Kitchen Catastrophe: Access Panels Fire Hazard

Kitchen Catastrophe: Access Panels Fire Hazard!!!  What’s wrong with this Grease Duct Access panel and inline fan connection?

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Well there are three obvious things:

  1.  The first problem is the fasteners (screws) penetrate into the grease duct, which is a big no no in NFPA-96: Fasteners, such as bolts, weld studs, latches, or wing nuts, used to secure the access panels shall be carbon steel or stainless steel and shall not penetrate duct walls.

The reason why you should never penetrate the grease duct is because if you do so, the hole created by the screw will not be liquid tight.  Thus it will allow grease and any fire/ smoke within the duct to potentially escape.  Further to this, and to a lesser degree grease can build up on and around the screw and create the potential for a fire.

  1.  The second problem is there is no gasket or sealant between the duct and access panel: Access panels shall have a gasket or sealant that is rated for 1500F and shall be grease tight.

Any time you have two separate metal components fastened together by screws there needs to be a gasket or sealant between them to protect against leakage of grease and smoke.

  1.  The third problem is the connection to the fan.  Again screws are used to fasten the grease duct to the fan.  Same problems as the screws used to fix the access panels. In-line fans shall be connected to the exhaust duct by flanges securely bolted as shown in Figure through Figure or by a system specifically listed for such use.


For the first mistake the contractor should have welded threaded fasteners to the outside of the grease duct.  Thus never penetrating the duct.

For the second mistake the contractor would apply a gasket or silicone sealant rated to 1500F between the panel and duct.

For the third mistake the following steps are to be taken [NFPA-96 2010 (d)]:

  1. ¼” carbon or stainless steel studs welded 4” on centre to the inline fan.  
  2. Apply a sealant rated to 1500F around the opening  
  3. Weld a 1”x1”x 1/8” angle flange to the duct
  4. Bolt the duct to the inline fan with a lock washer


If you are planning on opening a restaurant please seek out experienced and qualified contractors/ engineers.

Any questions feel free to contact us: or 604-837-8594