Fungus Resistance Testing
Fungus Resistance Testing evaluates a material’s ability to resist fungal or microbial growth under controlled conditions. The test exposes materials to specific fungi and examines changes such as surface growth, discoloration, degradation, or damage. Standards such as ASTM G21 and AATCC 30 help manufacturers assess product durability and improve resistance in humid or microbial-prone environments.
TRUSTED BY
Precision-driven testing for dimensional accuracy and compliance
- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
Fungus Resistance Testing Overview
Fungus resistance testing evaluates a material’s or product’s susceptibility to fungal growth under warm, humid conditions over a defined test period. The test involves inoculating the specimen with a standardised mixture of fungal spores and incubating it under controlled temperature and humidity conditions that simulate tropical or high-humidity environments. At the end of the exposure period, the specimen is examined for fungal growth and any associated physical or functional changes.
The test does not measure whether a product can kill fungi – it determines whether the material itself supports or resists fungal colonisation. A material that provides no nutritional value to fungi and shows no surface degradation after inoculation and incubation is considered fungus-resistant. A material that supports growth or shows discolouration, surface damage, or functional impairment as a result of fungal activity fails the test.
This is a required evaluation for products intended for use in tropical climates, high-humidity storage conditions, or environments where biological growth is a known risk – including military equipment, electronics, polymers, coatings, textiles, and packaging materials.
Fungus Resistance Testing Scope, Applications, and Benefits
Scope
Fungus resistance testing involves evaluating materials, components, and finished products against a standardised fungal challenge under controlled incubation conditions. The specimen is inoculated with a spore suspension of a specified fungal species and held at an elevated temperature and relative humidity for a defined duration. Results are reported as a growth rating on a standardized scale based on visual examination.
Commonly referenced standards include:
- ASTM G21 – standard practice for determining resistance of synthetic polymeric materials to fungi; covers plastics, rubbers, coatings, and related materials using a defined fungal mix and 28-day incubation
- AATCC 30 – antifungal activity assessment for textiles; covers mildew and rot resistance of textile materials, including fabric, yarn, and fibre
- MIL-STD-810 Method 508 – fungus testing for military equipment and materials intended for tropical environments; uses a 28-day exposure with a defined fungal mix
- IEC 60068-2-10 – fungal growth testing for electrotechnical equipment; defines fungal species, inoculation procedure, incubation conditions, and evaluation criteria
- ISO 846 – evaluation of the action of microorganisms on plastics; covers both fungal and bacterial resistance
Applications
- Military and defense equipment – electronics, cables, housings, and structural components destined for tropical deployment must pass MIL-STD-810 Method 508 fungus testing before acceptance
- Electronics and electrical equipment – PCBs, connectors, enclosures, and insulation materials tested per IEC 60068-2-10 to confirm they will not support fungal growth in humid operating environments
- Polymers, rubbers, and plastics – ASTM G21 is the standard reference for evaluating whether a polymer formulation, additive package, or coating resists fungal colonization
- Textiles and apparel – outdoor fabrics, technical textiles, military uniforms, and protective clothing evaluated per AATCC 30 for mildew and rot resistance
- Packaging materials – paper, board, films, and adhesives used in tropical or humid climate packaging, evaluated for fungal susceptibility to protect packaged goods
- Building and construction materials – insulation, sealants, membranes, and coatings tested for fungal resistance in applications with moisture exposure risk
- Aerospace components – non-metallic materials used in aircraft interiors or exposed areas, particularly for operators in high-humidity regions
Benefits
- Directly simulates the conditions that cause fungal failure in the field – 28-day incubation at 29°C and ≥95% RH replicates the tropical environmental conditions that trigger fungal degradation in real use
- Identifies susceptible materials before production or deployment – catching a formulation or material that supports fungal growth at the testing stage avoids costly field failures, warranty claims, or product recalls
- Covers a broad range of material types under one test framework – plastics, coatings, textiles, composites, and assembled products can all be evaluated using applicable method variants
- Required for market access in regulated industries – military procurement, aerospace qualification, and certain consumer product standards require fungus resistance data before a material or product can be accepted
- Supports material selection and formulation decisions – comparative testing of different grades, additives, or biocide treatments gives formulation teams clear data on which options provide fungal resistance and which do not
Fungus Resistance Test Process
Specimen Preparation
Specimens are prepared to the required dimensions and uniformly inoculated with fungal spore suspension.
1Incubation
Inoculated specimens are kept in a humidity chamber, typically at 29 ± 1°C and ≥95% RH, for 28 days.
2Growth Examination
Specimens are visually examined for fungal growth, discoloration, cracking, or surface degradation.
3Reporting
Fungal growth is rated on a standard scale and reported with observations, photos, and acceptance criteria.
4Fungus Resistance Testing Technical Specifications
| Parameter | Details |
|---|---|
| Fungal Species (typical mix) | Aspergillus niger, Aspergillus flavus, Penicillium funiculosum, Trichoderma viride, Chaetomium globosum |
| Incubation Temperature | 29 ± 1°C (ASTM G21 / MIL-STD-810); other temperatures per method |
| Relative Humidity | ≥95% RH |
| Test Duration | 28 days (standard); other durations per applicable method |
| Inoculation Method | Spore suspension spray or swab application to the specimen surface |
| Growth Rating Scale | 0 (none) to 4 (heavy, >60% coverage) |
| Specimen Types | Plastics, rubbers, coatings, composites, textiles, electronics, packaging |
| Nutrient Medium | Minimal salts agar (no added nutrients) to evaluate material as sole carbon source |
Instrumentation Used for Fungus Resistance Testing
- Environmental humidity chamber with temperature and RH control
- Biosafety cabinet for spore suspension preparation and inoculation
- Optical microscope or magnifier for growth examination
- Spray applicator or inoculation swabs
- Incubator for culture maintenance
- Photographic documentation setup for specimen imaging
Fungus Resistance Testing Results and Deliverables
- Test report – specimen description, applicable standard, fungal species used, incubation conditions, and duration
- Growth rating per specimen – visual growth rating (0–4 scale) for each specimen with supporting photographs
- Physical condition observations – any discolouration, surface degradation, cracking, or functional changes noted at post-incubation examination
- Pass/fail determination – result compared against the acceptance criterion of the applicable standard
- Control specimen records – uninoculated control results confirming test environment validity
- Photographic documentation – images of specimen surfaces before and after incubation showing fungal growth distribution
Frequently Asked Questions
It helps determine whether a material may support mold or fungal growth during storage, transport, or service.
Specimens are inoculated with fungal spores and incubated in a controlled humidity chamber for a defined period.
Testing is typically performed at elevated humidity and controlled temperature to encourage fungal growth.
Many fungus resistance tests run for 28 days, depending on the applicable standard.
A lower rating indicates better resistance to fungal growth.
Why Choose Infinita Lab for Advanced Materials Testing and Characterization?
At the core of this breadth is our network of 2,000+ accredited laboratories across the USA, offering access to over 10,000 testing methods and analytical services. From advanced materials characterization (SEM, TEM, RBS, XPS) to mechanical, chemical, environmental, biological, and standardized ASTM/ISO-compliant testing, we deliver unmatched flexibility, specialization, and scale. You are never limited by geography, facility, or methodology — Infinita Lab connects you to the right expertise and testing solution, every time.
Looking for a Trusted Partner for Accurate and Reliable Testing Services?
Send query us at hello@infinitlab.com or call us at (888) 878-3090 to learn more about our services and how we can support you.
Request a Quote
Submit your material details and receive testing procedures, pricing, and turnaround time within 24 hours.
Quick Turnaround and Hasslefree process
Confidentiality Guarantee
Free, No-obligation Consultation
100% Customer Satisfaction
