Selecting medical silicone tubing is not simply a matter of choosing an inside diameter and placing an order. For medical device manufacturers, pharmaceutical equipment builders, and healthcare product developers, tubing specifications directly affect fluid flow, connection security, pump performance, sterilization compatibility, patient safety, and regulatory documentation.

A tube that appears correct on a basic drawing may still fail in assembly if its wall thickness varies too much, its hardness is not suitable for the fitting, or its dimensions change after sterilization. A complete specification helps prevent those risks before tooling, sampling, and mass production begin.

This guide explains what to include when specifying medical grade silicone tubing for a custom OEM or ODM project.

Key Takeaways

• Specify ID, OD, wall thickness, length, and tolerances separately; do not rely on a general “standard tolerance” statement.

• The right tubing design depends on the application’s fluid, pressure, vacuum, temperature, bending, pump, and sterilization requirements.

• Material grade, Shore A hardness, color, cleanliness, and documentation should be defined early in the development process.

• For critical medical fluid paths, dimensional inspection alone is not enough; consider leakage, pull-off, kink, burst, and sterilization validation as applicable.

• Sending a complete RFQ package to your supplier reduces sampling iterations, tooling changes, and production delays.

Start With the Application, Not Just the Tube Size

Before defining dimensions, clarify what the silicone tubing must do in the final device or system.

Medical silicone tubing is commonly used in:

• IV infusion and drug-delivery devices

• Peristaltic pump systems

• Respiratory circuits and ventilator accessories

• Catheters and drainage assemblies

• Dialysis and fluid-management systems

• Pharmaceutical processing and fill-finish equipment

• Laboratory analyzers and diagnostic instruments

• Surgical suction and wound drainage systems

The same tubing dimensions can perform very differently depending on whether the tube transports saline, air, blood, a drug formulation, or process fluid. The correct design should account for the complete operating environment—not only the drawing.

Questions to answer before preparing a specification

1. What fluid, gas, or media will contact the tubing?

2. Is the tube part of a patient-contacting device, a pharmaceutical process, or laboratory equipment?

3. What are the normal and maximum operating pressure conditions?

4. Will the tube experience vacuum, repeated compression, bending, or clamping?

5. Is it connected to a barb fitting, luer component, molded connector, pump head, or other assembly?

6. What sterilization method will be used?

7. What regulatory, biocompatibility, or customer documentation is required?

8. Is this a prototype, pilot run, or long-term mass-production program?

Providing these answers allows the supplier to evaluate manufacturability and recommend an appropriate material and production route.

Define the Core Dimensions: ID, OD, and Wall Thickness

The three fundamental dimensions of silicone tubing are:

• ID — Inside Diameter

• OD — Outside Diameter

• Wall Thickness

The relationship is:

For example, a tube with a 3.0 mm ID and 5.0 mm OD has a nominal wall thickness of:

However, nominal dimensions are only the beginning. A medical tubing drawing should also define acceptable variation and the dimensions that are most critical to device performance.

Why ID matters

The ID typically has the strongest influence on:

• Fluid flow rate

• Pressure drop

• Compatibility with internal components

• Pumping performance

• Catheter or guidewire passage, where applicable

• Retained fluid volume

If a tube is used in a fluid path, the ID should be selected according to the intended flow requirement, viscosity of the fluid, tubing length, and allowable pressure loss.

Why OD matters

The OD is particularly important for:

• Fit with external connectors or housings

• Routing through device channels

• Clamp compatibility

• Tube retention features

• Overall device size and ergonomics

Why wall thickness matters

Wall thickness affects more than tubing strength. It can influence:

• Resistance to kinking and collapse

• Flexibility and bend radius

• Burst-pressure performance

• Vacuum resistance

• Compression behavior in pump applications

• Connector engagement and pull-off performance

A thinner wall may improve flexibility, but it can reduce resistance to collapse or increase variation risk. A thicker wall may improve robustness, but it can make assembly more difficult or affect pumping behavior.

Specify Tolerances Separately for Each Critical Dimension

One of the most common problems in custom silicone tubing sourcing is an incomplete tolerance callout.

Avoid specifying only:

“Medical silicone tube, 3 × 5 mm, standard tolerance.”

This leaves too much room for interpretation. Instead, specify the tolerance for each dimension that affects function.

Recommended dimensional items to define

There is no single “best” silicone tubing tolerance

Achievable tolerance depends on multiple variables:

• Tube size and wall thickness

• Material formulation and Shore hardness

• Extrusion process stability

• Whether the tubing is supplied in coils or cut lengths

• Required post-processing

• Inspection method

• Functional risk of the application

For critical device applications, it is better to identify critical-to-quality dimensions on the drawing. A supplier can then focus process control and inspection resources on the features that affect your assembly or clinical performance.

Choose the Correct Shore A Hardness

Silicone hardness is generally measured on the Shore A scale. In medical silicone tubing, hardness influences flexibility, resilience, assembly force, sealing behavior, and fatigue performance.

General selection guidance

The correct hardness should be selected based on the actual application rather than a generic preference for “soft” or “hard” silicone.

For example:

• A peristaltic pump tube may need consistent elastic recovery and fatigue resistance.

• A drainage tube may require a balance of patient comfort, flexibility, and kink resistance.

• A connector-mounted tube may require sufficient strength to resist pull-off or leakage.

• A respiratory circuit component may need softness, transparency, and resistance to repeated handling.

When in doubt, ask the supplier to review the tubing with the mating connector, pump head, or complete assembly conditions.

Consider Pressure, Vacuum, Kinking, and Repeated Flexing

A tube that works in a static sample test may fail during actual use if it is repeatedly bent, clamped, pressurized, or exposed to vacuum.

Performance requirements may include

• Burst-pressure resistance

• Leakage resistance

• Vacuum-collapse resistance

• Kink resistance

• Tensile strength and elongation

• Tear resistance

• Compression set

• Repeated flex fatigue

• Peristaltic pump life

• Pull-off force from connectors

Kink and collapse risk

Kinking is especially important in drainage, infusion, respiratory, and wearable medical devices. It may reduce or stop fluid or gas flow.

Kink resistance is influenced by:

• ID-to-wall-thickness ratio

• Material hardness

• Tube routing and bend radius

• Operating temperature

• Reinforcement design, if required

• Connector location and assembly stress

If the tubing will bend tightly in the finished device, provide the supplier with the intended routing path, minimum bend radius, and any expected clamping points. This helps identify whether a standard extrusion is appropriate or whether a design adjustment is needed.

Specify the Material Grade and Compliance Requirements Clearly

“Medical grade silicone” is not a complete technical specification by itself. Buyers should define the intended application, required documentation, and applicable standards.

Depending on the project, requirements may include:

• Medical-grade silicone raw material

• USP Class VI material test information, where applicable

• ISO 10993 biological evaluation support for the finished device

• FDA-related material compliance documentation, where applicable

• Latex-free declaration

• RoHS and REACH declarations for markets where they are relevant

• Batch traceability

• Certificate of Analysis or Certificate of Conformance

• Material lot information

• Change-control notification requirements

It is important to distinguish between material-level information and finished-device compliance.

For example, a silicone raw material may have supporting test data, but the final medical device still requires evaluation based on its intended use, patient-contact category, contact duration, sterilization method, processing conditions, and applicable market regulations.

For pharmaceutical fluid-path applications, material extractables and leachables may also be a central part of supplier qualification. See our related guide: Silicone Tubing for Pharmaceutical Manufacturing: Extractables, Leachables, and Regulatory Compliance.

Select the Right Color, Transparency, and Surface Finish

Medical silicone tubing can be transparent, translucent, or colored depending on functional and identification needs.

Transparent or translucent tubing

This is often preferred when users need to observe:

• Fluid movement

• Air bubbles

• Particulates

• Blockages

• Color changes in fluids

Colored tubing

Color can support:

• Product identification

• Line differentiation

• Assembly error prevention

• Brand-specific design requirements

If color is required, specify the color standard whenever possible, such as a physical sample, Pantone reference, or approved color chip. The specification should also clarify whether color consistency must be controlled across lots.

Surface finish

The desired surface condition should be included if it affects use or assembly. Consider:

• Smoothness

• Tackiness

• Parting lines or extrusion marks

• Particulate control

• Visual inspection requirements

• Compatibility with printing, marking, or bonding

Confirm Sterilization Compatibility Early

Sterilization may affect silicone tubing appearance, physical properties, packaging, or mating components. The final sterilization method should be considered during product development—not after mass production begins.

Common methods include:

• Ethylene oxide (EtO)

• Steam autoclave sterilization

• Gamma irradiation

• Electron beam sterilization

The actual effect depends on the silicone formulation, tubing geometry, additives, packaging configuration, sterilization cycle, and performance requirements.

For a critical application, validate the finished component or finished device after the intended sterilization cycle. Relevant checks may include:

• Visual appearance

• Color change

• Dimensional stability

• Hardness

• Tensile properties

• Leakage performance

• Odor or residual concerns

• Package integrity

Do not assume that a silicone tube suitable for one sterilization process will automatically be suitable for all sterilization methods.

Choose a Manufacturing Process That Matches the Design

Medical silicone tubing is commonly manufactured by extrusion. However, some applications require molded ends, integrated connectors, valves, seals, or more complex geometries.

Depending on the component design, an OEM supplier may recommend:

• Silicone extrusion for continuous tubing

• Cut-to-length tubing

• Extrusion with post-curing

• Liquid silicone rubber injection molding

• Compression molding

• Overmolding or insert molding

• Secondary assembly with plastic or metal components

For a detailed comparison, read: Medical Silicone Extrusion vs. Injection Molding vs. Compression Molding: Which Process Is Right for Your Component?.

In general, process selection should be based on geometry, annual volume, tolerance needs, assembly requirements, tooling cost, and validation strategy—not solely on piece price.

What Documents Should a Medical Silicone Tubing Supplier Provide?

Documentation requirements vary by project, but qualified medical device buyers commonly request some combination of the following.

Typical supplier documentation checklist

The document package should be agreed before production approval. This avoids a common purchasing problem: receiving acceptable physical parts but insufficient records for incoming inspection, supplier qualification, or regulatory files.

Medical Silicone Tubing RFQ Checklist

To receive an accurate quotation and practical engineering feedback, provide as much of the following information as possible.

Essential RFQ information

• 2D drawing, 3D model, reference sample, or written dimensions

• Tube ID, OD, wall thickness, and length

• Dimensional tolerances

• Required Shore A hardness

• Color and transparency requirements

• Application and fluid-contact details

• Operating pressure, vacuum, temperature, and bend requirements

• Sterilization method, if known

• Required tests or acceptance criteria

• Required compliance and quality documentation

• Packaging requirements

• Prototype, annual, and forecast quantities

• Required sample and mass-production timing

• Mating connector or assembly details, if available

If drawings are not yet complete, an experienced supplier can often support early-stage manufacturability review based on a sample, application description, and preliminary dimensions.

Why Work With Chensheng for Custom Medical Silicone Tubing?

Jinan Chensheng Medical Technology Co., Ltd. provides OEM and ODM support for medical-grade silicone tubing, catheters, molded silicone components, and related medical fluid-management products.

For custom projects, our team can support customers from early specification review through sampling and mass production, including:

• Medical silicone tubing dimension and material evaluation

• Custom extrusion and cut-to-length processing

• Mold development and molded silicone components

• OEM/ODM project support

• Manufacturing-process recommendations

• Quality documentation and traceability support

• Communication for overseas sourcing and remote supplier evaluation

Whether you have a complete engineering drawing or only an initial concept, providing your functional requirements early helps create a more reliable and cost-effective tubing solution.

Request a Custom Medical Silicone Tubing Quote

Looking for a medical silicone tubing manufacturer for an OEM or ODM project?

Send us your drawing, sample, tubing dimensions, target quantity, application, and documentation requirements. Our team will review the project and recommend an appropriate manufacturing approach.

Contact Chensheng to discuss your custom medical-grade silicone tubing project.

FAQ: Medical Silicone Tubing Specification and Sourcing

What information is required to quote custom medical silicone tubing?

At minimum, provide the ID, OD, wall thickness, length, hardness, color, quantity, and intended application. For a more accurate quotation, also include tolerances, sterilization method, connector details, packaging, required documentation, and a drawing or physical sample.

What is the difference between ID tolerance and OD tolerance for silicone tubing?

ID tolerance controls the internal fluid path and internal fit. OD tolerance controls external connector fit, device routing, clamps, and housing interfaces. Both should be specified independently when they are critical to product function.

Can medical silicone tubing be made in custom sizes?

Yes. Custom silicone tubing can be developed in different IDs, ODs, wall thicknesses, lengths, hardness levels, colors, and packaging formats. Final feasibility depends on the geometry, tolerance requirements, material selection, and production volume.

How do I choose the right Shore A hardness for medical silicone tubing?

Choose hardness based on the tube’s function. Consider flexibility, anti-kink performance, pressure or vacuum resistance, pumping behavior, connector fit, patient-contact requirements, and sterilization conditions. Testing the tubing in the final assembly is recommended for critical applications.

Can silicone tubing be used in a peristaltic pump?

Yes, silicone tubing is widely used in peristaltic pumping applications. However, pump-head geometry, compression level, operating speed, fluid, temperature, and required service life should be evaluated to select the right dimensions and material properties.

Is USP Class VI the same as ISO 10993 compliance?

No. USP Class VI and ISO 10993 are different frameworks. USP Class VI is commonly associated with material testing, while ISO 10993 addresses biological evaluation of medical devices based on their intended use and patient-contact conditions. The final device manufacturer remains responsible for the appropriate finished-device evaluation.

Can medical silicone tubing be sterilized?

Silicone tubing may be compatible with EtO, steam, gamma, or e-beam sterilization, depending on the material, design, packaging, and validated process. Compatibility should be confirmed for the final component or device under the actual sterilization conditions.

What is the typical lead time for custom silicone tubing samples and mass production?

Lead time depends on tubing complexity, material availability, whether tooling is required, testing requirements, sample revisions, order quantity, and packaging needs. Share your target schedule during the RFQ stage so the supplier can assess feasibility and plan accordingly.