Explain the concept of "flashpoint" and its significance when dealing with flammable liquids during cargo handling.

The flashpoint of a flammable liquid is the lowest temperature at which that liquid produces enough vapor to form an ignitable mixture with air near the surface of the liquid. This temperature is a crucial indicator of the liquid's flammability hazard. The lower the flashpoint, the easier it is for the liquid to form a flammable mixture and the greater the risk of fire or explosion. During cargo handling, knowing the flashpoint is essential for determining the appropriate safety precautions. Flammable liquids with low flashpoints require more stringent handling and storage measures, such as explosion-proof ventilation, spark-free equipment, and strict control of ignition sources. The temperature of the liquid and the surrounding environment must be kept well below the flashpoint to prevent the formation of a flammable atmosphere. For example, if a flammable liquid has a flashpoint of 25°C, the liquid and the surrounding air should ideally be kept below this temperature to minimize the risk of ignition. If the temperature is above the flashpoint, even a small spark or flame can ignite the vapors, leading to a fire or explosion. The flashpoint is also a key factor in determining the appropriate packaging, labeling, and stowage requirements for flammable liquids under the IMDG Code. Therefore, understanding the flashpoint is fundamental for ensuring the safe handling and transport of flammable liquids.