I have an existing foam/water deluge system covering vessels and sprinklers providing area coverage for pool fires. The sprinklers are smaller than K-5.6. The owner wants us to match the existing sprinklers.
In your opinion, is this acceptable?
For reference, NFPA 13 (2013) Section 8.3.4:
8.3.4 Sprinklers with K-Factors Less than K-5.6 (80).
188.8.131.52 Sprinklers shall have a minimum nominal K-factor of 5.6 (80) unless otherwise permitted by 8.3.4...
184.108.40.206 For light hazard occupancies not requiring as much water as is discharged by a sprinkler with a nominal K-factor of K-5.6 (80) operating at 7 psi (0.5 bar), sprinklers having a smaller orifice shall be permitted, subject to the following restrictions:
(1) The system shall be hydraulically calculated.
(2) Sprinklers with nominal K-factors of less than K-5.6 (80) shall be installed only in wet pipe sprinkler systems or in
accordance with the limitations of 220.127.116.11 or 18.104.22.168.
(3) A listed strainer shall be provided on the supply side of sprinklers with nominal K-factors of less than K-2.8 (40).
22.214.171.124 Sprinklers with nominal K-factors of less than K-5.6 (80) shall be permitted to be installed in conformance with 11.3.2 for protection against exposure fires.
126.96.36.199 Sprinklers with nominal K-factors of K-4.2 (57) shall be permitted to be installed on dry pipe and preaction systems protecting light hazard occupancies where piping is corrosion resistant or internally galvanized.
NFPA 15 (2017) Section 7.3.3. Flammable and Combustible Liquid Pool Fires
Water spray systems designed to control pool fires resulting from a flammable or combustible liquid spill fire shall be designed to apply a net rate of not less than 0.30 gpm/sqft of protected area.
I think my new design will require nozzles spaced at 100 square feet if the k-factor needs to be smaller than k-5.6 under NFPA 13.
Also, do you know of any non-aspirating nozzles that are listed for foam?
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