In commercial fire sprinkler systems or large farm irrigation systems, is the thrust produced by the water a major design consideration? At what stage in the design process is this taken into account?
Product design often involves juggling many parameters at the same time, prioritizing them, then testing a design. In sprinklers themselves, the forces associated with the thrust are much lower that the forces the sprinkler experiences during assembly or from internal pressure; so typically they are not a design priority.
For irrigation sprinklers the thrust is not a big consideration in the structural design, because the flow, and resultant thrust is comparatively small. It is however important for impact sprinklers, as it is their method of operation.
Fire sprinklers themselves don't generate a lot of force, but there is a lot of dynamic force on the pipe supports on large diameter pipes that turn corners to deliver water to the sprinklers. Fluids can exert very large forces without being a free jet. Here is a big nasty document on pipe engineering that might make your thermo fluids homework look nicer ;-)