42
Tube Products International January 2012
products & developments
Pipe exhumation
shows performance
of pipe lining
3M’s fast-setting polymeric pipe lining
products are used for optimising water
quality and minimising the risk of failure
of ageing iron drinking water pipes.
Their performance was demonstrated
following a routine pipe exhumation in
Northern England.
Once lined, returned-to-service mains
are routinely exhumed to sample the
effectiveness of the lining application,
and the results are added to the lining
records for that area. In this instance
a 125mm (5") diameter cast iron water
main, estimated to have been in service
for around 50 years, had been treated
two years previously with 3MScotchkote
rapid setting polymeric lining 169HB
in order to address significant water
quality issues.
A section of this main, buried
underneath a grass verge adjacent to a
main highway, was selected for retrieval
so the lining could be inspected and its
condition assessed.
The water supply to the main was turned
off, but the main remained charged with
water during excavation.
Once a length of
pipe had been
exposed to reveal
a jointed section,
the pipe was cut
either side of the
spigot and socket
joint to enable
recovery of the
joint section.
A sledgehammer
was then used
to remove the
cast iron pipe
between the cut sections and expose
the lining. Despite the aggressive nature
in which the pipe was removed, the
lining survived intact, and there was also
no evidence of water having permeated
the lining.
The removed section of lining showed
that the original application process,
using specialist lining equipment
to treat the pipe in situ, had been
successful in creating a smooth
internal layer with an even material
thickness which faithfully followed the
internal geometry of the pipe.
No defects were found within the pipe,
even after the aggressive recovery
process, showing the strength and
suitability of the product for in situ water
pipe lining.
Carl Bradley of 3M’s corrosion
protection products division explained,
“After many years and even decades in
service, the insides of cast iron pipes
can become clogged with minerals and
other contaminants, with potentially
major impact on water quality. They
are also more prone to physical failures
as they age. In situ lining has become
very much established as a reliable and
cost-effective alternative to excavation
and replacement of entire mains – and
this example clearly shows how modern
lining equipment and products are able
to deliver effective, consistent, robust
and long-lasting protection – mitigating
against issues of both water quality and
pipe failure.”
3M Scotchkote rapid setting polymeric
lining 169HB is a spray-applied, semi-
structural lining for the rehabilitation
of drinking water distribution pipelines
between 75 and 300mm in diameter.
It provides a high build lining that
will remain intact in the event of pipe
fracture due to ground movement. Its
rapid curing characteristics allow the
start of return-to-service procedures
within 60 minutes of application.
3MCorrosion Protection Products
– UK
Removal of a section of pipe
Inspection revealed a smooth
internal layer with an even
material thickness
