Selection Guide to Silicone Tube: How to Choose the Right Grade, Size and Durometer

Choosing the wrong tubing is an expensive mistake — it shows up as premature failure, contamination, or a line that fails validation months after installation. This selection guide to silicone tube is written for the people who actually carry that risk: design engineers, maintenance teams and procurement managers who need a part that performs in the real world, not just on a datasheet. Over three decades of manufacturing rubber components, we have seen the same handful of selection errors repeat across industries, and almost all of them are avoidable with a clear checklist.

Silicone earns its place in demanding applications because it stays flexible from roughly -110°C to +260°C, resists ozone and ultraviolet radiation, and is chemically inert enough for food and medical contact. But “silicone tube” is not a single product. The right choice depends on grade, hardness, dimensions, pressure rating and certification — and getting one of those wrong undermines the rest.

Start With the Application, Not the Catalogue

Before looking at any specification sheet, write down four things: what flows through the tube, the temperature it sees, the pressure or vacuum it carries, and the regulatory environment it operates in. A peristaltic pump in a dairy plant and a coolant line in an electronics enclosure may both use silicone, but almost nothing else about the specification matches.

A common procurement shortcut is to reorder by part number without revisiting the application. Processes drift — a higher clean-in-place temperature, a new aggressive cleaning chemical, a faster pump speed — and the original tube quietly becomes the wrong choice. Revalidate the requirement whenever the process changes.

Match the Grade to the Duty

Grade is the first hard filter in any selection guide to silicone tube.

Industrial Grade

General-purpose silicone for air, water, low-pressure transfer and protective sleeving. It is cost-effective where there is no food, medical or pharmaceutical contact. For most plant and original equipment manufacturer uses, this is the sensible default.

Food Grade Silicone Tube

If the tube touches anything ingestible, you need food grade silicone tube that complies with Food and Drug Administration 21 Code of Federal Regulations, Section 177.2600, or an equivalent standard. This matters for breweries, dairies, beverage filling and confectionery. Ask specifically whether the compound is tested for extractables, not just labelled “food safe.”

Platinum Cured Silicone Tube (Medical / Pharmaceutical)

Platinum cured silicone tube uses a platinum catalyst instead of peroxide. The result is lower extractables, no curing by-product odour, and far better biocompatibility — which is why it dominates pharmaceutical fluid transfer and medical devices. It costs more, so reserve it for applications that justify it rather than specifying it by reflex.

Get the Dimensions Right: Inner Diameter, Outer Diameter and Wall

Silicone tube diameter is defined by inner diameter, outer diameter and wall thickness. Inner diameter controls flow; outer diameter and wall thickness determine how the tube seats on fittings and how much pressure it can hold.

Three practical rules save a lot of grief:

1. Specify inner diameter and outer diameter together, with tolerances. A nominal “8 millimetre tube” means little without knowing whether that’s the inner diameter or outer diameter.

2. Thicker walls handle more pressure and resist kinking, but reduce flexibility around tight bends.

3. For barbed fittings, the inner diameter should be slightly smaller than the barb so the tube grips securely.

Choose the Correct Hardness (Durometer)

Hardness is measured on the Shore A hardness scale. Soft tubing, around 40–50 Shore A, is flexible and seals well on fittings but balloons under pressure. Harder tubing, around 60–70 Shore A, holds shape and pressure better but is stiffer to route.

For peristaltic pumps, hardness directly affects pump life and flow consistency, so follow the pump manufacturer’s recommended range.

Confirm Temperature and Pressure Limits Together

Silicone’s temperature rating is one of its biggest advantages, but high-temperature silicone tubing still has limits that interact with pressure. A tube rated to 200°C at ambient pressure will not hold the same pressure as it would at room temperature — elevated heat lowers the safe working pressure.

Always check the manufacturer’s pressure rating at your actual operating temperature, and apply a safety factor, commonly 3:1 or 4:1, over your maximum working pressure.

Do Not Skip Certification and Documentation

For regulated industries, the paperwork is part of the product. Depending on the sector, you may need United States Pharmacopeia Class VI, International Organization for Standardization 10993, Food and Drug Administration compliance, or a 3.1 material certificate.

Reputable suppliers back their tubing with batch traceability and test reports. At UMABOND, in-house American Society for Testing and Materials testing supports the compounds we supply, and you can review our silicone product range at umabond.com/silicon-profiles/ when scoping a specification.

A Quick Selection Checklist

To summarise this selection guide to silicone tube into something you can use at your desk:

• Define the media, temperature, pressure and regulatory environment.

• Select grade: industrial, food grade, or platinum cured medical.

• Specify inner diameter, outer diameter and wall thickness with tolerances.

• Choose durometer to balance flexibility against pressure stability.

• Verify pressure rating at operating temperature with a safety factor.

• Confirm certifications and demand documentation.

Run through these six steps and you will eliminate the overwhelming majority of field failures before the order is placed.

Frequently Asked Questions

1. What is the most important factor in a selection guide to silicone tube?

The application requirements — media, temperature, pressure and regulatory needs — come first. Every other specification, from grade to durometer, flows from those four inputs.

2. What is the difference between peroxide and platinum cured silicone tube?

Platinum cured silicone tube has lower extractables, no curing by-products and better biocompatibility, making it suited to medical and pharmaceutical use. Peroxide-cured silicone is more economical and fine for general industrial duties.

3. How do I choose the right silicone tube diameter?

Specify inner diameter for flow and outer diameter plus wall thickness for fit and pressure. Always quote tolerances, and size the inner diameter slightly under a barbed fitting for a secure grip.

4. Can high-temperature silicone tubing handle high pressure at the same time?

Not at its full rating. Elevated temperature reduces the safe working pressure, so check the pressure rating at your actual operating temperature and apply a 3:1 or 4:1 safety factor.

5. Is food grade silicone tube the same as medical grade?

No. Food grade silicone tube meets food-contact regulations such as Food and Drug Administration 21 Code of Federal Regulations, Section 177.2600, while medical grade adds biocompatibility standards such as United States Pharmacopeia Class VI and International Organization for Standardization 10993. Medical grade is the stricter specification.

Conclusion

A reliable selection guide to silicone tube comes down to discipline: define the duty, match the grade, lock the dimensions, set the durometer, verify pressure at temperature, and demand documentation. Skip a step and the savings disappear the first time the line goes down.

If you would like help specifying the right silicone product for your process, explore the silicone range at umabond.com/silicon-profiles/ or contact the UMABOND team for application-specific guidance backed by in-house American Society for Testing and Materials testing.