Inspection and Testing

After the pipe is welded, the weld must be tested to ensure it will withstand the immense pressures of its operating life, and is then coated to protect it from corrosion. Below is Oceaneering's mobile Automatic Ultrasound Testing van, operated by Alan Still and his crew.

This travelling head contains multiple ultrasound transducers which can see into the weld and surrounding metal seeking porosity, inclusions and any other flaws. You can just see the last welding crew a couple of butts ahead, thats how immediate the process can be.

 

The welds on tie-ins, usually down a hole in the ground, are still done the oldfashioned way, with radiography.

Setting up the marker tape and film

Everthing ready. Time to go......Quickly....

The line has been pressure tested from Exedown to the AGI here at Hadlow, and then "pigged" to clear water and debris from the pipe. Here the pigtrap has been cut off and compressed air is used to blow the pigs out of the trap.

This is Alan Still watching the output from the AUT in real time, and also recording the details of the weld at the same time. The advantage of this method over the old Radiography (bombing) is that the result is instant, no trips to the darkroom and waiting for X-ray films to dry, Any fault detected can be repaired before the welders have disappeared over the hill.

The "Bomb" is carefully carried down into the trench to radiograph the last tie-in weld at the top of Exedown.

 

 

Align the bomb itself.

Although the  whole pipeline is pressure tested during its final commissioning, sections such as this destined to be pulled into a bore under the road and railway are individually pressure tested and cleaned.

Two pigs come out easy, but the third needs an extra blast.

The pipe just patiently waits.