A gas processing plant in Queensland had fourteen 3/4 in. low point drain valves on its inlet gas header scheduled for replacement during a planned shutdown. Those drain points sit on live on-plot process piping, where conventional welded reinstatement brings hot work permits, fire watch, purging and post-weld NDT into an already tightly sequenced outage. Spread across seven separate inlet gas lines, fourteen welded connections would have absorbed a disproportionate share of the available shutdown hours. The plant needed a reinstatement method qualified under the ANSI/ASME B31 piping codes that put no flame anywhere near the plant.
Our Solution
PIPESERV specified LOKRING® fittings for the gas plant — fourteen 3/4 in. couplings from the LOKRING MAS-3000 carbon steel range — to reinstate every drain connection without welding. LOKRING couplings form a permanent metal-to-metal seal by cold-forming the fitting onto the pipe with hydraulic tooling, using the system’s Elastic Strain Preload (ESP®) design, so no heat, no filler metal and no welder is involved. PIPESERV verified each location against the work pack valve tags, P&IDs and line numbers, prepared the 3/4 in. connection points to the LOKRING installation requirements, and made off each coupling with the correctly sized tooling inserts. Every completed coupling was then visually inspected for seating, engagement and alignment, and recorded on the field installation checklist for that joint.
Results
All fourteen LOKRING couplings were installed and accepted inside the planned shutdown window, with zero welds- no welding permits, no purging or flushing and no radiographic inspection.
Frequently Asked Questions
What is a LOKRING fitting and how does it seal without welding?
LOKRING® couplings are cold-formed mechanical connections. Hydraulic tooling drives the coupling body along the pipe ends, and the fitting’s Elastic Strain Preload (ESP®) design holds a permanent metal-to-metal seal against the pipe wall. No heat, filler metal or welder is involved, so the connection is made without hot work. On this job fourteen 3/4 in. couplings were installed this way.
Can LOKRING fittings be used on ASME B31 process piping?
Yes. LOKRING fittings are certified for high-pressure systems under the ANSI/ASME B31 codes and are in service in oil and gas, power generation, marine and chemical processing. The size, material and pressure class are selected against the line’s design conditions, so confirm the service conditions with PIPESERV before specifying.
Does a LOKRING installation need NDT or radiography?
No. Because nothing is welded there is no weld to radiograph, and no purging or flushing is required. Verification is a visual inspection of each completed coupling for correct seating, engagement and alignment, supported by a signed installation checklist. On this job that record was completed for all fourteen locations and retained with the shutdown quality documentation.
How much faster is a LOKRING connection than a welded one?
PIPESERV puts LOKRING installation at around ten times faster than the equivalent welded connection. On a shutdown the larger saving is usually the work that disappears alongside the weld — the hot work permit, the fire watch, the purge and the post-weld inspection — which is what frees up critical-path hours.
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