A corroded section of cast iron pipe the size of a tissue box in Sydney’s northern beaches is to blame for the flooding of a mansion-dotted hillside and a sinkhole that caused part of the road to collapse and a fire truck to crash.
Ninemsn reported that Sydney Water confirmed that a cement-lined water main running through The Serpentine gave way due to a minor defect in the pipe's protective coating.
They said investigators had found a corrosive patch measuring 20cm by 10cm, slightly smaller than the size of a standard tissue box.
As a result of the defect, the pipe became corroded by soil, causing a section of it to break away.
Both here and overseas, several cases have been reported where ground surface collapsed leading to sinkholes near aging pipes prone to corrosion. Factors causing pipe deterioration and the effect of corrosion pits on the structural performance of pipes have been investigated by several researchers with emphasis on cast iron pipes. It was concluded that corrosion was the main factor influencing pipe deterioration. Cracks initiated at corrosion pits lead to progressive circumferential and longitudinal cracks in addition to blown-out holes.
Unlike metal piping, PVC pipe won't rust or corrode over time because it does not react with air and water the way metal does, which results in a significantly longer lifetime of the pipe.
Consequently, PVC pipe is the most cost effective and sustainable solution in applications where soil is aggressive. PVC pipe can be expected to outlast alternative pipes without the need for protective coatings or liners. PVC pipe is a proven and extremely durable alternative to traditional corrosion prone pipe materials.
Recognised by state, national and international agencies and standards organisations, it has been a benchmark since it was introduced in the sewer, water and drainage markets.