What Is PU Tubing?

Polyurethane tubing (PU tubing) is a commonly used piping material in industrial automation equipment and pneumatic systems. It is primarily applied for compressed air transmission and internal air supply connections within equipment.
In pneumatic systems, tubing is used to connect air sources to components such as valves, actuators, and control modules, forming the air delivery paths within the system.
Compared with other plastic tubing materials, PU tubing provides consistent flexibility and bending behavior under dynamic routing conditions.
As a result, it is commonly used in routing configurations where tubing needs to move, bend, or adapt to space constraints during equipment operation.

Typical Application Scenarios of PU Tubing

In pneumatic systems, PU tubing is commonly used in the following configuration scenarios:

• Dynamic routing where tubing moves or bends along with equipment operation
• Pneumatic piping in automation systems, including valves, actuators, and control modules
• Air supply connections for internal pneumatic components within compressed air systems

Tubing selection is determined by routing behavior and operating conditions, rather than material comparison alone.

→ Pneumatic Tubing Overview (Selection Criteria and Classification)

→ PU vs. Nylon Tubing: Selection and Application Differences

Whether the tubing needs to move with equipment is one of the key criteria in tubing selection.

When pneumatic lines may be exposed to sparks or high-temperature environments, flame-retardant tubing can be considered as part of the system configuration, such as in welding or metal processing applications. In SHPI's product classification, tubing designed for such conditions is referred to as Anti-Spark Tubing .

Structural Categories of PU Tubing

PU tubing is commonly available in single-layer construction. However, depending on installation requirements and operating conditions, different structural designs may be selected.

• Single-layer PU tubing: Designed for routing flexibility and dynamic bending conditions.
• Reinforced PU hose (three-layer construction): Incorporates a fiber reinforcement layer between inner and outer PU layers to control radial deformation under working pressure conditions.

→ Learn about reinforced PU tubing (3-layer construction): structural differences and applications

PU Tubing Material Structure: What Is the Difference Between ESTER and ETHER Types?

PU tubing exhibits different material behaviors depending on its polymer structure.
Differences between ESTER-type and ETHER-type PU tubing are mainly reflected in water resistance, long-term service stability, and applicable operating environments.

Comparison of ESTER-Type vs. ETHER-Type PU Tubing

PU tubing selection can be initially assessed based on operating environment conditions and routing requirements.
The differences between ESTER-type and ETHER-type PU tubing are summarized in the table above.

Further Reading

→ PU Tube FAQ — 15 Common Technical Questions by Automation Engineers

→ Reinforced PU Tubing (3-Layer Construction) | Structural Differences and Applications

→ Pneumatic Tubing Selection for Non-Stop Production | An Engineering Guide