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.
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  | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
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 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F, except DIN 477 No. 12: 250° F
| Number | Pipe Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
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 | 000000 |