HULL TANK STRUCTURE/AIR/HOSE TEST

GENERAL:

“Test procedures are to confirm the water-tightness of tanks and watertight boundaries, the structural adequacy of tanks and the weather-tightness of structures/shipboard outfitting.”

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Example of tank test plan

THERE’RE TWO TYPE OF TEST

1- Structure test 

Structural Testing is a test to verify the structural adequacy of the construction of the tank (hydro static test)

Structural testing may be carried out after the vessel is launched, some shipyard, they can be done in dry-dock.

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2-Air leak test

Leak Testing is a test to verify the tightness of the boundary (air testing, compressed air fillet weld testing, vacuum box testing)

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Tank air test may be carried during Block stage, Pre-erection stage or erection stage in dry-dock. Depending on yard work flow and schedule.

For speedup the process, The fillet air test can be carried out during block stage as below description:

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The Air pressure as Class required : 0.15 kg/cm2, but 0.2kg/cm2 to be keep at least 1 hour for allowing the air moving through the fillet joints.
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Vacuum test for erection joint outside the hull (ICCP, Speedlog, Eco-sounder ect.,). The vacuum pressure is about 0.2-0.27 kg/cm2 as Class requirement.
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This Hose test almost use for compartment WEATHER tighten test (Window, Door, Manhole, C.O Hatch ect.,)

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As the require, “2Bar during the test”

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QUESTION:

Pressure is Stactic pressure of included the Dynamic pressure ???

Pressure in Hose or Hose nozzle ??? ( Pressure in nozzle is Dynamic pressure v^2/2g)

Nozzle ~ 12.5mm – Fixed diameter

Hose diameter ??? how much is required (HHI use Fie hose 65 mm in Diameter)

The Bigger Hose the lower Velocity of Water jet

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There’s unavoidable some area can not be carried out Air test, as per the flexibility and agreement with Class site, MPI both side or PT can be done as alternatives (due to damaging equipment, inaccessible ect.,)

 

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