Hot Bolting On A Live Gas Pipeline: Critical Bolts Replaced, Line Never Stopped

Client

Live Flange Maintenance, Kopi

Location

Kopi, Gulf Province, Papua New Guinea

SCope of Work

CASE STUDY · PIPELINES & INTEGRITY · 2025

Live System under pressure	0 Shutdown hours, zero LTI	100% Bolts replaced to spec	1 Bolt at a time

Capability
Pipelines & Integrity

Sector
Petrochemical

Live flange maintenance and bolt replacement on a live gas pipeline at Kopi, Gulf Province, replacing critical flange bolts one at a time, at pressure, without shutting down operations or flaring.

Scope

Site-specific risk assessment, isolation review, and permit-to-work before tooling reached the flange.
Sequential one-at-a-time replacement of flange bolting on the live system, with joint integrity retained throughout.
Calibrated hydraulic tensioning of each new bolt to specified residual stress.
Inspection sign-off with torque records, photographs, and a completed handover pack on demobilisation.

Approach

Hot bolting means working a live, pressurised gas pipeline. Every bolt change is a controlled, single-fastener evolution with the rest of the flange holding the line. By changing one bolt at a time, joint integrity is maintained throughout the campaign: the flange stays structurally intact, the pipeline keeps operating at pressure, and the client avoids the cost and disruption of a full shutdown. At remote Kopi in Gulf Province, the MTIS field crew worked methodically through each flange, isolating, tensioning, and verifying every bolt to specification, with each step supervised, documented, and signed off to procedure.

Corroded flange bolts on a live gas pipeline before MTIS hot bolting works in Kopi PNG

Before: corroded carbon-steel flange bolting on the live line, degraded by years of service in a humid jungle-coastal environment.

Gas pipeline flange after MTIS live bolt replacement and flange maintenance in Kopi PNG

After: replacement bolting installed, tensioned to specification, and inspected. The line never came off pressure.

MTIS crew using hydraulic tensioning equipment for live flange maintenance on a gas pipeline in PNG

In progress: field crew working a flange with the hydraulic tensioning pump unit, one bolt at a time.

Kopi gas pipeline site in Papua New Guinea showing live flange maintenance access conditions

Kopi, Gulf Province: a remote site accessed by light aircraft and river, with crews and tooling mobilised in-country.

Outcome

The campaign was completed without incident, with zero LTI. Joint integrity was restored, the pipeline never came off pressure, and the asset returned to its operator with full documentation and a clean handover. The client recognised MTIS Group’s competency to deliver the work safely and on time.

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