Hydro Power Station Pipe Repair

Location: Near Inverness, Scottish Highlands

Application: Hydro-electric water pipeline

Product: VIP-WECO Repair Seals

Installer: JM Contracting

Project Partner: Fusion Pipe Products

The Challenge

A hydro-electric water pipeline near Inverness in the Scottish Highlands required urgent sealing work after several joints failed to meet the required pressure standard.

The 1.5km pipeline carries water from a river to a power generator as part of a 1.35MW hydro power scheme. During testing, joints at eight locations along the pipe were found to be leaking and unable to hold the required hydrostatic test pressure of 12 bar.

The pipe had been designed to operate at a working pressure of 1.5 bar, but the defective joints created a risk to the commissioning of the wider hydro power project.

Excavation would have been time-consuming, costly and disruptive. The failed joints were located along a 100 metre stretch of pipe, beginning around 80 metres from the entry point, meaning any repair system had to be quick to install, practical to move through the pipe, and capable of delivering a reliable long-term seal.

The Solution

VIP-Polymers supplied its VIP-WECO internal pipe seals to repair the leaking joints without the need for excavation.

The VIP-WECO system uses a rubber sealing sleeve, manufactured from EPDM or NBR compounds, which is positioned against the internal wall of the pipe and mechanically held in place using stainless steel retaining bands. This creates a durable internal seal without the need to dig down to the affected pipe sections.

Seven standard VIP-WECO seals were selected for the project, each 280mm wide. These were installed at five locations where the pipe was 1600mm in diameter and made from GRP, and at two locations where the pipe was 1400mm in diameter and made from polyethylene.

A final bespoke seal was manufactured for the point where the pipeline stepped down from 1600mm to 1400mm, with a section of 1600mm ductile iron between the two. This reducer seal was 480mm wide and included an additional retaining band to accommodate the 200mm variance in pipe diameter.

Installation

Keeping downtime to a minimum was a key requirement for the project.

The VIP-WECO retaining bands were supplied in two sections, making them easier to transport into the pipe and move along the pipeline to each repair location.

Five seals were installed in a single day, with the quickest installation completed in just 16 minutes. Two further seals were installed the following day. The final bespoke reducer seal was installed two weeks later, in line with the client’s operational requirements.

The installation was carried out by authorised VIP-WECO installers, JM Contracting.

The Result

The VIP-WECO seals successfully repaired the leaking joints and allowed the pipeline to achieve the required pressure standard.

By using an internal no-dig repair system, the project avoided the need for excavation, reduced disruption and helped keep the hydro power commissioning programme on track.

The flexibility of the VIP-WECO system also allowed the seals to accommodate deformation within the pipe caused by settlement of the six-metre pipe sections in the trench infill.

“The flexibility of the VIP-WECO system could accommodate this deformation and still achieve the desired pressure standard with ease.  The VIP-WECO design, based on split retaining bands, allowed us to quickly traverse the pipe and install the seals, keeping operational downtime to a minimum.”

John Mitchell, Managing Director, JM Contracting

Key Project Benefits

• No-dig repair avoided costly and disruptive excavation
• Eight leaking pipe joints successfully sealed
• Suitable for GRP, polyethylene and ductile iron pipe sections
• Bespoke reducer seal manufactured for a 1600mm to 1400mm transition
• Fast installation, with the quickest seal fitted in just 16 minutes
• Helped keep the hydro power project on schedule
• Long-term internal mechanical sealing solution

Product Used: VIP-WECO Internal Pipe Repair Seal

VIP-WECO is a no-dig mechanical pipe repair system designed to seal leaking joints, cracks, infiltration points and localised defects from inside the pipeline.

The system is used worldwide across water, wastewater, gas, fuel and industrial pipeline applications. It is particularly suited to projects where excavation is not practical, where downtime must be reduced, or where a long-term internal repair is required.