Pipe Lining

Pipe Lining

Christchurch was a limited user of pipe lining for underground pipe repairs but that changed after the earthquakes because of the efficiency and cost-effectiveness of this well-established type of trenchless technology.

Christchurch had been a limited user of the trenchless technology of pipe lining to repair underground pipe networks before the 2010 and 2011 earthquakes.

However, with pipe network repairs needed on a massive scale, the financial benefits offered by the 'no dig' pipe lining technology were compelling.

Stronger Christchurch Infrastructure Rebuild Team (SCIRT) Executive General Manager Ian Campbell said pipe lining offered estimated savings of 30% over digging trenches and relaying new pipes.

The technology was faster, substantially less expensive and much less disruptive to residential areas. It avoided having to dig trenches, sheet pile and stabilise trenches, and set up traffic management systems.

Importantly, it had been proven internationally, established as an accepted method of rehabilitating damaged pipes for several decades and was readily available.

Essentially, pipe lining is the insertion of a new plastic pipe within a damaged host using various techniques.

In the SCIRT programme, just over a quarter of the earthquake-damaged wastewater and storm water main lines were repaired using pipe lining techniques.

For Christchurch the challenges were in training contractors to use the technology well. The most used methods were the Cured-in-Place-Pipe method, Spiral Wound PVC and Folded PVC.

SCIRT developed a detailed specification which referenced international standards to guide contractors through the process and to ensure a quality result. The specification can be used widely in New Zealand.

A YouTube video about pipe lining in the Christchurch seaside suburb of New Brighton is available here: https://www.youtube.com/watch?v=EwC_cjDzfEk

Glossary terms:

  • CIPP: Cured-In-Place-Pipe