ESFR Sprinkler for Warehouse

[pwijaya]

I came across an insurance audit on the installation of ESFR sprinkler in a warehouse with ordinary hazards (NFPA 13). The roof of the warehouse is sloped to MORE than 2:12 (NFPA 13, Section 8.4.6.2).
This is not acceptable by the auditor.
Can someone help me please with the meaning of 2:12 slope ratio of NFPA 13 and what is suggestion to correct this situation?

Thanks a lot
Paul

[Marty Thompson]

NFPA 13-2016
8.4.6 Early Suppression Fast-Response (ESFR) Sprinklers
8.4.6.2 ESFR sprinklers shall be installed only in buildings where roof or ceiling slope above the sprinklers does not exceed a pitch of 2 in 12 (a rise of 2 units in a run of 12 units, a roof slope of 16.7 percent).

Change your roof slope or your sprinkler type.

[pwijaya]

Hi Marty,

Thanks for your response.
I know the requirement of 2:12 in NFPA 13. Why not 5:12, for example.
But why NFPA put it this requirement? Is it related to fire behaviour in the building?

I really appreciate if you can help me on this.

Thanks,
Paul

[Marty Thompson]

I am not a sprinkler man but I would assume that the center force thrust would be different with a larger slope and effect the water distribution hence the limit of 2 in 12 slope.

Other places in NFPA 13 where slope is mentioned....
8.4.3(4) Extended coverage upright and pendent sprinklers installed under smooth, flat ceilings that have slopes not exceeding a pitch of 1 in 3 (a rise of 4 units in a run of 12 units, a roof slope of 33.3 percent), where specifically listed for such use.

See Figure 8.6.4.1.4 for roof or ceiling (wood) with slope 4 in 12 or greater.

8.7.4.2.2 Sidewall sprinklers, where installed under a sloped ceiling with a slope exceeding 2 in 12, shall be located at the high point of the slope and positioned to discharge downward along the slope.

That leaves me to think that supplementary sideways mounted sprinklers are called for with slopes greater than 2 in 12.


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