TPT January 2008

128 / 140

Fittings, Couplings & Tubular Joints
January 2008 126 ›
Portuguese water company EPAL, based in
Lisbon, has employed a specialist coupling
developed by Viking Johnson, UK, for
terminating pipes that have been re-lined
with a thin-wall PE liner.
The DN800 LinerGrip couplings for the
rehabilitation work – on a concrete main in
Ota, 50km north of the city – were ordered
by Portuguese contractor Vacqualiner.
Vacqualiner is using the Subline® system
under licence from British company
Subterra and in cooperation with Dutch
company BAM Nellis Infra.
Explaining the reasons for the choice of
LinerGrip, Vacqualiner’s Mr Hugo
Santos said, “We needed to be
confident that the PE liner was
fully supported and held firmly in
place when we returned the main
to its operating pressure. This is
particularly important when using
thin-wall liners, because they rely
on the strength of the host main and
couplings for pressure retention.”
Other successful applications of
LinerGrip include 2.5km of concrete
main through the historic centre of
Haarlem in the Netherlands, and
a 9km cast iron supply main to a
service reservoir in the UK.
LinerGrip has an in-built gripping
arrangement to hold the PE liner
and prevent it from retracting inside the
host main due to changes in temperature
or the Poissons Effect. It also provides
a flanged end for connection to other
pipework in the make-up piece.
The support provided by LinerGrip prevents
damage by the shear forces arising as it
emerges from the host main. It ‘seals back’
onto the outside of the host, stabilising the
entire fitting and preventing the ingress of
ground water into the annulus between
host and liner pipes.
Corrosion protection is provided by factory
applied thermoplastic polymer Rilsan Nylon
11, which meets the stringent performance
standards of WIS 4-52-01 (Part 1) for the
highest adhesion, flexibility, penetration and
impact resistance characteristics.
As a result, LinerGrip products are well
equipped to withstand transport, storage,
site and corrosion damage, eliminating the
need for further protection such as on-site
wrapping.
Viking Johnson – UK
Fax: +44 1462 443311
Email:
Website:
Pipe coupling ensures relined mains
are leakproof
fi Viking Johnson’s LinerGrip has been used by Portuguese
water company EPAL