Overview
EN ISO 9073-9:2008 - Textiles: Test methods for nonwovens - Part 9 - specifies a standardized test method for determining the drapability of fabrics, including the drape coefficient. The scope covers nonwovens, as well as woven and knitted fabrics. The standard defines both a conventional manual procedure and an automatic image-processing procedure to quantify how a circular fabric specimen deforms when suspended.
Key Topics and Requirements
- Scope & units
- Applies to drapability testing of nonwovens, wovens and knits; uses SI units as the official measurement system.
- Terms and metrics
- Drape coefficient (ratio of projected shadow area to flat specimen area, %)
- Drape shape parameters: node number, wave amplitude, wavelength, minimum/maximum/average amplitude, variance
- Fourier-fit metrics (fitness factors) to identify dominant waves
- Two evaluation methods
- Method A - Paper-ring method: shadow cast onto a translucent paper ring; contour traced and cut; drape coefficient = mass of shadowed ring portion as % of whole ring. Requires balance (0.01 g accuracy) and rings with internal diameter 18 mm? (note: standard gives internal diameter 18 cm and external diameters 24, 30, 36 cm).
- Method B - Image processing method: shadow captured with a digital camera or scanner on a white sheet; image converted to monochrome, transformed to polar coordinates (angle 0°–360°, radial amplitude in cm) and analyzed to extract drape coefficient plus advanced shape statistics. Requires camera, frame/stand, evaluation software and white sheeting with high thread count.
- Apparatus
- Drape meter with two concentric horizontal discs (18 cm diameter), point light source, parabolic mirror, centre locating pin and translucent lid.
- Templates for marking specimen centres (24, 30, 36 cm diameters), stopwatch, balance, digital camera and PC/software for Method B.
- Sampling & conditioning
- Sampling follows ISO 186 and conditioning per ISO 139 (referenced normative standards).
Applications
- Product development and fabric selection (apparel, drapery, upholstery)
- Quality control and supplier acceptance testing for nonwovens and textile materials
- Research and R&D to quantify fabric behavior, compare finishes or constructions
- Specification writing for technical textiles where formability and hanging behavior matter
Who Uses This Standard
- Textile testing laboratories and certification bodies
- Nonwoven and woven fabric manufacturers
- Apparel and home-textile product developers
- Research institutions and university textile departments
- QA/QC teams in technical textile and upholstery industries
Related Standards
- ISO 9073 series (other test methods for nonwovens: mass, thickness, tensile, tear, bending, air permeability, etc.)
- ISO 139 (conditioning and testing atmospheres)
- ISO 186 (sampling paper/board - referenced for sampling procedures)
Keywords: EN ISO 9073-9:2008, drapability, drape coefficient, nonwovens test method, drape meter, image processing, textile testing.
