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Stair to be Sprinklered ?

Question asked by jsworks on Sep 19, 2019
Latest reply on Sep 24, 2019 by jsworks

#2_9-19-19

This is an unusual condition where a stairwell serving 7 occupied office floors + Bsmt + Sub-Bsmt has a sump-pump with control panel & disconnect switch at the Sub-Bsmt level. This stairwell serves as one of 2 - exits for the Sub-Bsmt level which is a Mech Area, aprx 58' x 127' in size. The Mech Area has a low exposed clg ht of 7'-1", and contains large water supply pipes set at different hts AFF and 2 additional sump pumps.##

 

The Sub-Bsmt portion of the stair was compartmentalized and separated from the rest of the stairwell with a 90 min door at the Bsmt level, and a 2 - hr rated drywall application underneath the sloped stair ceiling. There is a 72"H x 34"W opening from the stairwell to the 58' x 127' Mech Area. The compartmentalized portion of the stairwell has dual functions: (1) serves as part of the Mech Area, and (2) also serves an exit to the 90 min Bsmt dr. 

 

The Mech Area is fully sprinklered, but the compartmentalized stairwell with sump pump is not. My judgement call is that sprinkler water from the main Mech Area, will at best, have poor penetration thru the 72"H x in 34"W stairwell opng.

I believe the compartmentalized stairwell portion should be sprinklered because of the sump pump, control pnl, and disconnect switch contained therein, but found nothing in NFPA to address this unusual condition. Does anyone have comments regarding any code references that would indicate that sprinklering would be required? 

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