Reliability: 5 indicators of lack of maintenance

August 13, 2020

Each person is unique, their understanding and experiences will produce different reactions and actions for each situation.

So how can you expect a uniform and correct procedure without having well-defined and documented processes?

The maintenance team needs an effective and repeatable procedure that is independent of the employee’s mood.

A well-defined and documented maintenance procedure will serve as the basis for training the necessary skills of the maintenance staff, and will reduce the risk of rework and increase safety in the execution of tasks.

If the industry’s goal is to optimize equipment reliability, then effective and consistently repeated procedures will be required.

As well as getting feedback and continuously following up on procedures, this will encourage engagement and reduce errors, making continuous improvement a natural thing.


Corrective maintenance rates provided by institutions focused on maintenance in the national industry, among them ABRAMAN, show that currently the proportion of spending on corrective maintenance is between 38% and 46%.

This indicates that a high proportion of Brazilian industries are reactive and do not have a defined maintenance strategy.

People wait for the machinery to fail or break down so that, in the urgency of avoiding a disaster in the delivery of orders, they pay whatever is necessary to get the equipment back to normal operation as soon as possible.

What could be worse than having orders for your products and not being able to deliver them due to machinery breakdown?

The higher the rate of corrective maintenance, the less reliable the equipment is.

When the approach to maintenance is reactive – break and fix – it means that the whole organization, from the top to the shop floor, is reactive. It means that it does not control its processes, nor its costs.


Maintenance cost as a function of Asset Replacement Value (ARV) has been a metric applied by American industry since the 1980s.

The great benefit of its application is to compare the maintenance cost of industries of different size and asset value, and also to establish a benchmark.

If for example the maintenance cost is 20% of the replacement value of the asset, it means that the money spent on maintenance per year would be enough to buy a new plant every five years.

If this percentage is reduced to 5% it would take twenty years of maintenance costs to replace the assets.

Therefore, the lower this index, the higher the return on the capital initially invested in machinery, resulting in a more effective use of the assets.

The greater the focus on corrective maintenance, the worse this indicator will be.

Hence, the higher the percentage of maintenance costs in relation to the replacement cost of the asset, the worse the reliability of the plant.

If the production is not delivered on time, the reasons for the failures or stoppages need to be understood and corrected.

Otherwise, all that will remain is to exchange the asset for a new one before the industry, with this reactive practice, breaks down because of its high costs and it is too slow to produce.


Mean Time Between Failures, the MTBF index is what the name says, the average period between repairable failures of industrial machinery.

This indicator measures the reliability of the equipment, and the higher it is, the better. Its formula is defined by:

MTBF = Uptime (in hours)/No. of Failures.

In general, it is an indicator to be used on critical equipment or a set of assets.

Best suited for continuous process industry, those that manufacture continuous batches where it is difficult to differentiate between one unit and another.

Many petrochemical plants fall into this category.

In discontinuous manufacturing, that is, in the manufacture of various items, OEE (Overall Equipment Effectiveness) is indicated.

To measure MTBF it is important to clearly define which failures will be considered and how will the time be defined.

It does no good to use a manipulated metric so that your result is good and false.

There is extensive American literature on the subject including potential pitfalls to avoid.


The knowledge of the asset to be installed in an industrial park begins in the project.

In the acquisition process, besides the equipment specification, its operation manuals and preventive maintenance recommendations should be evidenced and analyzed.

Once the equipment is installed, it begins to suffer the natural consequences of wear and tear.

Misalignment, unbalance, lack of or inadequate lubrication are some of the factors that can translate into failure sooner or later.

Monitoring this machine through acceleration and temperature sensors and performing regular spectral analysis will allow you to diagnose the potential failure before it occurs.

It is also important to know where specifically to position monitoring devices so that the relevant parameters are read and proactive maintenance is carried out.

Industry 4.0 has a lot to evolve and benefit itself, by increasing reliability, with technologies that aim at equipment knowledge through continuous data collection of its operational condition.

Learn how the Solution can help increase the reliability of your industry’s most critical equipment.

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