Inspection and Testing

Testing

After tank cleaning has been accomplished it is mandatory to check the result. The intensity of the check depends on the cleaning standard that must be achieved.
Specific test methods are prescribed for the various cleaning standards. The test methods shall identify the presence and concentration of impurities.
Established methods are the Wall Wash Test and the Washing Water Analysis.

Tank Inspection

To verify the result of the cleaning operation the tank and all other equipment that was in contact with the cargo must be inspected. This can usually only be performed by entering the tank. All standards and procedures related to tank entry have to be followed strictly.

Inside the tank

• In the tank, the following items should be inspected, because they are known as potential problem areas.

• Entire tank surface for visible remainings.
• Wall should be touched and checked also for sensible remainings
• Shadow Areas of the cleaning machine
• Underneath heating coils
• Heating coil supports
• Pump suction well
• Loading line outlet
• Tank internals (ladder, cleaning machine, thermowells, Level indicators etc)
• Furthermore, the entire stainless steel tank surface should be inspected for discolouration and pitting.
• If the tank is coated the coating condition has to be checked.
• The entire tank should also be checked for Smell and Wetness/ Moisture.

Outside of the tank

• Although the inspection of lines is almost impossible as a minimum test the opening of manifold blind flanges should be carried out, to check lines as much as possible visually for residues and moisture. Also smell in the lines could indicate insufficient cleaning.
• The pump cofferdam should be purged to detect any possible contamination or seal leak.