I noticed this at a local home improvement store the other day. I don’t know if this is one of those normal things that I just haven’t noticed at other locations after all these years.
There are doors going from the partially enclosed outdoor/garden section to the main structure. Each of set of doors has a cluster of 3 deluge heads mounted about 2 feet above. These are NOT part of the dry sprinklers that the outdoor section has installed. There doesn’t seem to be any initiating device in that section for activation. Has anyone else seen something like this or worked on a system of this nature?