sprinklernotes
Auditoriums and Water Supplies
You asked the following questions: “We have a 4-floor building with floor
control valves in the stairwell. There are fire sprinklers in an auditorium
that span from the 1st level to the 2nd level. The water is supplied from the
2nd-floor level fire sprinkler piping as that is the level of the auditorium
ceiling space. The Baltimore office is requiring the water be from the
1st-floor level fire sprinklers as the sprinklers are ‘seen’ from that level
when looking up. The Baltimore office tells me that the 1st-floor feed
requirement is per NFPA 13. Is there such a requirement in any NFPA codes that
the fire sprinkler water be supplied from the floor level that you ‘see’ the
sprinklers?” In response to your question, we have reviewed the 2018 IBC, NFPA
13, 2016, and NFPA 72, 2016 editions as the applicable standards. Our informal
interpretation is this is a fire alarm issue.
Supplying a sprinkler system in this manner can create an issue for a fire
department responding to a fire event. Since the system is supplied from the
second-floor system riser and if a fire were to activate sprinklers in the
auditorium, the alarm system would be notifying the fire department that a fire
is located on the second floor and not the first-floor auditorium area delaying
firefighting efforts. Historically, this arrangement would have been acceptable
but since the advent of flow switches per floor, it now conflicts with the
zoning requirement for the fire alarm system. Additionally, the IBC Section
907.6.4 states: Each floor shall be zoned separately, and a zone shall not
exceed 22,500 square feet. The length of any zone shall not exceed 300 feet
(91,440 mm) in any direction. Technically, the auditorium is part of the first
floor as that is where the access would be from even though the ceiling is at
the same plane as the second-floor ceiling level.This section could be the
driving factor in why the AHJ is making that requirement. Furthermore, NFPA 72
Section 10.17.5.1 states: For the purpose of alarm annunciation, each floor of
the building shall be considered as a separate zone for the very reasons
explained above.
