For transport of liquid dangerous goods having viscosity less than 2,680 mm2/s at 20°C IMDG Code states portable tanks having a capacity more than 7,500 litres, and not divided by partitions or surge plates, must not be offered for transport with a degree of filling between 20 % & 80%.

Cargo may expand and contract due to exposure to varying ambient temperature hence maximum degree of filling is calculated considering the mean coefficient of cubical expansion of the liquid between the mean temperature of the liquid during filling and the maximum mean bulk temperature during transport.

• Visit here to know how to calculate maximum degree of filling

• Or use calculator to calculate degree of filling

Above rule of IMDG Code prohibits transport of liquids in tanks with a degree of filling between 20% and 80%.

IMDG Code, which is amplification of Chapter VII Part A of SOLAS & Annex III of MARPOL conventions deals with dangerous goods and harmful substances in packaged from. The objective of the IMDG Code is to enhance the safe carriage of dangerous goods while facilitating the free unrestricted movement of such goods and prevent pollution to the environment.

Should we apply 80/20 rule to non-dangerous goods liquids?

Many a times the question asked is “Can we transport non-dangerous liquids below 80%?”

Some think it is okay to transport non-dangerous liquids below 80% as IMDG Code rule is applicable only for dangerous goods.

When transporting liquid will move inside the tank leading to changing centre of gravity for the vehicle which may lead to dangerous driving conditions.

• 70 & 80%   -Noticeable surging
• 60 & 70%   -Severe surging
• 40 & 60%   -Dangerous surging -unstable when in motion

Whether dangerous or not dangerous, liquids in tanks must meet the 80/20 rule for safety reasons.

“Portable tanks should not be offered for shipment in an ullage condition liable to produce an unacceptable hydraulic force due to surge within the tank.”

Code of Safe Practice for Cargo Stowage and Securing (CSS CODE)

• Portable tanks must not be filled in excess of the maximum degree of filling specified in IMDG Code.
• Portable tanks shall not be offered for transport with a degree of filling, for liquids having a viscosity less than 2,680 mm2/s at 20°C or at the maximum temperature of the substance during transport in the case of a heated substance, of more than 20% but less than 80% unless the shells of portable tanks are divided, by partitions or surge plates, into sections of not more than 7,500 L capacity.

Read more about shippers’ responsibilities when using tank containers