Unless you oversized the rod that supported the sprinkler line, it may violate code.
Usually, plumbers (or any other trade) put the minimum required sized rod for their own hanger system. They don't upsize unless it's agreed upon before install.
I've been on a few jobs that I've actively gone to other trades and reworked the hanger systems.
For example - Our ductline took up the whole hallway. Engineered drawings stated HVAC elevation as ceiling down to 2' below ceiling. The electrical elevation was just below that. For them to hang their cable tray, they would have to anchor outside the duct, and then span the whole hallway with unistrut. (their cable tray was about 16" wide)
1- They would have to drop their threaded rod first down the length of the hallway as there was no "safe" way to get to the ceiling after the ductline was in. (And then I'd have to deal with their rods as I was installing)
2 - It's a waste of unistrut to put up 6 feet worth to span the hallway for a 16" cable tray.
3 - It's a waste of threaded rod for them to drop from the ceiling (although it was probable bid on, hanging from the bottom of the ductline would save them 4' of rod per hanger which equates to a higher profit for them.
4 - They would have to pull off another location to come and put in their anchors and rods which would have held up production for both us and them.
In the end, I made a deal with them that I would use their materials (upsized rod that would support both HVAC and Electrical tray AND their unistrut (which they would have used anyways to span the whole hallway) Saving the HVAC company the cost of rod and unistrut and saving the Electrical company the labour cost of installing their hanger system. - RWCheese