1 April 2025, Putra Heights, Selangor

On the second day of Eid, a peaceful residential morning was violently interrupted when a high-pressure gas pipeline ruptured underground. More than two hundred homes and vehicles were damaged, and many residents were forced to evacuate.

Early investigations confirmed no sabotage was involved. The pipeline had been operated under established safety protocols. Still, the incident has prompted deeper reflection within the engineering community. What can we learn from this, and how should we better understand the complex behaviour of buried infrastructure?

Beneath the surface: A case of ground movement

The affected section of the pipeline runs through a unique valley corridor, bordered by a steep hill on the southern flank and gently rising ground to the north. A natural stream, now converted into a monsoon drain, crosses the right of way before discharging into the Klang River to the east. Beneath the valley floor lies a thick deposit of soft, saturated alluvial clay, a type of ground that is prone to gradual compression and long-term settlement when disturbed or loaded.

The official reports referred to the incident as being influenced by anthropogenic factors, a term used in geology to describe changes in ground conditions linked to surrounding land use and surface modifications. In engineering terms, the changes observed here are consistent with the process of consolidation, the gradual squeezing out of water from clay layers when subjected to increased load or altered drainage conditions.

A simple way to picture this is to think of a wet sponge. When you place a weight on it, water seeps out slowly and the sponge becomes thinner. In clay, this water movement happens over months or even years, causing the ground to sink. The settlement is rarely uniform, and in a valley like Putra Heights it can produce a broad, shallow bowl-shaped depression.

For a buried pipeline, this means that some sections remain on relatively stable ground while others pass over softer deposits that settle more. The difference in movement bends and stretches the pipe. Even slow, small changes can gradually consume the pipe’s remaining safety margin, especially when combined with internal pressure, temperature changes, and the frictional bond between pipe coatings and surrounding soil.

Built strong, but less forgiving

Interestingly, the ruptured pipeline was the newest of three lines laid in parallel, built with thicker walls, high-grade steel, and advanced protective coatings. Despite its strength, several factors may have made it more vulnerable in this setting.

First, being the middle line, it was likely positioned over the thickest part of the alluvial deposit, where settlement over time would be greatest.

Second, its larger diameter meant that bending strains were higher along its outer surface, placing greater demand on welded joints and making them more prone to peeling or fracture.

Third, the older lines may have benefited from refurbishment or joint maintenance over the years, giving them additional resilience.

Finally, modern three-layer polyethylene (3LPE) coatings, while excellent for corrosion protection, bond more firmly to surrounding soil than older fusion bonded epoxy (FBE) coatings, increasing the frictional grip and the transfer of ground movement forces directly into the pipe.

Tools for seeing what lies below

Malaysia’s gas transmission infrastructure is governed by internationally recognised design codes, including ASME and API, and is subject to oversight by national safety authorities. The system has been affirmed to be safe and compliant, with ongoing reviews and upgrades continuously reinforcing operational reliability.

At the same time, industry stakeholders and technical experts are exploring forward-looking improvements to pipeline standards, regulatory practices, and monitoring technologies. This includes work on enhancing provisions in ASME B31.4 and B31.8, refining DOSH-related guidelines and EIA procedures, and adopting digital tools for integrity-based management of onshore pipelines.

Today, engineers have access to a wide range of technologies to better understand subsurface conditions and pipe behaviour. These include:

• Magnetic flux leakage and axial strain inspection

• Ultrasonic guided wave sensors

• Inertial mapping systems

• Distributed fibre optic and acoustic sensing

When integrated into a coordinated monitoring strategy, these tools can provide early detection of strain accumulation, ground movement, and pipe-soil interaction effects, particularly in environments with soft ground, long-term settlement, or historical disturbance.

Coordinating what lies below

Events like this remind us that what lies beneath is just as important as what we build above. Yet, data on buried utilities, borehole profiles, and subsurface risk often remains scattered between agencies and projects.

Malaysia may benefit from establishing a National Underground Infrastructure Commission, a central body responsible for:

• Consolidating subsurface data, including utilities and geotechnical records

• Coordinating excavation planning and development approvals

• Advising on long-term risk zones and mitigation strategies

• Enabling cross-agency collaboration in managing the underground environment

Countries such as Singapore, the United Kingdom and the Netherlands have implemented similar frameworks with measurable success. Such a commission could enhance safety, reduce accidental damage, and support smart infrastructure growth.

In parallel, there is merit in reviewing planning approval procedures and updating development policies to better account for climate related risks, particularly in areas surrounding gas pipeline Right-of-Way zones.

Conclusion: Understanding what lies beneath

The Putra Heights tragedy reminds us that infrastructure failures are not always sudden. Sometimes, they are the product of slow, silent forces building up over time. Understanding these forces and how they interact with infrastructure is a fundamental responsibility for the engineering profession.

By deepening our insight into ground-pipe interaction, integrating modern sensing technologies, and improving coordination of underground systems, we can reduce future risks and strengthen the safety of what lies beneath.

-- BERNAMA

Prof Ir Dr Hisham Mohamad is Chair of Civil & Environmental Engineering Department, Universiti Teknologi PETRONAS.