Hydrostatic Testing (HT)

• is a slow, costly, ancient and inefficient method to detect defects
• is performed when prescribed by a customer or in a material standard
• can often be replaced by Eddy Current testing
• has a low sensitivity when it comes to leak detection.

The normal testing pressure used in hydrostatic testing is 80 bar = 8 MPa, but this is naturally a function of the tube size. For larger sizes, the pressure is normally set at a maximum so that the stress in the material does not exceed 90 per cent of the guaranteed 0.2 proof stress limit. Testing at higher pressures can take place on request.

Hydrostatic testing has a low sensitivity when it comes to leak detection. The sensitivity is usually expressed in a volumetric flow and amounts for hydrostatic testing to approx. 0.1 cc/sec. Hydrostatic testing is performed when prescribed by a customer or in a material standard.
For thin-wall tubes, the method is substituted by Eddy Current testing, according to ASTM A 312, EN 10246-2 and SEP 1925.