ISO 376 is the international standard for calibrating and classifying force-proving instruments, such as load cells and proving rings, that are used to verify the force performance of materials testing machines. It defines the layer of traceability beneath machine verification. To calibrate or source a force-proving instrument, talk with our team.
What ISO 376 Calibrates
A force-proving instrument is loaded against forces traceable to national standards, and its response is evaluated for repeatability, reproducibility, interpolation, and reversibility. From these results the instrument is assigned a class and a calibrated range over which it may be used.
Instrument Classes
ISO 376 grades instruments by their measurement uncertainty, from the tightest class used for reference work to wider classes for routine verification:
| Class | Typical use |
|---|---|
| Class 00 | Reference and the most demanding calibrations |
| Class 0.5 | High-accuracy machine verification |
| Class 1 | General machine verification |
| Class 2 | Routine checks with wider tolerance |
Why It Matters
Machine force verification is only as trustworthy as the instrument behind it. A current ISO 376 calibration is what lets a force-proving instrument be used to verify a machine to ISO 7500-1, and in turn supports defensible tensile results to methods such as ISO 6892-1.
Reading the Designation
Cited as ISO 376:YYYY. Confirm the edition, since class limits and calibration procedures can change between revisions.
Related Standards
ISO 7500-1 uses ISO 376 instruments to verify machine force, and ASTM E74 is the ASTM practice for calibrating force-measuring instruments.
Request a Quote
Need a force-proving instrument calibrated or supplied? Request a quote and our team will help you build a system matched to your force range and instrument class.
TensileMill CNC products for ISO 376
Our specimen-preparation systems and testing equipment compatible with ISO 376:
Electro Mechanical Universal Testing System 5 kN / 50 kN with Precision Load Cell
Electro-Mechanical UTM · 5 kN / 50 kN with Precision Load Cell
Electro Mechanical Universal Testing System 50kN / 1000kN with Precision Load Cell
Electro-Mechanical UTM · 50 kN / 1000 kN with Precision Load Cell
Servo-Hydraulic Universal Testing Machine (300 kN – 3000 kN)
Servo-Hydraulic UTM · 300 kN – 3000 kN
Precision Alignment Device (NADCAP-Ready Precision Fixture)
NADCAP-Ready Precision Alignment Fixture
Equip your lab for ISO 376 with TensileMill CNC
TensileMill CNC designs and builds the systems labs use for standards-based mechanical testing. Our range includes load cells, alignment hardware, and the reference setups used for machine and extensometer verification. Send us your specimen types and target standards, and we will help you spec the right system.