Cargo tank inspections
To define and report the surface condition of (corroded) cargo tanks. As an update concerning the present surface condition or as a benchmark before loading aggressive cargoes.
Stainless Steel ( Drone ) Inspection
Standard cargo tank inspections will be executed by our inspectors from stairs and tank top.
If staging is not available , our inspector can be accompanied by a drone pilot (Class approved ) in order to have better indication of higher area s/ spots.
Scope of inspection:
- Visual Inspection General view
Pitting corrosion
Cracks / Weld damages
- Passivity check
- Roughness check
- Ferroxyl Test
- Chemical Tests if required
- Report with pics / tank rating / advice.
Surface Condition Tests
Passivity test
Measuring the Thickness of Chromium Oxide layer ( defines the actual corrosion resistance / sensibility of the stainless steel surface )
Passive readings indicates a corrosion resistant surface.
Active readings indicates a not corrosion resistance surface, with high risk on pitting corrosion or general corrosion
Device: Electronic Oxilyser 3
Roughness test
Measuring the roughness / smoothness of the surface
High roughness will accumulate impurities in / on the surface which might cause pitting corrosion.
High roughness will increase cleaning time for cargo residues will stick deeper in the surface
Device: Electronic Ra test device
For chemical tankers:
Standard surface roughness for Clad Steel ( 3 mm stainless steel layer on mild steel) 0,5 – 2,0 Mu
Standard surface roughness for solid stainless steel : 2,0 – 3,5 Mu
Ferroxyl / Blue Point test
On site chemical test to define iron / steel residues on the stainless steel surface
These impurities will decrease / remove the passive layer in that area and can cause pitting corrosion.
Device: Chemical solution and indicator paper
.
Chemical test
To remove slight corrosion, discolourations or cargo residue
Mostly required when tank will not pass cleanliness for next cargo or to upgrade the tank surface condition.
