API-580 Consequence of Failure Modeling Flashcards

In an API 580 qualitative consequence analysis, which factor best determines whether a fluid is classified in a high-consequence category?

Answer: High flammability, high toxicity, or high inventory under elevated pressure or temperature

Fluids are placed in high-consequence categories based on their intrinsic hazard properties—flammability, toxicity, and phase/pressure conditions that drive release severity.

According to API 580, what is the significance of the 'detection and isolation credit' in consequence modeling?

Answer: It reduces the effective release size by accounting for automatic shutdown systems that limit the released inventory

Detection and isolation systems limit the amount of fluid released before shutdown, reducing the effective inventory and therefore the calculated consequence area.

In API 580 consequence analysis, what does 'area-based consequence' measure?

Answer: The physical area (in square feet or square meters) potentially affected by a hazardous release event

Area-based consequence quantifies the geographic footprint of the hazard zone created by a release, used to assess potential impact on personnel and neighboring equipment.

Which of the following would MOST reduce the calculated consequence of failure for a high-pressure gas vessel in API 580?

Answer: Installing automatic isolation valves and high-integrity pressure protection systems (HIPPS)

Automatic isolation valves and HIPPS limit the releasable inventory by quickly shutting off flow, directly reducing the consequence of failure.

In API 580, what is the primary difference between 'flammable consequence area' and 'toxic consequence area'?

Answer: Flammable consequence is driven by energy release and ignition probability; toxic consequence is driven by dispersion and human dose thresholds

Flammable consequences depend on the energy available for combustion and ignition probability, while toxic consequences depend on atmospheric dispersion and the concentration required to cause harm.

According to API 580, in the risk matrix, what does consequence of failure determine in combination with probability of failure?

Answer: The risk ranking, which drives inspection planning and mitigation priority

Risk = POF × COF; the combination of both on the risk matrix produces a risk ranking that prioritizes inspection resources and mitigation efforts.