An air cooled heat exchanger at a PNG oil and gas facility developed severe tube degradation due to erosion corrosion at the tube-sheet region, resulting in up to 50% wall loss. The extent of the damage ruled out conventional repair methods — hammer-in and welded plugs were impractical given the compromised tube wall, and would have required specialist welders, hot work permits, and risked causing stress and structural damage to the tubesheet. A reliable, code-compliant solution was needed that could accommodate significant wall loss without introducing further risk to the unit or extending downtime.
Our Solution
Pipeserv recommended the EST Pop-A-Plug® mechanical tube plugging system, a solution compliant with ASME PCC-2 and well suited to tubes with compromised wall thickness. The application involved carbon steel tubes with an OD of 25.4mm and a wall thickness of 2.11mm. Prior to plug installation, preparation brushes included in the Pop-A-Plug kit were used to hone out the pitted defect areas, eliminating potential leak paths caused by erosion corrosion. The plugs were then installed within the tube-sheet area, permanently sealing the affected tubes. The mechanical installation process required no welding, no hot work permits, and no specialist trade labour.
Results
The air cooled heat exchanger tube plugging program at the PNG site was completed successfully, with the customer reporting very significant cost savings as a direct outcome. Each plug was installed in an average of just two minutes, dramatically reducing unit downtime compared to traditional welded plug methods. No weld permits or specialist welders were required, simplifying site logistics and eliminating associated delays. Following the successful repair, Pipeserv implemented H.E.A.T (Heat Exchanger Analysis Tool) onsite – an asset register to monitor and manage all heat exchanger units going forward.
Frequently Asked Questions
How does the Pop-A-Plug system provide such a seamless installation in Air cooled Heat Exchangers?
The Pop-A-Plug system has been specifically engineered to install plugs through deep header boxes. Extended pull rods, Go/No-Go gauges, preparation brushes and extension tooling allow technicians to prepare, test and install plugs at depth from the plug sheet entrance. The plug is correctly installed when the breakaway section “pops,” providing instant confirmation of a successful installation without guesswork
Will the plug remain reliable under high pressure and thermal cycling?
Yes. Pop-A-Plugs feature patented internally serrated sealing rings that create a permanent metal-to-metal seal designed to remain helium leak-tight during repeated thermal expansion and pressure cycling. The system has been successfully used in ACHE applications for over 20 years, with pressure ratings up to 560 bar.
Does installing a Pop-A-Plug damage the heat exchanger tube?
No. When the tube is correctly prepared, the Pop-A-Plug installs without damaging the tube or tube-to-tubesheet joint. Should future maintenance be required, the plug can also be removed using the dedicated EST extended removal tooling, preserving the integrity of the heat exchanger.
Are there references to what LNG plants use Pop-A-Plugs in Oceania?
Pop-A-Plugs have been successfully deployed across the major LNG facilities throughout Australia and Papua New Guinea, including QCLNG, APLNG, GLNG, Gorgon, Wheatstone, Ichthys, North West Shelf, Pluto, Darwin LNG, Prelude FLNG and PNG LNG. Their proven reliability and rapid, hot work-free installation have made them a preferred solution for permanent heat exchanger tube repairs during shutdowns and maintenance campaigns.
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