Top 10 Tips for Choosing the Best Silicone Tube for Your Projects
In any industrial or medical project, choosing the right silicone tubing can make all the difference for safety, efficiency, and durability. The silicone market is expected to grow steadily at 6.5% CAGR, reaching an estimated value of $24.4 billion by 2026 as the demand for high-performance materials continues to rise across the globe.
The silicon's unique molecular structure is what gives the tubing the flexibility, offering higher thermal stability and biocompatibility that rubber or plastics cannot match. If you are an engineer who is tasked with creating a medical silicone tube for life-saving medical equipment, or a procurement specialist who is looking to order a silicone tube for transporting food in a sanitary environment, it's important to know the important technical details. There are 10 research-backed tips that will help you choose the right silicone tube manufacturer and help you pick the best profile to suit your requirements.
1. Understanding Different Types of Silicone Tubes Available in the Market
Your first decision will be which grade of silicone you need for your application. Several different profiles are defined for the market:
- Medical-Grade Tubing: Particularly designed to be absolutely biocompatible. These tubes are non-immunogenic, meaning they are neutral to the immune system and non-reactive to body tissues, which makes them of great importance for the manufacturing of catheters and infusion systems.
- Food-Grade Tubing: These tubings are designed to move consumables, ensuring that the tubing will not induce any odor or taste. They meet FDA and NSF-51 standards for ensuring hygienic safety.
- Industrial-Grade Tubing: Designed for use in a wide range of fluid handling applications where it is not as critical to be as pure, but must also have good environmental resistance and physical strength.
- Peristaltic Pump Tubing: A specialised tubing that is manufactured with a guaranteed high fatigue and abrasion resistance, designed to endure the repeated and harsh mechanical compression of the pump rollers.
- Platinum vs. Peroxide Cured: Silicon that is cured with platinum is recommended for higher purity applications, such as medical or food grade applications, because it produces no by-products and has a greater clarity. Heavy industrial applications may require a peroxide-cured sealant as they are more cost-effective.
Expert Insight: For highly specialized jobs that demand high fuel and oil resistance, standard silicone will not work; for which Fluoro silicone grades tend to be a better option. In addition, some tubes have an external gear-type design that is specially made to achieve a high degree of accuracy in the control of pressure or flow for highly complex machines.
2. Key Factors to Consider When Selecting Silicone Tube Sizes and Dimensions
It is important to have accurate sizing for the integrity of the system. Flow capacity is influenced by the Inner Diameter (ID), with smaller IDs (0.5mm - 2mm) being ideal for precise fluid metering and larger IDs ideal for bulk fluid transfer. Another importance of the Outer Diameter (OD) is ensuring that the tube fits in connectors and is also safe to be routed through tight machine spaces.
If the wall is thicker, it can handle more stress. This makes them handle greater pressure and ensure higher vacuum resistance, but might result in compromises in flexibility, making installations harder in tighter bends. In many high-precision applications, such as medical, the tolerance is as low as ±0.02mm, which is necessary for a stable flow and 100% leak-free connection. The OD of an implanted medical catheter is usually measured in the French system, where 3Fr is equivalent to 1mm.
Expert Insight: If a tube is to be fitted by friction, the ID of the tube should be 0.05mm to 0.10mm less than the OD of the coupler in order to achieve an optimal fit. To achieve high roundness and eliminate belt traces on the surface of the tube, top-quality manufacturers may use vertical extrusion methods.
3. Evaluating Temperature Resistance Ratings for Your Needs
Silicone has a reputation for being highly resistant to heat. Typically, the best silicone tubes have a normal operating temperature range from -60°C to 200°C (-76°F to 500°F). In extreme conditions, there are special formulations of high-temperature stability that can withstand high temperatures up to 260°C or even 300°C for brief periods without compromising the structure.
The performance of silicone is also great at lower temperatures. Silicone is not brittle or fragile at temperatures as low as -90°C, whereas PVC is. It is also very resistant to thermal cycling, meaning it does not warp or crack after hundreds of heating and cooling cycles. This allows silicon tubing to withstand repeated autoclaving in steam at 121°C, making it suitable for sterilisation.
Expert Insight: Silicone has a very high burn point, but this does not make it flameproof; if fire exposure is a possibility, the engineer will have to test for "burn point" ratings. Remember that thermal aging tests may provide more information than conventional laboratory testing because they can show slight defects in lower quality formulations.
4. Importance of Durometer Hardness in Performance and Flexibility
The hardness, or Shore A Scale (usually 0 - 100), determines the physical feel and flexibility of tubing.
- Low Durometer (10A-30A): These soft tubes provide the most flexibility and are best suited for those applications where the tube will be balled up or manipulated continuously.
- Medium Durometer (50A-60A): This is an industry favorite and is perfect for medical applications and automotive applications due to its balance of performance and flexibility.
- Harder (70A-80A): A higher durometer will guarantee the necessary hardness to hold up under high internal pressure and under vacuum to prevent kinking.
As a natural result, softer silicone will offer outstanding kink resistance, but care needs to be taken as a sharp connector may, if pushed too hard, penetrate the silicone.
Expert Insight: This Shore 10A variant comes with such flexibility that it can be wrapped in a fist and will pop back into shape without breaking once you release it! A Shore 55A hardness is used in automotive prototyping to ensure factory-exact OEM dimensional stability.
5. Assessing the Chemical Resistance for Specific Applications
When it comes to silicone, they are known to be inert, or chemically stable, and do not react with most water-soluble substances, biological fluids, and medicines. Due to its general resistance, it is quite effective against water, air, mild chemicals, and ozone.
For most chemical processing applications, silicon tubes offer great resistance to weak acids and alkalis to ensure maximum safety. Silicon, however, may swell or degrade when exposed to concentrated fuels, oils, or strong solvents, so engineers need to consider this when designing it to be oil or solvent-resistant. Platinum-cured profiles lower the risk of extractables and leachables contaminating the transported fluid, thus assuring absolute product purity, especially in the pharmaceutical industry.
Expert Insight: Chemical exposure can cause silicone to swell; however, its remarkable ability to recover its original shape without losing properties will occur remarkably often once removed from the fluid. This silicone swelling process can be used in a desired manner by dipping tube ends into a swelling agent to create a permanent, tight fit around a difficult fitting.
6. Comparing Manufacturing Processes: Extrusion vs. Molded Tubes
Knowing about the construction of your tubing can affect your buying. The extrusion process is a continuous method and is the industry standard for bulk tubing manufacture for high volume and dimensional control. On the other hand, molding and injection processes are employed to make complex shapes, irregular forms, and over-molded connections (such as Y-connectors), which aren't possible with the extrusion process.
Impressive dimensional tightness can be achieved thanks to modern extrusion technology. With this technology, high-precision walls as thin as 0.1mm and with uniform roundness can be produced. Tubes for medical or pharmaceutical applications are required to be produced in Class 100,000 or Class 10,000 cleanrooms or facilities to avoid potential contamination and therefore any possible risk. Finally, secondary vulcanization (heat treatment after extrusion) is sometimes used to remove volatile residual materials and to guarantee tube purity to the highest standards.
Expert Insight: The multi-lumen tubes can be extruded with multiple parallel channels and can transport multiple liquids or gases at the same time. Vertical extruders can be superior to horizontal extruders for high-quality products, since there is no possibility of gravity-induced deformation (eccentricity) during the highly important curing phase.
7. Recognizing Compliance Standards in Industry Regulations
Compliance is your assurance of safety and performance. USP Class VI is the gold standard for medical silicone tube safety, as it includes extensive systemic and implantation testing. FDA 21 CFR 177.2600 compliance guarantees that the silicone is safe for direct food contact and will not leach out toxic substances into foods.
NSF-51 & NSF-61 certifications are used for water and food equipment to guarantee no harmful migration of substances. If a manufacturer has an ISO 13485 certificate, it means that they have a rigorous quality management system specifically oriented towards medical devices. In the case of wider industrial applications, the need for RoHS & REACH compliance means that there will not be any hazardous materials at all, such as heavy metals or phthalates.
Expert Insight: Certified biocompatible products have demonstrated in some comprehensive studies that operational risk can be decreased by more than 30% by using a certified biocompatible product versus a non-certified product. NSF-61 is an important, but often overlooked standard, that is only required for potable water plumbing components.
8. Evaluating UV, Ozone, and Environmental Resistance
Silicone is more stable than organic polymers in the outside environment because of its high molecular stability. Si-O (Silicon Oxide) bonds are much stronger than Carbon-Carbon bonds present in conventional rubber, which is the reason for the inherent UV resistance of silicone. In addition, it is extremely ozone resistant and will not crack or become brittle if placed near electrical ozone, making it suitable for use near high voltage motors.
When it comes to Silicone tubes, they are able to maintain 90% of their physical strength after suffering extended and direct sun exposure for outdoor use. It is completely weatherproof, meaning it will not be affected by moisture, driving rain, or high humidity, making it a long-lasting material that will last in severe climates all over the world. When it comes to Sustainability, silicone is comparatively more eco-friendly than disposable plastics, since it does not easily degrade into microplastics.
Expert Insight: The energy that comes from the UV light from nature is sufficiently high to break organic bonds, but it is not enough to break the incredibly stable inorganic chemistry of silicone. Very UV resistant, but it is still recommended to store tubes in a cool, dark environment for their impressive 10–20 year theoretical shelf life.
9. Assessing the Significance of Transparency and Clarity
Your tubing has a function and its visual characteristics. Visual monitoring is essential: clear tubes enable the fluid to be seen directly, dangerous air bubbles can be spotted, and this will be a real-time check for fluid discoloration and contamination. If absolute clarity is needed, then platinum vs. peroxide clarity comes into play. Platinum-cured tubing is always crystal clear and may not yellow over time, while peroxide-cured tubes can be slightly cloudy initially and may yellow over time.
With complex industrial systems, there is a special need for safety coding or media separation, which is offered by many silicone tube suppliers with customized color coding. Clearer glass is usually also a superior surface finish: a smooth inside bore that literally keeps bacteria from sticking and growing a biofilm. This transparency is especially critical when the reactions need to be monitored in a laboratory reactor, where it's all-important to understand the exact consistency of chemical reactions.
Expert Insight: Developing medical silicone tubing can be extruded with a highly visible X-ray radiopaque line, yet the remainder of the tubing is clear. For special light-sensitive compound projects, translucent tubes could be black shrink-wrapped to keep performance while still retaining base material properties.
10. Understanding Maintenance, Cleaning, and Sterilization Requirements
Good care can help you get the most out of your investment and avoid contamination. Follow these basic practices for maintenance:
- Sanitization: For just basic cleaning, using mild unscented dish soap and warm water, and with a very thorough rinse to remove all soapy residue.
- Sterilization Methods: Silicone is highly stable, making it compatible with various aggressive sterilization methods, such as steam autoclaving, ethylene oxide (EtO), gamma radiation, and electron-beam sterilization.
- Abrasive Warning: Never use abrasive Powders or Hard Scrubbers. Scratches on the bore will cause it to become rough and allow bacteria and mould to hide.
- Chemical Precautions: Don't use petroleum products or strong solvents (such as toluene) on silicone. They lead to immediate, permanent stickiness and destruction.
- Vertical Drying: Always hang vertically after cleaning. This will allow the moisture to flow away from the center due to gravity and allow the air to pass through freely without causing any mineral spotting.
Expert Insight: According to the experts, distilled water boiled for 5-10 minutes is a very effective and simple method for sanitizing heat-resistant silicone without the use of harsh chemicals. Though autoclaving is very effective, repeated gamma irradiation can, over time, affect the physical properties of silicone, which may, over time, make it more prone to kinking.
Conclusion
The selection of the appropriate silicone tube involves careful consideration of various parameters, including its size, grade, and environmental compatibility. With careful consideration of the following top ten tips, you can make the best silicone tubing selection that not only meets, but surpasses your application's requirements.
Ruixiang Precision Silicone Products is a world-renowned silicone tube manufacturer with more than 14 years of experience and expertise in the industry, offering high precision and safety for critical projects where it is absolutely necessary. Whether it is the production of custom medical silicone tubes in Class 100,000 clean rooms or the production of food-grade silicone tubes with FDA and LFGB certification, Ruixiang can offer you a complete solution to your tubing needs. To make the best use of your next engineering project, contact Ruixiang today for the finest craftsmanship, durability, and quality compliance.
FAQs
Q. How long does silicone tubing last?
A silicon of high-quality typically has a lifespan of 10-20 years in normal environmental conditions. In high-stress usage, such as a peristaltic pump, it usually has a life of more than 500 hours of operation before replacement.
Q. Can silicone tubing be used with fuels?
Most silicone types will swell and deteriorate on exposure to fuels. But special fuel and solvent-resistant fluorosilicone grades are specifically engineered for severe fuel and solvent resistance.
Q. What makes medical grade different?
Medical-grade tubing is only produced in certified clean rooms and is subjected to very stringent USP Class VI biocompatibility testing to confirm complete safety for direct contact with and implantation in humans.
Q. Is silicone better than PVC?
Yes, especially with respect to the long-term flexibility and temperature resistance. Silicone has a much greater range of flexibility and will not harden down to -60 °C up to 200 °C. PVC, on the other hand, has a much smaller range of flexibility and can become brittle.