ASTM E83: Calibration, verification, and classification of extensometer systems

ASTM E83 — Standard Practice for Calibration, Verification, and Classification of Extensometer Systems

ASTM E83 focuses on the performance of the extensometer system (the extensometer plus associated electronics and readout/recording) by comparing indicated strain to a controlled, accurately measured displacement applied by a verification apparatus.

This document is a practice (a calibration/verification procedure and classification framework), not a complete purchase specification for extensometers.

Quick Definition

What it is: A standard practice for calibrating/verifying extensometer systems and assigning a classification based on strain measurement error.

What it’s used for: Demonstrating and documenting extensometer system performance for standards-based mechanical testing.

What This Standard Covers

ASTM E83 describes procedures to calibrate and verify extensometer systems that indicate or record values proportional to changes in length corresponding to tensile or compressive strain.

It provides a classification approach based on measurement error (commonly referenced as Classes A, B-1, B-2, C, D, and E), helping users select an extensometer capability appropriate for the required accuracy.

It also distinguishes different extensometer system types (for example, systems that define gauge length at the extensometer, systems where gauge length is defined by specimen geometry/features, and optical/video-based approaches).

Why This Standard Matters in Testing

When tensile or compression results depend on strain (such as modulus, proof/yield behavior, or strain-to-failure calculations based on extensometer readings), extensometer error and setup consistency directly affect reported values and pass/fail decisions.

ASTM E83 supports traceable, repeatable strain measurement by defining how the extensometer system is checked against a controlled reference displacement and how the resulting performance is classified for use in the lab.

Common Materials, Product Types, or Applications Covered

Because it addresses extensometer system performance (not a specific material), ASTM E83 is broadly used anywhere strain is measured during mechanical testing, including:

• Metals tensile testing and compression testing

• Plastics and composites tensile testing where strain-based properties are reported

• High-accuracy R&D work where strain uncertainty needs to be controlled

• Production QA/QC programs that require periodic verification and documentation of extensometer performance

Bonded resistance strain gages directly bonded to a specimen are outside the intended calibration/verification approach used for extensometers with definite gauge points; those are typically addressed by other ASTM methods referenced within the standard.

Common Test or Verification Workflow

Most labs implement ASTM E83 as a controlled, documented verification activity associated with their mechanical testing program.

Common workflow: (1) confirm the extensometer system is in proper working condition, (2) set up the extensometer on a verification apparatus in a manner representative of normal use, (3) apply controlled displacements, (4) compare extensometer-indicated strain against the reference displacement, and (5) assign and record the resulting classification and supporting data.

Planning note for labs: Verification is typically treated as a periodic quality activity and may also be required after changes that could affect the measurement chain (sensor, electronics, cabling, software scaling, or mechanical contact components).

Equipment Commonly Used for This Standard

ASTM E83 is equipment-oriented: it requires a verification apparatus capable of applying controlled displacement to a simulated specimen and measuring that displacement accurately enough for the required class.

Common equipment: Extensometer calibration/verification frames (extensometer calibrators), fixtures/spindles to interface with clip-on or contacting extensometers, and reference displacement measurement devices such as interferometer-based systems, calibrated gauge blocks with an indicator, calibrated micrometer mechanisms, or calibrated laser displacement measurement systems.

Quoting considerations: Equipment selection is driven by extensometer type (contacting vs optical), gauge-length approach, target classification, displacement range, and how the extensometer is normally mounted and aligned. If you’re comparing verification frames, optical verification setups, or reference measurement options, you can request a detailed quote based on your strain range and accuracy targets.

How to Read This Designation or Revision

ASTM standards are commonly cited using the designation plus a year, such as ASTM E83-23 or ASTM E83-25.

Designation basics: The number after “E83” indicates the year of original adoption or (when revised) the year of the last revision. A year shown in parentheses indicates the year of last reapproval, and an epsilon mark indicates an editorial change since the last revision or reapproval.

Revision sensitivity: Calibration/verification details and referenced terminology can change between editions, so purchasing decisions and compliance documentation should match the exact year specified by your governing test method, customer requirement, or quality system.

Related Standards, Methods, or Frameworks

ASTM E83 is often used alongside mechanical test methods that require or recommend extensometer-based strain measurement and documented measurement capability.

Common related references (not a complete list): ASTM E6 (mechanical testing terminology) and ASTM E251 (performance characteristics for metallic bonded resistance strain gages, when strain gages are used instead of extensometers).

Discuss ASTM E83 equipment and setup

If you need a verification setup that matches your extensometer type (contacting, compressometer/deflectometer, or optical), target class, and displacement range, contact our team to discuss a practical configuration and documentation approach for your lab.