Dynalog C-SCAN 2000 Series, System Manual, Page: 39 / 91

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SYSTEM MANUAL Version 6.03i
36
iv) Start Point Screen
The START POINT screen in Fig. 6.8 is the final screen
before data is stored in memory. As before, an
overview of the data is given at the top of the screen,
but this time with the addition of the following:
│↔│ - Distance from previous location point.
As this is the first point Π#000 = 000ft is
shown
→│ - Chainage (0ft)
S#00 - Survey Number
To store this data, press the key and C-SCAN will
store the data and return to the START-UP screen.
To revert to the previous screen, press the
³
key.
Press the key now to store this Start Point. The first
survey point has now been completed.
6.4.5. Subsequent Samples
Now that a Start Point has been recorded, subsequent samples can be taken to assess
the condition of the coating between these sections. The Detector should now be moved
an appropriate distance ready for the next sample. The distance moved can depend on
many factors, such as:
•
The type of survey – Baseline surveys will have more regular survey points closer
together. Repeat surveys may vary their survey points
depending on the coating/area being surveyed
•
Attention to specific sections of pipeline – Road or river crossings or areas of high
consequence such as built up areas may
warrant closer inspection
•
Access to the pipeline – Survey points will often be dictated by the topography of the
area, and will vary if the ideal position is in the middle of a
river or road etc
•
Quality of coating – The further apart the samples are taken the less impact a single
anomaly will have on the overall attenuation. So survey points
taken 5000ft apart will require a large single anomaly or area of
general degradation before the Surveyor sees a significant rise in
overall attenuation
•
Any previous survey data – All results from C-SCAN are absolute, so can be compared
to previous surveys, but if a C-SCAN survey has been
carried out before then taking repeat samples at the same
points means that data can be directly compared to
previous samples with ease
Once a distance has been decided upon, the Detector should be moved to the new survey
point and the same process of finding the pipeline and obtaining an overhead should be
followed – steps 6.4.2 - 6.4.3. As before, once an overhead is obtained then a reading
should be taken – 6.4.4 i) & ii). This time, instead of being a Start Point a distance will be
entered.
Fig. 6.8 – Start Point screen