On a routine site survey to upgrade a base building we came across an existing restaurant adjacent to our space. We hope that this blog may be helpful for restaurant owners, trades and engineers alike to avoid some fire risks.
The photo below is of a grease duct access panel. Access panels are required in specific locations such that the grease duct may be easily and safely cleaned. Since the access panel is above 10′-0″ a work platform must be installed or an approved anchoring system as approved by WSBC. As per NFPA-96:
NFPA-96- Section 7.4.2 Vertical Ducts, Sentence (3): If not easily accessible from the floor or a 3 m (10 ft) stepladder, openings on vertical grease ducts shall be provided with safe access and a work platform.
In the photo below we have a grease duct connecting into an upblast kitchen exhaust fan. The issue here is that the exhaust will contain grease laden vapours and when tight elbows are used, centrifugal acceleration will result in the grease from the airstream to impinge in the grease duct wall. This will cause the build-up of grease increasing the risk of fire. Best practice would be to either use long turning radius elbows or better; install a utility kitchen exhaust fan
Here we have a grease duct access panel that has corrosion due to a missing 2nd coat of paint. The paint protects the grease duct from the elements and thus from rusting. NFPA-96 states that all 16 gauge black iron duct exposed to the elements must be painted:
NFPA-96- Section 7.6.4 All ducts shall be protected on the exterior by paint or other suitable weather-protective coating.
Further to the photos above we have a similar situation where the grease duct connecting to the kitchen exhaust fan is not painted at all.
Lastly we see some of the dangerous results of not properly weather proofing the grease duct. Corrosion has created a hole in the grease duct allowing grease to spill out. Over time the grease will build up on the roof creating a fuel source for a fire. The grease duct contains hot gases and sometimes fires in the event of the cooking appliances igniting. This potentially could ignite the grease causing the building to catch fire.
Any questions please feel from to comment or email us:
James Hicks P.Eng.
Evolve Mechanical Solutions
604.837.8594
#Fail #NFPA96