Question concerning "FM Data Sheet 8-9 Storage of Class 1, 2, 3, 4 and Plastic Commodities"

[SprinklerDesigner2]

Really pretty simple and straight forward but I just want to make sure I am interpreting this correctly.

The building peek is between 30'-0" but does not exceed 35'-0".

Lots and lots of water.... it appears I have two choices:

Choice #1: 12 K22.5 quick response sprinklers discharging at 63 psi +250 gpm hose stream.

Choice #2: 12 K25.2 quick response sprinklers discharging at 50 psi +250 gpm hose stream.

For the K25.2 I will have a minimum per sprinkler discharge of 178.2 gpm which might end up between 2,500 gpm and 2,600 gpm with the hose stream.

I think I am correct but I just want to make sure I am interpreting this correctly.

It appears not only is FM Global going this route but NFPA #13, 2025 has some big changes when it comes to the storage of plastic products. Forget the days of the 1,500 gpm fire pump that could cover just about everything.

 

[UFT12]

It seems about right. Are there any racks in the area?

 

[SprinklerDesigner2]

Thank you so much for the super fast reply!

No racks.

In our area we are required to have a 20 psi "cushion" at the fire pump suction when at 150% of capacity.

Not a whole lot of city water mains can provide 3,000 gpm @ 20 psi which would actually be close to 30 psi at the city main once compensating for the 10" backflow and suction pipe.

Say hello to more water storage tanks.

We still operate using NFPA #13 2019 edition but when it changes to the 2022 Edition look out when you have plastic storage!

NFPA Table 23.3.1 looks like ... well worse than FM Global requirements. 75 psi for a 22.4 ESFR sprinkler and 60 psi for a 25.4 ESFR sprinkler.

 

[UFT12]

Look closely, NFPA 13, ed.22 aligns with FM for 40' height. There 's just no criteria for lesser building heights, say 35' etc. Well, NFPA can be a bit savage sometimes...

 

[SprinklerDesigner2]

Look closely, NFPA 13, ed.22 aligns with FM for 40' height. There 's just no criteria for lesser building heights, say 35' etc. Well, NFPA can be a bit savage sometimes...

The days of playing with exposed plastics is about over.

Protection of palletized, solid-piled, or rack storage of Class I through Class IV and Group A commodities shall be in accordance with Table 23.3.1.

Look out for buildings exceeding 30'.