The American Society of Mechanical Engineers (ASME), the American Petroleum Institute (API) and National Board (NB) all allow and recommend a risk-based approach to fixed equipment integrity programs for tanks and pressure vessels. Benefits of this type of approach include:
1. Focusing on the ~10% of assets that are driving the bulk of the risks.
2. Extending inspection intervals on less “risky” equipment.
3. Reducing the number of equipment being opened and inspected during an outage.
4. Spending maintenance dollars in the right places.
5. Improving reliability using a consistent and proven approach.
6. Understanding and properly managing risk.
As noted in ASME PCC-3, Inspection Planning Using Risk-Based Methods, the risk of a failure can never be reduced to "zero". However, a systematic approach that understands risks, knowledge of damage mechanisms, and possible failure modes (i.e. general thinning, pitting, cracking) can greatly improve equipment reliability and mitigate risks.