A measure of the ability of tubing to resist damage by mechanical means.

Adhesive Lined Tubing

Multi-wall tubing. The outer wall provides abrasion resistance. The inner adhesive liner provides an environmental seal for moisture protection.


Generally refers to the environmental stimulus such as heat and light. Accelerated aging tests are performed to provide an indication of the performance of the material over its life.


Additive used to retard fungal growth in tubing, especially for applications in which tubing is exposed to damp environments.


Additive used to prevent yellowing of tubing and/or loss of strength during extrusion processing.

ASTM – American Society for Testing and Materials

A nonprofit industry wide organization that publishes standards, testing methods, recommended practices, definitions, and other materials.

AWG – American Wire Gauge

A method of specifying conductor size.

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Certificate of Compliance

A Quality Control Department certificate stating that the product being shipped conforms to test specifications.

Chemical Resistance

The capability of a compound to resist deterioration due to chemical reaction.

Cold Impact

A test designed to determine the brittleness of a compound by subjecting it to impact at low temperatures.

Color Code

A system for identifying wires, cables and products by covering them with various colors of tubing.

Colorant or Color Concentrate

Pigment additives used to introduce color to tubing.


A chemical mixture of base resin and desired additives, which can be extruded into tubing.


A comparison of the thinnest wall thickness to the thickest wall thickness.


A mechanical device used to physically and electrically connect two or more conductors.

Continuous Operating Temperature

The temperature range over which a tube will maintain its ideal performance.


A compound formed from the polymerization of two different monomers.

Core or Inner Liner

The inner wall of dual wall, heat shrinkable tubing.


Deterioration of a metal surface by chemical reaction.


The formation of three-dimensional covalent bonds between molecular chains in a polymer by means of chemical or electron bombardment, which improves its mechanical and thermal properties.

CSA – Canadian Standards Association

A non-profit independent Canadian organization which operates a certification service for electric and electronic materials and equipment with particular emphasis on safety.

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Any insulating material between two conductors which permits electrostatic attraction and repulsion to take place across it.

Dielectric Strength

The voltage that an insulating material can withstand before dielectric breakdown occurs.


A measure of surface resistivity or material hardness.

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Elastic Memory

The ability of a polymer to be altered to a predetermined shape, hold that shape for a period of time, and then return to its original shape upon the application of heat.


A class of long-chain polymers capable of being cross-linked to product elastic compounds.

Elongation / Ultimate Elongation

The maximum amount that tubing can be stretched in length before it breaks.

European Union Directive

The European Union – “EU” requires that by 1 July 2006, certain hazardous materials be eliminated from all components of automobiles and electronic equipment sold within the members’ counties. The primary concerns are lead, mercury, cadmium, and hexavalent chromium) and brominated flame retardants (polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE)) in new electrical and electronic equipment.


Ethylene-vinyl acetate.

Expanded I.D. – Expanded Inside Diameter

The Expanded I.D. measures the minimum size of the Inside Diameter after the tubing has been expanded. Heat shrink tubing is sold in its EXPANDED I.D. size.

Expansion Ratio

See Shrink Ratio.


A thermal and mechanical process used to create heat shrinkable tubing in which extruded tubing is enlarged in diameter while being reduced in wall thickness.


A material added to a plastic compound used to reduce the amount of resin required per unit value.


A machine designed to melt down plastic compound pellets, force the semi-soft material through a specially designed die, shaping it into tubular form.


The thermal and mechanical process by which a polymer compound is forced through a die to form tubing.

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Food & Drug Administration.

Flame Retardant

An additive that is included in tubing compounds to improve resistance to burning.


The measure of a material’s ability to support combustion.

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A measurement of resistance to compression, indentation and scratching that correlates well with mechanical strength, rigidity and resistance to abrasion. Usually measured using Shore scales.


Multiple wires or cables used to interconnect an electric circuit, usually with many breakouts, bundled together or secured in a section of tubing or sleeving.


High-density polyethylene.

Heat Shock

A test used to determine the stability of a material by sudden exposure to high temperature for a short period of time.

Heat Shrinkable

A polymer tubing that is capable of being reduced in size when exposed to heat.

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I.D. – Inside Diameter

The Inside Diameter of the tubing is measured in inches (in.) or millimeters (mm). Measure the open inside circle. Do not measure the tubing when it is flattened.


See Cross-linking.

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The outer wall of multi-wall, heat shrinkable tubing.

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Low density polyethylene.

Lead Free Tubing

See European Union Directive.

Liner or Melt Liner

The inner adhesive wall of multi wall heat shrinkable tubing.


Linear low-density polyethylene.

Longitudinal Shrinkage

Heat shrinkable tubing’s discreet loss of length during the recovery process.

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A concentration of substance (an additive, pigment, filler, etc.) in a base polymer.


Medium-density polyethylene.

Mil Spec

Military specifications issued by the US government.

Minimum Recovery Temperature

The minimum temperature required to fully recover heat shrinkable tubing.


Molecular weight.

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OFT – Optional Flame Test

Former CSA test for measuring the flame retardance of tubing. This test has been replaced with the VW-1 test.


A family of hydrocarbons with one carbon-carbon double bond.

Operating Temperature

The temperature range over which tubing may operate in continuous service.

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A chemical additive that is included in PVC compounds that softens and provides flexibility to plastics.

Polyethylene (PE)

A tough, flexible low cost plastic. Common applications are bags, film, and squeeze bottles. Low-density polyethylene (LDPE) is the most flexible. Linear low-density polyethylene (LLDPE) is the toughest and cheapest. High-density polyethylene (HDPE) is less transparent, but stiffer and more heat resistant.


A natural or synthetic compound consisting of large molecules made of many chemically bonded monomers. If two or more monomers are involved a copolymer is obtained.


A generic term for cross-linkable thermoset polymers. Polyolefin heat shrinkable tubing is usually made from polyethylene and its copolymers.

Polypropylene (PP)

Similar to high-density polyethylene, but more heat resistant and with high tensile strength and clarity.


A tough, abrasion resistant polymer having excellent low temperature properties and high clarity. Chemically resistant to fuels, oils and solvents, and available in a range of hardnesses.

Polyvinylchloride (PVC)

A resin that can be easily mixed with many different additives to change the resultant properties of the mixture.






Packaging for tubing products.


See Polyvinyl chloride.


Polyvinylidene fluoride.

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Recovered I.D. – Recovered Inside Diameter

When heat is applied to expanded tubing, the tubing will shrink or recover. The Recovered I.D. is the measurement of the Inside Diameter of the tubing after being allowed to FULLY SHRINK or RECOVER back to its original extruded size.

Recovery (Heat Shrinkable Components)

Heat activation of the elastic memory effect to cause expanded tubing to shrink down to its extruded size.

Recovery Temperature

See Minimum Recovery Temperature.


The base material in a plastic compound.


Compounds added to the resin to improve its resistance to flame, fire and smoke emissions.


Relative humidity.


The Restriction of Hazardous Substances in Electrical and Electronic Equipment (ROHS) Directive (Directive 2003/108/EC) as developed by the European Parliament.

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Secant Modulus

A measure of the flexibility of a material.

Shelf (Storage) life

The period of time after production during which a product that is stored under specified conditions retains its intended dimensional characteristics and performance capabilities.

Shore Hardness

A series of scales used to indicate hardness. The Shore A scale is most commonly used to measure the hardness of plastic tubing. Within a given scale, a higher number indicates a harder material.

Shrink Ratio

The ratio of the expanded diameter to the recovered diameter of heat shrinkable tubing.

Shrink Temperature

The particular temperature which effects complete recovery of a shrinkable product from its expanded state.

Specific Gravity

The ratio of the density (mass per unit volume) of a material to the density of water at a specified temperature.


A fusion process that permanently bonds two strands together without a connector.

Strain Relief

The reduction of the stress or strain on an object.

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Temperature Rating

The maximum and minimum temperatures at which insulating material can be used in continuous operation, without a deterioration of physical properties.

Tensile Strength

The ratio of the amount of axially applied force required to break or rupture a piece of tubing to the cross-sectional area of the tubing. It is expressed in units of force/area, such as pounds per square inch (psi).

Thermal Stabilizers

All PVC compounds have a thermal stabilizer to prevent the resin from decomposing when heated.


A polymer that can be repeatedly melted and hardened with only minimal degradation of the properties each cycle. Common examples are polyvinyl chloride (PVC) and polyethylene (PE).


A polymer, such as polyolefin, which hardens or “sets” when heat is applied and which, once “set,” cannot be re-softened through heating.


Thermoplastic elastomer.


Thermoplastic polyurethane.


Extruded material in self-supporting, hollow, tubular form.

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UL Certification

Underwriters Laboratories grants the UL mark for products that are tested and found compliant to a specific established set of standard tests.


Underwriter’s Laboratories – a non-profit independent organization which operates a listing service for electrical and electronic materials and equipment.

Ultraviolet (UV) Stabilizer

A tubing compound additive that retards the deterioration in strength and color caused by sunlight and other UV light sources.

Ultraviolet Degradation

The degradation caused by long-term exposure of tubing to sunlight or other ultraviolet rays.


See Polyurethane.


United States Pharmacopoeia (USP). Official compendium recognized by the Federal Food, Drug and Cosmetic Act which serves as the basis for enforcement actions by the U.S. Food and Drug Administration.



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Insultab trademark for a proprietary product, vinyl adhesive tubing.


A flammability test conducted by UL or CSA. Tubing with a VW-1 rating is highly flame-retardant.

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Wall Thickness

The difference between the outside diameter and the inside diameter of the tubing wall.

Water Absorption

The percentage weight of water that a material will absorb after a period of immersion.

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