Insultab has a lot of experience spotting where people go wrong when it comes to measuring heat shrink tubing. It’s actually simple when you have a common vocabulary and know the right formulas.
Here is the information you will need to get your tubing measurements right – so you get exactly what you need for your project. …or better yet, call Insultab’s Customer Service team, and they will do it for you.
One of the most important tasks is choosing the size of tubing needed for your project. Here is how it is done. First, take your tubing and lay it flat on a smooth surface. Next measure the width of the flattened tubing. Then multiply the width by 2 and divide this number by Pi (I bet you remember this one from school 3.1416) and you have your answer – this is the tubing diameter you will need for your project.
1. Determine the diameter size of the tubing.
Measure the diameter of the underlying materials to be covered – at the widest part.
Select tubing that is 20% – 30% larger than this measurement by referring to the product’s Technical Data.

2. Determine the shrink ratio of the tubing.
Heat shrinkable tubing is available in 2:1, 2.5:1 or 3:1 shrink ratios meaning the tubing has been expanded to twice, two and a half times or three times its fully recovered size. The greater the size variations of the underlying materials being covered, the larger the shrink ratio required.
For example:
- 2:1 shrink ratio: 1/2″ will recover to 1/4″ — 50% shrinkage.
- 3:1 shrink ratio: 3/4″ will recover to 1/4″ — 67% shrinkage.

3. Determine the wall thickness of the tubing.
Nominal Recovered Wall Thickness – The target thickness of the wall after complete recovery. The Wall Thickness of the tubing is measured in inches (in.) or millimeters (mm). Refer to the tubing’s Technical Data to determine the thickness of the wall.

4. Determine the length of the tubing.
Longitudinal Shrinkage: Heat shrinkable tubing has a small loss of length during the recovery process. Take into account the change of length of the recovered tubing (after shrinking). Longitudinal shrinkage varies from 5% to approximately 15% – depending on the material. Refer to the Tubing’s Technical Data for the shrinkage information.

Which Heat-Shrinkable tubing material should I use?
In selecting the best type of tubing for your application, the critical factor to consider is the environment where tubing will be used.
Material | Temperature Range |
---|---|
Polyolefin | -55°C to 135°C |
PVC | -20°C to 105°C |
Cross-Linked PVC | -20°C to 105°C |
Multi-Wall Polyolefin | -55°C to 110°C |
Multi-Wall PVC | -20°C to 105°C |
Polyvinylidene Difluoride (PVDF) | -55°C to 175°C |
Chlorinated Polyolefin Elastomer | -70°C to 121°C |
Fluoroelastomer | -55°C to 200°C |
Medical Grade | -55°C to 121°C |
Food Grade | -55°C to 121°C |
Material | Abrasion Resistance |
---|---|
Polyolefin | Good |
PVC | Excellent |
Cross-Linked PVC | Excellent |
Multi-Wall Polyolefin | Good |
Multi-Wall PVC | Excellent |
Polyvinylidene Difluoride (PVDF) | Excellent |
Chlorinated Polyolefin Elastomer | Excellent |
Fluoroelastomer | Excellent |
Medical Grade | Excellent |
Food Grade | Excellent |
Material | Acids | Solvents | Fuels/Oils |
---|---|---|---|
Polyolefin | Excellent | Good | Good |
PVC | Excellent | Excellent | Excellent |
Cross-Linked PVC | Excellent | Excellent | Excellent |
Multi-Wall Polyolefin | Excellent | Good | Good |
Multi-Wall PVC | Excellent | Excellent | Excellent |
Polyvinylidene Difluoride (PVDF) | Excellent | Excellent | Excellent |
Chlorinated Polyolefin Elastomer | Excellent | Good | Excellent |
Fluoroelastomer | Excellent | Excellent | Excellent |
Medical Grade | Resists a Wide Range of Chemicals | ||
Food Grade | Resists Many Chemicals & Oils |
Tensile Strength is a measurement of the amount of stretching required to break or rupture the tubing. Tensile strength may be affected by the thickness of the tubing wall.
Material | Tensile Strength |
---|---|
Polyolefin | 1500 psi 2600 psi |
PVC | 3000 psi |
Cross-Linked PVC | 3000 psi |
Multi-Wall Polyolefin | 2100 psi 2200 psi |
Multi-Wall PVC | 3000 psi |
Polyvinylidene Difluoride (PVDF) | 5500 psi |
Chlorinated Polyolefin Elastomer | 2100 psi |
Fluoroelastomer | 2400 psi |
Medical Grade | 3200 psi 3600 psi |
Food Grade | 2500 psi |
Material | Dielectric Strength |
---|---|
Polyolefin | 500 vpm 900 vpm |
PVC | 1083 vpm |
Cross-Linked PVC | 1083 vpm |
Multi-Wall Polyolefin | 700 vpm 800 vpm 900 vpm |
Multi-Wall PVC | 1,083 vpm |
Polyvinylidene Difluoride (PVDF) | 900 vpm |
Chlorinated Polyolefin Elastomer | 800 vpm |
Fluoroelastomer | 500 vpm |
Medical Grade | 1800 vpm 2,000 vpm |
Food Grade | 1,800 vpm |
Material | Water Resistance |
---|---|
Multi-Wall Polyolefin | Provides Flexible, Tough, Permanent, Water Resistant Protection |
Multi-Wall PVC | Provides Permanent, Water & Salt Water Resistant Protection, Excellent UV Resistance for Outdoor Applications, Irradiated Multi-Wall PVC Available |
Medical Grade | Self-Sealing – Unique Heat Sealable Property Without Glue Prevents Moisture from Entering Into the Underlying Substrate |
Material | Flexibility |
---|---|
Polyolefin | Very Flexible |
PVC | Flexible |
Cross-Linked PVC | Flexible |
Multi-Wall Polyolefin | Flexible |
Multi-Wall PVC | Flexible |
Polyvinylidene Difluoride (PVDF) | Semi-Rigid |
Chlorinated Polyolefin Elastomer | Flexible – Even at Low Temperatures |
Fluoroelastomer | Very Flexible |
Medical Grade | Flexible |
Food Grade | Flexible |
Material | UL VW-1 Flammability |
---|---|
Polyolefin | UL VW-1 Colors Only – Not Clear |
PVC | UL VW-1 Colors & Clear |
Cross-Linked PVC | UL VW-1 Colors & Clear |
Multi-Wall Polyolefin | UL VW-1 Outer Jacket |
Multi-Wall PVC | UL VW-1 Outer Jacket |
Polyvinylidene Difluoride (PVDF) | UL VW-1 |
Chlorinated Polyolefin Elastomer | No |
Fluoroelastomer | No |
Material | UV Resistance |
---|---|
Polyolefin | Poor |
PVC | Excellent |
Cross-Linked PVC | Excellent |
Multi-Wall Polyolefin | Poor |
Multi-Wall PVC | Excellent |
Polyvinylidene Difluoride (PVDF) | Fair |
Chlorinated Polyolefin Elastomer | Good |
Fluoroelastomer | Fair |
Medical Grade | NA |
Food Grade | NA |
Material | Shrink Ratio |
---|---|
Polyolefin | 2:1 3:1 |
PVC | 2:1 |
Cross-Linked PVC | 2:1 |
Multi-Wall Polyolefin | 2:1 3:1 2.5:1 |
Multi-Wall PVC | 2:1 |
Polyvinylidene Difluoride (PVDF) | 2:1 |
Chlorinated Polyolefin Elastomer | 2:1 |
Fluoroelastomer | 2:1 |
Medical Grade | 2:1 |
Food Grade | 2:1 |
Material | Standard Colors |
---|---|
Polyolefin | Black, Clear, White, Red, Yellow, Green, Blue |
PVC | Black, Clear, White, Red, Yellow, Blue Bright Colors – Crystal Clear |
Cross-Linked PVC | Black |
Multi-Wall Polyolefin | Black |
Multi-Wall PVC | Black |
Polyvinylidene Difluoride (PVDF) | Translucent |
Chlorinated Polyolefin Elastomer | Black |
Fluoroelastomer | Black |
Medical Grade | Black, Clear, Blue, White |
Food Grade | Black, Clear, Blue, White |
Material | Special Features |
---|---|
Polyolefin | Excellent Electrical, Chemical, Physical Properties |
PVC | 30% Stronger than Polyolefin, Low Shrink Temperature, Clear & Vivid Colors are UL VW-1, Excellent UV Resistance |
Cross-Linked PVC | Irradiated, 30% Stronger than Polyolefin, Highly Abrasion Resistant, Excellent UV Resistance |
Multi-Wall Polyolefin | Provides Permanent, Water Resistant Protection, Flame Retardant Jacket |
Multi-Wall PVC | Provides Permanent, Water Resistant Protection, Excellent UV Resistance, Flame Retardant Jacket, Irradiated Multi-Wall PVC Available |
Polyvinylidene Difluoride (PVDF) | High Abrasion, Cut-Through, High Temperature Resistance, Flame Retardant, Transparent |
Chlorinated Polyolefin Elastomer | Broad Operating Temperature Range, Excellent in Severe Outdoor Environments and Rugged Applications |
Fluoroelastomer | Excellent Continuous High Temperature Operating Performance |
Medical Grade | Highly Lubricious, Non-Toxic, Self-Sealing, Meets USP Class VI Requirements |
Food Grade | Environmentally Friendly, Resists Sunlight, Moisture, Fungus, Meets USFDA Requirements |