I had a conversation today with a fire suppression company about distance between hoods that may need to have simultaneous operations. I'm aware that then the are back-to-back without separation, end-to-end, or share common ducts the simultaneous operation is needed.
The question if one hood is on one wall of the kitchen and the second hood is on a wall perpendicular to the first wall. What would be the separation required the two to not need simultaneous operation??
Our Codes really don't address this to a point. NFPA 96 states the following:
10.3 Simultaneous Operation
10.3.1 Fixed pipe extinguishing systems in a single hazard area (see 3.3.44 for definition of single hazard area) shall be arranged for simultaneous automatic operation upon activation of any one systems
3.3.44 Single Hazard Area. Where two or more hazards can be simultaneously involved in fire by means of their proximity, as determined by the authority having
10.3.1.1 talks about positioning as noted above'.
10.3.1.2 Hoods installed end to end, back to back, or both that do not share a common exhaust duct and are separated by a wall(s) or other means to assure that grease laden-vapors exhausted under one hood cannot propagate to the other hoods' fore-extinguishing system(s) shall be independent and shall not be required to simultaneously discharge.
Based on the language in 10.3.1.2 what is the distance that grease-laden vapors are not pulled from one hood to the other?
Based on the language in 3.3.44 I can see that even thought the hoods are not butted up as noted in first paragraph that the adjacent hoods on two different walls could be pulling vapor from one to another.
Looking for some thoughts. Getting ready for a hood replacement project that could impact an existing hood.
Thanks
