A common question in ventilation design is: “How does a building exhaust air when fresh outdoor air is being introduced?”
One simple, passive solution is a Barometric Relief Damper, also known as a gravity relief damper.
One simple, passive solution is a Barometric Relief Damper, also known as a gravity relief damper.
What Is Barometric Relief?
A barometric relief damper contains lightweight metal blades that open automatically when indoor pressure rises above outdoor pressure. This creates a low-resistance path for excess air to exit the building. When indoor pressure falls, the blades swing closed to help prevent outside air from being pulled back in.
Barometric relief is typically installed on the return-air side of an HVAC system, often integrated directly into an economizer.
Why Building Pressure Matters
Introducing fresh outside air without a way for excess indoor air to escape causes positive building pressure. When pressure becomes too high:
- Doors can be difficult to open or may blow open
- Air can force its way through cracks and openings
- Conditioned air escapes, increasing energy consumption
- Elevator shafts may whistle
- Excessiv