What is the diameter of the hose line used for reverse laying with a gated wye supply line?

The diameter of the hose line typically used for reverse laying with a gated wye supply line is indeed three inches. This size is optimal for ensuring an adequate flow of water from the supply to the fire scene, while also allowing for sufficient pressure and volume to combat fire effectively.

In fire operations, a gated wye is often utilized to split the water supply from a larger diameter line to multiple smaller hoses. The three-inch diameter facilitates a robust water supply to one or more lines, making it a preferred choice when setting up for large-scale engagements or dealing with multiple fire streams.

Other sizes such as two inches, one and three-quarters, and five inches are less common in this specific application; two-inch lines are generally reserved for smaller or more maneuverable operations, while five-inch lines are often used for supply purposes rather than as a direct attack line. Therefore, the three-inch diameter strikes an appropriate balance for the requirements of reverse laying in fire suppression tactics.