Classification of tank containers

Tank containers are generally used to transport liquid or gaseous bulk cargo, and can also be used to transport dry bulk cargo if the conditions are suitable. Generally, they are pressure vessels with internal pressure, but tanks with negative pressure inside are not excluded. The minimum test pressure varies with different types of goods. Their minimum test pressure is between 45kPa and 2 200kPa.

Therefore, tank containers can carry dangerous goods within a certain range.

2. Classification of tank containers

The United Nations International Maritime Organization (IMO) and its Dangerous Goods Transportation Regulations (IMDG) classify such tanks into the following categories:

(1) Dangerous cargo tank

• Liquid chemicals with a flash point below 0°C;

• Certain highly toxic or corrosive chemicals;

• Spontaneously combustible cargo;

• Goods that can cause danger when wet;

• Cargo that oxidizes itself;

• Liquid cargo whose sealing pressure does not exceed the allowable pressure of the tank;

• For tanks carrying corrosive and unstable cargoes, special steel should be used and the necessary lining should be considered;

• The water vapor pressure in the tank at 65°C and the resulting other partial pressures plus 0.35kg/cm2 must not exceed the design pressure of the tank;

• The material can be discharged from the bottom or top of the tank.

Tank container

(2) Sub-dangerous cargo tanks

• Liquid cargo with a flash point of 0°C to 61°C and no other hazards;

• Certain chemicals that are less dangerous, toxic or corrosive;

• Liquid cargo whose sealing pressure is lower than 172.4kPa but not exceeding the allowable working pressure of the tank;

• Discharge from the bottom of the tank.

(3) Liquid gas tank box*

• Used for low-risk chemicals at room temperature;

• Non-refrigerated liquefied gas;

• Discharge from the bottom of the tank.

(4) Refrigeration liquid gas tank

• Tank container with insulation layer;

• Shipment of low-temperature liquefied gas that requires temperature control;

• Other liquid perishable goods;

,• Discharge from the bottom of the tank.

(5) IMO 0 type

• Non-dangerous goods with a flash point exceeding 61°C;

• Non-toxic and non-corrosive cargo;

• Goods not included in the embargo list of international enforcement agencies;

• Liquid food, but alcoholic beverages with a flash point of more than 21°C or an alcohol content of more than 25% should be shipped in IMO type 1 tanks;