Valve Hydrotest Pressure Calculator
API 598 shell, seat, and backseat test pressures — with test duration guidance
Valve Parameters
Shell test: API 598 Cl. 5.1 — 1.5 × MAWP, all joints visible, zero leakage
Seat test (liquid): API 598 Cl. 6.1 — 1.1 × MAWP, metal seat ≤ Class IV; soft seat = Class VI
Seat test (gas): API 598 Table 2 — 0.7 MPa (7 bar) or full rated pressure, as specified
Backseat: API 598 Cl. 6.4 — gate/globe only — stem packing zero leakage
Indicative values per ASME B16.34-2017 and API 598 (10th Ed.). Verify against current editions and purchase specification.
MAWP shown is for the valve body at 38°C — actual allowable pressure decreases at elevated temperatures.
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We supply Class 300 valves with API 598 hydrostatic testing and certificates as standard — quoted in 24 hours.
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