Shrink Test: Official and Practical Methods

The shrink test for plastic shrink wrap refers to a test performed to determine the amount of shrinkage a piece of plastic shrink wrap will undergo when subjected to heat. This test is usually performed to evaluate the suitability of the plastic shrink wrap for a specific application and to ensure that it meets particular shrinkage requirements.

The shrink test can also ensure the desired level of protection and security for the packaged item can be achieved. The results of the shrink test can help business owners, production managers, and purchasing agents make informed decisions about the use and performance of the shrink material and machines used.

There are official testing methods and practical testing methods for shrink wrapping. We will discuss each to determine which method your application will require. Several important factors can be noted and discussed after testing is completed.

Official Shrink Testing

There are many standard testing organizations all over the world. These organizations establish standardized testing for industries and products. Some military, medical, and other industries require standard testing methods for specific applications. Below are a few official shrink testing methods.

ISTA (International Safe Transit Association) Testing – The ISTA is a global organization dedicated to helping members control costs in packaging with testing, education, and support. The ISTA offers testing for many forms of packaging. For shrink testing, they offer several tests; below are three standard shrink tests.

ISTA 3A: This is a test method for evaluating the ability of heat shrinkable plastic packaging to protect products during transit. The test method simulates the environmental conditions that a package may encounter during transportation and assesses the ability of the heat shrink plastic to maintain its protective properties.

ISTA 2A: This is a test method for evaluating the ability of heat shrinkable plastic packaging to maintain its protective properties during storage and transit. The test method simulates the environmental conditions that a package may encounter during storage and transit and assesses the ability of the heat shrink plastic to maintain its protective properties.

ISTA 1A: This is a test method for evaluating the ability of heat shrinkable plastic packaging to protect products during transit. The test method simulates the environmental conditions that a package may encounter during transportation and assesses the ability of the heat shrink plastic to maintain its protective properties.

These ISTA test methods provide a standardized method for evaluating the performance of heat shrink plastic packaging materials, ensuring that they meet the requirements for safe transit and storage of products. Manufacturers and suppliers can use the results of these tests to evaluate the performance of their packaging materials and make improvements where necessary.

ASTM (American Society for Testing and Materials) International Testing – The ASTM standards provide a common set of specifications, test methods, and practices used to assess the performance and quality of materials, products, and systems. For heat shrink wrapping, the ASTM D2732 testing method is popular.

ASTM D2732: is a standard test method used to evaluate the heat shrinkage properties of plastic materials. Testing can measure the change in diameter and length of heat shrinkable plastic tubes or sleeves when exposed to heat.

The test involves preparing a sample of the heat shrink plastic material and then exposing it to a controlled temperature in an oven or other heating device. The temperature is typically set to the maximum temperature the material will be exposed to in its intended application. After the material has been exposed to heat, it is allowed to cool to room temperature.

The change in diameter and length of the sample is then measured and recorded. The results will show the heat shrinkage ratio of the material, which is defined as the change in length divided by the original length and the change in diameter divided by the original diameter.

ASTM D2732 provides guidelines for sample preparation, temperature control, and measurement procedures, ensuring that the test results are accurate and consistent. This standard is widely used in the plastics industry to evaluate the performance of heat shrink materials and to ensure that they meet the requirements of the intended application.

ISO (International Organization for Standardization) Testing – An independent, non-governmental international organization establishing standards across many industries and technologies.

ISO testing is usually performed by a third-party testing organization. It can cover various areas, including software development, quality management, environmental management, and health and safety management. ISO testing aims to demonstrate that the product, service, or system being tested meets the specified requirements, which helps to ensure its quality, reliability, and safety. For heat shrink testing, ISO 14616 is geared toward electrical shrink tubing.

ISO 14616: is an international standard that outlines the test methods used to evaluate the electrical properties of heat shrinkable plastic materials. This standard is used to determine the dielectric strength, volume resistance, and surface resistance of heat shrink materials, which are essential properties for their use in electrical and electronic applications.

There are other official shrink tests available from countries all over the world. Any nationality can have testing methods and standards for shrink film. They are important for manufacturers and users needing to display specific testing standards for the shrink film application.

Practical Shrink Testing

Practical shrink testing can use different forms of testing to determine shrink temperatures, suitable machines, and materials used for a specific application. Many official methods focus on one particular material and capabilities, while a practical shrink test can be for each application based explicitly on the user’s needs.

Drop Testing – Packaging for Amazon FBA requires many products to withstand drop testing. For a shrink wrap test, dropping products wrapped in a sample shrink film can help determine the type and thickness of the shrink film needed.

Drop testing heights can vary based on the application. It is preferred to perform several drops at varying heights on different Sides of the product. Dropping on flat sides, angles, and corners will ensure the material will hold up during transport.

Shrink Machine Testing – The proper machine can vary based on many factors. Testing to determine the best device for each application can save on disappointment after a purchase. The product size and desired production levels can play heavy elements in deciding the suitable shrink machine.

Locating the right shrink machine for your business will also be determined by the type of shrink material used. Some machines will simply not work with some shrink materials. Shrink sleeves are a perfect example. Some sleeves require steam tunnels for heating and shrinking. Standard recirculating tunnels will not work on the materials at any temperature.

Companies using a shrink material product requiring sealing and shrinking benefit tremendously from shrink testing. Understanding the type of materials needed and the processes required can be invaluable resources before committing to a shrinking machine.

Temperature Testing – Testing for shrink and seal temperatures can include several factors based on the product being wrapped. Determining the temperatures and heat exposure for shrinking materials will ensure the wrapped product will not become damaged or unusable after packaging.

Heat-sensitive products require another element for temperature testing. It is essential to determine the temperature and dwell times for the suitable materials and seal and shrink at lower rates not to cause damage to the product(s) being wrapped.

Chocolates and candies by themselves are perfect candidates for temperature testing. There are also frozen and chilled products, such as cakes, pies, and ice cream. The additional details of these sorts of products can make hands-on testing necessary.

Real-World Shipping Testing – The best way to determine how a packaging material will hold up is to expose the product and material to natural shipping stress. This testing is necessary before rolling out products with an exterior shrink film. It is also vital for many other forms of packaging when shipping pallet or parcel orders. Pallet shrink bags to secure pallet loads should also be tested by shipping a few full pallets to different locations.

For parcel shipments, companies should do real-world testing, shipping to multiple locations with various product varieties. Many simple and lightweight products may not require strenuous testing to ensure products reach customers intact, while others may require numerous tests to find the right solution.

Heavy products too small to ship freight but considered an oversized parcel package can be complex when finding the proper packaging. If shrink wrapping the product or the box, it is essential to know the package will make it to the customer as needed. Shipping testing is also vital for temperature-sensitive products. Aside from possible damages, companies need to know if products will reach the customer without spoilage and total loss. Vigorous testing may be required to keep ingredients separate and secured during shipping.


Any shrink-wrap test you can think of can be done officially or practically to ensure products will reach customers the same way they are packaged and shipped. Official shrink wrap testing is a standardized way to ensure the material meets the application’s needs. Practical shrink wrap tests help ensure that products and materials will reach customers intact with no damage. The reward for a successful shrink wrap test is happy customers and no product loss. For more information about performing a shrink wrap test, call us at 1-800-441-5090 to discuss today.

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