Effective Escalation and De-escalation in Tank Integrity Management

???Elevating tank performance: Escalation and de-escalation

When it comes to storage tanks: every component has its unique degradation behaviour, and thus, its own testing criteria. These criteria serve as a threshold value, and if a component falls below it, some action is required.

Consider the diverse options for action, such as escalating to a less conservative threshold. EEMUA 159 for example, provides a solid foundation for assessments, offering a starting point for various components. These are often simple calculations, conservative values, or a basis for visual inspection. Detailed calculations aren't typically provided because they are specific to the asset.

A critical aspect of these calculations is the parameters used in the calculations. While the mathematics of a formula may sometimes appear complex, the formula itself is generally straightforward; it's often the parameters you need to input that can be challenging.

As an example, when considering the simple calculation to be able to determine the minimum acceptable thickness (structural strength) of tank shell courses, you need to determine the maximum allowable stress. To do this you need to gather insight into multiple aspects like the used type of steel, environmental conditions and applicable safety factors. Among other things, specific information on factors like specific gravity, filling height, and internal pressure is crucial to complete a comprehensive analysis.

Starting from this foundation, with the right guidance, one can always escalate or de-escalate to a level that best fits the component's situation and aligns with business objectives.

Escalation Matrix

In the previous posts, we've elaborated on the four basic approaches which can be used to determine the degradation threshold. The four basic approaches to be used for assessing tank components are:

·???????? Visual assessment

·???????? Derivative assessment

·???????? OK / NOT OK assessment

·???????? Predictive assessment

Integrating these methodologies and degradation thresholds into a comprehensive escalation matrix empowers tank owners to substantiate deviations from industry baselines like EEMUA 159 or API standards. This matrix allows flexibility to escalate or de-escalate, aligning with each component's specific conditions and business goals.

Examples of Escalation and De-escalation

Escalating a Roof Plate assessment: Imagine a scenario where an in-service roof plate is tested against a conservative value and doesn't meet the criteria. You can take the tank out of service and repair the roof. ?Instead of immediately taking the tank out of service, a financially viable alternative could be performing an FEM analysis to approach the limit more specifically making the component temporarily acceptable.

Escalating a 'cornerweld' assessment: The cornerweld is assessed using a conservative value. Sometimes, essential data is overlooked, making it impossible to conduct this assessment. In such cases, de-escalation offers possibilities. This involves moving to a derivative assessment by using data from the annular and lowest shell course (which connects to the cornerweld) to infer the degradation.

De-escalating a 'Sagging' assessment: A sagging assessment, typically an OK/NOT OK calculation, can be de-escalated to a visual assessment with a strong rationale, such as the tank being piled and sitting on concrete.

De-escalating with a 'Similar Service Assessment': The Similar Service Assessment is a practical de-escalation approach. If a specific component can't be measured directly (for example, the upper shell courses due to accessibility issues), comparing it with an identical tank with similar use can transform it into a derivative assessment.

Systematic Approach

As highlighted in Step 3 in one of our earlier LinkedIn posts, the key characteristics of a good asset integrity management system are repeatability and agreement on results.

Step 4 is a further step in building a systematic approach to setting up the TIMS system. It establishes criteria against which results will be tested. Even in cases of escalation and de-escalation, actions should follow established agreements, ensuring reproducibility and transparency.

The key lesson is clear: for each component, a precise calculation and criterion is necessary, ensuring control over asset integrity and, by extension, control over financial considerations.

Because, let's face it—if you measure without a clear understanding of when something ceases to be acceptable, what exactly are you measuring?

Interested in learning more? Questions about how Inventure Technologies can assist you with Escalation and/or De-escalation assessments, or do you have additional questions? De not hesitate and feel free to get in touch with us! https://lnkd.in/dscQZKnR