If the maintenance budget of a plant increases every year but unexpected downtime does not decrease, the problem is usually not that too little maintenance is carried out. The problem is often that the same approach is applied to every piece of equipment in the plant. When the same periodic programme is applied to a critical compressor and to an extractor fan in the warehouse area, one of them receives more maintenance than necessary while the other is not monitored enough. In industrial maintenance, the real gain comes not from increasing maintenance but from matching the right method to the right equipment.
Criticality First, Method Second
The starting point of a maintenance programme is not the equipment list but the criticality ranking. Three questions are answered for each item of equipment: if this equipment stops, does production stop, does its failure create a safety or environmental consequence, and is there a spare unit and how quickly can it be brought into service?
The answers to these three questions divide the hundreds of items of equipment in the plant into a few groups on their own. The picture that emerges is generally surprising: a significant part of the maintenance hours is spent on equipment that does not affect production when it stops. In industrial maintenance planning, the first improvement begins when this imbalance becomes visible.
Three Approaches and Their Cost Curves
Intervention after failure is a sensible choice for equipment of low criticality that has a spare unit available. This is not neglect but a conscious decision; the equipment runs until it fails and is replaced when it breaks down.
Periodic maintenance works on equipment whose wear behaviour is predictable. Time based programmes, however, have a known weakness: when sound equipment is opened unnecessarily, new sources of failure such as assembly errors, gasket leaks or incorrect torque are created. Frequent maintenance does not always give a safer result.
Condition based maintenance takes the data of the equipment itself as its basis. Vibration measurement, oil analysis, thermography and bearing temperature monitoring show the development of a failure weeks in advance. On rotating equipment of high criticality, this method reduces both unnecessary opening and unexpected downtime at the same time.
A mature industrial maintenance programme does not choose one of these three; it uses all three together according to the criticality classes.
When the Shutdown Window Is Narrow, Preparation Determines the Job
Plants that measure how much of the time spent in planned shutdowns is actually devoted to mechanical work often come across an uncomfortable result. A significant part of the schedule is spent waiting for access to be established, for insulation to be removed, for work permits to be completed and for material to reach the site.
For this reason, the critical question in shutdown planning should not be "in how many hours can we do the work" but "at which hour can we start the work". When the steps of scaffolding erection, insulation removal, isolation and making safe are detailed before the shutdown, the same work list is completed in a noticeably shorter time. The hours lost on site usually arise not from the difficulty of the mechanical work but from the gaps in the preparation chain.
As the Number of Contractors Increases, the Coordination Cost Grows
When scaffolding is taken from one company, insulation from another and mechanical labour from a third in the same shutdown, everything may be set up correctly in technical terms. However, when a shift occurs in the schedule, the boundary of responsibility becomes unclear and the teams start waiting for one another. The scaffolding team erects the platform, the mechanical team is delayed, the scaffolding is moved to another site; when the mechanical work is finished, the insulation contractor cannot find access.
Planning access, insulation and mechanical work under a single responsibility largely removes this risk. The gain lies not only in the price negotiation but in the integrity of the schedule.
The Spare Parts Policy Is the Invisible Half of the Maintenance Programme
The cost of a failure to the plant is determined by the supply time of the part rather than by the duration of the intervention. A job that could be resolved in one day on site may spread over weeks because of the lead time of a critical part. For this reason, the output of the criticality analysis should determine not only the maintenance method but also the list of parts to be held in stock.
The decision rests on a simple comparison: the capital tied up by holding the part in stock against the cost of the downtime that would be caused by the absence of that part. On equipment of high criticality, this comparison almost always turns out in favour of stock. On the other hand, large stocks held for equipment of low criticality turn into a cost item that waits on the shelves for years and is often scrapped without being used.
The same logic applies to consumables and insulation elements. If the material needed to replace insulation removed during a shutdown is not available on site, the line cannot be brought back into service even though the mechanical work has been completed.
Maintenance Without Records Is Repeated Maintenance
Noticing that the same equipment has failed three times during the year for similar reasons is only possible when failure records are kept regularly. This is also the most neglected side of industrial maintenance: the intervention is carried out, the equipment runs, and the record is either never entered or passed over with the phrase "fault rectified".
Yet the valuable information lies in the detail. Which part was replaced, how the failure was noticed, how much time was lost, what the root cause was. As these data accumulate, the programme corrects itself; which equipment can have its interval extended and which needs to be brought into monitoring are determined by records rather than by discussion.
How Is the Maturity of the Programme Understood?
The real indicator of maintenance management is not the budget spent but the share of unplanned work within the total work. If this ratio falls over time, the programme is working. There are a few more indicators worth monitoring alongside it: the rate at which planned shutdowns comply with the schedule, the number of repeated failures on the same equipment and the share of the shutdown period actually devoted to mechanical work.
When these indicators are followed regularly, industrial maintenance ceases to be a cost item renegotiated every year and becomes a predictable part of production planning.
Frequently Asked Questions
Should the same maintenance programme be applied to every item of equipment?
No. An efficient programme separates equipment according to its level of criticality and applies a different method to each class: intervention after failure on equipment of low criticality that has a spare unit, periodic maintenance on equipment whose wear is predictable, and condition based monitoring on rotating equipment of high criticality.
Is frequent maintenance always safer?
No. Opening sound equipment unnecessarily may create new sources of failure such as assembly errors, gasket leaks or incorrect torque. For this reason, the maintenance frequency should be determined according to the criticality and the failure behaviour of the equipment.
How is the success of a maintenance programme measured?
The most meaningful indicator is not the budget spent but the share of unplanned work within the total work. If this ratio falls over time, the programme is working. The compliance of planned shutdowns with the schedule and the number of repeated failures are also indicators that should be monitored.