Name: Air Relief Valve DN150 Double Flange Two Chamber
Brand: Supreme Valves India
SKU: ARV-DN150-2CH
Availability: InStock
Rating: 4.8 (127 reviews)

Question 1

What does a two-chamber air relief valve do?

Accepted Answer

A two-chamber air relief valve combines two functions in a single valve body: (1) Air Relief Chamber — automatically releases accumulated air from a water pipeline during operation. When air collects in the upper chamber (due to being denser than water), the float drops, opening the air release orifice. Compressed air escapes to atmosphere, and the float then rises to close the orifice once water fills the chamber. (2) Vacuum Relief Chamber — prevents vacuum formation (negative pressure) inside the pipeline. When the pipeline drains or experiences rapid shutdown, vacuum can form as water column separates. The vacuum relief chamber opens to admit atmospheric air into the pipeline, preventing pipe collapse, infiltration of contaminated water through joints, and protection of downstream equipment. The DN150 two-chamber valve is the standard size for DN300–DN600 trunk mains.

Question 2

Why is a two-chamber design better than two separate valves?

Accepted Answer

A combined two-chamber air relief/vacuum relief valve offers three advantages over installing separate air release valve and vacuum breaker valves: (1) Single body, single flange connection to the pipeline — reducing installation cost and potential leak points by half; (2) Space savings — critical in chambers with limited headroom (e.g., under highway crossings); (3) The two chambers work independently inside a shared cast body, so one function can operate while the other is sealed. This is the standard specification for water transmission projects globally. For DN150 connection to DN300–DN600 mains, the two-chamber valve is the most cost-effective and hydraulically efficient solution.

Question 3

What is a 'double flange' air relief valve and when is it required?

Accepted Answer

A double flange air relief valve has flanges on both the inlet (pipeline connection) and outlet (discharge) sides of the body. The inlet flange connects to the pipeline air chamber or tee. The outlet (discharge) flange directs the discharged air/water mixture to a collection gutter or drainage channel. Double flange valves are used where the discharge must be captured and channeled away — particularly in pressurized pipelines where the discharged air could otherwise spray or cause flooding in a chamber. Single flange valves (with a threaded discharge port) are used where discharge can drip freely. For DN150 trunk mains in municipal water projects, double flange is the standard specification.

Question 4

What causes air to accumulate in water transmission pipelines?

Accepted Answer

Air enters water pipelines through several mechanisms: (1) Dissolved air coming out of solution when water temperature increases or pressure decreases along the pipeline profile; (2) Air pockets formed during pipeline filling or emptying procedures; (3) Air drawn in through joints and seals when vacuum forms; (4) Air intentionally or accidentally introduced during maintenance (pigging, filling operations). Air pockets reduce effective pipe cross-section (causing headloss and reduced throughput), cause water hammer when they pass through valves or fittings, can cause corroded pipe surfaces above the waterline, and in extreme cases can block flow entirely at high points. Air relief valves at high points are essential for efficient pipeline operation.

Question 5

What is the difference between an air release valve and an air relief valve?

Accepted Answer

The terms are often used interchangeably, but there is a technical distinction: (1) Air Release Valve (ARV) — has a small orifice (2–6mm) that releases small volumes of compressed air during pressurized pipeline operation. It operates when the pipeline is under pressure, releasing air that has come out of solution. (2) Air Relief Valve (also called Air Vent Valve) — has a larger orifice that opens when the pipeline is being filled or drained, releasing or admitting large volumes of air at low pressure. The two-chamber design combines both functions: the small-orifice chamber handles continuous air release during operation; the large-orifice chamber handles filling/draining and vacuum relief. Some specifications call the combination 'Kinetic Air Valve' or 'Combination Air Valve'.

Question 6

What maintenance do air relief valves require?

Accepted Answer

Air relief valves require periodic visual inspection and testing: (1) Float functionality — verify the float rises when water enters and falls when air is present; (2) Orifice seal — check that the seal seat is not worn or fouled (particularly in raw water or partially treated water); (3) Discharge port — ensure the outlet is clear and not blocked by debris; (4) Isolation valve — verify the upstream isolation valve (if installed) is functional. For valves in raw water applications, annual inspection of the float for corrosion or puncture is recommended. Many modern air relief valves have a test/isolation plug that allows the valve to be isolated and inspected without shutting down the main pipeline.

Component	Material Specification
Body & Bonnet	Ductile Iron (ASTM A536 / EN-GJS-400-15)
Stem / Spindle	SS 410 / SS 420
Seat / Trim	EPDM / NBR / Bronze

Parameter	Specification / Standard
Manufacturing / Design Standard	EN 1171 / AWWA C509 / BS 5163
Testing Standard	API 598 / EN 12266-1
Pressure Rating	PN16 / PN25

Relief Valve DN15/0

Air Relief Valve — DN150 Two-Chamber Double Flange

How the Two-Chamber Air Relief Valve Works

Air Relief Chamber

Vacuum Relief Chamber

Materials of Construction (MOC)

Technical Specifications