API 598 Test Pressure Quick Chart by Class
Technical reference · Supreme Valves India · Updated 2026-10-28
Direct answer: Under API 598 practice, shell (body) hydrostatic tests are typically about 1.5× the 100°F (38°C) rated pressure, and seat tests about 1.1×, with details by valve type and leakage class. Use the class rating from ASME B16.34 material groups — then confirm exact bar/psi on the ITP.
| ASME Class | Buyer note for RFQ |
|---|---|
| 150 | Most common process RFQs — state API 598 shell + seat on PO |
| 300 | Higher shell/seat pressures — witness points often added |
| 600 | Confirm packing/backseat tests if specified |
| 800 (forged) | API 602 valves still commonly tested to API 598 |
| 1500 / 2500 | High pressure — align test media and safety with procedure |
For numerical charts see valve testing pressure chart. PN valves often reference EN 12266 — do not mix acceptance criteria without stating the standard.
What to write on the RFQ
- Test standard: API 598 (or EN 12266)
- Shell + seat required
- Witness / TPI hold points
- Low-pressure air seat test if specified
Frequently asked questions
Is 1.5× / 1.1× always exact?
They are the familiar API 598 relationships buyers use for planning. Exact pressures depend on class, material group and the edition — put numbers on the ITP from the standard.
Does fire-safe testing replace API 598?
No. API 607 / fire-safe is a separate protocol. Most hydrocarbon balls need both soft-seat hydro/air testing and fire-safe design/test as specified.
Where is the full numeric chart?
See our valve testing pressure chart technical resource for tabulated values.
All technical resources · Request valve RFQ
Confirm governing values against the current standard edition and the approved datasheet for each order.