By Ian Clarke
Insituform Technologies Ltd deploys its pressure pipe lining system to solve no-dig contract along a country road in County Down.
Below fibre optic cables on the Portaferry Road in Newtownards, Co. Down, Northern Ireland runs a 30-year-old, cast iron, 76 mm (3 in) diameter water pipeline which, due to its maturity has suffered tuberculation and rusting of the inner and outer pipe wall.
The condition of the pipe was such that, without rehabilitation, the number of defects within the pipeline would increase. The pipeline had a number of service connections off it to the local houses and businesses which would be affected by this.
After careful consideration of the options available for the upgrading of the pipeline, client Northern Ireland Water, in association with the projects main contractor McNicholas and its design engineer Faber Maunsel, decided to utilise trenchless rehabilitation in the form of Insituform Technologies’ Thermopipe® lining system.
In all, some 2 km (1.2 miles) of the 76 mm (3 in) diameter pipeline was in need of rehabilitation.
Planning & Information
Given the location of the works on a country road, disruption to the local residents and businesses in the area was to be kept to a minimum. All stakeholders, including local residents, businesses and DRD Roads Service received notification of the installation one month prior to the start date.
During the planning stage all UK Health & Safety requirements were put into place and during the course of the works no incidents were reported.
Initial works to establish the existing state of the pipeline included:
- A sonde survey to trace the route of the host pipeline
- A CCTV survey to locate and establish measurements to service tappings and other connections which would need to be reconnected post lining
- Road Traffic Notifications and Management systems were put into place; and
- Customer Notifications and Public Relations leaflets were created and distributed across the area
This enabled the required access pits to be excavated and work areas to be created at predetermined distances along the pipe route to allow for the liner installation and the siting of the necessary generator, compressor, steam boiler and winches.
As this was an active water service pipe, arrangements had to be made for a continuous water supply using a temporary rider pipe.
In total, some 10 individual lining operations were completed during the course of the contract. The longest of these installations totaled some 250 m. Generally, one individual lining installation was completed per day. The installation works at Portaferry Road started in April 2008 and were successfully completed within a couple of weeks.
Pressure Pipe Liner
The Thermopipe system is a polyester reinforced, polyethylene structural lining system that offers major advantages for rehabilitation of pressure mains. The liner stops leakage by bridging and sealing holes and faulty joints, improves water quality, reduces social cost because of its low foot print, minimal downtime, and is a very cost effective way of extending the life of water supply infrastructure systems with its 50-year design life
The Insituform system provides an independent structural lining with an internal pressure rating of 12 bar (16 bar for 100 mm through 200 mm diameter). It’s available for pipe diameters from 60 to 300 mm. One of the system’s major advantages is the capability to rapidly install up to 300 m (1,000 linear feet) in just a few hours whilst being able to negotiate multiple bends in the host pipeline.
The system also carries several recognised approvals including:
- Certification by NSF International as complying with the requirements of NSF/ANSI Standard 61
- UK DWI Approval
- Manufactured under a Quality Management System approved to ISO 9000
Installation
The lining system is designed for rehabilitation of water mains (both raw water supply and clean water distribution) and other pressure pipe systems such as sewer pumping mains, fire water mains and industrial pressure applications. It’s supplied as a factory-folded ‘C’ shape liner, which is winched into the host pipe from a reel located at one of just two main access pits required for an installation. Once winched into place, the liner system utilises air pressure and steam to revert it to its fully round shape within the host pipe creating a jointless, leak-free lining able to carry the full pipe system internal design pressure, independent of the remaining structural strength of the host pipe. The process is simple and most installations can usually be completed within hours.
Once the installation was completed, the entire pipe was disinfected prior to a sample being taken and sent to the NI Water laboratory. The pipe was then made live and properties transferred on to the new main.
Shauna Herron, managing director of Insituform Environmental Techniques (InsitufromET) said: “We have a happy client who was pleased with the speed of the installation and the low-disruption technique selected. The close cooperation between the main contractor, McNicholas and InsituformET ensured a successful outcome of the project.”
Author’s Note:
Ian Clarke is a principal with NoDig Media Services, of Crewkerne, Somerset, UK, which prepared this article on behalf of Insituform Environmental Techniques Ltd., of Lisburn, Co. Antrim, Ireland. InsituformET is a subsidiary of Insituform Technologies, Inc., a leading worldwide provider of proprietary technologies and services for rehabilitating sewer, water and other underground piping systems without digging or disruption. Contact: +44 (0)2892 673111 or www.insituform.co.uk
