About Backflow-Prevention Valves
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Easy-to-Install Threaded Check Valves for Harsh Chemicals


To reduce installation time and allow for maintenance without detaching pipe connections, these valves have union fittings. The plastic body and fluoroelastomer seal provide excellent chemical resistance. Valves open to allow flow in one direction and close when flow stops or reverses.
Valves for drinking water meet NSF/ANSI 61.
PVC and CPVC valves come with unthreaded socket-connect female fittings in addition to the threaded NPT female fittings.
Polypropylene valves are more corrosion resistant than PVC or CPVC valves.
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 Use With:
BSPP thread type:
Butane, Kerosene, Liquid Carbon Dioxide, Natural Gas, Nitric Acid, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Water
NPT thread type:
Citric Acid, Diesel Fuel, Drinking Water, Ethylene Glycol, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Nitric Acid, Oil, Phosphoric Acid, Salt Water, Sodium Hypochlorite, Water - Ball Material: PVC Plastic
- Seal Material: Fluoroelastomer Rubber
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | Color | End-to-End Lg. | Specifications Met | Each | |
BSPP Female × BSPP Female | |||||||||
---|---|---|---|---|---|---|---|---|---|
1/2 | 6.3 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 4 1/4" | ASTM D1784 | 0000000 | 0000000 |
1 | 25 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 5 3/16" | ASTM D1784 | 0000000 | 000000 |
NPT Female × NPT Female | |||||||||
1/2 | 4.8 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 4 11/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 00000 |
3/4 | 7.7 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 4 3/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 00000 |
1 | 11 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 5 3/8" | ASTM D1784, NSF/ANSI 61 | 0000000 | 00000 |
1 1/4 | 25 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 6 1/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
1 1/2 | 45 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 6 3/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
2 | 130 | 150 psi @ 70° F | 1 | 40° to 140° | Dark Gray | 8 1/8" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
- For Use With: Citric Acid, Diesel Fuel, Drinking Water, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Nitric Acid, Phosphoric Acid, Salt Water, Sodium Hypochlorite, Water
- Ball Material: CPVC Plastic
- Seal Material: Fluoroelastomer Rubber
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | Color | End-to-End Lg. | Specifications Met | Each | |
NPT Female × NPT Female | |||||||||
---|---|---|---|---|---|---|---|---|---|
1/2 | 4.8 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 4 11/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
3/4 | 7.7 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 4 3/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
1 | 11 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 5 3/8" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
1 1/4 | 25 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 6 1/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
1 1/2 | 45 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 6 3/4" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
2 | 130 | 150 psi @ 70° F | 1 | 35° to 190° | Light Gray | 8 1/8" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
- For Use With: Air, Ammonia, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Ethanol, Ethylene Glycol, Isopropyl Alcohol, Kerosene, Methanol, Natural Gas, Oil, Oxygen, Phosphoric Acid, Salt Water, Soap Solutions, Sodium Hydroxide, Water
- Ball Material: Polypropylene Plastic
- Seal Material: Fluoroelastomer Rubber
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | Color | End-to-End Lg. | Specifications Met | Each | |
NPT Female × NPT Female | |||||||||
---|---|---|---|---|---|---|---|---|---|
1/2 | 4.8 | 150 psi @ 70° F | 1 | 35° to 160° | White | 4 11/16" | ASTM D4101 | 0000000 | 0000000 |
3/4 | 7.7 | 150 psi @ 70° F | 1 | 35° to 160° | White | 4 3/4" | ASTM D4101 | 0000000 | 000000 |
1 | 11 | 150 psi @ 70° F | 1 | 35° to 160° | White | 5 3/8" | ASTM D4101 | 0000000 | 000000 |
1 1/2 | 45 | 150 psi @ 70° F | 1 | 35° to 160° | White | 6 3/4" | ASTM D4101 | 0000000 | 000000 |
2 | 130 | 150 psi @ 70° F | 1 | 35° to 160° | White | 8 1/8" | ASTM D4101 | 0000000 | 000000 |
Threaded Check Valves for Harsh Chemicals
These valves open to allow flow in one direction and close when flow stops or reverses.
Valves for drinking water meet NSF/ANSI Standard 61.
Polypropylene valves are more corrosion resistant than PVC or CPVC valves.
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 Use With: Air, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Diesel Fuel, Drinking Water, Ethanol, Ethylene Glycol, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Methanol, Mineral Spirits, Natural Gas, Oil, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water
- Ball Material: PVC Plastic
- Seal Material: Fluoroelastomer Rubber
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | Color | End-to-End Lg. | Specifications Met | Each | |
NPT Female × NPT Female | |||||||||
---|---|---|---|---|---|---|---|---|---|
1/4 | 1 | 150 psi @ 70° F | 1.5 | 35° to 140° | Dark Gray | 3" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
3/8 | 3 | 150 psi @ 70° F | 1.5 | 35° to 140° | Dark Gray | 3" | ASTM D1784, NSF/ANSI 61 | 0000000 | 00000 |
3 | 250 | 150 psi @ 70° F | 1.5 | 35° to 140° | Dark Gray | 10 9/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |
4 | 400 | 150 psi @ 70° F | 1.5 | 35° to 140° | Dark Gray | 12 15/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 000000 |

- For Use With: Air, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Diesel Fuel, Drinking Water, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Mineral Spirits, Natural Gas, Nitric Acid, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Sulfuric Acid, Water
- Ball Material: CPVC Plastic
- Seal Material: Fluoroelastomer Rubber
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | Color | End-to-End Lg. | Specifications Met | Each | |
NPT Female × NPT Female | |||||||||
---|---|---|---|---|---|---|---|---|---|
3 | 250 | 150 psi @ 70° F | 1.5 | 35° to 190° | Dark Gray | 10 9/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 0000000 |
4 | 400 | 150 psi @ 70° F | 1.5 | 35° to 190° | Dark Gray | 12 15/16" | ASTM D1784, NSF/ANSI 61 | 0000000 | 00000000 |
Union-Insert Check Valves


- For Use With: Air, Argon, Helium, Krypton, Neon, Water, Xenon
- Piston Material: 316 Stainless Steel
- Spring Material: 316 Stainless Steel
- Seal Material: Fluoroelastomer Rubber
To reduce installation time and allow for maintenance without detaching pipe connections, these valves insert into a union fitting. Union fittings are sold separately. Valves open to allow flow in one direction and close when flow stops or reverses. 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.
Valves | Union Fittings | ||||||||
---|---|---|---|---|---|---|---|---|---|
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | End-to-End Lg. | Each | Each | ||
316 Stainless Steel Body | |||||||||
NPT Female × NPT Female | |||||||||
1/2 | 2.3 | 1,500 psi @ 70° F | 0.5 | -10° to 400° | 13/16" | 0000000 | 000000 | 0000000 | 0000000 |
1 | 6.1 | 1,500 psi @ 70° F | 0.5 | -10° to 400° | 1 1/16" | 0000000 | 000000 | 0000000 | 000000 |
1 1/2 | 19 | 1,500 psi @ 70° F | 0.5 | -10° to 400° | 1 5/16" | 0000000 | 000000 | 0000000 | 000000 |
2 | 33.3 | 1,500 psi @ 70° F | 0.5 | -10° to 400° | 1 9/16" | 0000000 | 000000 | 0000000 | 000000 |
Threaded Two-Stage Backflow-Prevention Valves for Drinking Water



- For Use With: Drinking Water
- Seal Material: EPDM Rubber
Keep backflow from contaminating your drinking water supply—these valves meet NSF/ANSI 61 for use with drinking water. They consist of a primary check valve and a secondary check valve. If the primary check fails to close when flow stops or reverses, the secondary check valve engages to prevent backflow.
Single-union valves have a union fitting on one end.
Double-union valves have a union fitting on both ends.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | End-to-End Lg. | Each | |
Brass Body—Single Union | ||||||
---|---|---|---|---|---|---|
NPT Female Inlet × NPT Female Outlet | ||||||
3/4 | 175 psi @ 180° F | 5 | 35° to 180° | 3 3/4" | 00000000 | 000000 |
1 | 175 psi @ 180° F | 5 | 35° to 180° | 3 3/4" | 00000000 | 000000 |
NPT Male Inlet × NPT Female Outlet | ||||||
3/4 | 175 psi @ 180° F | 5 | 35° to 180° | 3 3/4" | 00000000 | 000000 |
Brass Body—Double Union | ||||||
NPT Female Inlet × NPT Female Outlet | ||||||
1/2 | 175 psi @ 180° F | 5 | 35° to 180° | 3 3/4" | 0000000 | 000000 |
3/4 | 175 psi @ 180° F | 5 | 35° to 180° | 3 3/4" | 0000000 | 000000 |
1 | 175 psi @ 180° F | 5 | 35° to 180° | 4" | 0000000 | 000000 |