Edge Crush Test (ECT) — ISO 3037 / TAPPI T811

What Is Edge Crush?

The edge crush test (ECT) crushes a specimen cut from corrugated board, with the flute direction vertical, between two platens, and divides the force at collapse by the specimen width. The result is given in kN/m or N/m.

Purpose of Edge Crush

The purpose is to determine the material's capacity to carry stacking load. ECT is the fundamental material property used to predict box compression strength and is the value most often required in specifications.

Which Products Is Edge Crush Applied To?

Corrugated board sheets
Single-wall, double-wall and triple-wall corrugated structures
Shipping box raw materials
Carton components on a pallet

In Which Sectors Is Edge Crush Used?

PackagingLogisticsRetailLogistics

Standards Related to Edge Crush

TS EN ISO 3037 (corrugated fibreboard — determination of edgewise crush resistance, waxless method)
TAPPI T811 / T839
TS EN ISO 187 (conditioning)
ISTApackaging transport performance test series test

Edge Crush Conditions

Conditioning: In the standard atmosphere; humidity directly lowers ECT
Specimen cutting: Edges must be square and undamaged; a crushed edge lowers the result
Loading speed: Constant speed defined in the standard

Equipment for Edge Crush

Compression tester with ECT fixture
Precision specimen cutter
Conditioning room

Sample Requirements for Edge Crush

Specimens of the dimensions defined in the standard, with square edges
At least five specimens spread across the sheet surface
Specimens are not taken from creased, folded or printed areas
Flute type (B, C, E, BC, etc.) must be provided

Duration of Edge Crush

The measurement is short. Duration is set by conditioning and specimen preparation; since cutting quality directly affects the result, this step is not rushed.

Edge Crush Procedure

1Specimens are conditioned.
2It is cut to the dimensions defined in the standard, without crushing the edges.
3The specimen is placed in the machine with the flute direction vertical.
4Force is applied at constant speed.
5The collapse force is recorded and divided by the specimen width.
6The average and coefficient of variation are calculated.

Edge Crush Acceptance Criteria

The acceptance criterion is the minimum ECT value in the specification. Commonly used formulas predict box compression strength from ECT, but these are estimates; when box performance is required, it is measured directly with ISO 12048.

Evaluation of Results

Cutting quality is the biggest source of uncertainty in the result: a skewed or crushed edge gives a result markedly below the true value. A high coefficient of variation usually points to specimen preparation.

Edge Crush Report

Specimen identification, flute type and grammage
Conditioning conditions
Individual results (kN/m), average and coefficient of variation
Standard applied

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

EU 94/62/EC Packaging and Packaging Waste Directive
Regulation on the Control of Packaging Waste
EU 1935/2004 (materials in contact with food — where applicable)

Ambalaj Testleri — What Does This Testing Field Cover?

The section below describes the field that the Edge Crush test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Packaging testing examines two different functions separately: does the packaging protect the product during transport, and does the packaging material transfer harmful substances into its contents? These two questions require different laboratory infrastructure and must not be confused.

On the protection side, distribution simulation is carried out: drop, vibration, compression, stacking and, where needed, low pressure tests are applied in sequences representing the real shipping chain. These tests are meaningful as a SEQUENCE rather than individually; in real life too, packaging is exposed to successive loads and each load builds on the damage left by the previous one. Specifications such as ISTA and ASTM D4169 define these sequences by shipment type.

The shipment type determines the sequence itself. The exposure of a palletised load differs from that of a parcel shipped individually: the latter sees far more handling, more drops and impacts in a wider variety of orientations. The growth of e-commerce has brought this second scenario to the fore and turned parcel shipping simulation into a specification group of its own.

On the food contact side, MIGRATION is what counts: the amount of substance passing from the packaging material into the food is compared against overall and specific migration limits. For plastic packaging the list of permitted substances and the limits are defined in separate legislation; the declaration of conformity (DoC) rests on this assessment and is a document that every link in the supply chain must carry.

In a migration test the choice of SIMULANT is critical. Because testing with real food is not practical, liquids representing food are used: different simulants for aqueous foods, for fatty foods and for acidic foods. Choosing the wrong simulant invalidates the result; the choice depends on which food type the packaging will contact and at what temperature.

Barrier properties are a third axis. Oxygen and water vapour permeability directly determine the shelf life of the product; in pharmaceutical and food packaging these values are a design input. Barrier performance is sensitive to temperature and relative humidity, so the measurement conditions are part of the report.

Sterile medical device packaging is the most tightly regulated sub-body of this family. Here the packaging is a barrier maintaining sterility; seal strength, leak testing, distribution simulation and shelf-life studies run together as a validation package.

The packaging legislation side is becoming rapidly more demanding. Recyclability, recovered content ratio, packaging reduction and reuse targets must now be measurable and declarable; this turns packaging design from a material selection exercise into a conformity exercise.

Method groups in this field

Distribution simulation
Drop, random and fixed frequency vibration, compression, stacking, low pressure; as ISTA and ASTM D4169 sequences.
Mechanical strength
Edge crush (ECT) in corrugated board, bursting strength, box compression strength, tape peel adhesion.
Barrier measurements
Oxygen transmission rate (OTR), water vapour transmission rate (WVTR), permeability in film and sheet materials.
Migration
Overall and specific migration tests; simulant and temperature conditions are chosen according to the use scenario.
Seal and integrity
Seal peel strength, leak detection by dye penetration, bubble test, headspace analysis.
Shelf life
Real-time and accelerated ageing; part of the validation package in sterile packaging.

Commonly confused in this field

A single drop test is not a distribution simulation; the tests are applied as the sequence defined in the specification.
A migration test carried out with the wrong simulant or the wrong contact temperature is invalid.
Accelerated ageing does not replace real-time ageing; a shelf life claim is supported by real-time data.
Barrier values are valid together with the measurement temperature and relative humidity; an OTR/WVTR value given without conditions cannot be compared.
A packaging change (film supplier, seal parameter, box design) may require the validation to be repeated.
A food contact declaration of conformity is not a test report; it is a document that rests on reports but summarises a broader assessment.

Which decisions these results support

Reducing shipping damage and verifying the packaging design
Declaration of conformity for food contact packaging
Supporting the shelf-life claim
Validation of sterile device packaging
Recyclability and content declarations under packaging legislation

Related Tests

Frequently Asked Questions About Edge Crush

Can we calculate box strength from ECT?

You can estimate it. Common formulas predict compression strength from ECT, box perimeter and thickness. However, these are estimates; box design, cutting and closure method change the result. For critical applications, a filled-box test is performed.