I have an existing warehouse that has a overhead pipe scheduled system from the early 80's. It is all threaded schedule 40 pipe. The system schedules from 8" at the riser to 2" at the last piece off main.
I ran a calculation and this existing system and it equates to Ordinary Hazard Group 2 at 0.20 gpm / 1,500 sqft.
The owner has installed (4) racks sections (per plan), each one separated by 12-ft. All located in one portion of the warehouse.
The fire marshal requested that they submit for a permit to confirm that the existing sprinkler system is adequate. The storage is 25-ft. (5-ft above the top of the 20-ft rack.) The ceiling is 35-ft.
The commodity is Encapsulated Group A, nonexpanded plastics on wood pallets, on open shelves with a 6" flue.
Plan view of storage configuration
Does NFPA 13, 2019 edition, section 25.8, option 1, 2 or 3 allow me to install sprinklers only in these racks, as a stand alone design, without making modification to the overhead sprinkler system?
This may eliminate the need for the owner to upgrade the existing overhead system and install a fire pump.
Thanks in advance.
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5/3/2023 08:08:40 am
I'm not sure what's up with this. 126.96.36.199 says it doesn't have to be hydraulically balanced with the ceiling. That would be my persuasion campaign topic with AHJ.
5/3/2023 11:59:49 am
This question has nothing to do with balancing the in racks with the system above. the question is this: can the above system be left at an ordinary group 2 occupancy even with in-racks and 25 feet of storage.
5/3/2023 02:24:23 pm
I'd say no.
5/3/2023 05:01:16 pm
Please note that 188.8.131.52 indicates that the ceiling sprinkler density shall be designed based on the highest commodity hazard not protected by the in-rack sprinkler system.
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