About the standard
AATCC 174 carpet antimicrobial testing — what the standard covers
AATCC 174 carpet antimicrobial testing is the industry-recognised method for evaluating the antimicrobial efficacy of carpet materials. Formally titled “Antimicrobial Activity Assessment of Carpets” and developed by the American Association of Textile Chemists and Colorists (AATCC), this standard encompasses three distinct procedures: two assessments of antibacterial activity (Test I — qualitative; Test II — quantitative) and one qualitative antifungal assessment (Test III).
Airmid Healthgroup provides accredited AATCC 174 carpet antimicrobial testing services for carpet manufacturers, antimicrobial treatment suppliers, and brands seeking validated performance data for regulatory submissions, product claims, or supply chain qualification.
Test I
Qualitative
Antibacterial — zone of inhibition
Test II
Quantitative
Antibacterial — % reduction data
Test III
Qualitative
Antifungal — A. niger challenge
Test I
Qualitative antibacterial assessment
Test I follows a zone of inhibition methodology comparable to AATCC 147, with one key distinction: the test sample is placed across a single bacterial streak rather than multiple streaks or a lawn inoculation.
Procedure overview
01
Molten agar is poured into sterile petri dishes and allowed to solidify
02
The test microorganism suspension is diluted 1:10 in sterile distilled water
03
A single bacterial streak (~75mm) is drawn across the centre of the plate using a sterile inoculating loop
04
Carpet samples (25mm × 50mm) are placed transversely across the inoculum streak with uniform contact pressure
05
Treated and untreated control samples are incubated for 18–24 hours at the appropriate temperature
06
Plates are examined for growth interruption; any zone of inhibition is measured using the method-specified formula
Test II
Quantitative antibacterial assessment
Test II is a quantitative procedure for AATCC 174 carpet antimicrobial testing, structurally similar to AATCC 100, adapted with an adjusted inoculum volume for carpet substrates. Per the original AATCC 174 standard, S. aureus 6538 and K. pneumoniae 4352 are the specified test organisms.
Procedure overview
01
The test microorganism is cultivated in liquid culture medium and standardised by dilution in nutritive broth or sterile saline
02
Control and test carpet fibres are pre-wetted, then inoculated in triplicate — inoculum contact is limited to the fibres only
03
Baseline microbial concentrations are established at time zero via elution, serial dilution, and plate counting of control samples
04
Inoculated samples are sealed and incubated undisturbed at body temperature (37°C) for 24 hours
05
Post-incubation microbial counts are determined; percentage reduction is calculated relative to both initial concentrations and the untreated control
06
Neutralisation controls confirm effective neutralisation of the antimicrobial agent prior to enumeration
Test III
Qualitative antifungal assessment
Test III is adapted from AATCC 30 Test III and evaluates antifungal performance against A. niger 6275, using both face-up and face-down sample orientations to assess surface-specific efficacy. This third procedure completes the AATCC 174 carpet antimicrobial testing standard by covering fungal as well as bacterial challenges.
Procedure overview
01
A spore suspension is prepared from A. niger scrapings; concentration adjusted to 1×10⁶ spores/mL in sterile distilled water
02
Molten agar is poured into sterile petri dishes, solidified, then inoculated with the fungal spore suspension
03
Pre-wetted control and test carpet samples are placed on the inoculated agar in both face-up and face-down orientation
04
Petri dishes are sealed and incubated for 7 days at the appropriate temperature
05
Samples are rated based on the growth-free zone adjacent to the agar contact area and any fungal growth on the face-up surface
Performance considerations for AATCC 174 carpet antimicrobial testing
Strengths
✓ Both antibacterial and antifungal data within a single standard
✓ Test I delivers rapid, cost-effective qualitative screening
✓ Test II produces reproducible quantitative reduction data for performance claims
✓ Test III exposes samples to a high spore load — a rigorous antifungal challenge
Limitations
⚠ AATCC 174 does not define pass/fail criteria — performance thresholds are set by the sponsoring organisation
⚠ Test I results can exhibit natural variability, with inhibition zones that may lack clearly defined boundaries
Commission AATCC 174 carpet antimicrobial testing with Airmid Healthgroup
Airmid Healthgroup is an accredited testing laboratory specialising in antimicrobial efficacy testing for textiles, surfaces, and coatings — including full AATCC 174 carpet antimicrobial testing for carpet products. Our team works with clients at every stage, from initial product screening through to final validation data for market claims. Contact us to discuss your testing requirements or to request a project proposal.
Commission testing
Request AATCC 174 carpet antimicrobial testing with Airmid Healthgroup
Tell us your carpet product type and sample quantity — we will provide a tailored project proposal.
Related test methods
AATCC 100 — Fabric Antibacterial Testing
ASTM G21 — Resistance to Fungi
BS ISO 16869:2008 — Plastics Fungistatic
BS EN 13697:2015 — Surface Disinfectants
ISO 27447:2019 — Ceramic Antimicrobial
Industry page
Full overview of Airmid Healthgroup’s antimicrobial and performance testing services for textile manufacturers.
External authority references
Standards & regulatory references
AATCC ↗
TM174 — Official Standard
Test Method for Antimicrobial Activity Assessment of New Carpets
AATCC ↗
American Association of Textile Chemists and Colorists
The standards body responsible for AATCC 174 and related textile test methods
ISO ↗
ISO 20743 — Antibacterial Textiles
International standard for determination of antibacterial activity of antibacterial finished textile products
Client success
Related case studies
From the lab
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Commission AATCC 174 carpet antimicrobial testing
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Our team works with carpet manufacturers and antimicrobial treatment suppliers at every stage — from initial AATCC 174 carpet antimicrobial testing through to final validation data for market claims and regulatory submissions.
