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.
Reference: API 580, 2nd Edition (2016), Section 13.11
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According to API 580, risk reduction is primarily achieved through implementing mitigation activities that are designed to lower either the probability of failure (PoF), the consequence of failure (CoF), or both.
As stated in Section 10.1:
"Risk can be reduced by reducing the likelihood (probability) of failure, the consequence of failure, or both.
This is typically accomplished through mitigation activities such as inspection, process control, or equipment modification." This clearly confirms that "mitigation activities" is the most direct and encompassing method of achieving risk reduction in an RBI program. While the other options (like process control or inspection activities) may be forms of mitigation, they fall under the broader category of mitigation activities and are not the definitive general method.
Reference: API 580, 2nd Edition (2016), Section 10.1

As per API 580, Section 8.3:
"Once a credible damage mechanism(s) has been identified, the associated failure mode should also be identified. For example, local thinning could lead to a pinhole leak in the pressure-containing boundary." The example "pit-to-leak" accurately reflects a transition from a damage mechanism (pitting corrosion) to a failure mode (leak). Options B and C are damage modes or mechanisms, and D is a fabrication defect-not a failure mode.
Reference: API 580, 2nd Edition (2016), Section 8.3

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
Reference: API 580, 2nd Edition (2016), Section 4.3

API 580 Section 14.3.3 clearly states:
"Once a mitigation strategy is implemented it is prudent to determine how effective the strategy was in reducing the risk to an acceptable level. This should be reflected in a reassessment of the risk and appropriate update in the documentation." Thus, option B is correct. Updating standards or team members is not a listed reassessment trigger, and sensitivity analysis alone is a supporting tool, not a trigger.
Reference: API 580, 2nd Edition (2016), Section 14.3.3
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