Size, hardness, reinforcement, temperature, chemical compatibility, certification and application — the complete framework for choosing the right silicone tubing.

Overview

Selecting the right silicone tubing is critical for ensuring safe, efficient and compliant fluid transfer in food, pharmaceutical, biotech and industrial applications. This guide covers the essential factors that engineers and procurement teams should consider when specifying silicone tubing.

1. Inner Diameter and Flow Rate

The inner diameter (ID) determines the flow capacity of the tubing. Larger IDs accommodate higher flow rates but reduce pressure. Calculate the required ID based on your flow rate, fluid viscosity and acceptable pressure drop. Standard IDs range from 6 mm to 75 mm.

2. Wall Thickness and Pressure Rating

Wall thickness affects both pressure resistance and flexibility. Thicker walls handle higher pressures but are less flexible and harder to bend. For suction applications, choose reinforcement (braid or steel wire) rather than simply increasing wall thickness.

3. Reinforcement Type

Reinforcement options include polyester braid, glass fiber, aramid fiber and 316L stainless steel wire. Each offers different pressure resistance, flexibility and chemical compatibility. Steel wire reinforcement provides the highest pressure rating for demanding applications.

4. Temperature Range

Rekky platinum-cured silicone tubing operates from −40 °C to 220 °C. Consider both the operating temperature and any sterilization temperatures (CIP at 80–90 °C, SIP at 121 °C, autoclave at 134 °C).

5. Chemical Compatibility

Standard platinum-cured silicone handles most food and pharmaceutical fluids. For aggressive chemicals, solvents or oils, consider fluorosilicone (FVMQ) or fluororubber (FPM) inner layers for enhanced chemical resistance.

6. Regulatory Compliance

Verify that the tubing meets all applicable certifications: FDA 21 CFR 177.2600 for food contact, USP Class VI for pharmaceutical, ISO 10993 for medical devices, LFGB for EU food-grade, and REACH for EU chemical safety.

7. Hardness (Shore A)

Silicone tubing is available in Shore A hardness from 40 (soft, very flexible) to 80 (hard, rigid). Softer tubing is easier to bend and connect but may kink under vacuum. Harder tubing resists kinking and handles higher pressures but is less flexible.

Conclusion

By systematically evaluating these seven factors, you can select silicone tubing that provides optimal performance, compliance and longevity for your specific application. Our engineering team is available to help with product selection — request a consultation today.