Duration of test pressure for welded pipes of different diameters
For each size of SML pipe and welded pipes with D≤457 mm (18 inches), the test pressure shall be maintained for a specified time. For welded pipes with D>457 mm (18 inches), there are also corresponding test pressure maintenance time requirements.
Test conditions for threaded pipes
For threaded pipes, if agreed by both parties, the test shall be carried out on dynamically sealed joints, but pipes with D>323 mm (9 inches) may be tested in plain end conditions. For threaded pipes with sealed joints, if not specifically specified in the purchase order, the pipes shall be hydrostatically tested in plain end, threaded only or connected state.
Test records and calibration of pressure measuring devices
To ensure that each pipe is tested to the specified test pressure, in addition to the specific tester, each tester shall be equipped with a recorder that can record the test pressure and duration of each pipe, or have an active, automatic or interlocking device that prevents the pipe from being classified as tested before the test requirements (pressure and duration) are met. The relevant records or charts shall be available for inspection by the buyer's inspector at the manufacturer's factory. The test pressure measuring device shall be calibrated not earlier than four months before each use using a deadweight tester or equivalent device, and the manufacturer may choose to use a test pressure higher than required.
