NFPA 96 Fire Codes for Rooftop Grease Containment
7.8.2 Rooftop terminations
188.8.131.52 Rooftop termination shall be arranged with or provided with the following:
(4) The ability to drain grease out of any traps or low points formed in the fan or duct near the termination of the system into a collection container that is noncombustible, closed, rainproof, and structurally sound for the service to which it is applied and that will not sustain combustion.
(5) A grease collection device that is applied to exhaust systems that do not inhibit the performance of any fan.
 Listed grease collection systems that meet the requirements of 184.108.40.206(4) and 220.127.116.11(5)
8.1 Exhaust Fans for Commercial Cooking Equipment.
18.104.22.168 Upblast fans shall have a drain directed to a readily accessible and visible grease receptacle not to exceed 3.8 L (1 gal).