Section 903.3.3 of the IBC and the obstruction rules of NFPA 13 allows for sprinkler omission under obstructions less than 4ft wide. The intent of NFPA 13 is that the width of an object is the lesser of the two horizontal dimensions (with the length being the longer horizontal dimension). As such, sprinkler protection is not required under objects where the length is greater than 4 feet and the width is 4 feet or less. The ROOM Phone Booth is less than 4ft wide, therefore it meets the obstruction requirements per both IBC and NFPA 13.
Some AHJ require more stringent requirements for the buildings and in those cases, we can provide an access point for sprinkler installation.
Please reach out to us at firstname.lastname@example.org if you have additional questions.