The Essentials of Pre-Insulated Tubing

An overview of what pre-insulated tubing is, how it works, and industries using thermally insulated tube systems today

Pre-insulated tubes are a popular choice for many industries and engineering projects due to the benefits over their non-insulated counterparts when dealing with high or low temperatures within the piping process or surrounding environment.

In this post, we'll explore the main components of pre-insulated tube systems, including their construction and applications, as well as some common uses for these unique piping products.

What is Pre-Insulated Tubing?

The main components of a pre-insulated tube are the carrier tube and tracer, the insulating layer, and the outer protective jacket.

The Carrier Tube and Tracer

The carrier tube is the innermost layer of a pre-insulated tube. It is usually made of corrosion-resistant stainless steel, copper, or even plastic.

The purpose of using stainless steel is to prevent corrosion and provide a flexible option for use at a variety of pressure ratings.

Stainless steel tubes are very durable, offering outstanding high-pressure performance over long periods with minimal maintenance requirements. 

Copper pre-insulated tubes offer greater temperature tolerance but aren't suited for higher pressure ratings.

Plastic pre-insulated tubes are often used for short distances because they are lightweight and easy to install in tight spaces, but they cannot withstand high pressure and offer reduced thermal tolerances.

Pre-Insulated tubes with tracer tubes use an electrical or steam supply to heat the nearby tubing and avoid freezing in colder environments.

These tracers typically run in parallel to the main process tube and come in the same variety of materials as the core process tube.

This means you can mix and match stainless steel, Teflon, copper and other materials to find a perfect balance of cost, flexibility, weight, thermal characteristics, and other critical design considerations.

The Insulating Layer

The insulating layer acts as a barrier between the carrier pipe and the outer protective jacket, increasing thermal efficiency and allowing the tube to maintain internal temperatures and prevent heat or cold from transferring to or from the environment surrounding the piping system.

This insulating layer must function across a range of temperatures while still being flexible enough to expand and contract without breaking apart under pressure changes caused by the pipe system, such as temperature fluctuations, vibrations, or impacts due to vibrations caused by nearby construction activities.

In most cases, this insulation is made from non-flammable glass fiber.

However, some pre-insulated tube models also use aerogels, foams, and other fibrous substances

The type of insulation used will typically impact both flexibility and insulation characteristics.

Outer Protective Jacket

The outer jacket on a tubing bundle is typically made from polyvinyl chloride (PVC) or urethane.

Both materials have many benefits, including:
  • Effective protection from snags, punctures, or scratches
  • Good resistance to corrosion and chemicals
  • Excellent weathering characteristics
The jacket protects the thermally insulated tubing from damage during transportation and installation while also providing a barrier between the insulation and other materials in the system, such as steel pipe, concrete, and water.

Benefits of Pre-Insulated Tubing Bundles

Pre-insulated tubing is an excellent option for a wide range of use cases, environments, and industries.

If you're not sure if the product is ideal for your intended scenario, consider these benefits:

  • Improved thermal efficiency: Insulated systems help prevent heat loss, which can lower the energy required to maintain a desired temperature inside the tube.
  • Reduced maintenance costs: Because pre-insulated tubes are made to prevent heat loss, they can help reduce condensation and moisture problems. Combined with their durable, multi-layer design, this can significantly reduce maintenance costs.
    When needed, bending tools, heat-shrink end-seal boots, jacket patch kits, center line tools, and heat-shrink entry-seal boots can help streamline the replacement or upkeep of damaged tubes.
  • Improved safety: Pre-insulated tubes can enhance worker safety and reduce the risk of contact burns by reducing overall surface temperatures and eliminating the formation of hot spots within a pipe system design.
  • Extended service life: Many of the same traits that make pre-insulated tubes more affordable to maintain work to ensure a longer service lifespan—even under continuous use.

    This is particularly true for stainless steel insulated tubes thanks to their exceptional balance of overall durability, corrosion resistance, and strength.
  • Simplified installation: Supplied in pre-cut lengths, pre-insulated tubing is easier to install in tight spaces and doesn't require complex installation tools or techniques.

    You also don't need to worry about designing systems with room for manual pipe wrapping or sheathing.

Common Pre-Insulated Stainless Steel Tube Types

While exact product specs and options will vary between pre-insulated stainless steel tube manufacturers, options are available in various sizes and with varying insulation levels.

As mentioned above, they can also include trace and process tubes of different materials.

Some tubes will even include multiple process tubes within the insulated bundle.

However, the insulation type is the most significant consideration outside of materials and tube counts. Most pre-insulated tubes fit into one of three categories:

  • Single-layer pre-insulated tubes: Designed to offer basic environmental thermal protection and insulation, these tubes feature a single layer of insulation to help keep weight and costs low and improve flexibility.
  • Multi-layer pre-insulated tubes: Designed to offer enhanced thermal protection, these designs can include two or more layers of insulating material.

    Sometimes, insulating layers are made from multiple cores of insulating material. Materials can also vary between layers, providing a level of adaptability to suit nearly any use case or environment.
  • Flexible pre-insulated tubes: In situations where tubing must route through tight spaces or avoid obstacles, flexible tubing can help to ensure optimal performance without the risk of damage during installation.

    Most use rubbers or plastics to achieve these goals, so check thermal tolerances and other specifications to be sure the flexible pre-insulated tube you're considering is a good fit for your use case.

Sizing Pre-Insulated Tubes

Pre-insulated tubing bundles come in various sizes to suit different applications.

The size of the tube is typically determined by its inner diameter (ID)—the opening through which fluids or gasses flow.

Generally, tubes are available in IDs ranging from 1/4-inch to 6-inch.

The specific tube size you'll need is typically determined by the required flow rates and pressures of your piping process and the size of the equipment and piping system in which you will install the tubing.

In addition to the ID, pre-insulated tubing is also available in a range of outer diameters (ODs), which refers to the overall size of the tube, including any insulating layers, traces, or outer protective jackets.

OD is especially important when designing systems in tight spaces to ensure adequate clearance when routing your pre-insulated tubing.

Popular Uses for Pre-Insulated Tubing

Many industries have adopted pre-insulated pipe systems, including district heating, marine, industrial and offshore. Below, we'll explore a few of the common uses:

HVAC (heating, ventilation, and air conditioning)

Typically HVAC use involves the transport of hot or cold fluids or gasses, including but not limited to chilled water systems, hot water systems, steam systems, and hydronic systems used to help regulate temperatures and air quality within a building or space.


Pre-insulated tubing is present in nearly all refrigeration products ranging from the air conditioners in the typical residential home to the cooling cases at your local supermarket to the floors of food processing plants and cold storage facilities.

Industrial Processing

Pre-insulated tubing sees extensive use in some of the world's largest industries.
In most cases, the tubing is used to transport chemicals, fluids, or gases within processes or between processing systems.

You'll find them in chemical processing plants, pharmaceutical manufacturing plants, power generation plants of nearly all types, pulp and paper processing plants, mineral and mining operations, and oil, gas, and petrochemical processing plants.

Water and Wastewater Treatment

Stainless-steel pre-insulated tubing is an essential component in many desalination, drinking water, wastewater, and industrial water treatment facilities and is used within many stages of each process.


Access to water is an essential component of many agricultural processes.

Pre-insulated tubing can provide elemental resistance in the harsher environments of modern agriculture while also providing long-lasting, safe performance at nearly any scale.

Popular uses include aquaculture, greenhouses, irrigation, and livestock watering.


  • Pre-insulated tubes consist of three primary sections: the carrier tube, the insulating layer or layers, and the outer protective jacket.
  • The carrier tube can be made from multiple materials, including stainless steel, copper, or plastic.
  • Tracers can help to keep insulated tubes flowing in cold environments.
  • The insulating layer is often made from glass fibres, aerogel, and other materials, which can help to provide thermal isolation and shielding while also expanding and contracting as needed with the carrier tube.
  • The outer protective jacket on most pre-insulated tubing is made from PVC or urethane.
  • It helps to increase weathering resistance, provides additional protection from corrosion or chemical exposure, and can minimize damage from snags, punctures, or scratches.
  • Benefits of pre-insulated tubing include improved thermal efficiency, reduced maintenance costs, improved safety, extended service life, and simplified installation.
  • Most pre-insulated stainless steel tube comes in single-layer, multi-layer, or flexible configurations.
  • When choosing pre-insulated tubing, most list the size by the inner diameter. However, consider the outer diameter if you're designing for a tight space or have precise tolerances.
  • Pre-insulated tubing is popular in HVAC, refrigeration, industrial processing, water and wastewater treatment, and agriculture, among other industries.
Pre-insulated tubes are a versatile and cost-effective solution for your next building project. From heating systems to marine applications, these pipes come in a variety of sizes and can help you achieve the results you want without breaking the bank. If you're looking for more information about pre-insulated tubes or how they can benefit your next construction project, contact one of our expert sales analysts today!
Unified Alloys will not be responsible for the accuracy or currency of any of the information contained herein. The specifications and information contained in the brochures are subject to change without notice.
Unified Alloys expressly disclaims any liability for loss or damage caused by use of any information contained in this publication, including any special, incidental or consequential damages arising from such use.
Nothing in this publication shall create or imply any warranty whether expressed or implied.