Affinity Water – Cleaning 7km of Trunk Main Ahead of HS2 Flow Reversal

Ice Pigging helps Affinity Water prepare a major trunk main for flow reversal with minimal disruption and no reported water quality issues.

As part of infrastructure changes required to accommodate the construction of HS2, Affinity Water needed to reverse the flow of a DN450 ductile iron trunk main running from Perivale along the A40. With maintaining water quality a key priority, the network needed to be thoroughly cleaned beforehand to minimise the risk of sediment disturbance and discolouration.

Working at night to minimise disruption, SUEZ divided the trunk main into manageable sections, allowing each to be taken out of service for only a few hours at a time. In total, 7,250 metres of pipework were cleaned in under 49 hours, with an average of 170.57kg of sediment removed per kilometre. The process also saved an estimated 4,781m³ of water compared with traditional cleaning methods.

Following completion of the Ice Pigging programme, Affinity Water successfully reversed the flow and commissioned its new supply without any reported water quality issues or discolouration.