What is the correct construction type for Type I hoods over heavy-duty appliances?

Type I hoods are specifically designed to handle the grease and heat produced by heavy-duty appliances, such as fryers and griddles. The correct construction type for these hoods is steel, as it provides the necessary durability, heat resistance, and fire safety required in commercial kitchens.

Steel is non-combustible, which is essential for preventing the spread of fire that could occur due to the high temperatures and fatty residues associated with heavy-duty cooking appliances. Additionally, steel hoods can be easily cleaned and maintained to ensure they remain effective in capturing and filtering grease particles, which is a critical part of fire safety and kitchen hygiene.

Other materials, like fiberglass or wood, do not provide the necessary fire resistance and can compromise safety standards required by mechanical codes. Thermal insulation, while important in some contexts, does not fulfill the structural requirements of a Type I hood, which must withstand the physical demands and potential fire hazards inherent in cooking operations.