API · ASME · DIN · EN standard industrial valves
Double Orifice Air Valves
Double orifice air valves pair a large-orifice stage with a small-orifice stage in one body: the large stage discharge bulk air while pipelines fill and admit air while they drain, and the small stage bleeds the pockets that collect under pressure — the combination that protects transmission lines at both filling and steady state. The range covers body, bonnet, gland and cap top in ductile iron or cast iron with an SS304 ball, SS420 stem and stem nut, NBR gasket and SS304 or carbon-steel bolting, DN80 to DN200 at Class 150 to Class 300 or PN16 to PN40, built to DIN 3352 with DIN 2501 flanges and BS 6755 testing. Selection turns on line size, filling and draining velocity, and pressure class against the PN/Class band.
Part of the Air Release Valves family
Last updated: 2026-11
Family specifications
| body materials | Ductile Iron, Cast Iron |
|---|---|
| ball materials | SS304 |
| gland materials | Ductile Iron, Cast Iron |
| cap top materials | Ductile Iron, Cast Iron |
| washer materials | SS304, Carbon Steel |
| nut materials | SS304, Carbon Steel |
| bolt materials | SS304, Carbon Steel |
| gasket materials | NBR |
| stem materials | SS420 |
| stem nut materials | SS420 |
| size range | DN80 to DN200 |
| pressure class | Class150 to Class300, PN16 to PN40 |
| design standards | DIN3352 |
| flange standards | DIN2501 |
| testing standards | BS6755 |
| aav series | series 851 |
| aav orifice configuration | double orifice, triple action |
| aav design | double orifice, triple action air valves are designed to allow air to rapidly either escape or enter the pipe system when filling or draining, as well as for automatic discharge of accumulated air during normal working conditions. |
| aav aerokinetic design | The unique ‘Aerokinetic’ design allows air to rush out of the system at great speed without forcing the float upwards and closing it prematurely. |
| aav application | Air relief valve for drinking water (not wastewater) and neutral liquids |
| aav max working temperature | 70° C |
| aav model variant | 851/45-001 |
| aav end connections | Flanged |
| aav body material | Ductile iron |
| aav size range | DN50 - DN200 |
| aav pressure rating | PN16 |
| aav trim materials | SS 316 float, float guides and guide ring, A4 bolts |
| aav coating | 300μm coating |
| aav internal parts material | AISI 316 stainless steel |
| aav seal material | WRAS approved EPDM rubber |
| aav coating standard | DIN 3476 part 1 and EN 14901, GSK approved |
| aav features | A clever float design prevents air rushing out of the system from prematurely closing the valve, Large air flow capacity, No moving parts are touching the internal coating, The complete product is approved for drinking water |
| aav size table | 851-050-45-122000, 851-080-45-122000, 851-100-45-122000, 851-150-45-122000, 851-200-45-122000 |
| ddt typology | Double Orifice Air Valves |
| ddt size range | DN 50 - 200 |
| ddt pressure range | PN 10 - 40 |
| ddt body material | EN-JL1040 |
| ddt coating | inside enameled, outside epoxy / inside and outside epoxy |
| ddt application | Automatic air admission and air release of water pipelines in plants, buildings and valve chambers. |
| ddt media | potable water |
| ddt functions | Automatic air admission and release of the pipeline during filling, operational air release and during the emptying process. |
| ddt design features | Compact design with low weight, Large cross-section with maximum air admission and release rates |
| ddt operation | Automatic operational air release via lever with patented self-cleaning during each switching cycle |
| ddt coating options | Internally enamelled, or epoxy coated |
| ddt seawater option | Also available for seawater application |
| dga design | Double orifice air valve that combines both large orifice & small orifice functions within one unit. |
| dga low pressure sealing | Efficient low pressure sealing at 0.2bar. |
| dga size options | 50mm (2”) - 150mm (6”) |
| dga threaded connection | NPT threaded. |
| dga flanged inlet | Flanged inlet with various drillings. |
| dga outlet facility | Screwed outlet facility. |
| dga seal material | Viton rubber. |
| dga float options | Metal float assembly options. |
| dga orifice size | 9.5mm orifice size available. |
| dga options | Inflow / outflow check., Flushing attachment., Drainage boss., Isolating gate valve with or without bevel gearbox., Odour control unit., 25 bar version. |
| dga flange standard | EN 1092-2: 1997 PN16 |
| dga design standard | EN 1074-4 |
| dga application | Wastewater/Sewage |
| dga body test | 1.5 x PN |
| dga seat test | 1.1 x PN |
| dga working pressure | 0.2 - 16 Bar |
| dga working temperature | 0°C - 70°C |
| dga pressure class | PN16 |
| dga size range | DN50-150 |
| dga model | Fig 942 |
| dga model variants | 942 Standard Valve, 942LP Squat type / Low pressure valve, 942HP High pressure PN25 rated valve |
| dga body material | Ductile Iron |
| dga internal materials | 316 Stainless Steel |
| dga o ring material | Nitrile Rubber |
| dga sizing | Up to 200mm 1” outlet valve, Up to 450mm 2” outlet valve, Up to 600mm 3” outlet valve, Up to 900mm 4” outlet valve, Up to 1200mm 6” outlet valve |
| gasket | NBR |
| flanged end dimension | DIN2501 |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of double orifice air valves?
The published specification for this family lists DIN3352 as the design standards. Testing follows BS6755.
What sizes and pressure ratings are available for double orifice air valves?
The published size range is DN80 to DN200, and the published pressure ratings are Class150 to Class300, PN16 to PN40. Availability of a specific size and rating is confirmed at quotation.
What materials are double orifice air valves available in?
The published specification lists body materials: Ductile Iron, Cast Iron. Material availability for a specific size and rating is confirmed at quotation.
What should a quotation inquiry for double orifice air valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
Request a quote for double orifice air valves
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Get a quotation for Double Orifice Air Valves
Send the standard, pressure class and size for a quotation-ready inquiry — answered with documents and terms.