Learn the facts on burst strength and the importance of your cold chain packaging
Burst strength is the strength of material in pounds per square inch. Burst strength can be used to monitor the quality of cold chain packaging.
Often called the Mullen Burst Test, burst strength is an industry standard that measures the amount of force required to burst corrugated boxes and flexible packaging.
This test is typically used to understand how much force the corrugated or flexible packaging can manage during shipping, delivery, and handling and how much weight these packages can hold.
Your thermal packaging has an important role in maintaining the integrity, quality, and safety of your cold chain products. Tests including the burst strength test, edge crush test (ECT), and others are used to determine which packaging and corrugated materials are right for your cold supply chain.
Just as your products are unique, your cold supply chain is unique. How your cold chain products are manufactured, stored, packaged, shipped, delivered, and displayed determines what you need your thermal packaging to withstand.
For example, if your corrugated boxes are exposed to a lot of rough handling, you need to be confident that these boxes can stand up to drops, pressure, and other environmental and human impacts of shipping, transit, and delivery.
How is Burst Strength Measured?
Burst strength is measured in kilograms per square centimeter. The burst factor of a corrugated or flexible package is calculated using the burst strength and the grammage (density) of the packaging material.
Burst factor = Burst Strength (kg/cm2) x 1000/Grammage (gm/m2)
To measure this, the package is expanded, using a rubber diaphragm or other method until the package or its seals burst.
How to Test Cold Chain Packaging
To test cold chain packaging, packaging engineers and manufacturers may use one or more of the following packaging tests:
Burst Strength Test or Mullen Burst Strength Test: the package is expanded until the package, or its seals burst. This test is useful in determining how well the package can sustain pressure during storage, transit, or delivery.
Edge Crush Test (ECT): used to measure the strength of corrugated boxes when stacked. This is particularly useful when choosing packaging that is stacked and shipped on pallets.
Drop Test: measures the impact strength of cold chain packaging when dropped from a variety of heights. It’s important to know this when thinking about the conditions your cold chain products endure throughout the cold supply chain.
Seal Tests: several different testing methods are used to measure the strength, quality, flexibility, and integrity of packaging seals. For example, measuring the strength of the adhesive bonds in the package or the tear resistance of the package.
The type of packaging test data you need to know is based on your cold chain products. For example, if you specialize in food products such as milk and milk alternatives, you should know the amount of force needed to open bottles, jars, or closures. Or if you specialize in pharmaceutical products, you need to know the burst strength of packaging for any gels, liquids, or creams.
Did You Know? The American Society for Testing and Materials (ASTM) and the International Organization for Standardization (ISO) have specific package testing requirements and standards. These standards include ISO 2759, ISO 11607, ASTM F1140, ASTM F2054, and ASTM F88.
The Importance of Cold Chain Packaging in the Cold Supply Chain
Your cold chain packaging needs to protect your cold chain products from the risks inherent in the cold supply chain.
Make sure you know these risks to the cold supply chain:
Equipment failure and poor thermal packaging decisions are the biggest risks to your cold chain products. A cold chain best practices GAP analysis can help you mitigate these risks and protect you from loss.
Lack of cold chain infrastructure can make even the most advanced cold chain technology ineffective.
Insufficient regulatory knowledge, compliance, and due diligence can create delays in document approval, customs clearance, and even prevent port entry.
Natural disasters, pandemics, and unexpected threats can cause a complete break-down in the cold supply chain and supply chain. It’s imperative you have a cold supply chain disaster management plan in place to mitigate short- and long-term impacts.
Successful shipping, delivery, warehousing, and storage of your cold chain products may be compromised by the improper handling of goods, hardware and coolant failure, supply chain interruptions such as traffic slowdowns or clogged transport hubs, and more.
Along with protecting your products from cold supply chain risks, this same packaging must communicate your brand message, display important product information such as nutritional information or safety concerns, be easy to display on store shelves, and be attractive to your B2B and B2C customers.
Does your packaging make it easy for customers and 3PL logistics teams to store your products? Can your packages be stacked easily without concerns over bursts or compression?
Is it easy to unpack and display your cold chain products on store shelves, in refrigerators, or in warehouses? Can your packaging withstand environmental factors and potential drops, falls, or rough handling?
Does your cold chain packaging clearly and easily communicate your brand message, tone of voice, logo, and product features? How well do the colors, printing, lamination, and other design features withstand shipping, delivery, unwrapping, and handling?
- Product Communication
Is the nutritional information, ingredient list, best before date, usage instructions, dosage, and other product detail easy to read and accessible?
What does your cold chain packaging say about your company, products, and brand? Is it designed to maintain the integrity, quality, and safety of your cold chain products? Remember, your B2B and B2C customers have a low tolerance for damaged packaging and products – and while this damage might not be your fault, customers typically do not know how products move through the cold supply chain.
Cold Chain Packaging and Burst Strength Tests
Burst strength tests are useful for a range of thermal packaging types including:
- Flexible pouches and bags
- Thermal envelopes
- Sealable and resealable trays
- Panel Containers
- Corrugated boxes
- Molded insulated containers
Burst strength test data is essential when choosing your thermal packaging. You need to be confident your cold chain products are not put at risk due to packaging that bursts under pressure. Additionally it’s important to understand what the failure points are in your packaging options – this information is valuable when discussing thermal packaging design and overseeing your inventory and logistics management.
When it comes to thermal packaging, there is a wide range of factors that determine which packaging types are right for your cold chain products.
Do not leave these decisions to chance – make sure you ask your thermal packaging supplier about burst strength, ECT, drop, and seal tests.
Sign up for Cold Chain Tech blog to learn the latest in thermal packaging technology and trends, how to protect your cold chain products, and how the Cold Chain Tech team helps you manage a secure cold chain process.