35% REDUCTION IN
EXPANSION JOINT COUNT BY PIPELINE OPTMISATION

Iceland’s capital is a global pioneer in harnessing geothermal energy, extensively using it to provide sustainable and efficient district heating with minimal environmental impact. As part of a new district heating project in the city, a critical pipeline section was planned with operating temperatures reaching 95°C at 12 barg and installation temperatures around 8°C.

CLIENT ISSUE
The client needed expert guidance on selecting and positioning onestep (single-use) Expansion Joints, which play an essential role during the network’s initial start-up by absorbing thermal expansion and protecting the pipework from stress.

These Expansion Joints were to be welded at 55°C to fix their length, with further expansion managed by cushions and the natural flexibility of the system layout.

Complicating matters further, parts of the network had to cross a high-traffic area, where trenchless installation methods needed to be employed to avoid surface disruption. This meant installing two 54-metre pipe segments inside buried casing pipes, which left the inner pipes unrestrained by the surrounding soil along their full length, introducing potential stability risks under thermal and pressure loads.

Given these factors, the client engaged Belman Design to provide specialised engineering support focused on optimising the Expansion Joint arrangement and addressing the stability considerations of the pipeline section.

BELMAN DESIGN SOLUTION

Achieving 35% fewer Expansion Joints with targeted optimisation

A key focus was striking the right balance between single-use Expansion Joints and expansion cushions, providing the necessary thermal flexibility while avoiding overstress in the system. To address the critical unsupported segments, Belman Design performed detailed structural simulations to evaluate buckling risks. These analyses guided the strategic placement of expansion elements and confirmed that the long, unrestrained-by-soil sections would remain stable under combined thermal and pressure loads. In parallel, we worked to standardise connection types by prioritizing Type A fittings wherever technically feasible, simplifying procurement and reducing lead times without compromising design integrity. At the client’s request, a second design iteration followed, achieving a 35% reduction in the number of onestep Expansion Joints. This optimisation was made possible by extending the length and reinforcing the layering of the expansion cushions, enhancing their capacity while fully maintaining safety margins and functional reliability, even in the most space constrained sections of the network.