Definition
In-rack heads supplement (or replace) ceiling sprinklers when storage height exceeds the listed maximum free height for ESFR or CMSA. EN 12845 specifies in-rack levels every 3.5 m of storage above the limit; NFPA 13 follows similar logic with horizontal and longitudinal barriers. Hydraulically demanding — typically 4–8 heads per branch line operating simultaneously.
Referenced in
- EN 12845
- NFPA 13