Which system is NOT supplied by the firemain via cross connects?

The correct answer is the Freshwater Supply system. The firemain system is primarily designed to supply water for firefighting and emergency scenarios, and it is typically utilized to support systems like magazine sprinklers and auxiliary seawater supply.

The Freshwater Supply system, however, operates independently and is not generally reliant on the firemain for its water source. Instead, it draws from dedicated freshwater resources to ensure that potable water and other freshwater needs are met without depleting the firefighting resources. This separation is crucial, as it ensures that firefighting capabilities remain unaffected during situations where the freshwater supply might be in use or compromised.

Other systems like Main Drainage, Emergency Auxiliary Seawater Supply, and Magazine Sprinklers are connected to the firemain through cross connects, allowing them to utilize the firemain's pressurized water for fire suppression and emergency management, reflecting their prioritization in safety protocols.