Operating the Tank
Safety
Common Dangers
Seaco tanks are extremely safe for all modes of transport and provide secure and robust cargo containment in transit.
The greatest risk of cargo spillage or damage to the tank or its fittings occurs during loading and discharge. Some common dangers to be avoided include:
Flash Spill
What can cause it?
Opening manhole or hose connection when tank is pressurised. May result in 'flash spill' of product and lid or cover being thrown.
How can I prevent it?
Examine pressure gauge if fitted and relieve any pressure before opening manlid or hose connection by careful opening of the airline valve. Take care not to vent off dangerous vapours into the atmosphere
Asphyxiation/ Poisoning
What can cause it?
Entering a tank which is oxygen depleted or has a contaminated atmosphere. May cause poisoning or asphyxiation.
How can I prevent it?
Check cleaning certificate and last cargo. Check tank atmosphere with appropriate analyser before entry. If necessary, carry out gas-freeing procedure. A second person should be stationed outside the manhole with a lifeline to the person in the tank.
Hose Whiplash
What can cause it?
Disconnection of hose when the tank is pressurised, could cause injury to operatives.
How can I prevent it?
Ensure that tank and hose are de-pressurised before disconnection.
Chemical Reaction/ Product Contamination
What can cause it?
Tank and fittings not efficiently cleaned of previous product or moisture; product loaded in uncleaned tank; incorrect cleaning agent used. May result in contamination of new cargo, violent chemical reaction, crusting/congealing of residues in tank and fittings, or damage to tank lining.
How can I prevent it?
Ascertain previous product carried. Check cleanliness of tank before loading. Check cleaning agent compatibility before use.
Accident cargo discharge
What can cause it?
Careless opening of outlet valve or disconnection of hose from tank containing cargo or leakage via incorrect fittings or hose. May result in a chemical reaction, toxic or inflammable flumes or other potential dangers to personnel and equipment.
How can I prevent it?
Check if cargo is present before opening valves or disconnecting fittings. Check that hoses and fittings are correct for a particular tank.
Overpressure
What can cause it?
Excessive operating pressure resulting in rupture of hoses or tank or release of cargo through the pressure relief valves, with possible risk of injury and spillage.
How can I prevent it?
Note the maximum working pressure marked on the tank and ensure that it is not exceeded.
Excessive steam pressure
What can cause it?
Excessive pressure introduced into heating system. May damage tank or rupture hose causing failure of heating and escape of steam, or contamination or escape of cargo.
How can I prevent it?
Do not exceed the maximum working pressure of the heating system marked on tank.
Vacuum collapse (implosion)
What can cause it?
Vacuum created in tank during pumping out, or as a result of tank cooling after cleaning, or after discharge of heated cargo. Could result in damage to tank shell.
How can I prevent it?
Ensure that tank is vented (via manhole or airline) during cargo discharge or after cleaning or discharge of heated cargo. If a vacuum valve is fitted check that it operates freely.
Note: Special precautions should be taken when handling hazardous cargo to guard against venting of harmful vapours.
Hoses kinked or flattened
What can cause it?
Hoses unable to pass air or liquid. Could cause over-pressure or vacuum collapse.
How can I prevent it?
Hoses should be periodically tested before use and correctly laid out before fitting. Wheeled equipment should be prevented from entering area where hoses are crossing the ground.
Heat damage to empty Tank
What can cause it?
Heating tank prior to cargo loading, exceeding maximum design temperature of shell. Could cause deformation/damage to shell and fittings.
How can I prevent it?
Limit pre-heating temperatures such that the shell or heater tubes do not exceed the maximum product temperature indicated on the date plate.
Care should be taken not to overheat small quantities of cargo, especially cargo residue.
Cargo vapour explosion
What can cause it?
Naked light or electrical spark in presence of cargo vapours during loading/discharge
or in presence of cargo leakage may cause fire or explosion.
How can I prevent it?
Strictly observe the 'no naked light' rulings in the vicinity of tanks. Ensure good earth connection has been made to the tank during loading/discharge. Check tools and clothing (especially boots) for spark risk.
Tank overheating
What can cause it?
Exceeding operating temperature, may damage the tank shell, insulation and fittings.
How can I prevent it?
Do not exceed the maximum operating temperature indicated on the tank. Check that the temperature gauge is in working order.
