Corrosion caused burst pipes: PUB
It will check all water pipes in Bukit Batok
National water agency PUB is checking all 100km of water pipes in Bukit Batok after initial observations found that corrosion caused two water pipes there to burst in the span of less than a week.
Investigations into the incidents are ongoing, added PUB on Wednesday (Oct 4), even as it looks to speed up a project to renew old water pipes islandwide.
On Sept 26 and Oct 1, pipes burst at Bukit Batok West and Bukit Batok East respectively. Water spouts rose several storeys and caused localised flooding.
Mr Michael Toh, director of PUB's Water Supply (Network) Department, told reporters during a site visit to Bukit Batok that both pipes were laid in the 1980s when Bukit Batok New Town was being developed.
The pipe that burst at Bukit Batok West was a 700mm-diameter high-pressure steel pipe and supplied water to the whole of Bukit Batok estate. The one at Bukit Batok East was a smaller 150mm ductile iron distribution pipe.
Starting later this week, PUB will replace 170m of pipeline within the Bukit Batok Street 21 area, which includes Blocks 222 and 223, where the most recent incident occurred.
The works are expected to be completed by the end of the year.
PUB will also examine the condition of the old pipes that will be dug out in Street 21 before deciding whether to step up the frequency of inspections elsewhere in the estate.
(PUB) has an excellent and responsible response team that is the envy of many other places.Associate Professor Tan Soon Keat of the National University of Singapore's School of Civil and Environmental Engineering
Mr Toh said the pipes in the estate were checked in January, in accordance with PUB's practice of checking all pipes in Singapore at least once a year.
He said that although the two recent leaks in Bukit Batok were quickly detected, water continued spouting for a while because the agency was rerouting water from other pipelines to ensure an uninterrupted supply to customers.
In response to additional queries, a PUB spokesman said pipe leaks could also be caused by wear and tear, damage from other works in the area, soil settlement and pipe corrosion due to high water table or high salinity in the soil.
Singapore experiences about six leaks per 100km of pipes a year. Around 5 per cent of the water supply is "unaccounted for" - lost through events such as leakage, firefighting and maintenance.
This beats many other developed cities - according to a report by the Smart Water Networks Forum, unaccounted-for water in 2011 stood at 25 per cent in Hong Kong and 28 per cent in London.
Associate Professor Tan Soon Keat of the National University of Singapore's School of Civil and Environmental Engineering, said zero pipe leak or burst incidents is not possible and detecting them has always been a challenge.
"(PUB) has an excellent and responsible response team that is the envy of many other places," said Prof Tan.
PUB is looking into acoustic technology that would enable the agency to identify worn-out pipes with thinning walls that could be on the verge of springing leaks.
Last year, it renewed 20km of pipelines. It said it would accelerate the programme and aims to renew an additional 125km of its 5,500km of potable water pipes by 2019. - ADDITIONAL REPORTING BY TAN TAM MEI