Availability & Reliability

Availability & Reliability

Risk Based Inspection

 Risk Based Inspection (RBI) is a risk based approach to planning plant inspections, for optimum plant maintenance. It is a systematic technique focused at achieving optimum asset integrity management and system integrity. With RBI, there is the outlook for future savings in cost emanating from the optimal use of resources.

Savings arise from modified/ reduced direct inspection costs.
RBI program techniques focus inspection resources on parts of the plant where they will have the greatest benefit, and hence result in reduced downtime. In line with the principles of ALARP (As Low As Reasonably Practicable), RBI aids prioritising of resources for equipment with higher probabilities of failure. Because RBI focuses on the critical equipment and identifies priorities for inspection based on the risk of failure, it introduces additional safety benefits for the system.
The effectiveness of the RBI program is dependent on the accuracy of the reliability analysis and risk assessment data used, and the RBI reviews and audits.
It is now widely accepted that the traditional time-based approach to planned plant inspection by a competent person has a number of shortcomings. In particular, the use of fixed intervals between inspections may be too conservative and lacks the freedom to benefit from good operating experience.
EPConsult Energies employs the highest standards in our RBI study methodology e.g. API RP 580 and API RP 581.


Good quality information and the correct interpretation of data are essential for the relative accuracy of RBI analyses. Central to valid RBI methods is the correct identification of damage mechanisms, failure modes and conditions that bring on deterioration. See also FMECA.

As part of our best practices for RBI programs, all plant maintenance data gathered will be subject to review and validation by our competent consultants nominated for a specific study before being established in the Data Manual for use.

Central to defining risk levels associated with the failure of a piece of equipment is determining the probability of failure and the consequences of failure of each identified item of mechanical equipment, or piping, that may lead to a critical event. Our RBI study methodology includes the consideration of the probability of failure and its consequences usually in a probability-consequence matrix.

The risk ranking resulting from the probability-consequence matrix is thus used to prioritise and plan the Inspection of equipments within a process unit. As the risk ranking is a direct function of the active and potential damage mechanisms that can cause a release - and the damage rate associated with it - it follows that the plant inspection priorities are based on the specific risk of failure. See also reliability centred maintenance.

We use the information from the damage rate data and the value of the inspection to determine the period to the next risk based inspection.
To discuss your challenges please contact us at enquiries@ep-consult.co.uk.