API-580 Probability of Failure Analysis Flashcards

In API 580, the 'injection point' damage factor is specifically associated with which phenomenon?

Answer: Accelerated local corrosion or erosion at chemical injection nozzles and mixing zones

Injection points experience elevated local damage rates due to turbulence, mixing, and concentration effects that accelerate corrosion or erosion beyond what occurs in the main process stream.

Which factor primarily drives the 'high-temperature hydrogen attack (HTHA) damage factor' in an API 580 analysis?

Answer: Operating temperature and hydrogen partial pressure relative to the Nelson curve

HTHA susceptibility is evaluated using the Nelson curves, which define safe and unsafe operating regions based on temperature and hydrogen partial pressure.

How does the concept of 'inspection confidence' relate to POF reduction in an API 580 quantitative assessment?

Answer: Higher inspection confidence allows a larger reduction in the damage factor, lowering POF

In quantitative API 580, the credit applied to reduce the damage factor scales with the confidence level (effectiveness) of the inspections performed.

According to API 580, what is the typical outcome when no inspections have been performed on a piece of equipment?

Answer: The damage factor is assigned a high value representing maximum uncertainty about equipment condition

With no inspection history, API 580 requires using the maximum damage factor to reflect the highest level of uncertainty about the actual condition of the equipment.

In API 580, which term describes the damage factor applied when both internal and external damage mechanisms are present simultaneously on the same component?

Answer: Combined or total damage factor that accounts for all active mechanisms

When multiple damage mechanisms are active, API 580 calculates a combined (total) damage factor that reflects the cumulative effect of all contributing mechanisms.

According to API 580, how is the final quantitative Probability of Failure (POF) value typically expressed for comparison in a risk matrix?

Answer: As failures per year (failure frequency), derived from the adjusted generic failure frequency

API 580 expresses quantitative POF as a failure frequency (failures per year), calculated by adjusting the generic failure frequency with applicable damage and management factors.