PU pipe and pneumatic pipe: the short answer
In many markets, “PU pipe” and “pneumatic pipe” are everyday names for flexible polyurethane (or nylon) tubing on compressed-air lines. The name matters less than the specification. To order the right tube, state the material, the outer diameter (OD), the inner diameter (ID) and the length. A “6 mm PU pipe” is most often a 6 mm OD tube, but confirm the OD and the ID in writing before you order.
Pipe, tube, tubing and hose: what the words mean
| Word | Usually means | What to specify |
|---|---|---|
| PU pipe, pneumatic pipe | Flexible plastic tubing for air lines, sold on a roll | Material, OD and ID, length, color |
| Tubing, tube | The same flexible product, the term used on data sheets | Model number, OD and ID, working pressure |
| Hose | A heavier or reinforced flexible line, often with fixed end fittings | Inner diameter, working pressure, end fittings |
| Pipe (rigid) | Steel, copper or PVC pipe that is not coiled on a roll | Nominal size and pressure class |
Because “pipe” can also mean rigid pipe, always add the material and the OD/ID when you ask for a flexible air-line pipe. Our tubing glossary defines each term.
PU tubing sizes sold as PU pipe
These are the metric sizes in our PU tubing model table, written OD/ID in mm. A tube is named by its OD because the OD has to match the push-in fitting.
| Common name | OD/ID (mm) | Wall (mm) |
|---|---|---|
| 4 mm PU pipe | 4/2.5 | 0.75 |
| 6 mm PU pipe | 6/4 | 1.0 |
| 8 mm PU pipe | 8/5, 8/5.5, 8/6 | 1.5, 1.25, 1.0 |
| 10 mm PU pipe | 10/6.5, 10/8 | 1.75, 1.0 |
| 12 mm PU pipe | 12/8 | 2.0 |
| 14 mm PU pipe | 14/10 | 2.0 |
| 16 mm PU pipe | 16/12 | 2.0 |
Inch sizes (1/8, 1/4, 3/8, 1/2 and 3/4 in) are separate sizes. A 6 mm tube is not a 1/4 in tube; they differ by 0.35 mm. See the PU tubing models and the tubing size chart.
What to put in a PU pipe order
- Material: standard PU, polyether PU for damp conditions, or nylon (PA6, PA12) where pressure matters more than flexibility. See PU vs nylon.
- Size: OD/ID in mm, for example 8/5.
- Length: the roll size or the cut length, and the quantity.
- Color: standard or a reference.
- Conditions: medium, working pressure and temperature.
Then request a sample of the exact size, or send your requirements.
Frequently asked questions
Is PU pipe the same as PU tubing?
For compressed-air work, yes: both names describe flexible polyurethane tubing sold on a roll. Data sheets use “tubing” and give the OD and ID, which is the safest way to specify it.
Is a 6 mm PU pipe 6 mm OD or 6 mm ID?
It is usually the OD, so a 6/4 tube. Because buyers use the name in different ways, write both the OD and the ID in your order, for example 6/4 mm.
What is the difference between PU pipe and nylon pipe?
PU is more flexible and bends at a tighter radius. Nylon (PA6, PA12) carries a higher working pressure at the same size. Compare both in the pressure table by size.
Which fitting fits a PU pipe?
A push-in fitting takes the OD of the tube: a 6 mm fitting takes a 6 mm OD tube. See matching tubing to fittings.
Sources and scope
- PU Tubing — English data sheet (v3-20261020)
- PA6 Nylon Tubing — English data sheet (v4-20261020)
- PA12 Nylon Tubing — English data sheet (v5-20261020)
Use these documents for the identified product models and stated test conditions. General material comparisons and selection checklists do not establish a different grade’s rating, fitting compatibility or project approval. Confirm the exact model, medium, temperature, pressure and required evidence before ordering.
Content review: zhangkexin · Marketing
Review scope: market information and document references.
