During high-rise operations, which arriving engine company shall establish a secondary water supply?

In high-rise operations, the fourth arriving engine company is tasked with establishing a secondary water supply. This is crucial because high-rise buildings require significant water supply to effectively fight fires and protect occupants. Typically, the first arriving engine company will focus on securing the primary supply through the standpipe system, while the second and third companies may assist with initial firefighting efforts or additional supply lines. The arrival of the fourth engine company is essential, as by this time, the incident command can assess the situation and determine that a secondary water supply is necessary to ensure adequate resources are available for sustained operations. Establishing this secondary supply enhances operational redundancy and safety, allowing for continued firefighting efforts without interruption.