IEC 60584-1 and ASTM E230 share EMF data; only class names differ.
Two Standards, One Physics
IEC 60584-1 (International) and ASTM E230 (USA) both define the EMF vs. temperature relationship for standardised thermocouples. They use the same ITS-90 temperature scale and produce EMF values that are identical for all practical purposes (differences below 1 µV). The standards differ primarily in terminology, tolerance class naming, and associated testing standards — not in the underlying thermoelectric data.
Tolerance Class Equivalents
| IEC 60584-1 | ASTM E230 | Type K Error at 1000 °C | Notes |
|---|---|---|---|
| Class 1 | Special Limits of Error | ±4.0 °C | ~2× better than Class 2 |
| Class 2 | Standard Limits of Error | ±7.5 °C | Standard industrial grade |
| Class 3 | — (no ASTM equivalent) | ±12.5 °C | Rarely used for base metals |
The tolerance formula is identical: a fixed error band at low temperatures (±X °C) transitioning to a percentage of reading (±Y%) at higher temperatures. IEC and ASTM use the same mathematical expression but different class names.
Key Differences
1. Associated Testing Standards
ASTM E230 references ASTM E220 (calibration by comparison) and ASTM E1350 (thermocouple homogeneity testing). IEC 60584-1 references IEC 60584-2 (tolerances) and IEC 60584-3 (extension and compensating cable).
2. Colour Codes
IEC 60584-3 and ANSI MC96.1 define different insulation colour codes for the positive and negative legs. An IEC-colour-coded Type K cable (green/white) connected to an ANSI-colour-coded instrument will read incorrectly. Always verify the colour-coding standard your instrument expects.
3. Regional Preference
- Europe: IEC 60584-1, with DIN EN 60584 as the German adoption
- North America: ASTM E230 / ANSI MC96.1
- Japan: JIS C 1602 (closely aligned with IEC)
- China: GB/T 16839 (equivalent to IEC 60584-1)
How to Specify Dual Compliance
If your application requires both IEC and ASTM certification, specify “dual certification to IEC 60584-1 Class 1 and ASTM E230 Special Limits” on your purchase order. The wire is manufactured to the same tolerance — we simply issue two Material Test Certificates (MTCs) referencing the respective standards. There is no additional charge for this service.
What to Ask Your Supplier
When ordering thermocouple wire, confirm:
- Which standard the wire is manufactured to (IEC, ASTM, or both)
- Which tolerance class applies
- Whether the MTC includes EMF calibration data
- Whether the batch is traceable to a furnace number
Need dual-certified thermocouple wire? We manufacture to IEC 60584-1, ASTM E230, DIN EN 60584, JIS C 1602 and GB/T 16839 — single or dual certification at no extra charge. Request a quote →
Frequently Asked Questions
Are IEC 60584-1 and ASTM E230 thermocouple EMF values the same?
For all practical purposes, yes. Both standards use the ITS-90 scale and produce EMF values that differ by less than 1 µV. The real differences lie in terminology, tolerance class naming and the associated testing standards.
What is the ASTM equivalent of IEC 60584-1 Class 1?
Class 1 corresponds to ASTM Special Limits of Error. For Type K at 1000 °C that means ±4.0 °C, against ±7.5 °C for Class 2 / Standard Limits of Error.
Can one spool of wire be certified to both IEC and ASTM?
Yes. Specify dual certification to IEC 60584-1 Class 1 and ASTM E230 Special Limits on the purchase order. The wire is manufactured to a single tolerance, and two Material Test Certificates are issued referencing each standard.
Why does a Type K cable read incorrectly after changing the connector?
Because IEC 60584-3 and ANSI MC96.1 assign different insulation colour codes to the legs. An IEC-colour-coded Type K cable (green/white) wired to an ANSI-colour-coded instrument reverses polarity and reads wrongly.
Bottom line: IEC 60584-1 and ASTM E230 are the same physics with different paperwork: identical tolerance formulas and EMF data, different class names, colour codes and testing standards. Where you sell into both regions, specify dual certification — it costs nothing extra and removes a whole class of connector and documentation errors.