External vents

A system for providing forced exhaust through a penetration in a building surface comprising

• a covered vent structure, a duct connector to a duct from an exhaust source within the building, to direct an exhaust flow from the building,
• the covered vent structure being provided with at least one opening perpendicular to the exhaust flow direction,
• the at least one opening comprising a rigid window structure situated at an upstream side of the opening and
• a recessed guide portion tapered in an upstream direction for alignment with the duct connector adapted to extend through the building surface for connection to a duct from the exhaust source with the building,
• the duct connector being provided with integrally formed inward pierced openings,
• the pierced openings having formed on an upstream end of the duct connector, and
• the pierced portion being sloped toward a downstream end of the duct connector,
• wherein when the downstream end of the duct connector is slidably engaged with the upstream end of the covered vent structure, and
• the sloped pierced and bent inward portions align with the window portions and both are stretched during engagement until the duct connector enters the windows of the covered vent structure,
• whereupon both portions return to their original shapes and become permanently locked together.