Another FM Data Sheet Question-You would think I would know this by now

[SprinklerDesigner2]

Got an FM job where we are dealing with FM Data Shhe 8-9 Table 8. Ceiling-Level Protection Guidelines for Class 4 and Cartoned Unexpanded Plastic Commodities in Open-Frame Rack Storage Arrangements.

The height of the building is 17'-6" at the highest point.

I would like to use the K25.2EC sprinklers where I need 6 heads discharging at 22 psi.

I know it is in the data sheets somewhere, I have actualy seen it before, but with six heads how many heads per line to I need open? My guess it is 3 per line but... can someone point out where the answer is in the data sheet? Been trying to find it for a few hours now....

Thank you.

 

[UFT12]

See table 1, §2.3.3.7.2.6, Interim Revision April 2025

 

[SprinklerDesigner2]

Three heads per line!

Thank you.... UFT12

 

[TravisMack]

I believe they do it like CMSA in NFPA 13. You take the number of sprinklers req'd by the MAX coverage permitted for the sprinkler. So 6 sprinklers at say 196 is 1176 sq ft. Your length along the branch line is then 1.2√1176 or 41.15'. As long as your spacing is 13.7' or greater, you would do 3 & 3. If you are <13.7' then it would be 4 & 2.