Clothes dryer exhaust ducts should not be located within assemblies required to be what rating?

Clothes dryer exhaust ducts should not be located within assemblies required to be fire-resistant due to the potential fire hazards associated with lint accumulation and the high temperatures that can occur during dryer operation. Fire-resistant assemblies are designed to prevent the spread of fire and ensure that building occupants have enough time to escape in the event of a fire. Placing exhaust ducts within these assemblies could compromise their effectiveness, as any lint buildup could act as a fuel source, increasing the risk of ignition and fire spread.

Moreover, ensuring that dryer vents are routed properly and do not penetrate fire-rated walls or ceilings helps maintain the integrity of the fire-resistance rating, thereby enhancing the overall safety of the building. This standard is imposed to protect both the structure and the occupants from the dangers associated with dryer exhaust systems.