What is the acceptable material for all kitchen vent ducting?

For kitchen vent ducting, metal with a smooth inside is considered the most acceptable material. This is primarily due to its durability, fire safety, and efficiency in handling high temperatures and moisture that are common in kitchen environments. Metal ducts can withstand higher heat levels without warping or melting, which is particularly important given that kitchen exhaust systems are designed to handle smoke, steam, and grease-laden air.

Additionally, metal ducting reduces the risk of fire, an essential consideration when venting appliances like stoves and ovens. The smooth inner surfaces of metal ducts promote better airflow, minimizing friction and potential blockages that could occur with textured surfaces. This efficient airflow is crucial to effectively remove cooking odors and byproducts, ensuring proper ventilation.

In contrast, other materials presented in the choices do not meet the safety and performance standards required for kitchen venting. Plastic is not recommended due to its susceptibility to heat and potential melting. Flexible ducts can be less rigid and may create traps for grease, while cardboard is not suitable at all due to its flammability and lack of durability in humid or high-temperature environments. Overall, metal ducts with a smooth interior are the preferred choice for safety and efficiency in kitchen venting systems.