In a project to renew a 24” cast water main in Plymouth for South West Water, Brent Ltd used a pipe pushing machine manufactured by Steve Vick International to insert, in one push, half a kilometre of 400mm diameter PE pipe weighing a total of 22.5 tonnes. The operation was part of an ongoing 2.5 km mains renewal contract.
South West Water and Brent have formed an integrated partnership to undertake repair, maintenance and rehabilitation work on the water distribution system in the city. This is a result of the strategy drawn up by the water company to assess water quality compared with specific thresholds and to identify those trunk mains and distribution mains that require attention.
Iron from corroding cast iron water mains is the main reason for nonconformity. For this reason, part of the Mannamead Road 15” cast iron water main was identified as contributing to water quality problems within the Plymouth system.
The large number of properties supplied from the 15” main made it impractical to isolate it for rehabilitation. Brent therefore proposed sliplining an existing 24” main which ran parallel to the 15” main with 400mm SDR11 ProFuse pipe supplied by Uponor Ltd.
The work in Plymouth is being undertaken in three phases and will rehabilitate approximately 2,500 metres of water main. Once the sliplined main is commissioned the existing cross connections will be transferred from the old 15” main.
Steve Vick International supplied Brent with a 500mm hydraulic pipe pushing machine capable of inserting pipe at up to 4 metres per minute. The machine, which measures just 1200mm by 800mm allows long sections to be sliplined in one operation.
Paul Morris of Brent says “I am very impressed by the performance of this machine bearing in mind that each 12 metre length of ProFuse weighs over 500 kg. In one operation it pushed 44 lengths of pipe – a total distance of 533 metres – overcoming any frictional resistance due to bends in the main. The total weight of the pipe pushed in this section equalled 22.5 tonnes!”
Steve Vick International manufactures a range of pipe pushing machines ranging from small manual machines for handling services to a pneumatic model for pushing 40mm to 125mm diameter pipe. Larger hydraulic machines are available for handling pipe up to 500mm diameter although even larger models can be made to special order. Each machine can be adjusted with shells to take different pipe diameters.
A spokesman for Steve Vick says, “To our knowledge, this is the first time our pushing machines have been used to handle ProFuse. This PE pipe, made by Uponor, has an outer cover offering protection against external damage and weathering during storage and handling. The peelable cover meant that we had to make adjustments to the clamping force of our pushing machine to allow the jaws to grip the hard surface of the covered pipe.”
To put into perspective the impact on the Plymouth distribution system of this renewal programme, it should be noted that the 15” main is involved in supplies to over 25,000 properties and also has an important role in providing back-up support for the 26” Crownhill system.
Date published – 12th July 2007