Vacuum Breaker Valves | McMaster-Carr

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	Pipe Size Pipe Size

	Thread Type Thread Type

GHT

NPT

	Body Material Body Material

	For Use With For Use With

	Connection Style Connection Style


Threaded	Unthreaded

	Mounting Orientation Mounting Orientation

Horizontal

Vertical

Any Position

	Shape Shape


Straight	90° Elbow

	Maximum Pressure Maximum Pressure

	Gender Gender


Female	Male

	Valve Type Valve Type	Show

Vacuum Breaker

	Valve Type Valve Type	Hide

	Connection Type Connection Type


Pipe	Tube

Hose

	Connection Connection

Inlet

Outlet

	Valve Function Valve Function

Backflow Prevention

	Maximum Temperature Maximum Temperature

100° to 249.9° F

250° to 499.9° F

	Minimum Temperature Minimum Temperature

-49° to 0° F

1° to 99° F

	Actuation Actuation

Vacuum

	Fitting Type Fitting Type

Connector

Adapter

	Flow Coefficient (Cv) Flow Coefficient (Cv)

4.6

6.6

Not Rated

	Seal Material Seal Material

EPR Rubber

Fluoroelastomer Rubber

Rubber

Silicone Rubber

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

	Color Color

	Light Gray
	Gray

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	System of Measurement System of Measurement

Inch

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42 Products

About Backflow-Prevention Valves

Vacuum-Breaking Valves

Also known as vacuum breakers, these valves have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping.

Chrome-plated bronze valves are more corrosion resistant than brass valves.

303 stainless steel valves have the best corrosion resistance.

Elbows are designed for intermittent flow. They discharge liquid directly and should not be installed in areas where spillage could cause damage.

Straights are often used with steam coils, heat exchangers, and space heaters.

For technical drawings and 3-D models, click on a part number.

Elbows

For Use With: Water
Seal Material: Silicone Rubber

				Brass Body		Chrome-Plated Bronze Body
Pipe Size	Max. Pressure	Temperature Range, °F	Port-to-Port Lg.		Each		Each
NPT Female Inlet × NPT Female Outlet
1/4	125 psi @ 70° F	35° to 180°	1"	000000	00	0000000	000000
3/8	125 psi @ 70° F	35° to 180°	1"	000000	00	0000000	00000
1/2	125 psi @ 70° F	35° to 180°	1 1/4"	000000	00	0000000	00000
1/2	125 psi @ 70° F	35° to 180°	1 5/16"	00000000	000000	000000	00
3/4	125 psi @ 70° F	35° to 180°	1 1/2"	00000000	00000	0000000	00000
1	125 psi @ 70° F	35° to 180°	1 5/8"	00000000	00000	000000	00
1 1/4	125 psi @ 70° F	35° to 180°	2"	00000000	000000	000000	00
1 1/2	125 psi @ 70° F	35° to 180°	2 1/4"	00000000	000000	000000	00
2	125 psi @ 70° F	35° to 180°	2 3/4"	00000000	000000	000000	00

Straights

NPT Male Inlet ×
NPT Female
Outlet Straight

NPT Male Inlet ×
Unthreaded
Female Outlet

For Use With: Air, Argon, Helium, Krypton, Neon, Steam, Water, Xenon
Seal Material: EPR Rubber

						Brass Body		303 Stainless Steel Body
Inlet Pipe Size	Outlet Pipe Size	For Outlet Tube OD	Max. Pressure	Temperature Range, °F	End-to-End Lg.		Each		Each
NPT Male Inlet × NPT Female Outlet
1/2	3/8	__	300 psi @ 70° F	-20° to 365°	1 3/4"	0000000	0000000	0000000	0000000
3/4	1/2	__	300 psi @ 70° F	-20° to 365°	2 1/8"	0000000	000000	0000000	000000
1	3/4	__	300 psi @ 70° F	-20° to 365°	2 3/8"	0000000	000000	0000000	000000
NPT Male Inlet × Unthreaded Female Outlet
1/2	__	11/16"	300 psi @ 70° F	-20° to 365°	1 3/4"	0000000	000000	0000000	000000
3/4	__	13/16"	300 psi @ 70° F	-20° to 365°	2 1/8"	0000000	000000	0000000	000000
1	__	1 1/16"	300 psi @ 70° F	-20° to 365°	2 3/8"	0000000	000000	0000000	000000

High-Pressure Vacuum-Breaking Valves

For Use With: Air, Argon, Helium, Krypton, Neon, Oil, Water, Xenon
Seal Material: Fluoroelastomer Rubber

Rated for 12 times the pressure of standard vacuum-breaking valves, these can handle up to 1,500 psi. Also known as vacuum breakers, they have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping. Body is 316 stainless steel for excellent corrosion resistance.

Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.

For technical drawings and 3-D models, click on a part number.

316 Stainless Steel Body
Outlet Pipe Size	Inlet Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Temperature Range, °F	End-to-End Lg.		Each
NPT Male × NPT Female
3/4	1/2	4.6	1,500 psi @ 70° F	-10° to 400°	1 5/16"	0000000	0000000
1	3/4	6.6	1,500 psi @ 70° F	-10° to 400°	1 7/8"	0000000	000000

Vacuum-Breaking Valves with Garden-Hose Fittings

With Set Screw

With Tamper-Resistant Set Screw

For Use With: Air, Water
Seal Material: Rubber

Prevent dirty, contaminated water from backing up into your garden hose line—install these valves between a faucet and a garden hose. Also known as vacuum breakers, these valves have a built-in check valve that blocks backflow, so you can leave your hose in a utility sink full of dirty water without the water going back into the line.

When the check valve is closed, it has vents that open to release the water. This reduces pressure in the line and confirms the valve is working. Because these valves vent water, use them in environments where spilled water won’t cause a problem. This design adheres to ASSE Standard 1011 for valves with a vent.

Mount valves to faucet outlets with a set screw, and easily thread or unthread a hose while the valves stay in place.

Valves comply with Uniform Plumbing Code (UPC) and are CSA certified, so they're safe to use in sanitary plumbing systems because they prevent contamination from flowing backward into your line.

These valves are designed to be used intermittently. They've been tested under ASME A112.1.3, which assumes the valves will not be used for more than 12 hours at a time.

Chrome-plated brass valves are more corrosion resistant than plain brass valves.

Valves with tamper-resistant set screws have a head that breaks off after tightening to prevent valve removal after installation.

Valves that meet NSF/ANSI Standard 372 are certified lead free.

					Brass Body		Chrome-Plated Brass Body
Thread Size	Max. Pressure	Temperature Range, °F	End-to-End Lg.	Specifications Met		Each		Each
GHT Female × GHT Male
With Set Screw
3/4"	125 psi @ 70° F	30° to 180°	1 1/2"	ASSE Standard 1011, Uniform Plumbing Code, CSA Certified, CAN/CSA B64.2, ASME A112.1.3	00000000	000000	00000000	000000
3/4"	125 psi @ 70° F	30° to 180°	1 1/2"	ASSE Standard 1011, Uniform Plumbing Code, CSA Certified, CAN/CSA B64.2, NSF/ANSI 372, ASME A112.1.3	00000000	00000	00000000	00000
With Tamper-Resistant Set Screw
3/4"	125 psi @ 70° F	30° to 180°	1 1/2"	ASSE Standard 1011, Uniform Plumbing Code, CSA Certified, CAN/CSA B64.2, ASME A112.1.3	00000000	00000	00000000	00000
3/4"	125 psi @ 70° F	30° to 180°	1 1/2"	ASSE Standard 1011, Uniform Plumbing Code, CSA Certified, CAN/CSA B64.2, NSF/ANSI 372, ASME A112.1.3	00000000	00000	00000000	00000

Vacuum-Breaking Valves for Chemicals

A plastic body withstands pH neutralizing, cleaning, and plating solutions containing sodium hydroxide, methyl ethyl ketone, and other harsh chemicals. Also known as vacuum breakers, these valves have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping.

For technical drawings and 3-D models, click on a part number.

Diaphragm

For Use With: Air, Ammonia, Argon, Beverage, Carbon Dioxide, Chlorinated Water, Diesel Fuel, Drinking Water, Ethylene Glycol, Food, Helium, Hydrochloric Acid, Kerosene, Krypton, Liquid Carbon Dioxide, Methanol, Methyl Ethyl Ketone, Mineral Spirits, Natural Gas, Neon, Nitric Acid, Nitrogen, Oil, Oxygen, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water, Xenon
Diaphragm Material: Fluoroelastomer Rubber
Seal Material: Fluoroelastomer Rubber

PVC Plastic Body
Pipe Size	For Pipe Schedule	Max. Pressure	Min. Opening Pressure, psi	End-to-End Lg.	Color	Temperature Range, °F		Each
NPT Male × NPT Male
1/2	80	100 psi @ 75° F	1	4 5/16"	Gray	40° to 140°	000000	0000000
3/4	80	100 psi @ 75° F	1	4 5/8"	Gray	40° to 140°	0000000	000000
1	80	100 psi @ 75° F	1	5 1/8"	Gray	40° to 140°	0000000	000000
CPVC Plastic Body
NPT Male × NPT Male
1/2	80	100 psi @ 75° F	1	4 5/16"	Light Gray	40° to 180°	0000000	000000
3/4	80	100 psi @ 75° F	1	4 5/8"	Light Gray	40° to 180°	0000000	000000
1	80	100 psi @ 75° F	1	5 1/8"	Light Gray	40° to 180°	0000000	000000

Spring-Loaded Piston

For Use With: Air, Ammonia, Argon, Beverage, Carbon Dioxide, Chlorinated Water, Diesel Fuel, Drinking Water, Ethylene Glycol, Food, Helium, Hydrochloric Acid, Kerosene, Krypton, Liquid Carbon Dioxide, Methanol, Methyl Ethyl Ketone, Mineral Spirits, Natural Gas, Neon, Nitric Acid, Nitrogen, Oil, Oxygen, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water, Xenon
Piston Material:
PVC Plastic Body: PVC Plastic
CPVC Plastic Body: CPVC Plastic
Spring Material: Plastic Polymer
Seal Material: Fluoroelastomer Rubber

PVC Plastic Body
Pipe Size	For Pipe Schedule	Max. Pressure	Min. Opening Pressure, psi	End-to-End Lg.	Color	Temperature Range, °F		Each
NPT Male × NPT Male
1 1/2	80	100 psi @ 75° F	1	7 15/16"	Gray	40° to 140°	0000000	0000000
2	80	100 psi @ 75° F	1	8 1/2"	Gray	40° to 140°	0000000	000000
CPVC Plastic Body
NPT Male × NPT Male
1 1/2	80	100 psi @ 75° F	1	7 15/16"	Light Gray	40° to 180°	0000000	000000
2	80	100 psi @ 75° F	1	8 1/2"	Light Gray	40° to 180°	0000000	000000