ISO 3035 specifies a laboratory method for determining the flat crush resistance of corrugated fibreboard used to make shipping containers.
This test is commonly used to compare board structures, monitor production consistency, and qualify incoming materials for corrugated packaging. If you need help aligning your test setup to the exact edition cited in your packaging specification, talk with our team.
ISO 3035:2025 — Corrugated fibreboard — Determination of flat crush resistance
ISO 3035 is an ISO test method focused on “flat crush” performance of corrugated fibreboard when it is compressed through the thickness of the board between platens.
The current published edition is ISO 3035:2025. It is written for corrugated fibreboard used in the manufacture of shipping containers, with clear applicability limits based on board construction.
Quick Definition
ISO 3035 (Flat Crush Test / FCT): A compression test that measures how much force a corrugated fibreboard specimen can resist in a flat orientation (loading applied perpendicular to the board surface) before the corrugated structure crushes.
What This Standard Covers
ISO 3035 specifies a method for determining the flat crush resistance of corrugated fibreboard.
Applicable products: Single-faced and single-wall (double-faced) corrugated fibreboard.
Not applicable (per scope limitations): Double-wall (double-double-faced) corrugated fibreboard and microflute corrugated fibreboard, because the test end-point is not clearly defined or observable for those constructions.
Why This Standard Matters in Testing
Flat crush resistance is widely used as an indicator of how well a corrugated structure can maintain its flute geometry under compressive loading. In practice, this supports decisions about board design, process control, and material qualification for packaging lines.
Because the measured response depends strongly on specimen preparation, conditioning, and compression system behavior, ISO 3035 is typically used as part of a controlled lab workflow rather than as an on-line production measurement.
Common Materials, Product Types, or Applications Covered
ISO 3035 is most commonly applied to corrugated fibreboard intended for shipping containers and similar transport packaging.
Common use cases: Comparing flute/liner combinations, monitoring corrugator performance over time, checking consistency between lots/suppliers, and supporting packaging QA requirements where a flat crush metric is specified.
Common Test or Verification Workflow
ISO 3035 is typically run as a controlled lab compression test on conditioned specimens.
Typical workflow steps (high level): (1) sample the material from a lot, (2) condition specimens in a standard atmosphere used for paper/board testing, (3) prepare specimens to the required geometry, (4) compress the specimen between parallel platens using a compression testing apparatus, and (5) record the force response used to express flat crush performance.
Practical note: For corrugated materials, small differences in conditioning, specimen cut quality, and platen alignment can noticeably shift results, so repeatability depends on tight control of preparation and machine setup.
Equipment Commonly Used for This Standard
ISO 3035 points to a compression test setup designed for paper/board products, with stable, aligned platens and suitable force measurement capability.
Common equipment: A fixed-platen compression testing machine (or equivalent compression force measuring apparatus) with parallel platens; a calibrated force measurement system (load cell and readout/controller); specimen cutting tools/fixtures appropriate for corrugated board; and a conditioning chamber or controlled-environment space used to prepare test pieces prior to testing.
Selection caution: When quoting or configuring equipment, the details that most often affect usability are platen size/flatness, alignment, force range and resolution, and how the system controls and records compression for the required test endpoint definition.
How to Read This Designation or Revision
ISO standards are commonly cited using the standard number and the publication year (for example, ISO 3035:2025).
Revision sensitivity: Test setup and reporting expectations can depend on the exact edition referenced in a customer specification. If a contract, datasheet, or QA plan cites an older edition (for example, ISO 3035:2011), align your procedure and reporting to that cited version unless your customer approves an update.
Related Standards, Methods, or Frameworks
ISO 3035 is commonly used alongside other corrugated fibreboard and paper/board lab standards to make the overall workflow consistent.
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ISO 3037: Edgewise crush resistance (often paired with flat crush when evaluating corrugated board performance).
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ISO 186: Sampling of paper and board to obtain representative test material from a lot.
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ISO 187: Standard atmosphere for conditioning and testing paper/board materials.
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ISO 13820: Description and calibration of compression-testing equipment used for paper, board, and corrugated fibreboard.
Discuss ISO 3035 equipment and setup
If you are equipping a lab for ISO 3035 flat crush testing, we can help translate your cited edition and throughput needs into a practical compression tester configuration (platens, force range, and reporting). You can request a detailed quote for an ISO 3035-oriented setup.