Volume-II of IV - GAIL

4.3 Procedure
a) The application procedure shall be in accordance with
manufacturers instruction and the minimum requirements specified
below whichever are the most stringent and shall be demonstrated
to and approved by the owner.
b) Applicators for coating application shall be given necessary
instructions and training before start of work by the
CONTRACTOR. To verify and qualify the application procedures,
all coating applied during the qualification test, shall be removed for
destructive testing until the requirements stated in sections
‘Inspection’ and ‘testing’ of this specification are met.
c) Prior to surface cleaning, the surface shall be completely dry. An
effective heating equipment which shall not give rise to deposits
shall be used. Care shall be taken to avoid damage to existing
coating.
d) All pipe joint surfaces shall be thoroughly examined before the
application of the coating in order to ensure that the surfaces are
free of oil, grease, rust, mud, earth or any other foreign matter.
e) Liquid epoxy primer shall be applied on the joints immediately after
the completion of heating operation.
f) The heat shrink sleeve is then wraparound the joint while the primer
is still wet and shall overlap the existing pipe coating by minimum
100 mm on each side.
g) The wraparound sleeve is shrunk on pipe joint with a propane torch
moved back and forth over the surface when heated above 125°C,
the sleeve shall shrink tightly around the substrate on to the wetprimer.
At the time of application of the primer, th pipe surface
temperature shall be at least 60°C at every point. To check this,
approved temperature indicators shall be used . temperature
indicating crayons shall not be used.
h) The wraparound sleeve shall be entirely wrapped around the pipe
positioning the closure patch off to one side of the pipe in 10m or 2
O’clock position, with edge of the undergoing layer facing upward
and an overlap of min. 100 mm.
i) Heat shrinking shall be procedure shall be applied to shrink the
sleeve in such a manner that all entrapped air is removed using
gloved hands and hand rollers. The complete shrinking of entire
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