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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Low-Pressure Iron and Steel Threaded Pipe Fittings
Use these fittings for low-pressure applications in noncorrosive environments.
Adapters for tanks create an inlet or outlet connection on the surface of any tank, pressure vessel, or drum. Adapters with weld end allow for a permanent connection. Adapters with extension fit tightly into the hole, which keeps the fitting steady during welding.
NPTF (Dryseal) threads, NPSC (National Pipe Straight Coupling) threads, and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.
For technical drawings and 3-D models, click on a part number.
![](/prerenderstable/mvPRE/contents/gfx/imagecache/125/12555k82multipositive_top_positive_front_washer_1648761483_635@halfx_637843403317619122.png?ver=imagenotfound)
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Specifications Met: ASTM A181, ASME B1.20.1
Pipe Size | For Hole Dia. | OD | Lg. | Material | Each | |
NPT Female × Weld | ||||||
---|---|---|---|---|---|---|
1/8 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 00000 |
1/8 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
1/4 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 0000 |
1/4 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
3/8 | 15/16" | 1 5/16" | 3/8" | Carbon Steel | 00000000 | 0000 |
3/8 | 15/16" | 1 1/2" | 9/16" | Carbon Steel | 00000000 | 0000 |
1/2 | 1 1/8" | 1 5/8" | 7/16" | Carbon Steel | 00000000 | 0000 |
1/2 | 1 1/8" | 1 3/4" | 5/8" | Carbon Steel | 00000000 | 0000 |
3/4 | 1 5/16" | 1 15/16" | 1/2" | Carbon Steel | 00000000 | 0000 |
3/4 | 1 3/8" | 2 1/8" | 11/16" | Carbon Steel | 00000000 | 0000 |
1 | 1 5/8" | 2 3/8" | 3/4" | Carbon Steel | 00000000 | 0000 |
1 | 1 11/16" | 2 1/4" | 9/16" | Carbon Steel | 00000000 | 0000 |
1 1/4 | 2" | 2 9/16" | 9/16" | Carbon Steel | 00000000 | 00000 |
1 1/4 | 2" | 2 11/16" | 3/4" | Carbon Steel | 00000000 | 0000 |
1 1/2 | 2 1/4" | 2 13/16" | 9/16" | Carbon Steel | 00000000 | 0000 |
1 1/2 | 2 1/4" | 3" | 3/4" | Carbon Steel | 00000000 | 0000 |
2 | 2 5/8" | 3 3/8" | 5/8" | Carbon Steel | 00000000 | 0000 |
2 | 2 5/8" | 3 1/2" | 27/32" | Carbon Steel | 00000000 | 00000 |
2 1/2 | 3 1/8" | 4 1/16" | 1" | Carbon Steel | 00000000 | 00000 |
3 | 3 5/8" | 4 5/8" | 1" | Carbon Steel | 00000000 | 00000 |
4 | 4 11/16" | 5 13/16" | 1 7/32" | Carbon Steel | 00000000 | 00000 |
![](/prerenderstable/mvPRE/contents/gfx/imagecache/125/12555k52multinegative_top_positive_front_washer_1648759861_871@halfx_637843387412671955.png?ver=imagenotfound)
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Specifications Met: ASTM A105, ASTM A181
Pipe Size | For Hole Dia. | OD | Lg. | Material | Each | |
NPT Female × Weld | ||||||
---|---|---|---|---|---|---|
1/4 | 3/4" | 1 1/4" | 5/16" | Carbon Steel | 00000000 | 00000 |
3/8 | 15/16" | 1 1/4" | 3/8" | Carbon Steel | 00000000 | 00000 |
1/2 | 1 1/8" | 1 1/2" | 1/2" | Carbon Steel | 00000000 | 0000 |
3/4 | 1 3/8" | 1 3/4" | 5/8" | Carbon Steel | 00000000 | 0000 |
1 | 1 11/16" | 2 1/8" | 5/8" | Carbon Steel | 00000000 | 0000 |
1 1/4 | 2" | 2 1/2" | 3/4" | Carbon Steel | 00000000 | 0000 |
1 1/2 | 2 3/8" | 3" | 3/4" | Carbon Steel | 00000000 | 00000 |
2 | 2 7/8" | 3 1/2" | 13/16" | Carbon Steel | 00000000 | 00000 |
2 1/2 | 3 1/2" | 4 1/4" | 1" | Carbon Steel | 00000000 | 00000 |
3 | 4 1/8" | 4 3/4" | 1" | Carbon Steel | 00000000 | 00000 |
4 | 5 1/8" | 5 3/4" | 1 3/16" | Carbon Steel | 00000000 | 00000 |
![](/prerenderstable/mvPRE/contents/gfx/imagecache/169/1698t12-@halfx_637672085011521796.png?ver=imagenotfound)
- For Use With: Diesel Fuel, Gasoline, Oil, Water
- Pipe Nipples and Pipe: Use Schedule 40 steel