NFPA 96-2011 18.104.22.168 (2) regarding roof top terminations states "roof top terminations shall be arranged or provided with the following... (2) a minimum of 1.5m (5ft) of horizontal clearance from the outlet to any combustible structure...".
In this project, we are wanting to have an in-line fan inside the attic, and then discharge up through the roof. The question is what is considered "horizontal" clearance for this application. Our understanding is as follows.
Any comments on the proposed would be greatly appreciated. For information, the building is 4 storeys and of combustible construction. We are limited on the permitted height of the discharge due to specifics of the project. I will note, IMC 506.3.13.1 does require a minimum 40" vertical clearance above the roof for terminations, but I do not see the same requirement in NFPA96.