VENTILATION DUCT UNIT

The object of this invention is a ventilation duct unit (1), which comprises an inlet (2), an outlet (3), a flow channel (4), which extends from the inlet to the outlet, and which is delimited by a wall (5) between the inlet and the outlet, a closing part (6), which is arranged into the flow channel, and which in open position enables flow in the flow channel (4), and in closed position prevents flow in the flow channel, and a closing member (12), which as a response to detecting fire, sets the closing part (6) to a predetermined position. In order to test the functioning of the closing part of the ventilation duct unit simply, easily and quickly in case of fire, the ventilation duct unit comprises a position switch (20) of the closing part (6), which is in first state, when the closing part (6) is in said predetermined position, and which is in second state, when the closing part (6) is not in said predetermined position, and a fire testing unit (21), which at predetermined times triggers testing of the fire safety functions, wherein the closing member (12) sets the closing part (6) to said predetermined position, and which after triggering testing of the fire safety functions indicates that testing of the fire safety function was successful, if it detects that the position switch (20) of the closing part (6) is in first state.