Before the test
- Test package approved with marked-up isos and limits
- Test pressure = 1.5 × design × (Sa/Sd), per Para. 345.4.2
- All welds visible (no insulation, no painting on welds)
- Calibrated pressure gauges (range ~1.5–4× test P), dead-weight or master gauge available
- Test medium quality: potable water, chloride limit for SS (typ. <50 ppm)
- PSVs, control valves, instruments, orifice plates removed or isolated
- Vents at high points and drains at low points fitted
- Temporary supports for water weight verified
During the test
- Fill from the lowest point, vent all air
- Pressurise in stages (e.g. 25 / 50 / 100 %), hold and inspect at each stage
- Hold at test pressure for the specified period (commonly ≥ 10 min, then leak inspection at design pressure)
- Walk the line; no leaks, no permanent deformation
Reinstatement
- Drain completely (especially SS — chloride concentration on drying)
- Reinstall PSVs, control valves, orifice plates, instruments with correct gaskets
- Torque flanges per project bolting procedure
- Update test pack, punch list and as-built isos
- Hand over for N2 purge / dry-out / commissioning
Key references
- · ASME B31.3 Chapter VI
- · ASME PCC-2 (repairs)
Use of this content
This page is a decision-support and training reference. It is not a substitute for the governing code, the project specification, or the judgement of a responsible engineer. Always validate against the current edition of the applicable standard before use on live engineering work.