Volume-II of IV - GAIL

about the degree of cleanliness of pipeline and provide detailed daily site
report for each run in the approved format before commencing the
subsequent run. Choice of the type of cleaning pig has been left to the
contractor. Contractor may deploy brush cleaning pig, magnetic cleaning
pig, combination of brush and magnet, scrapper pig etc. the cleaning pigs
should be able to pass over negotiate lateral tees or bends on the pipeline
8.0 CALIPER PIG RUN
CONTRACTOR to carry out adequate number of electronic geometry
(caliper) pig runs each pipeline covered under SCOPE OF WORK including
pig tracking for each pipeline decided after findings of gauging pig run to
generate valid and interpretable geometry data of the pipeline and
analysis of data of the caliper survey to detect the nature, extent and
location of geometry defect. Contractor to provide detailed daily site
report for each run in the approved format before commencing the
subsequent run. The caliper should be capable of inspecting entire length
of the pipeline i.e. from launcher to receiver in single run. Battery life
should be adequate to commensurate with the run time required to travel
the pipeline length. The electronic recorder system should have requisite
data storage capacity. The drive cups should have requisite resistance to
wear and tear to maintain effective seal throughout the entire run time.
The measurement shall cover the entire 360° of internal pipe wall
circumference using properly oriented and suffcient quantity of sensors.
For internally coated pipelines adequate care shall be taken by using soft
cups so that no damage takes place to the internal coating of pipe. The
tool shall be capable to identify and locate the following features as
minimum.
- Individual Girth weld
- Dent, ovality, buckles, or any other out of roundness, change in
pipeline I.D. and difference of thickness.
- Bend with bend radius and degree of bend.
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