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The handling, installation and maintenance of PolySteel pipe work should
only be carried out by trained personnel. The following information is
provided as a supplement to standard handling and installation procedures
and
good safe work practices.
Pipe Handling
Lifting, moving and positioning PolySteel spools must be conducted by
locating slings or spreader bars at two
or more points along the length of
the pipe in order to support the load in a safe and secure manner.
It will
also minimise the stress induced due to pipe bending during lifting.
Under no circumstances must the pipe spools be lifted from the centre or
one end only.
Pipe Supports
Spacing for pipe supports can vary for each individual project and
assistance from Duriduct technical support personnel should be sought if
there is any doubt as to spacing and load requirements.
It is important that pipe supports be designed so that pipe flanges have
sufficient clearance from the
ground and surrounding structures.
The following procedures should be taken into consideration where
PolySteel piping is to be placed directly
on the ground without supports:
-- Uneven or unstable soil should be compacted so as to provide
adequate support along the entire pipe run.
-- Rock should be removed from the pipe bed to ensure that the pipe
load does not rest on the rock.
-- Soil adjacent the flange joints must be “scalloped” away to
prevent the flanges from sitting the soil
Pipe Preparation and Installation
Flange protection
PolySteel piping spools and fittings are shipped with backing boards or
flange protection fitted.
In order to prevent damage to the flange sealing
face the protective covers should not be removed until
the flanges are
ready to be bolted into position.
If covers are removed for inspection purposes prior to installation they
should be replaced.
If pipe is removed from the pipeline for any reason protective flange
covers should be fitted.
Rubber joint gaskets
Rubber ring joint gaskets may be specified in higher pipeline operating
pressure applications (over 10 bar - 1000kPa) or piping systems of such
length that thermal stresses may result in deformation of the plastic
sealing face.
In these applications a reliable seal can be achieved using
a 1.6mm ring joint such as a Klinger PSM-AS
For further advice about PolySteel jointing requirements contact Duriduct
technical support.
Pipe Installation Preparation
-- Prepare the laying site in accordance with appropriate and safe working
practice
-- Provide uniform pipe support at all times
-- Align the mating flanges to ensure they can be brought together
squarely
-- Support pipe by crane during bolt tightening
Pipe Jointing Procedure
-- PolySteel piping spools leave the factory with one flanged end fitted
with a backing board and the “poly” liner flange face fitted tightly
against the steel flange. The other flanged end of the spool will have the
“poly” liner
and its flange face protruding from the steel flange. (Refer
Fig 1 below). This protrusion is a design feature
and the extent of protrusion
will vary according to the length of the spool and ambient temperature.
-- During installation the liner will be compressed inside the steel pipe
casing by sequentially tightening flange bolts
in stages until the “poly”
flange meets the steel flange. (Refer Fig 2 below). Jointing is achieved by
fitting two or three extended length compression bolts or threaded rod to
the connecting flanges and tightening evenly until
the distance between
jointing flanges allows specified bolts to be fitted. Compression bolts
should be tightened alternatively from adjacent sides of the flange and no
more than one turn of the nut at a time.
-- Spacer rings (Refer Fig 3 below), if specified, should be fitted before
inserting the extended length compression bolts. The spacer ring can be
designed to fit inside or outside the bolt circle, depending on the size
and standard
of the flange specified.
-- Once the correct flange bolt length is reached during the compression
process the specified flange bolts,
nuts and washers are installed and the
extended compression bolts or threaded rod removed and replaced with
the
specified bolts. Flange bolts should be tightened in a sequence (Refer Fig
4 and 5 below).
Leaking joint during Installation
In the event of a leaking joint during testing of the pipeline and
providing the bolts where the leak has occurred
have been properly
tightened then they should not be further tightened otherwise permanent
damage to the
sealing face could result.
The following process of rectification is recommended:
-- The bolts on the opposite side to the leak should be loosened a half
turn at a time and those on the
leaking side tightened by the same amount.
-- If the leak persists the bolts should be removed and the sealing face
examined for damage such as scratches
and dents across the face which
could provide a leak path.
-- Any damage which does not exceed 10% of the liner thickness at the
sealing face may be repaired by hand polishing using a very fine abrasive
cloth or paper, taking care to maintain an even liner thickness across
the
whole sealing face.
Avoid heat damage
Avoid welding, brazing, soldering or flame cutting to or adjacent to
PolySteel pipe and fittings, because
excessive heat can permanently damage
the “poly” liner.
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