Pneumatic tubing carries compressed air between components in your system. The wrong choice leads to burst tubes, leaks, chemical degradation or inadequate flow — all of which cause downtime. With several materials, sizes and wall thicknesses available, this guide will help you specify tubing correctly from the start.
Polyurethane (PU) Tubing
Polyurethane is the most widely used material for pneumatic tubing in industrial automation. It offers an excellent combination of flexibility, kink resistance, light weight and good working pressure — typically 10–15 bar at room temperature depending on wall thickness.
PU tube is available in a wide colour palette, which is important for circuit identification. It is the standard choice for connecting valves to cylinders in machine building, robotic cable tracks and anywhere flexibility is needed.
Temperature range is typically -20°C to +60°C. Above 60°C, use nylon tubing instead.
Nylon (PA) Tubing
Nylon tubing is stiffer than PU but offers a higher temperature rating (typically up to +100°C) and better resistance to oils, fuels and many chemicals. It is preferred for routing fixed runs of tubing through machine panels, along cable trays or in environments with elevated temperatures such as near ovens or motors.
Nylon tubing has slightly higher pressure ratings than equivalent PU tube and is less prone to deformation under constant pressure. Its higher stiffness makes it easier to route in straight runs but harder to manage around tight bends.
Polyethylene (PE) Tubing
Polyethylene tubing is lighter and more economical than PU or nylon. It is commonly used in low-pressure pneumatic circuits, fluid transfer and food and beverage applications where chemical inertness is important. Standard PE is not suitable for high-pressure compressed air.
PTFE Tubing
PTFE (polytetrafluoroethylene) tubing handles extreme temperatures (-200°C to +260°C), is chemically inert to virtually all substances, and has a very low coefficient of friction. It is used in high-temperature, high-purity and aggressive chemical environments. PTFE is more expensive and less flexible than PU or nylon.
Understanding Tube Sizes: OD and Wall Thickness
Pneumatic tubing is specified by outside diameter (OD) and wall thickness. Common metric sizes are 4, 6, 8, 10, 12 and 16mm OD. The inside diameter (ID) is OD minus twice the wall thickness — for example, 8mm OD with 1mm wall gives 6mm ID.
The ID determines flow capacity. Under-sized tubing creates back-pressure and slows cylinder speed. For most machine-building applications, 6mm OD is adequate for pilot signals, 8mm for cylinder drives, and 10–12mm for main supply lines.
Key Selection Checklist
- Operating pressure — check the tube rated burst and working pressure at your operating temperature
- Temperature range — PU to 60°C, nylon to 100°C; higher requires PTFE or stainless steel
- Chemical compatibility — oils, coolants and cleaning agents can degrade PU; nylon or PTFE may be required
- Flexibility requirement — robotic and moving axes need high-flexibility PU; fixed runs suit nylon
- Flow requirement — size the ID to meet your actuator speed requirements with margin
- Colour coding — use consistent colour conventions to identify circuits
We stock a wide range of pneumatic tubing in polyurethane and nylon, available in standard 25m and 100m reels. Browse our pneumatic tubing range to find the right material, size and colour for your project.
Frequently Asked Questions
What is the difference between PU and nylon pneumatic tubing?
Polyurethane (PU) tubing is more flexible and lighter, ideal for moving applications and robotic cable tracks, rated to around 60u00b0C. Nylon (PA) tubing is stiffer with a higher temperature rating (up to 100u00b0C), better chemical resistance and is preferred for fixed runs in higher-temperature environments.
How do I measure pneumatic tubing size?
Pneumatic tubing is sized by outside diameter (OD). Measure the outer diameter of the tube, not the inner bore. Common metric sizes are 4mm, 6mm, 8mm, 10mm and 12mm OD. The OD determines which push-in fittings will fit the tube.
What pressure can pneumatic tubing handle?
8mm OD PU tubing with 1mm wall thickness is typically rated to 10u201312 bar working pressure at 20u00b0C. The pressure rating decreases as temperature rises. Always check the manufacturer datasheet for your specific tubing, as ratings vary between grades and manufacturers.
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