ASTM D8171-18 PDF

Full title and description

ASTM D8171-18 — Standard Test Methods for Density Determination of Flax Fiber. This document specifies two accepted laboratory procedures for measuring the density of flax (linen) fiber: Test Method A (gas pycnometry) and Test Method B (buoyancy/Archimedes method). The methods are intended for fibers of any length and provide guidance on sample conditioning, outgassing assessment, and reporting of results for use in research, quality control, and composite constituent calculations.

Abstract

ASTM D8171-18 provides detailed test procedures to determine the true density of flax fiber using either gas pycnometry (preferred where specimen conditioning and outgassing control are possible) or the buoyancy (Archimedes) method (acceptable as an alternative when lower accuracy is acceptable or when outgassing prevents valid pycnometry results). The standard states units in SI, includes precision/bias considerations, and specifies specimen conditioning recommendations (e.g., oven drying and outgassing checks) to ensure reliable density values for material specification, volume fraction calculations in composites, and research comparisons. Committee D13 (Subcommittee D13.17) developed the standard; DOI: 10.1520/D8171-18.

General information

• Status: Active (D8171-18; reapproved/reaffirmed as D8171-18R25).
• Publication date: Original publication: January 1, 2018; Reaffirmation / reapproval: June 1, 2025; Historical last updated: July 9, 2025.
• Publisher: ASTM International.
• ICS / categories: 59.060.10 — Natural fibres (textile materials).
• Edition / version: D8171-18 (reapproved 2025, sometimes shown as D8171-18R25).
• Number of pages: 8 pages.

Scope

These test methods cover two procedures for determination of the density of flax fiber and are applicable to fibers of any length. Test Method A (gas pycnometry) is the more accurate method and is preferred where specimen conditioning (oven drying) and outgassing control can be applied; Test Method B (buoyancy/Archimedes) is an acceptable alternative when less accuracy is sufficient or when outgassing prevents valid pycnometry results. Values are stated in SI units. The standard includes guidance on specimen conditioning (including oven drying below about 55 °C to equilibrium with a 0 % RH environment when needed), purge and pressure stability checks for outgassing assessment, and reporting requirements including precision/bias considerations.

Key topics and requirements

• Two approved procedures: Test Method A — Gas pycnometry; Test Method B — Buoyancy (Archimedes) method.
• Specimen conditioning rules (oven drying guidance to control moisture and outgassing; recommended drying below ≈55 °C where applicable).
• Outgassing assessment: perform purge/pressurization and pressure-stability checks in pycnometry to detect sample outgassing that can bias results.
• Precision and bias considerations: standard includes precision and bias tables to assess accuracy and inter-laboratory variability.
• Reporting requirements: record method used, conditioning details, instrument settings, calculated density, units (SI), and any deviations or observed outgassing.
• Application notes: use fiber density with linear mass to estimate effective area, use density as constituent property in composite volume/void calculations.

Typical use and users

Analytical and materials testing laboratories, textile manufacturers, flax/linen producers, composite materials researchers and engineers, quality control and R&D groups working with natural-fiber reinforcements. Common uses include specification of fiber properties, calculation of reinforcement volume fraction in composites, comparison of fiber lots, and academic studies of flax fiber structure and properties.

Related standards

Standards and documents commonly associated with or referenced by D8171 include ASTM D7879 (Standard Test Method for Determining Flax Fiber Widths Using Image Analysis), ASTM D6798 (Standard Terminology Relating to Flax and Linen), ASTM D7076 (Standard Test Method for Measurement of Shives in Retted Flax), ASTM D6961 (Standard Test Method for Color Measurement of Flax Fiber), and other D13 series textile/bast-fiber standards (Book of Standards, Vol. 07.02; developed by Subcommittee D13.17).

Keywords

flax, linen, fiber density, density determination, gas pycnometry, pycnometer, buoyancy method, Archimedes method, natural fibers, D8171, textile testing, D13.17, DOI 10.1520/D8171-18

FAQ

Q: What is this standard?

A: ASTM D8171-18 is a set of standardized laboratory test methods for determining the true density of flax (linen) fiber using gas pycnometry or the buoyancy (Archimedes) method.

Q: What does it cover?

A: It describes two procedures (Test Method A — gas pycnometry; Test Method B — buoyancy/Archimedes), specimen conditioning guidance (including oven drying and outgassing checks), precision/bias information, reporting requirements, and applicability to fibers of any length. Values are specified in SI units.

Q: Who typically uses it?

A: Textile testing laboratories, flax producers and processors, composite materials researchers and engineers, and quality control groups who need reliable fiber density data for specifications, material selection, or composite volume calculations.

Q: Is it current or superseded?

A: The original standard was published January 1, 2018 (designation D8171-18). It was reapproved/reaffirmed in 2025 (commonly referenced as D8171-18R25) and is shown as active in ASTM listings as of mid-2025. Users should verify the current status on ASTM records before formal use.

Q: Is it part of a series?

A: Yes. D8171-18 is part of the ASTM D13 textile standards (Book of Standards volume for bast fibers and plants, Subcommittee D13.17) and is commonly used alongside other flax-related standards such as D7879, D6798, D7076 and D6961.

Q: What are the key keywords?

A: Flax, linen, fiber density, gas pycnometry, pycnometer, buoyancy, Archimedes method, natural fibers, textile testing, D8171.