ASTM G21: Resistance of Synthetic Polymeric Materials to Fungi
ASTM G21 is the standard practice used to determine how well synthetic polymeric materials resist colonisation and growth by fungi. Airmid Healthgroup carries out this testing to support product claims across surface technologies, textiles, and polymer-based materials.
Scope of ASTM G21

ASTM G21 is the standard practice for determining the resistance of synthetic polymeric materials to fungi.
Products tested: Synthetic polymeric materials.
How the ASTM G21 Test Works
- Fungi are grown on solid medium and a spore suspension is prepared from Penicillium, Aspergillus, Chaetomium, Trichoderma, and Aureobasidium.
- A small volume of the pooled spore preparation is applied directly to the test samples.
- Petri dishes are sealed and incubated for up to 28 days.
- Samples are given a semi-quantitative performance score based on fungal growth after 28 days.
5 Fungal Species
Penicillium, Aspergillus, Chaetomium, Trichoderma, and Aureobasidium are used in the pooled spore preparation.
28-Day Incubation
Sealed Petri dishes are incubated for up to 28 days before fungal growth is scored.
5-Week Turnaround
Results, including third-party validation, are typically available within 5 weeks.
Third-Party Validation
On passing this test, the product can be labelled as tested by Airmid Healthgroup to ASTM G21, in support of any claim relating to the test and data received.
Accreditation & Compliance for ASTM G21
iAIR Labs offers high-quality testing, inspection, compliance and certification across several regulatory systems. Our labs are routinely, externally audited to ensure that your data is reliable, repeatable, and scientifically accurate. We meet the requirements for submission to both the US EPA and the US FDA. Whether you’re interested in early R&D for your product or GLP testing for a 510(k), contact us with your testing needs.
Good Laboratory Practices (GLP)
The Good Laboratory Practices were enacted as law in 1978 to ensure that all data submitted to federal regulatory agencies is performed safely and reliably. The GLPs were introduced to assure that a study is conducted by qualified personnel working in well-maintained facilities with appropriate materials and calibrated equipment, using properly designed experiments recorded with clear and complete detailed documentation, overseen by an independent Quality Assurance Unit, and safely archived for audit/inspection by regulatory agents.
EPA GLP
EPA Good Laboratory Practices (GLP) ensures the quality and integrity of test data submitted to the Environmental Protection Agency. The EPA writes regulations, provides guidance, reviews submitted data, inspects for compliance, registers toxic materials, and enforces legal action for violations.
FDA GLP
FDA GLP prescribes good laboratory practices for conducting nonclinical laboratory studies that support or are intended to support applications for research or marketing permits for products regulated by the Food and Drug Administration (FDA). This program supports customers requesting a GLP assessment, as the FDA does not provide a certificate of compliance.
At iAIR Labs, we pride ourselves on adhering to the highest standards of regulatory compliance. All our testing services are conducted in strict accordance with FDA and EPA guidelines and cGLP (current Good Laboratory Practice) regulations, ensuring our clients receive results that are both reliable and recognised by regulatory bodies.
Need ASTM G21 Testing for Your Materials?
Contact Airmid Healthgroup to discuss fungal resistance testing requirements for your synthetic polymeric materials and receive a tailored quote.
Frequently Asked Questions
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Relevant External Links
- ASTM International โ G21 Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi
- ISO 20743:2013 โ Textiles: Determination of Antibacterial Activity
- ISO 13629-1:2012(en) โ Textiles: Determination of Antifungal Activity
Related Tests
- ISO 13125:2013
- ISO 16212:2011 โ Yeast and Mold Enumeration in Cosmetics
- ISO 27447:2019 โ Ceramic Antimicrobial Surface Validation
- BS ISO 16869:2008
- BS EN 1040:2005
- BS EN 1275:2005 โ Evaluation of Basic Fungicidal or Yeasticidal Activity
- BS EN 1276:2009 โ Evaluation of Bactericidal Activity of Chemical Disinfectants and Antiseptics
- BS EN 1650:2008
- BS EN 1884:1999 โ Feather and Down Bacterial Analysis
- BS EN 13610:2002 โ Virucidal Claim Verification
- BS EN 13697:2015
- BS EN 13704:2018
- BS EN 13727:2003
- ASTM E2149-10
- ISO 13629-2 โ Antiviral Textile Testing
- JIS Z 2801 โ Antimicrobial Activity and Efficacy of Plastics
- AATCC 100 โ Fabric Testing and Claim Verification
- AATCC 174 โ Antimicrobial Activity Assessment of New Carpets
- Microbial Strikethrough โ Bacteria Penetration Test
Word Tags
ASTM G21 | Standard Practice | Resistance | Synthetic Polymeric Materials | Fungi | Mold | Textiles | Smart Textiles | Antimicrobial Surfaces



