Check the wording in IBC first, and if that give you an out, that is what should be enforced....
If 13 applies, than check the wording in the 13 edition adopted by the ahj.
2019 NFPA 13
9.3.5
* Vertical Openings.
9.3.5.1
* General.
Unless the requirements of
9.3.5.4 are met, where moving stairways, staircases, or similar floor openings are unenclosed and where sprinkler protection is serving as the alternative to enclosure of the vertical opening, the floor openings involved shall be protected by closely spaced sprinklers in combination with draft stops in accordance with
9.3.5.2 and
9.3.5.3.
9.3.5.2 Draft Stops.
Draft stops shall meet all of the following criteria:
- (1)
The draft stops shall be located immediately adjacent to the opening.
- (2)
The draft stops shall be at least 18 in. (450 mm) deep.
- (3)
The draft stops shall be of noncombustible or limited-combustible material that will stay in place before and during sprinkler operation.
9.3.5.3 Sprinklers.
9.3.5.3.1
Sprinklers shall be spaced not more than 6 ft (1.8 m) apart and placed 6 in. to 12 in. (150 mm to 300 mm) from the draft stop on the side away from the opening.
9.3.5.3.2
Where sprinklers are closer than 6 ft (1.8 m), cross baffles shall be provided in accordance with
10.2.5.4.2.
Where the features of the opening warrant sprinklers that are spaced at intervals of less than 6 ft (1.8 m), as described in
9.3.5.3.2, the installation of baffles between adjacent sprinklers prevents the occurrence of the cold solder effect. The use of such devices is discussed in the commentary following
10.2.5.4.2 for standard spray sprinklers.
Sprinklers used to achieve the protection outlined in
9.3.5 can be of the open type or the automatic type. Privately conducted tests using closed sprinklers have indicated their effectiveness. The use of deluge-type water curtains has become quite rare since the early 1960s. Accidental discharge of deluge-type water curtains results in considerable water damage, as well as potential injury to persons on escalators.
9.3.5.4 Large Openings.
Closely spaced sprinklers and draft stops are not required around large openings such as those found in shopping malls, atrium buildings, and similar structures where all adjoining levels and spaces are protected by automatic sprinklers in accordance with this standard and where the openings have all horizontal dimensions between opposite edges of 20 ft (6.1 m) or greater and an area of 1000 ft2 (93 m2) or greater.
