Pro Pipe Services was recently engaged by one of Australia’s major pipeline operators to remove two 34-Inch (DN850) Class 600 LOCK-O-RING Plugs installed over 46 years ago on the Moomba to Wilton Pipeline.
The job had many challenges associated with it including the remote location, the extreme weather with flooding and heat, and the fact the plugs were installed over 46 years ago.
Pro Pipe Services was initially engaged to install two 34-Inch (DN850) full bore ball valves, weighing approximately 14 tonne each, and to retract and remove the LOCK-O-RING Plugs through the valves to provide gas for a new compressor station.
Using a TDW 936 tapping machine, the first retrieval was completed in a matter of days, however the second plug proved to be more difficult than the first.
Some of the segments that hold the plug in place on the second LOCK-O-RING flange would not retract and after several attempts, it was decided that a line isolation was required to depressurise a section of pipe, to allow for the removal of the plug and installation of the new 34-inch ball valve.
A TDW 34-inch Class 600 STOPPLE fitting was welded onto the pipeline and Pro Pipe Services was engaged to complete the 34-inch high pressure hot tap and line isolation.
“This was a very challenging job, given the temperature at the time was around 39˚ Celsius, it was extremely hot, the equipment is very heavy, the Sandwich Valve weighs 8 Tonne, and big Cranes were required to make the lifts,” the company says.
The hot tap and line isolation were all completed safely and without any issues. The Pro Pipe Services team achieved an excellent isolation with no leak coming from the sealing element.
This then allowed the Pro Pipe Services technicians to use the TDW 936 tapping to remove the LOCK-O-RING Plug.
During the removal process, it was discovered that some of the segments holding the plug in place had possibly been damaged 46 years ago, therefore making it difficult to remove the plug the conventional way.
The team at Pro Pipe Services developed a method to safely retract the damaged segments allowing for the safe removal of the plug.
Once the plug was removed, a 34-inch gas bag was installed into the fitting to allow the technicians to overhaul and rebuild the LOCK-O-RING flange.
The flange was pressure tested and the 34-inch valve installed, the bag removed and the valve closed.
The Pro Pipe Services technicians then retracted the STOPPLE plugging machine and installed the completion plug.
Whilst there were a number of challenges associated with the job, the customer was satisfied as the project was delivered on time, safely and without any incidents.
Pro Pipe Services is proud to be an Australian owned company, utilising Australian technicians and resources to service Australia’s pipeline industry. It is also proud to be associated with the largest high pressure line isolation performed in Australia.
This article featured in the May edition of The Australian Pipeliner. Access the digital copy of the magazine here.
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