
In industries dealing with flammable, toxic or high-pressure gases — such as oil & gas, petrochemicals or hydrogen production — a compressor or blower failure can have serious safety consequences.
The human and reputational cost of an incident is incalculable, but the direct financial costs (forced shutdowns, regulatory fines, investigations and legal proceedings) can be devastating.
4. Contractual Penalties and Customer Loss
For industries providing continuous services to third parties — gas transportation, power generation or water treatment — an unplanned shutdown can trigger contractual penalty clauses and, in the long term, lead to the loss of contracts and customers.
5. The Cost of Excessive Preventive Maintenance
Paradoxically, the absence of predictive maintenance also creates unnecessary costs through excessive preventive maintenance.
Without real data on equipment condition, companies tend to replace components according to conservative schedules, changing parts that are still in good condition simply to “guarantee” reliability.
This waste can represent 30% to 40% of total maintenance costs in operations without proper monitoring.
What the Industry Says: Numbers That Matter
Industry references consistently point to the same conclusions:
- Predictive maintenance can reduce maintenance costs by 25% to 30%
- It can increase equipment availability by 10% to 20%
- The average ROI of a properly implemented predictive maintenance programme ranges between 8:1 and 10:1
- Failures in rotating equipment account for more than 50% of unplanned shutdowns in many industrial facilities
Perspective: For every euro invested in predictive maintenance, industry studies suggest an average return of €8 to €10 in avoided costs. Few industrial investments offer this level of return with such predictability.
Preventive vs Predictive Maintenance: What’s the Real Difference?
Preventive Maintenance (Fixed Schedule)
Intervenes according to a predefined time-based plan — for example, quarterly bearing inspections or annual seal replacement. It is better than purely corrective maintenance, but it has clear limitations:
- It does not distinguish between healthy equipment and equipment degrading rapidly
- It may result in unnecessary replacements (cost) or fail to detect accelerated degradation (risk)
- It requires scheduled shutdowns that impact production
Predictive Maintenance (Condition-Based)
Intervenes when data indicates it is necessary.
The main indicators monitored in rotating equipment include:
- Vibration analysis: detects imbalance, misalignment, bearing wear and structural issues
- Temperature monitoring: identifies overheating in bearings, seals and motors
- Oil and lubricant analysis: detects metallic particles indicating internal wear
- Pressure and flow monitoring: identifies deviations from the optimal operating point
- Electrical current analysis: in motor-driven equipment, detects variations indicating mechanical problems
How to Implement a Predictive Maintenance Programme
Step 1: Inventory and Criticality Assessment
Identify all rotating equipment within your facility and classify it according to operational criticality.
Not all equipment requires the same level of monitoring — start with the assets most critical to the process.
Step 2: Establish Baseline Parameters
For each critical asset, establish baseline values under normal operating conditions.
Without this baseline, it is impossible to detect significant deviations.
Step 3: Monitoring Technology
Choose between continuous monitoring (permanent sensors, ideal for critical equipment) or periodic monitoring (portable instrumentation inspections, suitable for less critical equipment).
Industry 4.0 technologies now allow vibration, temperature and pressure data to be integrated into real-time analytics platforms.
Step 4: Specialist Technical Partner
Interpreting monitoring data requires technical expertise in rotating equipment.
An incorrect diagnosis can be just as harmful as the absence of monitoring — leading to unnecessary interventions or allowing real problems to go unnoticed.
The Role of Optimistic in Predictive Maintenance
Optimistic provides specialised predictive, preventive and corrective maintenance services for industrial rotating equipment — compressors, fans and blowers — supported by an experienced engineering team and rapid response capability.
Our services include:
- Vibration analysis and technical diagnostics
- Periodic and continuous monitoring of critical equipment
- Tailor-made maintenance programmes for each facility
- Certified repair of critical components
- Complete overhaul and refurbishment of equipment
With experience across industrial projects in Portugal and internationally, Optimistic has the know-how required to support the transition from reactive maintenance strategies to a truly predictive approach.
Conclusion: Predictive Maintenance is Not a Cost — It is an Investment
The real cost of not monitoring rotating equipment does not appear in maintenance invoices.
It lies in unplanned shutdowns, cascading damage, contractual penalties and, potentially, safety incidents.
In an increasingly competitive industrial environment, companies that treat maintenance purely as a cost centre to minimise are ultimately choosing the most expensive path in the medium and long term.
Those investing in data, monitoring and preventive diagnostics are building a real and measurable operational advantage.
In summary: Predictive maintenance reduces costs, increases equipment availability and improves operational safety. For critical rotating equipment, it is not an option — it is a strategic necessity.
Contact Optimistic to learn how to implement a predictive maintenance programme at your facility: info@optimistic.pt
