Probable Cause
Careless opening of outlet valve or disconnection of hose containing cargo or leakage via incorrect fittings or hoses.

Precaution 
Check if cargo is present before opening valves or disconnecting fittings. Check that hoses and fittings are correct for the tank.

Probable Cause
Tank and fittings not properly cleaned of previous cargo and / or cleaning agents.
Incorrect cleaning agent used. May result in contamination of new cargo, violent chemical reaction, crusting / congealing of residue in tank and fittings or damage to the tank.

Precaution 
Ascertain previous cargo carried and check Cleanliness Certificate. Check cleanliness of tank outlet valves and other fittings in contact with cargo before loading. Check cleaning agent compatibility before use.

Probable Cause
Excessive operating pressure. May result in rupture of the tank or hoses or release of
cargo through the pressure-relief valves, with possible risk of spillage and injury.

Precaution 
Note the maximum working pressure marked on the tank data plate and ensure that it is not exceeded. Ensure that the correct ullage space is provided to enable expansion of the cargo.

Probable Cause
Excessive pressure introduced into heating system. May damage tank or rupture hose causing failure of heating, escape of steam, contamination or escape of cargo.

Precaution
Do not exceed the maximum working pressure of the heating system marked on the tank data plate.

Probable Cause
Hose kinked or flattened so unable to pass air or liquid. May cause over-pressure or
vacuum collapse.

Precaution
Hoses should be inspected before use and correctly laid out before filling. Hoses
should be clearly marked to prevent constriction caused by objects being placed on them.

Probable Cause
Heating tank prior to cargo loading, exceeding maximum design temperature of shell. May cause deformation of or damage to shell and fittings.

Precaution
Ensure pre-heating temperatures do not exceed the maximum design temperature
indicated on the tank data plate. Care should be taken not to overheat small quantities of cargo, especially cargo residue. Verify that the thermometer is in working order.

Probable Cause
Exceeding maximum operating temperature and / or the maximum working pressure of the steam heating system. May damage tank shell, insulation, fittings, and cargo.

Precaution
Do not exceed the maximum operating temperature marked on the tank data plate.
Verify that the thermometer is in working order.

Probable Cause
Vacuum created in tank during pumping out, or as a result of tank cooling after system cleaning, or after discharge of heated cargo. May result in damage to tank shell and injury to personnel.

Precaution
Ensure tank is vented (via manhole or air-line) during cargo discharge and after steam cleaning and discharge of heated cargo. If a vacuum valve is fitted to the pump and / or tank, check that it operates freely.

NOTE. Special precautions must be taken when handling hazardous cargo to guard against venting of harmful vapours to atmosphere.