Leaders in Pipelin
e Survey Systems
C
C
C
-
-
-
S
S
S
C
C
C
A
A
A
N
N
N
2
2
2
0
0
0
1
1
1
0
0
0
SYSTEM MANUAL Version 6.03i
56
There are 4 recognised methods to survey near to, or across, an Insulation Joint:
Use a link to bridge the IJ.
Both sections of the pipeline either side
of the joint can be surveyed as if the joint
were not there
Use the IJ as the injection point
This has the additional benefit that
the
entire
signal will be sent in one direction
along the pipeline.
Use the IJ to separate between the
injection and earth points – there’s no
need for a separate earth connection
In this instance two separate surveys can
be carried out. One in either direction.
Use the
Earth Spikes
for the ground
connection
In this instance
only
, run the earth cable
parallel to the pipeline
