Right first time - the German approach to quality assurance of cured in place pipe (CIPP) lining of sewers Iain A Naismith

Abstract

This paper explains the development of Quality Assurance approaches to Cured in Place Pipe (CIPP) lining for gravity and pressure sewers, evolved over past 25 years with German sewer network owners, by the not-forprofit IKT – Institute for Underground Infrastructure. It particularly highlights where publicly available reports on the findings can be accessed. In the early 2000s, at the request of sewer network owners, IKT excavated and examined sections of CIPP lined sewers, concluding that most of the abnormalities/defects observed related to installation issues and highlighting the importance of quality assurance. This led to the examination of samples from hundreds of new installations using short-term tests and the subsequent publishing of annual reports on the results of this testing. Research then extended to comparing the performance of rehabilitation and repair techniques for lateral sewers, lateral connections, manholes and pressure sewers, using test rigs at the one-to-one scale comprising sewers with simulated damage scenarios selected by the network owners. Each of these projects resulted in recommendations for application of quality assurance by sewer network owners in procurement, during installation and post installation to enable right first-time CIPP installations. The paper also highlights current international research on CIPP in larger diameter sewers being undertaken by IKT, that Water Agencies are participating in with Water Services Association of Australia.

Techniques