§ 27-521.8 Smoke control.
AC § 27-521.8
(a)In all atriums there shall be provided a system of mechanical ventilation of sufficient capacity to exhaust at least six air changes per hour of the combined volumes of the atrium and all spaces with an open connection to the atrium, or 1 cfm/sq. ft. from all such spaces, whichever is greater, using either dedicated fan equipment or the building ventilation system arranged to shut down automatically, with manual override capability. Make-up air shall be supplied at the lowest level of an atrium at a rate equal to seventy-five percent of exhaust.
(b)All atriums shall have a gravity ventilation system equipped with remote manual controls to remove smoke if the mechanical exhaust system fails.
(c)A ventilation system serving an atrium shall not be interconnected with any other system serving another space.
(d)Ventilation systems supplying occupied spaces shall not be interconnected with the general atrium supply.
