Grease fires are the #1 kind of restaurant kitchen fires, Insurance companies and local fire codes mandate having your entire hood system cleaned on a regular basis. The grime and grease that accumlates under the hood over time and may drip on the grills and start a fire. Kitchen Exhaust Cleaning should always include the following:    Fan- Including Bowl and Blades Grease Containment System- This is mounted on Exterior of fan and prevents grease from landing on rooftop Ductwork and all access panels untill reaching Hood Hood- Plenum Area located behind Grease Filters all Grease Tracks and exterior of hood  All areas of your entire exhaust system need to be cleaned to bare metal to be in compliance with your Insurance company, Fire Inspectors, Health Department. Below is the recommended NFPA 96 Exhaust System Inspection Schedule Type Or Volume Of Cooking Frequency Systems serving solid fuel cooking operations--- MONTHLY Systems serving high volume cooking such as 24 hour cooking,charbroiling, or wok cooking-- QUARTERLY Systems serving moderate volume cooking operations-- SEMIANNUALLY Systems serving low-volume cooking operations--ANNUALLY ...read more