Whirlwind Utilities Ltd has developed a process to remove tubercles and otherdeposits from the internal pipe walls of potable water mains prior to relining.Tubercles form as the result of corrosion inside cast water mains and consist oflayers of corrosion product (rust), building up over time to form lumps and moundsover local areas of metal loss.Tubercles can severely reduce the internal bore of pipes, leading to reduced flow anddiscolouration, affecting both the quality and supply of water to the customer