Under Pressure: Trenchless Renewal Solutions for Pressure Pipelines

Abstract

This paper examines Australia’s looming ‘infrastructure cliff’ – the challenge posed by ageing water pipelines and the urgent need for sustainable, cost-effective renewals. As much of the nation’s water infrastructure nears the end of its lifecycle, traditional dig-and-replace methods are increasingly unsustainable. The paper advocates for proactive, trenchless renewal technologies tailored to the unique challenges of pressure pipelines, balancing innovation, established methods, and local conditions. It explores the critical importance of comprehensive condition assessments to identify pipeline failure mechanisms and guide technology selection. The structural classification of liners (per ISO 11295) is explained, emphasising distinctions between fully structural, semistructural, and protective solutions. Key trenchless technologies, including cured-in-place pipe (CIPP), melt-in-place pipe (MIPP), spray-in-place pipe (SIPP), die-reduced polyethylene, fold-and-form, flexible fabric reinforced pipe (FFRP), and flexible reinforced plastic hose (FRPH), are described, with detailed discussion of their strengths, limitations, and appropriate applications. The paper also addresses the complexity of technology selection, considering service life, operating regime, pipe size, alignment, fittings, and cost. Special attention is given to the nuances of liner bonding and the structural performance of different technologies in defective pipes. The conclusion highlights the need for collaborative approaches between utilities and delivery partners, incentive structures for innovation, and holistic renewal strategies to overcome barriers to implementation. Ultimately, the work provides a practical framework for matching renewal technologies to real-world pipeline issues, ensuring the resilience of Australia’s water infrastructure. 1 No-Dig Down Under 2025 Under pressure: Trenchless renewal solutions for pressure pipelines Will Zillmann