curtain board

curtain board

[′kərt·ən ‚bȯrd] (building construction) A fire-retardant partition applied to a ceiling.

curtain board, draft curtain

A substantial noncombustible curtain, hung tightly against a roof or ceiling along the perimeter of a special-hazard area; acts as a partition in directing heat and smoke within the curtained area toward vents and preventing the spread of fire.