We can't survey where the pipeline goes under a
survey this section?
Yes. It can survey over any tarmac/blacktop. If
the traffic is active, you can take a reading
either side of the road. This will give an indication
of the coating quality across the road.
There is a field with cattle in. We don't want
to survey in there as the wire (CIPS) will get
broken. How can we survey this field?
You can either take the
into the field, or if the cattle are not 'friendly'
you can take a survey point either side of the
field. This will tell you if you need to go into
the field to find any fault that is indicated.
Our pipeline goes across a marsh that is always
in at least 8 inches
(20 cm) of water. Our
present method cannot survey here. Can
is completely immersion proof to about 2
feet (600mm). So yes you can survey here.
We have two parallel pipelines that are cross-bonded.
However we cannot find one cross-bond. How can
we find it?
Walk between the two pipelines with the
When you pass over the cross-bond the
will show 'overhead'.
We have a problem surveying two parallel lines
that are so close they are touching and the cross-bonds
are buried. How do we survey this?
If the pipes are that close and are cross-bonded,
you can treat both pipes as one. Do a survey as
normal. Any faults that are found could be on
either pipe. It is not possible (by any method)
to distinguish between these two pipes. It would,
however, be impossible to excavate only one of
Our pipeline crosses another (not ours). How can
we tell if they are touching?
If the pipelines are cross-bonded, disconnect
this. Survey on your pipeline. If you get a fault
in the crossing area, take another reading on
the other pipeline. If you get a reading, the
two pipelines are touching.
We suspect that a pipeline we have been contracted
to survey has sunk due to wet ground. This could
be placing a strain on the pipeline. How do we
Take depth readings along the pipeline section.
This will show any bowing and by how much. You
can use the 'close interval mode' on the
2010 for this.
We need to make a map of the pipeline we are surveying.
Is there any way of doing this?
2010 has a built in GPS unit (you can use an external
GPS with the 2000 unit), the report made by DCAPP,
has a GPS plot. You can either scale this plot
and overlay it on your map or you can take the
latitude and longitude readings (also printed
out) and input this to a GIS system.
Our pipeline has an IJ. How can we survey this?
An IJ will interrupt the current flow, so you
can either bridge it out if you need to do a continuous
survey, or you can connect one side to a convenient
ground point and survey up to it. If the IJ is
not bridged or grounded, surveying will show increased
attenuation as you approach the IJ. This is because
the current leaves the pipeline before the IJ.
We have been using the
2000 and we have a problem. When surveying a pipeline
in very high resistance ground (desert). An injected
current of 800mA, using a CP ground bed as earth,
cannot reach the first test post (1 km away).
How can we possibly survey this pipeline if the
signal cannot go this far (we lose it all after
This indicates that you have a serious fault within
the first 200m. If the attenuations are all high
then the coating is completely gone and surveying
the pipeline is a waste of time as it is all faulty
(at least the first 200m). If you only have one
very high attenuation then there is a very bad
fault in that place. Fix this first before continuing
to survey. This fault will stop the CP from doing
its job on the rest of the pipeline and is therefore
important that it is fixed as soon as possible.