Risk Based Inspection is a procedure used for designing optimized inspection plans based on knowledge of the risk of failure.
It uses a process to identify, assess and categories the risk raised as a consequence of industrial equipment or structures depreciation or failure. The collected data is then used to analyze the probability of failure of each component as well as to plan a proper inspection and maintenance programme.
RBI process is predominantly utilized by the industry for examination of equipment such as pipelines, industrial plants, pressure vessels and heat exchangers.
In the past, the inspection schemes were determined based on industry’s common practices and prescriptive codes and health and safety legislation. Factors such as equipment’s age, operation type and likely damage were not taken into consideration when planning the inspection frequency and extent. However, as the operational experience was increased and the industry gain better appreciation of ageing equipment and hazards, RBI which is a more comprehensive inspection method that factors in the risk of failure within regulatory expectations was developed.
Why use Risk Based Inspection (RBI)?
Risk Based Inspection is an economical substitute to the lengthy inspection processes as well as utilizing the automated NDT or non-invasive inspection schemes as more effective inspection resource substitutes. To satisfy the regulatory authorities, the RBI processes need to be conducted in a rigorous manner to ensure that the inspection decisions are being made based on accurate and reliable data and expertise.
RBI is also a technique that helps planning the NDT inspection activates in order to gain more confidence in the extent of the equipment’s true damage extent and the dynamics that are leading to that.
The resulting inspection plan may outline the type and scheduling of inspection for an asset. In addition to NDE, additional risk mitigation activities identified by an RBI assessment might include a change in material of construction, installation of corrosion resistant liners, operating condition changes, injection of corrosion inhibition chemicals, etc.
Having a consistent and repeatable analysis is crucial for the effectiveness of an RBI program as RBI is based on relative risks. Collecting data for performing RBI analysis could be carried out using various techniques of qualitative or quantitative methods and when carrying out RBI analysis, close attention should be paid to how the data at different stages of screening and analysis have been collected and analyzed as it can have a major impact on the final results and validity of the findings.
Benefits of using Risk Based Inspection (RBI):
A properly performed RBI process results in findings such as:
- Identification of the potentially available damage
- Location of the damage
- The rate at which the damage may evolve
- Identification of the danger of catastrophic failure
Areas at high risk usually have credible damage mechanisms combined with high consequences from structural failure, the release of hazardous substances or stored energy. By deploying a proper inspection scheme that uses reliable techniques and takes the damage mechanisms into account, we can find more confidence in the conditions of the components.
Inspection programs that are designed based on the risk level have some benefits such as:
- Getting a clear image of the risk that is currently present
- Reducing the risk for the assessed assets
- Complying to the regulations and maintaining license to operate
Another major benefit of using RBI, especially in the oil and gas industry is reducing revenue loss by minimizing the turnaround times. Turnarounds are necessary to conduct maintenance services, however, RBI can help reduce this cost by reducing the number of inspections during the scope of a turnaround and consequently having a major impact on the revenue.
RBI also helps to extend inspection intervals and reduce scope. Based on the assessments, the equipment that possess low risk are identified and excluded from the items that require extensive inspection. On the other hand, the higher risk equipment are prioritized based on the acceptable risk level they hold.
As the number of inspections is reduced, the volume of data is proportionally reduced as well, leading to a smaller data set and more accurate information.
TWI SEA Risk Based Inspection services:
Here at TWI we offer RBI solutions as part of our risk and reliability engineering services. With our extensive knowledge of materials degradation processes and our track record of RBI services to numerous clients, we can assure you that you can rely on our expertise in developing the right plan for each scenario.
Using an established methodology and TWI’s bespoke RiskWISE® software, we can develop maintenance or replacement solutions, giving guidance on managing your assets in the most effective manner, from individual component studies through to turnkey, plant-wide projects – tailored to your needs. Our asset integrity management and plant life assessment services work together to maximise the reliability and efficiency of a structure or component.
If you are interested in our Risk Based Inspection services, get in touch with us for an appointment to discuss about your options.