Which factor must be considered when determining the order of loading of dissimilar products through the same piping system aboard a tanker?

When loading dissimilar products through the same piping system on a tanker, it is crucial to assess contamination of the cargo. This is essential because incompatible products can react with one another, leading to contamination that could compromise the integrity and safety of the cargo. Mixing products with different characteristics can result in undesired chemical reactions, changes in physical properties, or even hazardous situations that may create safety risks or regulatory violations.

Understanding contamination is vital in maintaining the quality of each individual product and preventing any degradation during transport. Specifically, the order of loading must ensure that the more sensitive products are loaded before those that are less sensitive to contamination. Proper management of loading sequences protects the tanker's cargo and complies with safety and environmental regulations.

While factors like flash points, specific gravities, and Reid vapor pressures are also important in their own right, they primarily relate to safety and handling procedures specific to individual cargoes rather than the potential of one cargo contaminating another loaded through the same system. Thus, contamination stands out as the critical consideration when establishing the loading order to maintain the cargo's purity and safety.