ASTM D4496-21e1 PDF

Full title and description

Standard Test Method for D-C Resistance or Conductance of Moderately Conductive Materials — designation ASTM D4496-21e1. This test method defines procedures and apparatus for measuring the direct-current (D-C) resistance, conductance, and derived resistivity (volume and surface) of materials classified as moderately conductive, and includes the e1 editorial amendment.

Abstract

This standard specifies how to prepare specimens, apply direct-voltage stress, measure steady-state resistance or conductance, and compute volume or surface resistivity for materials whose conductivity falls between good insulators and good conductors. It is intended for material comparison, quality control, specification, and selection in applications where moderate conductivity and shielding or voltage-stress distribution are relevant.

General information

• Status: Active.
• Publication date: Current edition approved Jan 1, 2021; editorial amendment e1 noted Dec 8, 2022.
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 29.050 — Superconductivity and conducting materials / Electrical insulation and conducting materials test methods.
• Edition / version: D4496-21e1 (edition 2021, editorial e1).
• Number of pages: 5 pages (short test method).

Scope

This test method covers determination of electrical resistance and resistivity for materials categorized as moderately conductive — generally those with volume resistivity from about 10^0 to 10^7 Ω·cm and surface resistivity from about 10^3 to 10^7 Ω per square. Measurements are referenced to standard laboratory conditions (23 °C, 50 % RH) though principles may be applied at other conditions where noted. The method is intended for specimens subjected to direct-voltage stress and subsequent steady-state measurement to compute resistivity.

Key topics and requirements

• Definition of "moderately conductive" materials and applicable resistivity ranges.
• Specimen conditioning procedures (reference to Conditioning Practice D618 and standard laboratory atmosphere).
• Application of direct-voltage stress and measurement of steady-state resistance or conductance; steady-state criterion specified.
• Computation of volume and surface resistivity from measured resistance/conductance and specimen geometry.
• Apparatus and techniques aligned with related test methods (references to Test Methods D257 and D991).
• Notes on anisotropy of commercially available moderately conductive materials and implications for specimen orientation and test interpretation.

Typical use and users

Used by materials scientists, quality-control laboratories, electrical and cable manufacturers, and test laboratories to compare materials, verify product consistency, develop specifications, and select materials for wires, cables, bushings, high-voltage rotating machinery, shielding, and other electrical apparatus where moderate conductivity and voltage-stress distribution are important.

Related standards

References and related test methods commonly cited by this standard include ASTM Test Methods D257 (surface and volume resistivity of insulating materials), D991 (rubber property — volume resistivity), Practice D618 (conditioning plastics for testing), Terminology D1711, and dimensional/thickness methods such as D374/D374M; adjunct drawings for the carbon-black test cell (Adjunct ADJD4496) are available for apparatus assembly.

Keywords

moderately conductive, D-C resistance, conductance, volume resistivity, surface resistivity, electrical shielding, specimen conditioning, steady-state measurement, ASTM D4496-21e1.

FAQ

Q: What is this standard?

A: ASTM D4496-21e1 is a test method that defines how to measure direct-current (D-C) resistance or conductance and compute volume or surface resistivity of materials categorized as moderately conductive.

Q: What does it cover?

A: It covers specimen conditioning, application of direct-voltage stress, measurement of steady-state resistance or conductance, and calculation of resistivity (volume and surface) for materials with nominal resistivity ranges described in the scope; tests are normally performed at 23 °C and 50 % relative humidity unless otherwise specified.

Q: Who typically uses it?

A: Material and quality engineers, test laboratories, cable and electrical-equipment manufacturers, and researchers concerned with material selection, shielding performance, and voltage-stress distribution use this method.

Q: Is it current or superseded?

A: The current edition is D4496-21 with the e1 editorial amendment (designation D4496-21e1). The edition was approved Jan 1, 2021 and includes editorial updates (e1) recorded in late 2022; the standard is listed as active.

Q: Is it part of a series?

A: It is part of ASTM's series of electrical-materials test methods overseen by Committee D09 (subcommittee D09.12) and appears in the Annual Book of ASTM Standards (Volume covering electrical insulation and related tests). Adjunct documents (e.g., ADJD4496) provide drawings for test cells.

Q: What are the key keywords?

A: Moderately conductive, DC resistance, conductance, volume resistivity, surface resistivity, shielding, steady-state measurement, specimen conditioning, ASTM.