The purpose of a risk assessment in maintenance is to identify the risks associated with equipment deterioration in order to ensure a good operational condition of all equipment and facilities.
The process of a risk assessment can be summarised by the following 5 steps:
Information → Inspection → Evaluation → Planning → Maintenance and Revision
In the first stage, the aim is to collate all the relevant and necessary information regarding the buildings and equipment. This includes floor plans and engineering schemes, maintenance history, previously identified failures etc.
Next, it’s important to perform a detailed inspection of the infrastructures and equipment which are being assessed. Evaluation criteria should be clearly defined in order to create checklists and documents to use throughout the inspection.
Based on the information and data collected in the inspection, an estimation of the lifespan of the device should be made and then they should be put in categories from A to D, where:
A. VERY GOOD: The equipment is in optimum condition and is expected to function properly until the end of its normal lifespan;
B. GOOD: The equipment is in good condition with only some signs of deterioration;
C. OPERATIONAL: The equipment is operational but needs major reparation works or even some parts replacements
D. UNSTABLE: The equipment is unstable and in danger of breaking down.
There is also an intermediate category B/C, which means the equipment is currently in category B but will switch to category C within 5 years.
The risk assessment stage involves estimating when failures might occur and their potential consequences.
It should take into account the probability of failure (categorised from 1 to 5, where 1 = rare; 2 = unlikely; 3 = possible; 4 = likely; 5 = certain) and the severity of the consequences (categorised from 1 to 5, where 1 = insignificant; 2 = low; 3 = moderate; 4 = high; 5 = catastrophic), according to the following matrix:
The values shown correspond to a product of the level of probability of failure and the level of severity of the consequences. The colours represent the different associated risk levels: low (green), moderate (yellow), significant (orange) and high (red).
For instance, if the occurrence of a failure is likely (3) and the potential consequences are of a high severity (4), then the risk equals 3*4=12 (significant risk).
After the results of the risk assessment above are presented, the maintenance plan for the equipment or buildings should be prepared. Priority should naturally be given to those whose associated risk is either significant or high.
Finally, the execution of the necessary maintenance works follows, according to the previously defined plan. It is essential that the risk assessment performed is reviewed annually, to take into account the continuous deterioration of the equipment, works performed meanwhile and new equipment acquired.
Only now, once we have implemented the previous 4 steps, can we go ahead with the necessary maintenance works. This risk assessment should be reviewed annually to account for deterioration throughout the year and to give time for more works to be applied and for new equipment to be purchased.
It is recommended that a new detailed inspection is elaborated and applied every 5 years.
After the assessment is completed, we can begin implementing measures to prevent future failures in assets of high priority. Considering the weight that these measures may have in a company’s budget, it’s necessary an efficient plan that minimises the risks involved.