How to Identify and Measure Fittings
Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.
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Nuts for High-Pressure Nipples for Compressed Gas
Slide a high-pressure hose nipple for compressed gas into one of these nuts to connect a pipe to the inlet of a pressure regulator. They are also known as CGA (Compressed Gas Association) nuts and inlet nuts.
Brass nuts have good corrosion resistance and are softer than 316 stainless steel nuts, so they're easier to thread together. Aluminum-plated brass nuts have better corrosion and wear resistance than unplated brass. Chrome-plated brass nuts have comparable corrosion and wear resistance to aluminum-plated brass nuts, and have a bright, shiny appearance. 316 stainless steel nuts have excellent corrosion resistance.
Nuts with a plastic grip can be tightened by hand instead of with a wrench.
Nuts with left-hand threads are identified with a notch.
Note: Nuts have a CGA, BS, or DIN number that corresponds to a specific type of gas. Choose a nut with the same number as your tank and other system components.
For technical drawings and 3-D models, click on a part number.
- Maximum Pressure: See table
- Maximum Temperature: 120° F, except DIN 477 No. 9: 250° F
Number | Thread Size | Pipe Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Brass | ||||||||
|---|---|---|---|---|---|---|---|---|
| CGA 200 | 0.628"-20 | __ | NGO | Right Hand | 500 psi @ 72° F | Acetylene | 000000000 | 00000 |
| CGA 280 | 0.750"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Medical Gas Mixtures | 000000000 | 00000 |
| CGA 300 | 0.830"-14 | __ | NGO | Right Hand | 500 psi @ 72° F | Ethyl Chloride | 000000000 | 0000 |
| CGA 320 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 0000 |
| CGA 326 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Nitrous Oxide | 000000000 | 0000 |
| CGA 330 | 0.830"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Boron Trifluoride, Carbonyl Sulfide, Hydrogen Bromide, Hydrogen Chloride, Hydrogen Iodide, Hydrogen Sulfide, Methyl Bromide, Silicon Tetrafluoride, Sulfur Tetrafluoride | 000000000 | 00000 |
| CGA 346 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Air | 000000000 | 0000 |
| CGA 347 | 0.830"-14 | __ | NGO | Right Hand | 4,700 psi @ 72° F | Air | 000000000 | 00000 |
| CGA 350 | 0.830"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Carbon Monoxide, Ethane, Ethylene, Hydrogen, Methane, Methyl Fluoride, Natural Gas | 000000000 | 0000 |
| CGA 410 | 0.855"-14 | __ | NGO | Left Hand | 500 psi @ 72° F | Acetylene | 000000000 | 0000 |
| CGA 520 | 0.899"-14 | __ | NGO | Right Hand | 500 psi @ 72° F | Acetylene | 000000000 | 0000 |
| CGA 540 | 0.908"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Oxygen | 000000000 | 0000 |
| CGA 555 | 0.908"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Butane, LP Gas | 000000000 | 0000 |
| CGA 577 | 0.965"-14 | __ | NGO | Right Hand | 3,500 psi @ 72° F | Oxygen | 000000000 | 00000 |
| CGA 660 | 1.035"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Refrigerant Gases | 000000000 | 00000 |
| CGA 701 | 1.108"-14 | __ | NGO | Right Hand | 4,700 psi @ 72° F | Oxygen | 000000000 | 00000 |
| DIN 477 No. 9 | __ | 3/4 | BSPT | Right Hand | 4,300 psi @ 72° F | Oxygen | 000000000 | 00000 |
Brass with Plastic Grip | ||||||||
| CGA 320 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
| CGA 346 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Air | 000000000 | 00000 |
| CGA 540 | 0.908"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Oxygen | 000000000 | 00000 |
Aluminum-Plated Brass | ||||||||
| CGA 170 | 9/16"-18 | __ | UN/UNF (CGA) | Right Hand | 3,000 psi @ 72° F | Air, Argon, Butane, Carbon Dioxide, Helium, Krypton, Methane, Natural Gas, Neon, Nitrogen, Oxygen, Propane, Propylene | 000000000 | 00000 |
| CGA 180 | 5/8"-18 | __ | UN/UNF (CGA) | Right Hand | 3,000 psi @ 72° F | Air, Argon, Butane, Carbon Dioxide, Helium, Krypton, Methane, Natural Gas, Neon, Nitrogen, Oxygen, Propane, Propylene | 000000000 | 00000 |
| DIN 477 No. 6 | W 21.8 | __ | Metric | Right Hand | 3,000 psi @ 72° F | Argon, Carbon Dioxide, Cyclobutane, Dichlorotetrafluoroethane, Helium, Krypton, Sulfur Hexafluoride, Trifluoroethane, Xenon | 000000000 | 00000 |
Chrome-Plated Brass | ||||||||
| CGA 320 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
| CGA 326 | 0.830"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Nitrous Oxide | 00000000 | 00000 |
| CGA 350 | 0.830"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Carbon Monoxide, Ethane, Ethylene, Hydrogen, Methane, Methyl Fluoride, Natural Gas | 000000000 | 00000 |
| CGA 540 | 0.908"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Oxygen | 000000000 | 00000 |
316 Stainless Steel | ||||||||
| CGA 670 | 1.035"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Hydrogen Fluoride, Nitrogen Trifluoride, Tungsten Hexafluoride | 000000000 | 00000 |
| CGA 677 | 1.035"-14 | __ | NGO | Left Hand | 6,400 psi @ 72° F | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
| CGA 705 | 1.125"-14 | __ | UNS | Right Hand | 3,000 psi @ 72° F | Ammonia | 000000000 | 00000 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F, except DIN 477 No. 12: 250° F
| Number | Thread Size | Pipe Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Brass | ||||||||
|---|---|---|---|---|---|---|---|---|
| CGA 296 | 0.803"-14 | __ | UNS | Right Hand | 3,000 psi @ 72° F | Oxygen Mixtures | 000000000 | 00000 |
| CGA 500 | 0.880"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Medical Gas Mixtures | 000000000 | 00000 |
| CGA 510 | 0.880"-14 | __ | NGO | Left Hand | 500 psi @ 72° F | Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride | 000000000 | 0000 |
| CGA 580 | 0.960"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 0000 |
| CGA 590 | 0.960"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Sulfur Hexafluoride | 000000000 | 0000 |
| CGA 680 | 1.040"-14 | __ | NGO | Right Hand | 4,700 psi @ 72° F | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
| CGA 702 | 1.120"-14 | __ | NGO | Right Hand | 6,400 psi @ 72° F | Air | 000000000 | 00000 |
| DIN 477 No. 12 | __ | 3/4 | BSPT | Right Hand | 4,300 psi @ 72° F | Nitrous Oxide | 000000000 | 00000 |
Brass with Plastic Grip | ||||||||
| CGA 500 | 0.880"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Medical Gas Mixtures | 00000000 | 00000 |
| CGA 510 | 0.880"-14 | __ | NGO | Left Hand | 500 psi @ 72° F | Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride | 000000000 | 00000 |
| CGA 580 | 0.960"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
Aluminum-Plated Brass | ||||||||
| BS 341 No. 3 | __ | 5/8 | BSPT | Right Hand | 3,000 psi @ 72° F | Air, Argon, Helium, Krypton, Neon, Nitrogen, Oxygen, Perfluoropropane | 000000000 | 00000 |
Chrome-Plated Brass | ||||||||
| CGA 510 | 0.880"-14 | __ | NGO | Left Hand | 500 psi @ 72° F | Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride | 000000000 | 00000 |
| CGA 580 | 0.960"-14 | __ | NGO | Right Hand | 3,000 psi @ 72° F | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
| CGA 590 | 0.960"-14 | __ | NGO | Left Hand | 3,000 psi @ 72° F | Sulfur Hexafluoride | 000000000 | 00000 |
Nuts for Barbed Hose Fittings for Compressed Gas
Also known as CGA (Compressed Gas Association) nuts, these are designed for low-pressure welding applications downstream of your tank and pressure regulator. Slide a barbed hose adapter for compressed gas into a male or female nut to make a threaded connection to torches or pressure regulators.
Nuts with left-hand threads are identified with a notch.
Brass nuts have good corrosion resistance. Stainless steel nuts have excellent corrosion resistance.
Note: Nuts have a CGA number that corresponds to a specific type of gas. Choose a nut with the same CGA number as your tank and other system components.
For technical drawings and 3-D models, click on a part number.
- Maximum Pressure: 200 psi @ 72° F
- Maximum Temperature: 120° F
| CGA Number | Gas Fitting Size | Thread Size | Thread Type | Thread Direction | For Use With | Each | |
Brass | |||||||
|---|---|---|---|---|---|---|---|
| 020 | A | 3/8"-24 | UN/UNF (CGA) | Right Hand | Oxygen | 0000000 | 00000 |
| 021 | A | 3/8"-24 | UN/UNF (CGA) | Left Hand | Acetylene, Butane, Fuel Gases, LP Gas, Natural Gas, Propane | 000000000 | 000 |
| 022 | B | 9/16"-18 | UN/UNF (CGA) | Right Hand | Oxygen | 000000 | 000 |
| 023 | B | 9/16"-18 | UN/UNF (CGA) | Left Hand | Acetylene, Butane, Fuel Gases, LP Gas, Natural Gas, Propane | 000000 | 000 |
| 024 | C | 7/8"-14 | UN/UNF (CGA) | Right Hand | Oxygen | 000000000 | 0000 |
| 025 | C | 7/8"-14 | UN/UNF (CGA) | Left Hand | Acetylene, Butane, Fuel Gases, LP Gas, Natural Gas, Propane | 000000000 | 0000 |
| 026 | D | 1 1/4"-12 | UN/UNF (CGA) | Right Hand | Oxygen | 000000000 | 00000 |
| 027 | D | 1 1/4"-12 | UN/UNF (CGA) | Left Hand | Acetylene, Butane, Fuel Gases, LP Gas, Natural Gas, Propane | 000000000 | 00000 |
316 Stainless Steel | |||||||
| 022 | B | 9/16"-18 | UN/UNF (CGA) | Right Hand | Oxygen | 000000000 | 00000 |
- Maximum Pressure: 200 psi @ 72° F
- Maximum Temperature: 120° F
| CGA Number | Gas Fitting Size | Thread Size | Thread Type | Thread Direction | For Use With | Each | |
Brass | |||||||
|---|---|---|---|---|---|---|---|
| 030 | A | 3/8"-24 | UN/UNF (CGA) | Right Hand | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
| 031 | A | 3/8"-24 | UN/UNF (CGA) | Left Hand | Air, Water | 000000000 | 0000 |
| 032 | B | 5/8"-18 | UN/UNF (CGA) | Right Hand | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 0000000 | 0000 |
| 033 | B | 5/8"-18 | UN/UNF (CGA) | Left Hand | Air, Water | 0000000 | 0000 |
| 034 | C | 7/8"-14 | UN/UNF (CGA) | Right Hand | Argon, Helium, Krypton, Neon, Nitrogen, Xenon | 000000000 | 00000 |
| 035 | C | 7/8"-14 | UN/UNF (CGA) | Left Hand | Air, Water | 000000000 | 00000 |