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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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 is designed to sit inside a threaded nut (sold separately) so you can make a threaded connection.
316 stainless steel nipples have excellent corrosion resistance.
- Maximum Pressure: See table
- Maximum Temperature: 120° F
Regulator Connection | ||||||
|---|---|---|---|---|---|---|
| For Number (Max. Pressure) | Pipe Size  | Thread Type | Lg. | For Use With | Each | |
316 Stainless Steel—Tighten With Wrench | ||||||
| CGA 705 (3,000 psi @ 72° F) | 1/4 | NPT | 2 1/2" | Ammonia | 000000000 | 000000 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F
| Number | Gender | Thread Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
316 Stainless Steel | ||||||||
|---|---|---|---|---|---|---|---|---|
| CGA 705 | Female | 1.125"-14 | UNS | Right Hand | 3,000 psi @ 72° F | Ammonia | 000000000 | 000000 |
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.
316 stainless steel nuts have excellent corrosion resistance.
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.
- 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 | |
316 Stainless Steel | |||||||
|---|---|---|---|---|---|---|---|
| CGA 705 | 1.125"-14 | UNS | Right Hand | 3,000 psi @ 72° F | Ammonia | 000000000 | 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 ultra-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 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
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.
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.
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 | |
316L Stainless Steel Gasket | ||||
|---|---|---|---|---|
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 0000000 | 00000 |
Silver-Plated 316L Stainless Steel Gasket | ||||
| 1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
Nickel Gasket with Retaining Tabs | ||||
| 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 |
Quick-Disconnect Tube Couplings for Chemicals
Couplings consist of a plug and a socket (sold separately) that join with a latch, so you can frequently connect and disconnect your line. To connect, insert the plug into the socket; to disconnect, press the latch on the socket and remove the plug. Plugs and sockets are polypropylene, which has excellent chemical, impact, and abrasion resistance.
Plugs and sockets with shut-off have a valve to stop the flow when the coupling is separated so fluid won’t spill from your line.
Note: For a complete coupling, order a plug and a socket with the same coupling size.
- For Use With: Ammonia, Ethanol, Phosphoric Acid (70%), Sodium Carbonate
- Temperature Range: 32° to 160° F
Open Flow | With Shut-Off | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | Coupling Size | Plug OD | Material | Color | Max. Pressure | Each | Each | ||
NPT Threads | |||||||||
| 1/8 | 1/8 | 5/16" | Polypropylene Plastic | Beige | 120 psi @ 72° F | 00000000 | 00000 | 00000000 | 000000 |
| 1/4 | 1/4 | 7/16" | Polypropylene Plastic | Beige | 120 psi @ 72° F | 00000000 | 00000 | 00000000 | 00000 |
| 3/8 | 3/8 | 3/4" | Polypropylene Plastic | Gray | 60 psi @ 72° F | 00000000 | 0000 | 00000000 | 00000 |
| 1/2 | 3/8 | 3/4" | Polypropylene Plastic | Gray | 60 psi @ 72° F | 00000000 | 0000 | 00000000 | 00000 |