In the case of Type I hoods, what is the minimum clearance allowed when using gypsum with certain materials?

For Type I hoods, the minimum clearance when using gypsum in conjunction with certain materials is indeed 0 inches. This provision is established to accommodate the use of non-combustible materials, as gypsum board is classified as non-combustible when tested in accordance with recognized standards. Consequently, when a Type I hood is installed with non-combustible materials like gypsum, there is no required minimum clearance to maintain, since these materials do not pose a fire risk that would necessitate additional space.

In the context of mechanical code, Type I hoods are typically used over cooking appliances where grease-laden vapors are produced. The design and installation of these hoods, including clearance specifications, are crucial for ensuring proper ventilation and fire safety. Since gypsum board has the fire-resistance characteristics that allow for strict clearance requirements to be relaxed, the code allows for this closer proximity. This is important for space efficiency in kitchen designs, where higher clearances could complicate layout and functionality.