Free API API-580 Practice Exam with Questions & Answers | Set: 2

According to Section 7.2.3:

“Quantitative RBI uses logic models depicting combinations of events that could result in severe accidents and physical models depicting the progression of accidents… Hence more detailed information and data are needed for a fully quantitative RBI in order to provide input for the models.”

The need for detailed data in quantitative analysis is primarily to enable the use of logic and physical models in assessing risk.

According to API 580, Section 9.4.3:

“It is important to link the damage mechanism to the most likely resulting failure mode. For example:

a) pitting generally leads to small-hole-sized leaks;

b) stress corrosion cracking can develop into small through-wall cracks or in some cases rupture…”

This highlights that identifying the specific failure mode (e.g., leak, rupture) related to the damage mechanism is critical for accurate probability and consequence analysis.

In RBI, risk is typically calculated using the basic formula:

      Risk = Probability of Failure (PoF) × Consequence of Failure (CoF)

Based on the question:

Probability of Fire = 0.00001 per year

Consequence of Fire = $50,000,000

Applying the formula:

      Risk = 0.00001 × $50,000,000

      Risk = $500/year

This is the annualized risk estimate associated with the fire event originating from a leak in the crude vacuum tower.

As per API 580, Section 10.2.1:

“A common approach used to express risk is to multiply the probability of failure by the consequence of failure. This simple equation is useful for determining the relative risk ranking among equipment items.”

And in Section 10.3.1:

“Risk can be expressed in various units such as monetary value per year (e.g., $/year)... This allows for comparison of risk levels in economic terms.”

Hence, the correct calculated value, $500/year, corresponds to option A.

API 580 Section 6.6 specifies:

“The resources and time required to implement an RBI assessment will vary widely between organizations depending on a number of factors including... g) degree of precision required.”

Other listed factors include knowledge and training, data availability, and complexity of analysis, but not the number of mitigation activities or whether CoF or PoF is the dominant risk driver.

According to API 580, Section 6.2.8:

“An RBI assessment made on new equipment or a new project while in the design stage may yield important information on potential risks. This may allow potential risks to be minimized by design and have a RBI plan in place prior to actual installation.”

This statement confirms the value of performing RBI even in the absence of historical data, especially for forward-looking risk identification.

According to Section 9.1 of API 580:

“The POF analysis shall address all credible damage mechanisms to which the equipment being reviewed is or can be susceptible. Further, it shall address the situation where equipment is or can be susceptible to multiple damage mechanisms (e.g. thinning and creep).”

Thus, C is the most accurate and complete choice. Option D is incorrect because the analysis is focused on equipment-specific mechanisms, not the entire site.

As clearly stated in API 580, Section 7.2:

“The precision of the data should be consistent with the RBI method used. The individual or team should understand the precision of the data needed for the analysis before gathering it.”

This means qualitative, semi-quantitative, and quantitative approaches may require different levels of data precision.

According to API 580’s glossary of terms:

“Unmitigated risk: The risk prior to mitigation activities.”

This definition is also applied in Section 5.6.2 where RBI plans must address unmitigated risk and propose mitigation strategies if it is deemed unacceptable.

Other options are either incorrect interpretations or irrelevant to RBI methodology.

API 580, Section 13.1 states:

“Inspection may not always provide sufficient risk mitigation or may not be the most cost-effective method. The purpose of this section is to describe other methods of risk mitigation.”

And further clarifies:

“RBI offers the added advantage of identifying gaps or shortcomings in the effectiveness of commercially available inspection technologies… In cases where technology cannot adequately and/or cost-effectively mitigate risk, other risk mitigation approaches can be implemented.”​

According to API 580, multiple API inspection codes include provisions for RBI. Section 4.3 of API 580 clearly states:

“The RBI methodology is recognized in the API inspection codes — API 510, API 570, and API 653 — as an acceptable method to determine inspection intervals.”

Each of these codes outlines both the requirements and limitations for using RBI in their specific contexts:

API 510 — for pressure vessels

API 570 — for piping systems

API 653 — for aboveground storage tanks

On the other hand:

API 573 is a recommended practice for the inspection of fired heaters and does not include formal RBI provisions.

API 578 focuses on Positive Material Identification (PMI) and is unrelated to RBI methodologies or requirements.

Therefore, the correct selection includes:

✔️API 510

✔️API 570

✔️API 653