We are used to classifying maintenance into three main types – preventive, corrective, and predictive – but experience tells us that several tasks do not fit perfectly into any of these categories.
Failure-finding tasks are a good example. But what is this about failure-finding maintenance, anyway? Should it be part of your maintenance plan? If so, when should you apply it? Is the universe infinite? We’ll see about that.
Maintenance focused on reliability and failure finding
Often, looking of rfailures is part of a maintenance strategy focused on reliability. The aim of this type of maintenance is to ensure that the equipment is available for as long as possible. But what happens when we cannot ensure that a piece of equipment is reliable only through routine inspections? The answer is to actively search for failures. In other words, failure finding.
What are failure finding tasks?
Failure finding tasks are inspections we make of a particular piece of equipment to discover defects or hidden failures. Therefore, they do not fit within a specific type of maintenance. In these cases, the goal is not to maintain a certain asset, but to test whether it still works. Therefore, we can also call them “functional checks”.
It is important to underline this aspect because this is what differentiates failure finding from preventive and predictive maintenance. We are not trying to prevent or predict a failure, we are looking for it.
For example, a malfunction in an electrical generator that is used as a backup in a hospital or a hotel will never be detected during the normal operation of the building. If by any chance the generator is broken and we haven’t actively looked for failures previously, we will only find out when the light fails… which is too late! The same happens with fire alarms or smoke detectors, which are only activated under specific circumstances.
In short, failure finding tasks are necessary to have maximum reliability of security and backup mechanisms. Here are some of the systems that need this type of screening and testing regularly:
- alarm systems such as fire alarms, smoke detectors, and motion detectors.
- systems and electrical circuits, to test the load and current capacity.
- relief systems, such as pressure relief valves or control valves.
- mitigation systems to minimize the effect of possible failures, such as fire extinguishers.
- backup systems, such as electrical backup generators or secondary water heating systems.
- shutdown systems, components that automatically trigger and shut down the equipment (e.g. when it overheats) before damaging more expensive parts, such as the engine.
- protection systems, such as electrical protection systems, including against lightning strikes (lightning rods), earth, or anti-seismic systems.
In what situations is failure finding recommended?
This type of maintenance is justified whenever a failure is not evident under normal circumstances or cannot be detected through routine preventive maintenance tasks. Also, functional checks are justified when:
- there is no way to prevent the malfunction (and therefore any possibility of preventive maintenance is excluded);
- tests and screenings can be performed without this implying any changes to the normal functioning of the building;
- the risk of a “hidden” malfunction in a given system is high;
- the probability of the tests causing a serious malfunction is very low;
- the cost of failure fiding tasks is lower than the cost of corrective maintenance.