Pressure testing (hydrostatic pressure testing)

Commonly used as a pre-service integrity validation of the pipe and components by pressurizing to a level above the intended operating pressure.

A regulatory requirement for new pipe sections, to uprate existing pipe sections, and conversion from vapor to liquid service.

Destructively detects defects so they do not subsequently fail while in service.

Done by sectioning line according to terrain elevations. One or more valve sections can be included within test segment.

Allows the establishment of the real minimum strength of the pipeline and components, as opposed to the mill tensile test, which is based on a sample of pipe.

Requirements and procedures defined in regulations and industry standards.

Hydrotesting service is usually provided by a specialty contractor overseen by operating company staff.

Cathodic protection (CP) inspections and surveys

Determines the adequacy of cathodic protection voltages and currents for protecting the pipeline against corrosion and to detect areas of potentially defective coating.

Rectifier inspections are done to ensure that the rectifiers are in service and providing the required impressed current for cathodic protection.

Station tests or surveys are done to measure CP voltages at test station locations. This also includes readings taken at pipe casings under roads and railway crossings.

Various forms of close interval surveys (CIS) are taken at intervals of 2 to 10 ft along a pipeline to provide a profile...