During what conditions should the source pumper operate?

The source pumper should operate in a relay operation as the largest capacity source because this ensures that a sufficient water supply is consistently maintained throughout the firefighting operation. In a relay operation, multiple pumpers are utilized to transport water from the source to the fire scene. The source pumper, being the largest capacity unit, is vital as it can handle the highest volume of water, thereby ensuring that there is no disruption or decrease in water flow during critical moments of firefighting efforts. This capability is crucial, particularly in large-scale incidents where water demand may exceed that of smaller pumpers involved in the operation.

Operating under this specific condition also allows for increased efficiencies, support for multiple lines, and helps mitigate the risks associated with running out of water during an emergency response. In the design of operations, using the largest capacity pumper in this role maximizes overall effectiveness and helps ensure the safety and success of the firefighting tactics being employed.