Nozzles & Equipment
Water Thief
A water thief is an appliance that splits a supply line into one same-size outlet and one or more smaller gated outlets. It lets a crew tap a line for a handline without interrupting the main flow passing through.
Where a wye divides one line into branches of the same size, a water thief carries the main line straight through while gating off a smaller branch or two. That lets an attack line draw from a supply lay without cutting the flow continuing downstream.
Like any appliance, the water thief adds a loss as water turns and divides inside it, and any branch it feeds runs behind the same nozzle-pressure-plus-friction-loss math as a line off the pump. Budget the appliance loss or the tapped line runs weak.