An edge crush test tests the ability of corrugated cardboard to offer safety to goods during transportation.

Knowing what an edge crush test is and apply it is essential for transportation in corrugated cardboard boxes and packages, since it allows you to test the quality of this raw material and improve whatever is necessary to ensure the safety of the load.

What is an edge crush test

An edge crush test (ECT) is a laboratory test method used to measure the cross-section crushing of corrugated cardboard. This offers the necessary information to determine the ability of a sheet of corrugated cardboard to resist crushing forces.

When performing an edge crush test, a cross-sectional load is applied on corrugated cardboard until it collapses, thereby calculating the maximum compression force that the material can withstand without failing.

An edge crush test for corrugated boxes yields the exact resistance of a material. Using this data, it is possible to manufacture boxes, packages and other products taking into account the material’s protective capabilities.

The test measures the resistance of the edges to crushing, since it is the corners and edges of the boxes that are mostly responsible for bearing the loads. Therefore, performing an edge crush test means knowing the strength of the factor that contributes the most to a box’s resistance.

This edge crush test can be performed using specific, in-house machinery, or commission it to laboratories and research centers for the packaging industry.

Historically, the Bursting Strength Test (BST) would be used to measure the force that was required to pierce corrugated cardboard, anticipating how a rough or careless handling could affect the material.

However, nowadays this new standard – the edge crush test –, which is directly related to the stacking resistance, is seeing increasing use to test the resistance of corrugated cardboard. A standard that offers a measurement tailored to modern-day transportation, where boxes are stacked on pallets.

The edge crush test machine can calculate the resistance to compression at the edge of corrugated cardboard. The edge crush test graph therefore shows the resistance in pounds per lineal inch (lb/in), though it is usually expressed as ECT.

These values will always be minimum and varied, since different processes may be used to manufacture the same type of corrugated cardboard.

Advantages of ECT packaging

The edge crush test is a useful tool both for cardboard manufacturers wishing to perform a quality control, and for box manufacturers looking to test the protective ability of their raw material.

The first advantage of ect packaging is that an ect box offers greater safety to transported goods, since the level of protection offered by it during the distribution cycle has been calculated.

Furthermore, in addition to offering an exact value for the material’s resistance, ect packaging allows for the use of less materials. This is because, by performing the test, it is possible to determine the exact amount of corrugated cardboard that will ensure the goods’ protection, thereby optimizing the packaging.

Related reading: Types of packaging materials: features for storage and transport

All of this also leads to a lower energy consumption and less pollution across all phases of the packaging cycle.

Which standards include an edge crush test?

There are a series of international standards that include an edge crush test among their requirements.

The most widespread standard in Europe is the DIN EN ISO 3037, which outlines a paraffin-free method for the edges and applies to all qualities of corrugated cardboard. Its purpose: to determine the resistance of the corrugated cardboard’s edge to crushing.

Other standards for the performance of the edge crush test include:

  • APPITA/AS 1301.444s
  • FEFCO 8
  • ISO 13821
  • SCAN P33
  • TAPPI T811
  • TAPPI T823
  • TAPPI T838
  • TAPPI T839

While all of them aim to measure the crushing force and its nature, the required type of sample or tooling may vary. Some such cases are the FEFCO 8, TAPPI T838 and TAPPI T839 standards, which require a different geometry for the corrugated cardboard sample and the clamps used for testing.

Some transport companies require the compliance with certain specifications:

  • For example, both UPS and FedEx require that packages weighing up to 30 pounds (13.6 kg) have at least 200 BST or 32 ECT and comply with ISTA standards.
  • For heavier packages, both organizations require higher cardboard qualities than those used in rail or road transportation.
  • In the case of some airlines, they publish detailed standards that are directly related to the transportation of certain special products.

If you want to know more: FedEx drop test: characteristics and procedures

The edge crush test formula: how to calculate it, step by step

Performing an edge crush test for corrugated boxes requires the following steps:

  • Preparation of the sample to be tested, which must be accurately cut at a right angle and have no prior damage.
  • Place the sample on an edge crush test machine so that the face on which the force will be applied is perfectly parallel to the dish that will compress it.
  • Performance of the test, which will involve the application of a force that is exactly perpendicular to the surface of the sample.

This requires the use of a certified compression tester that can perform the edge crush test.

At Safe Load Testing Technologies we have been helping packaging and transportation companies to certify their packages and guarantee the protection of the goods.

Are you looking to perform the edge crush test and obtain a certified ect box?

Get in touch with us and we will walk you through the process with a personalized plan.