Project Appreciation and Objectives
Transferring private sewers and lateral drains to Sewerage Undertakers in 2011 will increase the sewerage lengths owned by 70-100%. A proportion of these pipes are constructed from pitch fibre, which, according to Defra (2003), only have a 40 year design life expectancy - which many pipes have now exceeded.
A recent Portfolio project estimated that > 65,000 km of pitch fibre pipes were manufactured for use in the UK with "hot spots" identified in the South and West of England, East Anglia, South Wales, Lancashire, West Yorkshire, Northern Ireland and Scotland. Asbestos was found in all pitch fibre samples taken, 11% containing the more dangerous form, Amosite (brown asbestos); which requires licensed disposal. Cured-in-place (CIPP) linings within these pipes showed up to a 65%
reduction in flexural modulus due to organic chemicals within the pitch.
This project will identify the best ways of managing legal, operational and technical aspects of pitch fibre pipes:
- conducting comprehensive test programmes on causes of reduction in flexural modulus of CIPP linings and reviewing methods of renovation;
- updating the UK pitch fibre pipe location map and database of failure modes; and
- reviewing the UK regulations for asbestos and available methods for renovating pitch fibre pipes.
Benefits to Clients
- Identify the geographic location of pitch fibre pipes and understand the scale of the problem.
- Be prepared for the risk and regulatory implications of ownership, repair and replacement arising from presence of asbestos fibres in pitch fibre pipes.
- Understand the detrimental effects of the pitch fibre on CIPP linings and allow the most appropriate technical options.
- 1. Confirm objectives and finalise work programme at initial meeting.
- Conduct comprehensive CIPP lining trials within pitch fibre pipes to investigate the influence of linings on CIPP mechanical properties.
- Perform comprehensive review of current UK asbestos legislation relating to responsibility, handling, disposal and duty of care in relation to pitch fibre.
- Identify newly available renovation methods including structural design guidance.
- Collect pitch fibre location data and pipe samples and update the existing location map and failure mode database.
- Inception report.
- Interim, draft and final project report.
- Dissemination workshop.
- How to Solve the Pitch Fibre Pipe Problem, CP275, 2006.
- The Drain Repair Book, 2 Edition, 2005.
- Managing the risks presented by pipeburst, redundant and live asbestos cement water distribution mains, 2004.