PROJECT
47
Building a structural liner
according to the pipe.
Using a Renssi RCM cleaning machine with a
cutting head, Nu Flow technicians cut through
the piece of wood and accumulated blockage,
working from the bottom of the downpipe
upwards. Once the main blockage was opened
and the conduit loosened, they then hooked the
conduit pipe from the top with a drain machine
and pulled it out, discovering that it was two
metres long.
They relined the pipe with the shifted joint
with a Nu Flow structural liner to create a new
seamless pipe within the leaking host pipe. The
pipe was a 75mm galvanised pipe with two
90-degree bends at the top of the pipe and one
at the bottom.
THE PROCESS OF PIPE RELINING
Step One: CCTV pipe inspection
CCTV pipe inspection cameras are used
throughout the entire pipe relining process.
The camera is a lining technician’s eyes in the
pipe and without it, the process could not be
done properly. Nu Flow installers use a pipe
inspection camera for the initial survey of the
pipeline to determine the full scope of works
required. A camera is used before and after
cleaning the pipe in preparation for relining to
ensure the pipe is thoroughly cleaned.
Other reasons for using a camera during the
process, are to measure the pipe length, pipe
diameter, and the exact position of junctions
and bends, and to ensure that while liners are
being inserted into the pipe and pulled into the
correct position, that they are placed correctly,
especially when the pipe line has junctions
and tees. Finally, the camera is used for the
post-lining survey to check that the liner has
successfully been installed prior to the job been
signed off.
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Step Two: Pipe cleaning
It is imperative that pipes are thoroughly cleaned
beyond normal cleaning standards, prior to pipe
relining. If a pipe is not properly cleaned, the liner
will not bond to the host pipe and it could allow
fluid between the liner and the host pipe, through
the dirt not having been removed, and it could
then still leak.
Pipe relining also takes the shape of the host
pipe, so scale build-up, dirt in the belly of the
pipe, or bumps not removed will be lined over,
leaving those bumps and abnormalities in the
pipe’s profile forever. It is for this reason that
Nu Flow installers prefer to do their own pipe
cleaning, as opposed to allowing the client to
have the pipes cleaned themselves prior to lining.
Nu Flow teams also have pipe cleaning
equipment that cleans pipes to a far higher
standard than what the average contractor
does. This is especially true on cast iron pipes
with scale build-up, where traditional cleaning
methods unblock the pipe, but it does not return
the pipe’s inner surface to bare metal again.
Step Three: Pipe relining
Once the pipe has been camera-inspected, cleaned,
and camera-inspected again, the technicians are
ready to reline! The roll of liner is cut to the correct
length, prepared for installation, impregnated
with Nu Flow’s two-part 100% solid epoxy resin,
and pushed (or pushed and pulled) into the pipe,
carefully positioned to cover the problem area.
Once in position, the bladder inside the liner is
inflated to push the epoxy-saturated liner against
the interior walls of the pipe. The bladder is left
inflated until the epoxy has cured, after which the
bladder is removed, leaving behind a ‘nu pipe’
within the old deteriorated pipe. PA
April 2019 Volume 25 I Number 2