Automatic Air Release Valve -- Single Chamber Cast Iron
Float-Operated Automatic Air Vent for Water Pipelines and Pump Stations
Document No.SV-DS-WAT-001
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers single-chamber automatic air release valves in cast iron with epoxy coating for automatic venting of accumulated air from water distribution pipelines, pump stations, and tank outlets.
Technical Specifications
| Parameter | Specification |
|---|
| Size Range | DN25 to DN100 (1" to 4") |
| Pressure Rating | PN10 / PN16 / Class 150 |
| Body Material | Cast iron GG25, epoxy coated inside and out |
| Float Material | Polyethylene or SS304 hollow float, leak tested |
| Orifice Size | 1.5 mm to 6 mm depending on pressure class |
| Temperature Range | 0°C to +80°C (water service) |
| Operating Principle | Float rises with water to close orifice; drops as air accumulates to vent |
| End Connections | Screwed NPT / BSPT, flanged BS EN 1092-1 PN10/16 |
| Features | Single chamber, float operated, small orifice, anti-shock, drain plug |
| Coating | Fusion-bonded epoxy (FBE) 250 µm minimum |
Materials of Construction
| Component | Material |
|---|
| Body | GG25 cast iron, sand cast, machined orifice and float chamber, epoxy coated |
| Cover | GG25 bolted cover with gasket groove and vent outlet |
| Float | Polyethylene or SS304 thin-walled hollow float, leak tested, guided by SS304 cage |
| Orifice Plug | Brass or SS316 precision-machined orifice with smooth edge to prevent float cutting |
| Seat | NBR or EPDM rubber seat ring, replaceable, captured in orifice plug |
| Guide | SS304 float guide cage with anti-rotation ribs |
| Gasket | EPDM rubber gasket for body/cover joint |
| Hardware | SS304 bolts, nuts, and washers for wet environment corrosion resistance |
Testing & Inspection
| Test | Requirement |
|---|
| Test Standard | Hydrostatic shell test 1.5x PN; float action test at operating pressure |
| Certification | CE, ISO 9001, WRAS on request |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | BS EN 1074-4 / AWWA C512 |
Notes
- Air release valve must be installed at highest points of pipeline and at regular intervals (typically every 500 m to 1 km on level ground).
- Orifice size must be selected based on operating pressure; larger orifices at low pressure provide higher air discharge capacity.
- For sewage or effluent service, specify SS316 float and anti-clogging orifice shield to prevent solids fouling the small orifice.
- Fusion-bonded epoxy coating must be inspected for damage after installation; touch up with compatible epoxy if scratched.
- In freezing climates, install valve in an insulated pit or specify thermostatically controlled heater to prevent ice formation in chamber.
