How to Identify and Measure Fittings
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High-Pressure Nipples for Compressed Gas
Commonly used in high-pressure welding applications, these nipples connect your tank to the inlet of a pressure regulator. One side has a threaded pipe end and the other side has a rounded end that sits inside a threaded nut (sold separately) so you can make a threaded connection.
Brass nipples have good corrosion resistance and are softer than 316 stainless steel nipples, so they're easier to thread together. Chrome-plated brass nipples have better corrosion and wear resistance than unplated brass nipples and have a bright, shiny appearance.
Nipples that tighten by hand should be paired with a nut with a plastic grip.
For technical drawings and 3-D models, click on a part number.
- Maximum Pressure: See table
- Maximum Temperature: 120° F
Regulator Connection | ||||||
|---|---|---|---|---|---|---|
| For Number (Max. Pressure) | Pipe Size  | Thread Type | Lg. | For Use With | Each | |
Brass—Tighten With Wrench | ||||||
| CGA 170 (3,000 psi @ 72° F) | 1/8 | NPT | 1 1/4" | Air, Argon, Butane, Carbon Dioxide, Helium, Krypton, Methane, Natural Gas, Neon, Nitrogen, Oxygen, Propane, Propylene | 000000000 | 000000 |
| CGA 180 (3,000 psi @ 72° F) | 1/8 | NPT | 2" | Air, Argon, Butane, Carbon Dioxide, Helium, Krypton, Methane, Natural Gas, Neon, Nitrogen, Oxygen, Propane, Propylene | 000000000 | 00000 |
| CGA 320 (3,000 psi @ 72° F) | 1/4 | NPT | 2 1/2" | Carbon Dioxide | 000000000 | 0000 |
| DIN 477 No. 6 (4,350 psi @ 72° F) | 1/4 | NPT | 3 1/2" | Argon, Carbon Dioxide, Cyclobutane, Dichlorotetrafluoroethane, Helium, Krypton, Sulfur Hexafluoride, Trifluoroethane, Xenon | 000000000 | 00000 |
Brass—Tighten By Hand | ||||||
| CGA 320 (3,000 psi @ 72° F) | 1/4 | NPT | 2 33/64" | Carbon Dioxide | 000000000 | 00000 |
Chrome-Plated Brass—Tighten With Wrench | ||||||
| CGA 320 (3,000 psi @ 72° F) | 1/4 | NPT | 2 1/2" | Carbon Dioxide | 000000000 | 00000 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F
| Number | Gender | Thread Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Brass | ||||||||
|---|---|---|---|---|---|---|---|---|
| CGA 320 | Female | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
Brass with Plastic Grip | ||||||||
| CGA 320 | Female | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
Aluminum-Plated Brass | ||||||||
| CGA 170 | Female | 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 | Female | 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 | Female | 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 | Female | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
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.
Nuts with a plastic grip can be tightened by hand instead of with a wrench.
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 | |
Brass | |||||||
|---|---|---|---|---|---|---|---|
| CGA 320 | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 000000000 | 00000 |
Brass with Plastic Grip | |||||||
| CGA 320 | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Carbon Dioxide | 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 |
High-Pressure Threaded Fittings for Compressed Gas
Designed to handle high-pressure welding applications, these fittings are commonly used to connect pressure regulators to compressed gas tanks or cylinders. Fittings are also known as CGA (Compressed Gas Association) fittings. They are brass for good corrosion resistance.
Note: Fittings have a CGA number that corresponds to a specific type of gas. Choose a fitting 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: See table
- Maximum Temperature: 120° F
CGA Number | Tank Connection | Regulator Connection | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tank | Regulator | Thread Size | Thread Type | Thread Direction | Thread Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Brass | |||||||||||
| 320 | 580 | 0.830"-14 | NGO | Right Hand | 0.960"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Argon, Carbon Dioxide, Helium, Krypton, Neon, Nitrogen, Xenon | 0000000 | 000000 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F
CGA Number | Tank Connection | Regulator Connection | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tank | Regulator | Thread Size | Thread Type | Thread Direction | Thread Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Brass | |||||||||||
| 580 | 320 | 0.960"-14 | NGO | Right Hand | 0.830"-14 | NGO | Right Hand | 3,000 psi @ 72° F | Argon, Carbon Dioxide, Helium, Krypton, Neon, Nitrogen, Xenon | 0000000 | 000000 |
Ultra-High-Polish Gasket Fittings for Stainless Steel Tubing
- For Use With: Ammonia, Argon, Butane, Carbon Dioxide, Chloride, Fluoride, Fluorocarbon, Germane, Halide, Helium, Hydrogen, Krypton, Laser Gas, Natural Gas, Neon, Nitrogen, Oxygen, Silane, Sulfur Hexafluoride, Tungsten Hexafluoride, Xenon
- Temperature Range: -420° to 1000° F
- Tubing: Use with 316/316L stainless steel
- Compatible With: Swagelok® VCR
Polished to at least a 15 Ra finish on the inside, these fittings have an ultra-smooth interior surface that helps prevent contamination. Also known as ultra-high-purity fittings, they’re packed in a Class 100 clean room, cleaned, and double bagged. They are commonly used in semiconductor applications. Fittings use a metal gasket (sold separately), which generates fewer particles than a rubber gasket and creates a strong seal in high-pressure and high-vacuum applications. Fittings are 316 stainless steel for excellent corrosion resistance.
To assemble, place a gasket between the gasket ends before gently rotating the female-threaded fitting onto the male-threaded fitting. Tighten until 1/8 of a turn past finger tight.
Choose threaded fittings to attach directly to other fittings.
For technical drawings and 3-D models, click on a part number.
| For Tube OD | Pipe Size | Material | Max. Pressure | Max. Vacuum | Interior Smoothness, Ra | Environmental Rating | Each | |
NPT Threads | ||||||||
|---|---|---|---|---|---|---|---|---|
| 1/2" | 1/2 | 316L Stainless Steel | 3,500 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 0000000 | 000000 |
Retaining
Tabs
Nickel gaskets are softer than stainless steel gaskets, so they won’t wear down sealing surfaces as much, and they’re easier to tighten. They’re reactive to carbon monoxide and ozone, so they shouldn’t be used with those chemicals.
Hard and heat resistant, stainless steel gaskets can be used in a wider range of applications than nickel gaskets such as carbon monoxide and ozone. However, they’re harder to tighten than nickel gaskets, and they’ll wear down sealing surfaces more quickly.
Silver-plated stainless steel gaskets are softer than unfinished stainless steel gaskets, so they won’t wear down sealing surfaces as much, and they’re easier to tighten. However, they oxidize when exposed to air, and silver particles might flake off during assembly.
Gaskets with retaining tabs stay in place during installation, so you don’t have to hold the gasket while fastening fittings together. This also means they’re less likely to scratch or nick your fittings by rotating during installation.
| For Tube OD | Max. Vacuum | Environmental Rating | Each | |
Nickel Gasket | ||||
|---|---|---|---|---|
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 00000 |
316L Stainless Steel Gasket | ||||
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 0000000 | 0000 |
Silver-Plated 316L Stainless Steel Gasket | ||||
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
316L Stainless Steel Gasket with Retaining Tabs | ||||
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |