Senior Minister of State Lee Yi Shyan's reply to Parliament Questions on Gas and Water Pipelines

Questions

Dr Lim Wee Kiak: To ask the Minister for Trade and Industry in the light of the recent gas pipe explosion in Taiwan (a) what are the safety features or processes in place here to prevent a catastrophic gas pipe leak, especially in crowded areas; (b) how frequently are checks carried out to detect if there are any leaks in all the gas pipes and how are these maintenance checks carried out; (c) during the past five years, how many cases of gas leaks were detected; and (d) is there a replacement programme for old pipes and what is the age of the oldest underground gas pipe.

Er Dr Lee Bee Wah: To ask the Minister for Trade and Industry (a) what measures are in place to maintain all underground gas and water pipes in good working order; (b) what is the lifespan of these pipes before they are replaced; (c) how are underground pipes inspected; and (d) what are the safeguards to prevent leaks that can cause a serious explosion.

Oral Reply by Mr Lee Yi Shyan, Senior Minister of State for Trade and Industry

1. Ensuring the safety of our utilities infrastructure is a key priority.  EMA has put in place robust regulatory requirements, and conducts regular inspections, to ensure the reliability and safety of Singapore's gas pipelines.

2. Careful attention is paid to the planning and design of our gas network.  SP PowerGrid (SPPG), which manages Singapore’s gas network, must conduct a risk assessment and meet the requirements set by SCDF and other authorities, before constructing a pipeline.

3. All high-pressure gas pipelines are constructed using high-strength steel with anti-corrosion coating.  Pipelines on the mainland are buried at a depth of 1.5 metres on average and further protected by concrete slabs to ensure pipeline integrity.  Gas that is distributed to consumers is also odourised to facilitate detection in the event of any leak.

4. To ensure that the pipeline network remains in good working condition, SPPG carries out various surveillance and maintenance measures, as required by the Gas Transporter Licence and relevant codes of practice such as the Gas Safety Code and the Gas Supply Code.  SPPG continuously monitors pipeline pressure and flow for any anomalies.  It also surveys the pipeline network regularly for leaks using gas detectors.  Such surveys are conducted more frequently in crowded and residential areas.  For example, SPPG inspects the pipelines in the vicinity of MRT stations on a monthly basis, while non-residential areas are surveyed on an annual basis.  In addition, SPPG conducts annual mechanical inspections of critical pipeline components and inspects high-pressure pipelines using pipeline inspection gauges every 5 years, to ensure that the pipelines remain in good working conditions.  EMA conducts annual audits and enforcement checks to ensure that SPPG carries out the pipeline surveillance and maintenance processes as scheduled.

5. The service life of gas pipelines is about 50 years.  SPPG systematically replaces pipelines before the end of their service lives, or earlier if the condition of these pipelines is found to have deteriorated.  Our high-pressure pipelines are less than 20 years old, which is well within the estimated service lifespan.

6. As for water pipes, PUB’s water mains are relatively new, with an average age of 24 years.  Since the 1980s, older pipes have been systematically replaced with cement-lined ductile iron and steel mains, which are more durable and have an expected lifespan of 70 years.  A strict maintenance regime is in place to ensure that our water pipes remain in good working condition.  There is a dynamic leak detection programme in which all water pipes are checked for leaks at least once a year.  Our leak rate is 6 leaks per 100km of pipes each year, which is among the lowest in the world.