What Are the Differences Between Silicone Tubing Grades?

Silicone tubing grades differ according to the formulation of the silicone compound, the curing system used and the performance or compliance requirements of the intended application.

This means that two silicone tubes may look almost identical while being designed for very different uses.

For an engineer or procurement team, choosing the right grade is therefore not simply a matter of selecting the correct bore and wall thickness. Temperature, flexibility, chemical contact, cleanliness, regulatory requirements and the way the tube will be used all need to be considered.

Some applications only require a general-purpose industrial silicone tube. Others may demand a higher-purity material, a particular curing method or documented suitability for contact with specific substances.

Understanding these distinctions helps avoid both under-specification and unnecessary over-specification.

What does a silicone tubing grade actually refer to?

The word “grade” is used broadly in the rubber industry.

It may refer to a particular silicone formulation, a curing method, a level of purity or a material intended to meet defined regulatory or application requirements.

As a result, there is no single universal list of silicone tubing grades that applies to every manufacturer.

Instead, buyers should focus on the measurable properties and requirements attached to a particular product.

These may include:

• Silicone type and formulation
• Hardness
• Temperature capability
• Tensile and elongation properties
• Curing system
• Colour or translucency
• Regulatory or compliance requirements
• Suitability for contact with particular fluids
• Dimensional tolerances

The most appropriate tubing grade is therefore the one that satisfies the actual operating conditions rather than simply carrying the most technical-sounding description.

How do peroxide-cured and platinum-cured silicone differ?

One of the most important distinctions between silicone tubing types is the curing method.

Silicone rubber must be cured to transform the material into a stable elastomer. Two commonly discussed curing systems are peroxide curing and platinum curing.

Peroxide-cured silicone

Peroxide curing is an established manufacturing method used for many silicone rubber products.

It can be suitable for a broad range of industrial applications where the required physical properties and service conditions are compatible with the compound.

Depending on the formulation and post-curing process, peroxide-cured silicone may contain residual by-products associated with the curing system.

Whether this matters depends entirely on the application.

For a general industrial seal or tube, these residual characteristics may have no practical significance.

For applications where purity, odour, extractables or sensitive product contact are important, a different curing system may be preferred.

Platinum-cured silicone

Platinum-cured silicone uses an addition-cure system rather than peroxide chemistry.

It is often selected where high purity and cleanliness are especially important.

This can make platinum-cured silicone attractive for specialist tubing applications where the material needs to meet more demanding process or contact requirements.

However, platinum curing should not automatically be treated as “better” for every application.

A general industrial tube may not require the additional characteristics associated with a high-purity material.

The appropriate choice depends on what the tube must actually do.

Is platinum-cured silicone always the highest grade?

“Highest grade” is not necessarily a useful way to compare silicone tubing.

A material can only be judged against the requirements of the application.

Platinum-cured silicone may be particularly appropriate where purity and controlled material composition are important.

That does not mean it provides a meaningful advantage for every engineering use.

For example, tubing used as a flexible sleeve around equipment may have very different requirements from tubing used to carry a sensitive process fluid.

The first application might prioritise temperature resistance and mechanical flexibility.

The second may place greater emphasis on cleanliness, extractables and regulatory documentation.

Both tubes could be completely suitable for their intended purposes even though they use different silicone grades.

This is why engineers should specify required properties rather than relying on labels alone.

Are food-grade and medical-grade silicone the same?

No.

Terms such as food-grade and medical-grade describe different application requirements and should not be used interchangeably.

A silicone product intended for food-related applications may need to satisfy requirements relevant to food contact.

Medical applications can involve a different set of standards, testing requirements and documentation.

A material marketed for one application should not automatically be assumed suitable for another.

The same principle applies to pharmaceutical and laboratory uses.

These descriptions are important because silicone itself is only the base material. The complete formulation, manufacturing process, curing system and documentation can all influence whether a particular tubing product is appropriate for a controlled application.

Where compliance is essential, purchasers should ask for the relevant material documentation rather than relying solely on a generic product description.

What is general-purpose silicone tubing?

General-purpose silicone tubing is intended for applications where specialist regulatory or high-purity requirements are not the primary consideration.

It can be useful in a wide range of industrial settings where flexibility, temperature resistance and the general characteristics of silicone rubber are required.

Applications may involve machinery, equipment assemblies, protective sleeving or non-critical fluid transfer, depending on the precise compound and service conditions.

However, “general purpose” should not be interpreted as meaning suitable for everything.

Temperature, pressure and chemical compatibility still need to be assessed.

A tube designed for an ordinary industrial application should not automatically be used for food, pharmaceutical or medical contact simply because both products are manufactured from silicone.

How do silicone tubing grades differ in temperature performance?

Silicone rubber is known for its ability to retain useful properties across a broad temperature range, but the precise performance of a tube depends on the compound.

Different silicone formulations can have different recommended operating limits.

The way the tube is used also matters.

A tube exposed externally to heat faces different conditions from a tube carrying a hot liquid under pressure.

Continuous operating temperature should normally receive more attention than a short-term temperature maximum.

Repeated heating and cooling can also affect the complete system.

For instance, the silicone may expand differently from the connectors or fittings used around it.

The tube’s ability to remain flexible can be beneficial, but engineers still need to ensure that dimensions, connections and pressure requirements remain suitable across the expected temperature range.

Does hardness vary between silicone tubing grades?

Yes.

Silicone rubber can be compounded to different hardness levels.

Hardness affects how readily the tubing compresses, bends and deforms.

Softer tubing may provide greater flexibility, while firmer compounds can offer more resistance to deformation.

Neither is inherently superior.

For a tube that needs to route around tight spaces, flexibility may be a priority.

For another application, excessive softness could allow the tube wall to deform too easily.

Hardness should therefore be considered alongside bore size, outside diameter and wall thickness.

The combined geometry and material properties determine how the finished tube behaves.

Buyers looking at silicone rubber tubing should therefore treat dimensions and material grade as connected parts of the specification.

Do tubing grades have different pressure capabilities?

Pressure capability cannot be determined from the silicone grade alone.

Tube dimensions are crucial.

Wall thickness, internal diameter, material hardness, operating temperature and any external reinforcement all influence how a tube behaves under pressure.

Higher temperatures can also affect mechanical performance.

A tube that performs adequately under one combination of pressure and temperature should not automatically be assumed suitable under more demanding conditions.

Connections and fittings are equally important.

The complete fluid system should be designed for the expected pressure rather than considering the tube in isolation.

For critical pressure applications, suitability should be confirmed for the exact product and operating conditions.

How important is chemical compatibility?

Chemical compatibility is one of the most important factors in tubing selection.

Silicone offers useful properties in many environments, but it is not universally resistant to every liquid, gas, solvent or chemical.

Exposure to an incompatible substance may cause swelling, softening, changes in mechanical properties or other deterioration.

Different silicone formulations can also behave differently.

Before specifying a tube, engineers should establish exactly what will pass through it and what substances may contact the outside surface.

Cleaning chemicals also need to be considered.

A tubing material may be compatible with the normal process fluid but unsuitable for a cleaning or sterilisation agent used between production cycles.

This is particularly relevant in applications where regular cleaning forms part of the operating procedure.

Why does purity matter in some tubing applications?

In some processes, the tube is not simply a mechanical component.

It may come into direct contact with a material that must remain controlled or uncontaminated.

Here, the composition and cleanliness of the silicone can become especially important.

A high-purity tubing grade may be selected to reduce concerns around unwanted residues or substances that could migrate from the tube into the material being transported.

This is one reason platinum-cured silicone can be considered for specialist uses.

However, purity requirements should be defined specifically.

Using a more specialised material without understanding the actual requirement can increase cost without improving performance.

Conversely, choosing a general industrial grade for a purity-sensitive process could create unnecessary risk.

What dimensional differences exist between silicone tubes?

Silicone tubing is usually defined by dimensions such as internal diameter, external diameter and wall thickness.

These measurements influence flow capacity, flexibility and mechanical behaviour.

Because silicone is an elastomer, dimensional tolerances should reflect rubber manufacturing rather than rigid machining.

The tube may also deform slightly during handling or measurement.

For OEM applications, it is especially important to identify which dimensions affect assembly.

The internal diameter might need to fit over a connector, for example, while the external diameter may need to pass through a housing or clip.

Wall thickness may influence both flexibility and robustness.

Rather than applying unnecessarily demanding tolerances to every measurement, manufacturers and designers should agree which dimensions are functionally critical.

Can different grades look identical?

Yes.

Appearance alone is not a reliable way to identify the performance or compliance characteristics of silicone tubing.

Two tubes can have similar colour, translucency and dimensions while being manufactured from different formulations or curing systems.

This is particularly important in controlled manufacturing environments.

If different grades are used within the same facility, clear product identification and purchasing controls can help prevent the wrong tubing from being installed.

Colour coding may sometimes be useful for identification, but colour itself does not confirm material grade or compliance.

Documentation remains the more reliable reference.

How should OEMs choose silicone tubing?

OEM manufacturers need to consider both end-product performance and production consistency.

A tube must fit correctly during assembly, remain compatible with surrounding components and continue performing throughout the expected service life.

A useful specification should therefore define the relevant dimensions and required material characteristics.

Temperature range, chemical exposure, flexibility, pressure conditions and environmental exposure should all be considered.

The method of attaching the tube also matters.

A tube pushed over a connector may need sufficient elasticity to create a secure fit without becoming excessively difficult to assemble.

If clamps are used, the tubing needs to behave predictably when compressed.

For volume production, consistent fit can be just as important as the nominal dimensions shown on the drawing.

What should buyers ask before ordering silicone tubing?

Rather than asking simply for a particular “grade”, buyers can provide the manufacturer with details of the actual application.

Useful information includes what will pass through the tube, its operating temperature, whether pressure is involved and whether the tubing requires any particular compliance or purity characteristics.

Required internal and external dimensions should also be stated.

If the tube forms part of an existing assembly, information about fittings and installation can help clarify what is functionally important.

Buyers should also identify whether the material will be used indoors, outdoors or in contact with cleaning substances.

This allows the tubing specification to be considered as a complete requirement rather than focusing on a single material property.

Frequently Asked Questions

What is the difference between platinum-cured and peroxide-cured silicone tubing?

The main difference is the curing system used to turn the silicone compound into a finished elastomer. Platinum curing is often chosen for applications where high purity is important, while peroxide-cured silicone is used widely across general industrial applications. Suitability depends on the required performance and application.

Is food-grade silicone tubing suitable for medical use?

Food-contact suitability should not be assumed to mean medical suitability. These applications can involve different standards and documentation requirements. The exact tubing specification should be checked against the intended use.

Which silicone tubing grade is best for industrial equipment?

There is no single best grade. The correct choice depends on temperature, chemical contact, pressure, dimensions, flexibility and any compliance requirements. General-purpose silicone may be entirely suitable where specialist purity or regulatory characteristics are unnecessary.

Choosing the right silicone tubing grade

The differences between silicone tubing grades can involve much more than appearance.

Curing method, hardness, purity, temperature capability, dimensions and application-specific requirements can all influence which tube is suitable.

The most effective specification begins with the operating conditions.

Engineers should establish what the tubing will carry, the temperatures and pressures involved, how it will be installed and whether any particular regulatory or purity requirements apply.

From there, a suitable silicone formulation and tubing construction can be selected without unnecessarily over-specifying the product.

Silco Products supplies silicone tubing and other silicone rubber products for industrial and specialist applications. If you need help discussing tubing dimensions, material requirements or a bespoke silicone component, contact Silco Products.

Phone: 01903 732088
Email: sales@silcoproducts.co.uk
Find out more: https://siliconerubberproducts.co.uk/