Tags: Risk Based Inspection
Our Senior Corrosion and Mechanical Integrity specialists provide useful insights into the determination of the process information to be used for Risk Based Inspection (RBI) projects. Incorrectly assigning process conditions for a particular piece of equipment can result in overlooking a variety of applicable damage mechanisms and a skewed calculation of risk. Guidance derived from experience is provided to ensure the process conditions are appropriately identified for a number scenarios that have an impact on damage mechanisms and consequence calculations.
This is the first in this eight-part series.
Risk Based Inspection (RBI) implementation and revalidation efforts require process engineers to provide process information on representative fluids, operating temperatures, operating pressures, and toxic fluids to be used in consequence models of RBI software. To streamline the work process and minimize the effort expended by the process engineer in gathering, scrubbing, and tabulating the required information for each piece of piping and equipment covered in the RBI effort, this process data is usually also used as the primary data for performing a Damage Mechanism Review.
Taking into consideration that process conditions in a unit may vary significantly due to breaches in operating conditions, cyclic service, process upsets, and frequency of shutdowns, it is sometimes difficult to determine the actual values to use for the process data. Yet the impact of the values that are selected to be used can be significant in the risk that is calculated by the RBI software (due to the impact on the consequence model), the damage mechanisms that apply, and to the inspection plans that are generated.
As an example, an insulated 304SS vessel from the 1960's had an operating temperature that varied from 320°F to 480°F and was assigned an average operating temperature of 400°F. Taking into consideration the 400°F operating temperature that was provided by the process engineer, the vessel had not previously been assigned a chloride stress cracking (Cl-SCC) environmental damage mechanism since external wetting is not expected at these high temperatures. However due to actual operating conditions of frequent shutdowns and cyclic service operation where the temperature cycled from ambient to 480°F, the vessel experienced external Cl-SCC and had to be replaced.
It is more straightforward to assign process data in some units and equipment than in others and the required level of sensitivity in providing process data may vary with the process unit being evaluated or with the particular equipment being assessed. Therefore, it is important for the process engineer and other RBI team members work closely to ensure there is a good level of understanding of how the process information provided will affect the damage mechanisms that are assigned and the risk levels that are calculated by the RBI software since the risk levels and damage mechanisms will drive the types of inspections that are to be carried out as well as the frequency and extent of inspection.
This series of short articles will provide guidelines on assigning process conditions for RBI efforts. Over the course of the next few weeks / months we will be discussing guidelines for each of the following:
Stay tuned for the next entry in this eight-part series.
AOC has delivered thousands of sustainable Risk Based Inspection (RBI) programs earning the trust of owner operators.
One of the most important steps in an RBI project is the corrosion study or damage mechanism review.
When evaluation of inspection results suggest that an asset is near its end of useful life, Fitness for Service evaluations can determine if the asset us suitable for continued operation.
How well do you know RBI? Take this short quiz to test your knowledge of the API 580 risk-based inspection (RBI) work process.
Create mechanical integrity (MI) program value rather than it being seen as a necessary cost to minimize.
A high level overview intrucing Mechanical Integrity and Risk Based Inspection
What impact does Risk Based Inspection (RBI) have on my organization?
Is your Risk Based Inspection (RBI) program aligned with the API 580 Recommended Practice? Are you ready for certification?
What's actually going on inside all of that fancy software? An introduction to the API 581 methodology.
A deep dive into quantitative Risk Based Inspection (RBI) as outlined in API 581.
What are the hidden benefits of implementing Risk Based Inspection?
This is a practical approach to incorporating the new PHMSA gas well rules into your integrity program with the rest of your surface and subsurface assets.
A look at how the financial sector's concept of Asset Value Management can be applied to the petrochemical industry.
An example to compliment our earlier proposal for a risk analysis option that allows for individual damage mechanism risk calculation in API 581
A proposal for a risk analysis option that allows for individual damage mechanism risk calculation in API 581
A look at how RBI adds value whether you are just starting out or transitioning from a traditional methodology.
A look at several of the secondary benefits of Risk Based Inspection
Additional process data may be needed when environment, stress, and metallurgy are so alligned so as to indicate susceptibility to environmental cracking.
A simple screening to determine HTHA susceptibility and factors to consider when more data is required.
Since the evaluation of inspection effectiveness for RBI can be so subjective, following these suggestions can greatly improve the process.