Free API API-580 Practice Exam with Questions & Answers | Set: 3

As per Section 9.2 of API 580:

“POF is typically expressed in terms of frequency. Frequency is expressed as a number of events occurring during a specific timeframe.”

Further clarified in the same section:

“For probability analysis, the timeframe is typically expressed as a fixed interval (e.g. one year) and the frequency is expressed as events per interval (e.g. 0.0002 failures per year).”

This confirms thatfrequencyis the correct term used to express probability of failure in RBI. Other options like deterioration rate or time are influencing factors but not the standard unit of expression.

Section 5.3.6 of API 580 states:

“Use of expert opinion will typically be included in most risk assessments regardless of type or level.”

This confirms that expert judgment is a fundamental component across all levels of RBI, whether qualitative, semi-quantitative, or quantitative.

API 580 outlines the required contents of an inspection plan in Section 12.3 and also in the "Output" section:

“The RBI inspection plan should include:

b) inspection methods that should be used;

c) extent of inspection (percent of total area to be examined or specific locations);

d) inspection interval or next inspection date (timing).”​

Therefore, "examination methods to be used" is a fundamental part of the inspection plan, as explicitly stated. Probability and consequence of failure are inputs to the risk analysis but not part of the inspection plan structure itself.

According to Section 6.6 of API 580 (2016), titled “Estimating Resources and Time Required,” it is clearly stated:

“The resources and time required to implement an RBI assessment will vary widely between organizations depending on a number of factors including the following:

a) implementation strategy/plans.

b) knowledge and training of implementers.

c) availability and quality of necessary data and information.

d) availability and cost of resources needed for implementation.

e) amount of equipment included in each level of RBI analysis.

f) degree of complexity of RBI analysis selected.

g) degree of precision required.”

This confirms the following are among the officially listed influencing factors:

A. Knowledge and training of implementers✔

C. The degree of precision required✔

D. Amount of equipment included✔

However:

B. Cost of mitigation activities —✘Not listed in Section 6.6 as a driver for time/resources during implementation.

E. Type of damage mechanisms involved —✘Relevant to PoF modeling, but not a direct listed factor for estimating time/resources needed to implement the RBI.

API 580 Section 14.3.2 clearly states:

“Users should set default maximum time periods for reassessments. The governing inspection codes (such as API 510, API 570, and API 653) and jurisdictional regulations, if any, shall be reviewed in this context.”

This means the codes and regulations are explicitly consulted to determine maximum allowable intervals between RBI reassessments. This ensures compliance with inspection frequency expectations across different jurisdictions and standards.

API 580 defines environmental consequence cost as the sum of “cleanup + fines + other costs” (Section 10.5.6). In this question:

EPA fine = $1,650,000

Cleanup = $1,145,000

Environmental cost = 1,650,000 + 1,145,000 = $2,795,000

Costs like downtime and vessel replacement are part of business interruption or capital loss, not environmental consequence.

API 580, Section 13.11 states:

“Water curtains mitigate water-soluble vapor clouds by absorption as well as dilution... Early activation is required to achieve significant risk reduction. The curtain should preferably be between the release location and ignition sources or locations where people are likely to be present.”

Toxic scrubbers are used for venting or building protection, but water curtains directly mitigate dispersion of water-soluble acidic clouds in open areas.