I built a fort with a fire sprinkler system once. I put cisterns full of water over my central stairwell and my booze stockpile, and if I do it in the future I'll put one over the hospital and one in any area where dwarves work near magma. I made the fire alarm levers out of realgar. To prevent any flooding disasters, I connected my sprinklers to closed cisterns that were filled with just enough water and then sealed (rather than a constant supply of water), and made sure to build adequate drains for all sprinklered areas.
I know many players go to the consideration of providing individual plumbing to their nobles' rooms, so I suggest that such projects are also a good opportunity to plan for fire safety.