The completed pipe string floating
in Main Canal.
AIRPIPE PTY LTD has recently
successfully carried out a sliplining project for Griffith City Council. Airpipe was
contracted to undertake the renovation of more than 900 metres of a 600-mm diameter
sewerage rising main located adjacent to the citys main shopping district. The main
took waste from Yoogali and Collina districts and the industrial area.
Griffith is home to more than 23,000 people
and has become the major service centre for a vast part of south-western New South Wales.
Griffith was designed by Walter Burley Griffin, the architect of Canberra, and named after
Sir Arthur Griffith, the first Minister for Public Works in NSW.
The existing sewer main, located along
Twigg Road, between Jondaryan Avenue and Lenehan Road in Griffith was originally
constructed in about 1946 using cast iron pipes. The section of pipeline to be renewed had
experienced a number of bursts due to the internal deterioration of the cast iron. The
cast iron pipes had been continually subjected to the effects of sulphuric acid, a product
of the oxidisation of the hydrogen sulphide that naturally occurs in sewer mains. As the
acid builds up it corrodes and weakens the pipe and causes it to crack and burst. The
extent of the deterioration didnt become evident until a C.C.T.V. was carried out
prior to installation of the new liner.
The new liner was constructed using 560-mm
OD PN 8 PE 100 polyethylene pipes supplied by Iplex Pipelines Australia Pty Ltd. The pipes
were butt-fusion welded together to form a continuous string prior to insertion into the
pipeline. As the pipes were being welded, each joint was debeaded.
The location of the existing sewer -
sandwiched between a busy industrial-use roadway that ran through the citys main
shopping area and adjacent to the main water supply canal for the area - meant there was
little room for the welding and construction equipment. To alleviate this, permission was
sought, and granted, from the owners of Main Canal, Murrumbidgee Irrigation, to utilise
the canal for storing the completed pipe string prior to installation.
The first string was inserted as one
continuous length of over 600 metres. This is a substantial distance given the size of the
polyethylene pipe in relation to the internal diameter of the existing main. By using
specialised equipment for the sliplining procedure we were able to achieve such a long
distance with just one pull. The second string was pulled through at nearly 300 metres.
The new liner exposed for the connection of the two
strings. This picture shows the proximity of the road (top left) and Main Canal (top
right), as well as the level of the water table.
By inserting the new liner in just two
strings only one hole had to be opened in the existing pipeline, apart from the connection
points at either end of the renovated length. This also reduced the number of fittings
needed to join the strings together. No problems were encountered and in fact the actual
sliplining only took 2 days to complete.
Mr Peter Gin, Water and Sewer Manger for
Griffith City Council was extremely happy with the work that was carried out on this
project. The direct cost-saving to the Council when comparing the two viable methods of
replacing this main proved once again that the best solution is a trenchless method.
OCCUPATIONAL HEALTH & SAFETY
Airpipe Pty Ltd achieved accreditation
with Sydney Water for our Corporate Occupational Health Safety & Rehabilitation
Management System during 1999. This followed many months of documenting our existing work
methods and quality procedures.
Airpipe QLD Pty Ltd was incorporated
in March 1999. Peter Coles and Kelvin Slade, with Kelvin running the day-to-day
operations, jointly own the new company. Kelvin can be contacted on mobile 0409 608 787.
Airpipe is still the major
polyethylene welder for the bore liners throughout the Blue Mountains, west of Sydney. We
have been carrying out this work for more than 8 years for a number of drilling companies
that are involved in the construction of bores for Sydney Water to provide sewerage
services to the residents of the Blue Mountains.
We have successfully carried out the
welding, debeading and installation of bore liners up to 500 mm OD PN 20. Due to the
nature of the terrain in the region, most jobs have to be carried out in extremely
difficult situations, with pipe and equipment having to be lowered into deep trenches or
onto built-up platforms. In one instance the butt-fusion welding machinery had to be
lowered down a ravine and placed on a purpose-built platform off the side of a cliff in
order to give direct access to the borehole.
Peter Coles, Managing Director, Airpipe Pty
Ltd, P O Box 240, Picton 2571 Australia can be contacted for further information on mobile
0409 205 696 or phone: +61 2 4683 2363, Fax: +61 2 4683 2364, Email: firstname.lastname@example.org