ISO 16000-43:2025

Overview

ISO 16000-43:2025 - Indoor air, Part 43 - defines a standard method for assessing the reduction rate of culturable airborne fungi by air purifiers using a test chamber. The document specifies controlled chamber tests to evaluate how effectively single-room air purifiers lower concentrations of culturable fungi (expressed in colony forming units, cfu). Tests consider chamber homogeneity and the natural decay rate of aerosolized fungi and report fungal reduction rates as percentages.

Key topics and technical requirements

• Test principle: Nebulize a fungal suspension into a sealed test chamber, measure initial culturable fungi concentration, then measure concentration after a defined time with and without the air purifier operating to calculate reduction rate.
• Test chamber: Airtight, low-emission materials (e.g., stainless steel), aseptic conditions, and environmental controls. Minimum volume: 8 m³ (typical: 15–30 m³). Features include UV‑C decontamination, glove-transfer or similar systems, negative-pressure flushing and environmental indicators.
• Environmental conditions: Default test conditions follow ISO 16000‑9:2024 - (23 ± 1) °C and (50 ± 5) % RH (other documented conditions may be used).
• Aerosol generation: Nebulizer capable of producing particles in the 0.05 µm to 5 µm size range to generate largely individual fungal particles.
• Sampling method: Impaction sampling onto culture media (impactors) for quantifying culturable fungi; initial concentrations must be below method detection limits.
• Performance metrics: Natural decay rate (no purifier) and fungal reduction rate (with purifier) expressed in percent; comparison of concentrations immediately after nebulization and after defined testing time.
• Safety and biosafety: Tests involve fungal species (e.g., Penicillium roqueforti); operators must follow biosafety procedures and use Class II biological safety cabinets for culture work.
• Quality assurance: Requirements for homogeneity checks, control of background concentration, validity conditions, and reporting (see annexes for chamber design, homogeneity, and procedure diagram).

Applications and users

This standard is intended for:

• Air purifier manufacturers validating claims on fungal removal performance.
• Independent testing laboratories conducting standardized chamber tests.
• Certification bodies and regulators comparing device efficiency.
• Building scientists, HVAC engineers, and occupational health professionals assessing indoor air cleaning strategies. Use cases include product performance benchmarking, regulatory compliance testing, and research on indoor bioaerosol control.

Related standards

• ISO 16000 series (indoor air quality standards)
• ISO 16000-9:2024 (emission test chamber method - referenced for temperature/humidity control)

Keywords: ISO 16000-43:2025, indoor air, air purifiers, airborne fungi, culturable fungi, test chamber, fungal reduction rate, nebulizer, impaction sampling, natural decay rate.