N.Y.C. Admin. Code § 27-957: § 27-957 Sprinkler alarm system.

(a) A sprinkler alarm system shall be provided in accordance with the applicable provisions of reference standards RS 17-2, RS 17-2A, RS 17-2B and RS 17-3. Where the building is provided with a class E or modified class E fire alarm signal system, compliance with the applicable provisions of reference standard RS 17-3A or RS 17-3B shall be acceptable in lieu of compliance with provisions of reference standard RS 17-3.

(b) A sprinkler alarm system shall be required when more than thirty-six heads are installed in any fire area or section. See table 17-2 for general requirements.