What is the TDM cut test (EN ISO 13997), and when does it govern?
Technically reviewed: 2026-07-31
In short
The TDM test (EN ISO 13997) measures, with a straight blade in a single stroke, the force — in newtons — needed to cut through a material. Its result is the A–F letter on protective-glove markings (A: ≥2 N … F: ≥30 N). On blade-blunting, high-cut materials (HPPE, glass and steel fibre) the traditional coupe test can mislead — there, the TDM result governs.
How the measurement works
The TDM (tomodynamometer) draws a straight blade across the material under controlled force, in a single stroke, and records the force at which cut-through occurs over the reference stroke. The test repeats across blades and force levels — every cut gets a fresh blade edge, because edge condition feeds directly into the result. The outcome is the cut-through force in newtons.
The A–F scale
| Letter | Cut-through force |
|---|---|
| A | ≥ 2 N |
| B | ≥ 5 N |
| C | ≥ 10 N |
| D | ≥ 15 N |
| E | ≥ 22 N |
| F | ≥ 30 N |
In the marking, the TDM letter follows the EN 388 digit string — in 4X43D, the X shows the coupe result is not applicable (blade-blunting material) and the D shows ≥15 N protection per TDM.
Why it replaces coupe at high cut protection
Modern cut-resistant materials — HPPE, glass- and steel-fibre reinforcement — blunt the coupe test’s rotating blade mid-test, so the measured index can flatter the material. The straight-blade, single-stroke TDM measurement is immune to that distortion: that is why EN 388 makes the ISO 13997 result governing for blade-blunting materials, and why customers increasingly ask for TDM data explicitly.
Why the equipment matters
TDM is precise and sensitive. Where laboratories use self-built rigs, comparability suffers — differences in blade, force chain and calibration land directly in the measured newtons. BIMEO therefore measures on a commercial MESDAN machine of the type referenced as an example in the standard: the result is not only accurate but comparable with other laboratories measuring on the same machine type.
For whom, and what for
Glove manufacturers in development (does the construction reach the target letter), lot verification and customer data supply; importers and brands verifying a declared cut level independently. The test runs quickly and routinely here — results are recorded in a report issued as the laboratory of a notified body (NB 1524).
Frequently asked questions
- How is TDM different from the coupe test?
- The coupe test uses a rotating circular blade with repeated strokes and yields an index number (1–5). TDM uses a straight blade in a single cutting stroke and expresses the cut-through force in newtons — the source of the A–F letter. On blade-blunting materials the coupe result becomes unreliable; the TDM result does not.
- When is the TDM test mandatory?
- If the material blunts the coupe test's blade, EN 388 makes the ISO 13997 (TDM) result the governing one, and the letter must appear in the marking. High cut-protection classes can, in practice, only be credibly declared with a TDM result.
- Why does the machine matter?
- TDM is a sensitive, precise measurement: blade, force measurement and cut-stroke calibration feed directly into the result. Between self-built rigs, results compare poorly — a value measured on a commercial machine of the type referenced as an example in the standard is the basis of comparability.
- Does BIMEO perform TDM testing?
- Yes, in-house, on a commercial MESDAN (Italy) TDM machine — a machine type referenced as an example in the standard. Results are recorded in a report issued as the laboratory of a notified body (NB 1524); the test runs quickly and routinely.
Related standards
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