Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...

consultant born out of the corporatization of the Public Works Department and acquired by the Australian
Downer group in 2003. Designs make reference to the tender documents and a PUB Sewerage
Rehabilitation Manual, which draws heavily on U.K. and U.S. practice and references the WRc, WIS, and
ASTM standards. PUB is rigorous on sampling and testing from installed liners and uses its engineering
staff to supervise works. However, the scale of current works is so substantial that staff are very stretched
to cover all the installation activities. Works are routinely CCTV surveyed after two years in service (i.e.,
on completion of the warranty period), and problems encountered include wrinkling, coating defects such
as blistering, and poor quality lateral reinstatement. Contractors are required to remedy defects.
The emphasis in Phases 3 and 4 on private drain lines and exfiltration has encouraged the PUB to trial
various proprietary lateral lining and top hat connection systems and this has encouraged a number of
epoxy resin system developers such as Epros, RS Lining, and MC Bauchemie to concentrate on the
Singapore market. At the present time, PUB has specified that all sewers up to 225 mm (9 in.) shall be
lined with epoxy-resin-based systems. This practice, implemented to avoid shrinkage associated with
polyester use, is not without problems because of the tropical climate experienced in Singapore. Mixing
two-component epoxy systems can give rise to difficulties with premature curing in high ambient
temperatures and when large batches are mixed. Experienced contractors such as OLiner Pte Ltd. have
equipped themselves with static mixer equipment and limited batch sizes to minimize installation risks.
Other less experienced contractors have not always been so fortunate and there is an undercurrent of
rumors about site problems. Some system providers (Epros, MC) have established local depots providing
technical support, central mixing and impregnation facilities to service less experienced contractors and
this has helped to minimize difficulties. Some system providers have also introduced resins formulated
for warmer climates.
In a recent development, the principal CIPP contractors and PUB have established, in June 2009, a
Singapore Society for Trenchless Technology (SgSTT). This body will work with PUB to establish a
good practice consensus and revise the local Sewer Rehabilitation Manual. PUB is keen to work with its
contractors to establish training and certification schemes so that all parties involved in sewer
rehabilitation can attain minimum standards. SgSTT affiliated with ISTT in November 2010 prior to the
International No Dig Conference and Exhibition to improve access to international experience and raise
standards. Current initiatives are focused on provision of CCTV and CIPP training.
PUB Consultants Private Limited (PUBC) is the commercial arm of PUB and plays strategic and active
facilitative roles in assisting PUB to achieve its goal in developing the Singapore Water industry. PUBC
harnesses PUB’s operational experience and resources to support the Singapore-based water companies in
their overseas ventures in projects relating to infrastructure development and operation and maintenance
of municipal systems in water supply, used water treatment and disposal in the key markets of the Middle
East, North Africa, China, Southeast Asia, Australia and India water reclamation and recycling. It can be
expected that PUB’s substantial experience in managing sewer rehabilitation projects will play a role in
PUBC activities in Southeast Asia in future years.
C.8 Brisbane Water (BW)
BW was interviewed in Brisbane on April 19, 2010. BW distributes water and collects wastewater in the
City of Brisbane, Australia. It is Australia’s second largest water and wastewater utility. In July 2010, it
merged with four adjacent utilities to form Queensland Urban Utilities (QUU). QUU is jointly owned by
the five local authorities and operates as a statutory authority. QUU is one of the largest water retail
distributors in Australia, providing service to more than 1.3 million residents. This report focuses on the
experience of BW rather than that of QUU as a whole, since the adjacent utilities have minimal
experience of sewer rehabilitation. BW operates a sewer network of 6,844 km (4,253 mi) with an
additional 740 km (460 mi) of laterals. BW was the first user of CIPP for sewer rehabilitation in
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