System Protection Area Limitations.

[RMERMP]

8.2 System Protection Area Limitations.

(4) Storage—High-piled storage (as defined in 3.9.1.17) and storage covered by other NFPA standards — 40,000 ft2(3716 m2)

any exception for this code? when you exceed to 3716m2 do we really need 2 risers? for example the warehouse area is 3721 m2? it just exceeded 5m2. thanks

 

[TravisMack]

Per strict interpretation - yes.

But, is this 100% storage. Are there some areas that may be office, bathrooms or other ancillary areas. 40k sq ft is the max storage area. 52k sq ft is max system size. So, you can have 12k sq ft of light and ordinary hazard combined with 40k sq ft of storage.

Also, you may be able to discuss with your AHJ. What are they really getting for the extra 5m2? You are getting another valve in the system that is a point of possible failure - closed valve. You are adding extra annual maintenance costs, etc.

The latest factory mutual datasheets do not provide a system area limitation. It is basically self governed by hydraulic calculations. The pipe gets so large, that it becomes more economical to put in multiple system controls. So, you may be able to present a sensible argument that a second system is not required for that additional area.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

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