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Power tool cleaning using grinding stone to remove loosely adhering
rust and existing coating. It
also needs to create a certain degree of roughness on the surface to
enhance mechanical anchor of coating on the substrate. The 16” O.D pipe was
provided by Chinese Petroleum Corp. (CPC)
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Artificial defect dimensions
as marked on the pipe spool # 2 (length – 150mm, width –6.5mm, depth –
9.45mm)
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Take measurements of pipe spool #1
anomaly (artificial defect) with a vernier caliper and depth micrometer
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Preparation
of pressure gage equipment for pipe spool # 1
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Fill
up the anomaly (artificial defect) with Corro-Dur 561 FS up to the level of
the original external pipe wall of pipe spool #2.
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After
filling the defect area, Corro-Dur 561 FS was applied over the
pre-determined length of repair
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Continue
application of Corro-Dur 561 FS on the underside portion of the pipe
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The first roll of Corro-Wrap
(size of roll 6” x 30’) is
being used to wrap the pipe
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During
the wrapping process, water is sprayed on the Corro-Wrap and the pipe.
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After the first roll of
Corro-Wrap was used, a perforated shrink wrap was wrapped around the pipe
to give it a snug fit.
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After
a few minutes, the shrink wrap was removed to continue application of the
required number of rolls
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The
wrapping is completed and water was sprayed on the entire area to complete
reaction of Corro-Wrap
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Both
test spools are now ready for testing. Pipe spool # 1 (without the wrap) is subjected to
hydrostatic pressure testing.
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Pipe
Spool # 1 artificial defect area has ruptured at 125 kg/ sq.cm. and pipe
spool # 2 is also subjected to hydrostatic pressure testing which will be
maintained at 70 kg/sq.cm for 24 hours
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The next day, pipe spool # 2 pressure printout
shows that it almost reach 105 kg/sq. cm but went down to 62 kg/ sq. cm due
to expansion and contraction of the material (pipe and water). At the same time it was observed
that there was a leak on the pipe fitting which affected the pressure
readings.
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This part of the fitting that exhibits the leak
is connected to the pressure
gage printout instrument
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The
printout didn’t give an accurate data due to the leak in the fitting and so
it was decided to do a re-testing of pipe spool #2.
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The
water in the pipe was removed and it will be transferred inside the
warehouse so as not to be affected by temperature changes.
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Continue
draining water from the pipe
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Attach
all the necessary fittings and instruments prior to re-testing
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Set
the printout gage at 70 kg/sq.cm which shall be maintained for another 24 hours.
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The
entire set up was completed for re-testing of pipe spool # 2. Corro-Wrap finally passed CPC’s testing when it has maintained its pressure
at 81kg/sq.cm., then it was
increased to 105 kg/sq. cm. and
maintained for 30 mins. Afterwards, the pressure was
increased and the pipe ruptured or showed signs of leakage at 145 kg/ sq. cm. which is way beyond
the designed pressure
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