Outer diameter, wall thickness, and length must meet specified limits.

Tensile test, flattening test, bending test (for pipes ≤DN50 mm), and hydrostatic test (or non-destructive testing).

No cracks, laps, or harmful defects. Galvanized pipes must have a continuous, adherent zinc layer.

Test pressure = 5 MPa (or 2.5 MPa for galvanized pipes); held for ≥5 sec without leakage.

Alternative to hydrostatic testing; methods include eddy current or ultrasonic testing.

GB/T 3091-2015 replaces the 2008 version, with updates to:

Widely used in construction, plumbing, firefighting, and low-pressure gas/water supply systems.