Pressure control
API 6A PSL 1 vs 2 vs 3 vs 3G vs 4 — Differences Explained | Riis Energy Services
Ingrid Solheim, Chief Engineer, Pressure Control · Publisert · Oppdatert
Kort svar
API 6A Product Specification Levels (PSL 1 to 4) define increasing requirements for material testing, NDE, traceability and pressure testing. PSL 3G adds a gas test on top of PSL 3. Higher PSLs are chosen for higher pressure, sour service, gas wells and wells close to people or the environment.
What PSL controls
PSL does not change the pressure rating. It changes how much the manufacturer must test and document: material qualification, hardness testing, volumetric NDE, traceability and the hydrostatic test holding periods.
Quick comparison
| PSL | Typical use | Key additions |
|---|---|---|
| 1 | Low-pressure, sweet, remote wells | Baseline requirements |
| 2 | General production | More NDE, traceability by job lot |
| 3 | High pressure, sour service | Full traceability, volumetric NDE, extended test holds |
| 3G | Gas wells | PSL 3 plus gas test |
| 4 | Critical HPHT or high-consequence wells | Strictest material and NDE requirements |
How to choose
API 6A Annex A gives a decision tree based on pressure, H2S content, gas/oil and proximity. Many operators also set a minimum PSL in their own specifications.