Air Release Valves Explained: Single vs Double Orifice
Air trapped in a water pipeline reduces flow capacity, causes pressure surges, and accelerates corrosion. An air release valve exists specifically to vent that trapped air automatically, without needing anyone to manually bleed the line. Jaideo Automation supplies air release valves for water distribution and building water systems.
How an Air Release Valve Works
Inside the valve, a float rises and falls with the water level in the valve body. When air accumulates and pushes water down, the float drops and opens a small orifice, venting the trapped air to atmosphere. Once the air has escaped and water rises back up, the float lifts and reseals the orifice, preventing water loss during normal operation.
Single Orifice vs Double Orifice (Chamber) Air Valves
A single orifice air valve uses one float and one venting orifice, suited to smaller air volumes and lower flow lines. A double orifice (double chamber) air valve adds a second, larger orifice specifically for high-volume air release during pipeline filling or draining, when much larger quantities of air need to escape quickly, alongside the smaller orifice for ongoing small air-pocket release during normal operation.
Comparison
| Single Orifice | Double Orifice | |
|---|---|---|
| Air venting capacity | Lower | Higher — handles bulk air release |
| Best for | Smaller lines, general air pocket release | Larger pipelines, filling/draining events |
| Complexity | Simpler | More components (two chambers) |
Why Air Release Matters
- Prevents pressure surges caused by trapped air pockets collapsing suddenly
- Maintains flow capacity — trapped air reduces the effective cross-section available for water flow
- Reduces corrosion — trapped air accelerates internal pipe corrosion at the air-water interface
- Protects pumps from air-related cavitation and performance loss
Where Air Release Valves Are Installed
Typically specified at high points in a pipeline profile, where air naturally accumulates, and at the start of long transmission mains where initial filling requires significant air release capacity.
Where This Fits
For the complete valve and flow-control selection picture across Jaideo’s range, see our Industrial Valve Selection Guide.
Frequently Asked Questions
What does an air release valve do?
An air release valve automatically vents air trapped in a water pipeline, using a float that opens an orifice when air accumulates and reseals once water returns.
What is the difference between a single and double orifice air valve?
A single orifice air valve handles smaller air volumes through one venting orifice, while a double orifice valve adds a second, larger orifice for high-volume air release during pipeline filling or draining.
Where should air release valves be installed on a pipeline?
Air release valves are typically installed at high points along a pipeline profile, where trapped air naturally accumulates, and at the start of long transmission mains.