What is the maximum flame spread and smoke development rating for duct covering insulation in assembly occupancy?

The maximum flame spread and smoke development rating for duct covering insulation in assembly occupancy is established by the relevant building codes and standards, which typically set stringent requirements to ensure safety in public facilities where large groups of people may gather.

In assembly occupancies, where the risk associated with fire and smoke is heightened due to the number of occupants and the potential for rapid fire spread, it is necessary for materials used in construction, including duct coverings and insulation, to exhibit low ratings.

A flame spread rating of 25 indicates that the material has a slow rate of flame spread, which is crucial in reducing the speed at which a fire can propagate through the ductwork, thereby giving occupants more time to evacuate safely. In addition, a smoke development rating of 50 limits the amount of smoke generated, which is important because smoke can impede visibility and cause confusion during a fire event.

Therefore, the correct choice reflects the standards that are typically implemented to promote safety in environments designed for assembly, ensuring that the materials used do not significantly contribute to the hazards associated with fire and smoke during an emergency.