1. Purpose of Hydrostatic Pressure Testing
Before any industrial piping loop, manifold, or pressure vessel spool containing Sakshi Forge flanges and pipe components is commissioned into live hydrocarbon, steam, or chemical service, it must undergo proof pressure testing. Hydrostatic pressure testing verifies structural integrity, validates joint leak-tightness, and releases residual manufacturing stresses in welds.
2. Test Pressure Calculation Formula (ASME B31.3)
Under ASME B31.3 Process Piping Code paragraph 345.4.2, the minimum hydrostatic test pressure $P_t$ at any point in a metallic piping system is calculated by:
P_t = 1.5 × P × (S_t / S)
- P_t: Minimum hydrostatic test gauge pressure (bar or PSI)
- P: Internal design pressure of the piping system
- S_t: Allowable stress of pipe/flange material at test temperature
- S: Allowable stress of pipe/flange material at maximum design temperature
Note: If S_t / S exceeds 6.5, a ratio of 6.5 is used to avoid yielding the steel.
3. Water Quality & Chloride Control for Stainless Steel
When performing hydrotests on stainless steel (SS 304, SS 316L, Duplex 2205), water quality is of paramount metallurgical importance:
| Water Parameter | Maximum Permissible Value | Risk of Non-Compliance |
|---|---|---|
| Chloride Content (Cl⁻) | < 50 ppm (Preferably < 30 ppm demineralized water) | Severe Stress Corrosion Cracking (SCC) during dry-out |
| pH Level | 6.5 to 8.5 | Acidic pitting corrosion on freshly machined flange faces |
| Water Temperature | Min 16 °C (60 °F) to prevent brittle fracture | Brittle cleavage failure in low-alloy steel fittings |
| Post-Test Draining & Drying | Complete dry-air blowdown within 4 hours | Microbiological Influenced Corrosion (MIC) from standing water |
4. Sakshi Forge Factory Hydrotest Certificate Audit
Every individual flanged manifold, electropolished spool, or custom forged body manufactured in Sakshi Forge facilities is tested on calibrated automated hydraulic test rigs. Pressure recording charts documenting a minimum 30-minute hold time with zero pressure drop are permanently attached to the EN 10204 3.1 Inspection Certificate bundle.