D4920-13 – Standard Test Method Technical Guide

The ASTM D4920-13 standard defines technical terms for conditioning, chemical, and thermal properties in textiles, ensuring consistent language across testing and quality control. It compiles definitions not found in general sources and references other key standards for comprehensive coverage.

📚 Key Terminology for Conditioning and Thermal Properties

Absolute humidity refers to the mass of water vapor in a unit volume of air, with common units of grams per cubic metre or grains per cubic foot. The standard emphasizes that this differs from humidity ratio, which is mass per unit mass of dry air.

Absorption involves a material taking in a substance, like moisture absorption by fibers, while adsorption is a surface phenomenon where molecules adhere to the surface. Both are key to understanding textile conditioning.

Accelerated conditioning uses precise humidity and temperature controls to achieve equilibrium in a standard atmosphere quickly, often within 2 to 10 minutes, compared to typical conditioning times.

Atmosphere for testing refers to ambient air conditions that vary with local weather. For standardized testing, a standard atmosphere for testing with specified conditions ensures reproducibility.

📐 Referenced Standards and Their Roles

To provide comprehensive context, D4920 references standards such as D123 for general textile terms, E41 for conditioning terms, and D1776 for conditioning and testing practices. These standards ensure consistency across different textile applications.

The following table lists select referenced standards from D4920: