What must you verify when loading a petroleum cargo at below average ambient temperatures?

When loading a petroleum cargo at below average ambient temperatures, it is crucial to verify that there is room for expansion. This is because as the temperature of the petroleum cargo increases, it expands. If there is insufficient space in the tank to accommodate this expansion, it can lead to overpressure conditions, which may result in cargo overflow or potentially hazardous situations.

In colder temperatures, petroleum products are denser and may have a higher viscosity, which can affect their flow and loading characteristics. However, once loading is complete and the temperature rises (for instance, during transport), the cargo will expand. Therefore, ensuring that adequate space is maintained allows for safe operations and prevents potential accidents.

While other factors like sealing vents and having vapor baffles are important safety measures, the primary concern in this scenario focuses on the physical properties of the liquid cargo and its behavior under varying temperature conditions.