Cross Zone Detection for Gas Suppression system.
Cross-zoning is a design decision to achieve a specific fire performance objective that is well beyond the requirements of any code or standard. Basically you are trying to optimize or improve your design; so, NFPA 72 or other codes do not tell you to do this nor do they prevent you from doing it. It is professional judgment based on the risk, the configuration of, and the available fire hazards in the room or structure you are protecting. In NFPA 72 (2019), cross-zoning detection would be covered in general under Section 126.96.36.199 Nonrequired Coverage.
Edit: See past posting on cross-zoning here - https://community.nfpa.org/message/61062?commentID=61062#comment-61062
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