Meeting API 618 minimum requirements produces a compliant report. It does not guarantee a system that performs reliably in service. The difference is analytical depth, experience, and engineering judgment.
API 11P governs packaged reciprocating compressors for production service and references API 618 for pulsation analysis. The 3rd Edition revision underway will update requirements for skid design and documentation.
API 618 governs reciprocating compressors. API 688 covers all positive displacement machinery. API 674 governs reciprocating pumps. Understanding which standard applies to your equipment determines your analysis obligations.
Dynamic loading evaluation is required by ASME B31.3 — not optional. Small-bore fatigue assessment is required. These are the most common compliance gaps in compressor piping stress analyses.
API 618 5th Edition introduced mandatory vessel dynamic analysis that was not explicitly required under the 4th Edition. Projects budgeted on 4th Edition scope will be underfunded for new work.