ISO 20645-2004 PDF

Full title and description

ISO 20645:2004 — Textile fabrics — Determination of antibacterial activity — Agar diffusion plate test. This International Standard specifies a qualitative agar diffusion (zone of inhibition) method for assessing antibacterial treatments applied to woven, knitted and other flat textile materials.

Abstract

ISO 20645:2004 describes an agar diffusion plate test used to detect antibacterial activity in textile fabrics. The method is intended for hydrophilic, air‑permeable materials or for antibacterial agents incorporated in fibres or finishes where the active substance can diffuse into the agar. The test provides qualitative information (presence/absence and relative strength of activity) and may be unsuitable for treatments that do not diffuse or that react with agar.

General information

• Status: Published (International Standard — reviewed/confirmed in 2024).
• Publication date: December 2004 (Edition 1, 2004-12).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 59.080.01 (Textiles in general); commonly cross-referenced under textile fabrics categories.
• Edition / version: Edition 1 (2004).
• Number of pages: 9 (ISO edition document length).

Key bibliographic details above are taken from the ISO bibliographic record and national adoptions.

Scope

Applies to woven, knitted and other flat textile materials to determine the antibacterial effect of treatments using the agar diffusion technique. The method is primarily qualitative and requires that the antibacterial agent diffuses from the textile into the agar medium; it is therefore not suitable for products whose active agent does not diffuse or which chemically interfere with the agar. The procedure can be adapted for other material types if appropriate precautions and validations are made.

Key topics and requirements

• Test principle — agar diffusion (zone of inhibition) around the specimen indicates antibacterial activity.
• Specimen preparation — standard specimen size, controls and conditioning of textiles before testing.
• Test organisms — specified bacterial strains are used as test organisms (as defined in the standard).
• Incubation and observation — incubation conditions, measurement or qualitative assessment of inhibition zones and growth beneath the specimen.
• Limitations and interpretation — qualitative outcome; requires diffusion of active agent into agar; not recommended for agents that react with agar or for non-diffusing products.
• Reporting — results, test conditions, controls and any deviations must be documented in the test report.

These topics summarise the principal requirements and limitations of the ISO 20645 agar diffusion method.

Typical use and users

Used by textile testing laboratories, manufacturers of antibacterial textiles and finishes, quality assurance teams, R&D groups developing antimicrobial treatments, and regulatory or conformity assessment bodies that need qualitative evidence of antibacterial effect on fabrics. The method is often used as an initial screening test before quantitative methods are applied.

Related standards

Relevant complementary or alternative ISO standards include ISO 20743 (quantitative methods for determination of antibacterial activity of textile products — absorption/transfer/printing methods) and ISO 18184 (methods for determination of antiviral activity of textile products). National and regional adoptions exist (for example EN/BS/DIN adoptions of ISO 20645). These standards are commonly used together to provide both qualitative screening (ISO 20645) and quantitative evaluation (ISO 20743) where required.

Keywords

ISO 20645, antibacterial, antimicrobial, textile testing, agar diffusion, inhibition zone, qualitative test, textile fabrics, antibacterial finishes, screening method.

FAQ

Q: What is this standard?

A: ISO 20645:2004 is an International Standard that specifies an agar diffusion plate test (qualitative) for determining antibacterial activity in textile fabrics.

Q: What does it cover?

A: It covers the agar diffusion (zone of inhibition) test procedure, specimen preparation, test organisms, incubation and interpretation guidelines for woven, knitted and other flat textiles where the antibacterial agent can diffuse into agar. It is primarily a qualitative screening method.

Q: Who typically uses it?

A: Textile test laboratories, manufacturers of antibacterial textiles and finishes, R&D and QA personnel, and conformity assessment bodies use the standard—typically as an initial screening test prior to more quantitative methods.

Q: Is it current or superseded?

A: ISO 20645:2004 remains the published edition from 2004 and was reviewed/confirmed in ISO’s review cycle (confirmed status noted in ISO bibliographic records). Users should check the ISO catalogue or national standards bodies for any later revisions or national adoptions.

Q: Is it part of a series?

A: It is part of a family of ISO documents addressing antimicrobial/antiviral testing of textiles; commonly referenced complementary standards include ISO 20743 (quantitative antibacterial test methods) and ISO 18184 (antiviral activity tests).

Q: What are the key keywords?

A: Antibacterial, agar diffusion, inhibition zone, textile fabrics, screening test, antimicrobial finishes, ISO 20645.