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NFPA 409 Group II Hangar Closed Head Sprinkler Operation Area

Question asked by musul on Mar 21, 2018

NFPA 409 Group II Aircraft Hangar System and Design

7.6 Closed-Head Foam-Water Sprinkler System.


7.6.1 Closed-head foam-water sprinkler systems shall be
designed and installed in accordance with NFPA 16. AFFF shall be used. Wet pipe foam-water systems shall not be required to be
preprimed with foam-water solution.
7.6.2 The minimum discharge density shall be 6.5 L/min/m2
(0.16 gpm/ft2) of foam solution over the entire storage and
service area.



7.3.7 Foam-Water Wet Pipe, Dry Pipe, and Preaction Systems. Total Design Area.
(A)* The total design area shall be 5000 ft2 (465 m2).
(B) Where applicable occupancy standards specify design areas
different from that specified in, the occupancy
standards shall take precedence.


my question is


What will be our operation area when doing hydraulic calculation?

NFPA 16 (465m²) or NFPA 409 7.6.2 

Having 6.5 densities for the entire hangar means opening all the sprinklers around?