This Aura Gravity Ventilator is 8 inches in diameter and has an 8 inch tall collar or neck. Model number is AV-08-C08 and has 50 inches of net free area (NFA). All 8 inch gravity ventilators come with a standard 13″ x 13″ square flange flashing.
Aura Gravity Exhaust Ventilators with an 8 inch tall collar are for ventilating flat or low slope roofs. Most roofs have a pitch to them, even roofs that are considered flat. For this reason, Aura exhaust gravity vents work efficiently if they are installed on the upper portion of a low sloped roof since warm air rises. This particular gravity vent can go on a 0/12 to 7/12 pitch roof. Roof vents of this tall height are not recommended for steep slope roofs.
The Aura Gravity Ventilator works like a roof turbine but with no moving parts.
Aura Gravity ventilators rely on the Venturi Effect (the creation of an upward draft) when wind blows against the outer louvers.
Even the smallest breeze can create exhaust ventilation so that air is drawn out of the gravity vent. This movement of air is proportional to the wind speed, and is measured in cubic feet per minute (CFM). Wind speeds of 11 mph for a 8 inch Aura Gravity Ventilator, produces 185 cfm of air exhaust for attic ventilation.
With an 8 inch tall collar these gravity vents are rated for both tropical and temperate climates. This covers regions that experience a decent snow pack. Occasional snow storms that drop a foot or more of snow will not adversely affect these roof vents.
Aura Gravity Ventilators are UL Listed and rated up to 50+ PSF or wind pressure above 200 MPH. Certified by Texas Department of Insurance, Florida State Approved & Conforms to the Standards of CALFIRE.