ISO/DIS 17597:2026(en)

ISO/TC 142

Secretariat: UNI

Date: 2025-11-26

Test Method for Measuring in-duct Airborne Microorganisms Inactivation/Removal Effectiveness (AMIRE).

© ISO 2026

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Contents

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

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This document was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

Airborne microorganisms, including pathogens, spread readily through indoor air, and can cause a variety of diseases. A number of removal and deactivation technologies have been developed to deal with this situation.

Relevant existing standards include:

— ASHRAE Standard 185.1 ‘Method of Testing UVC Lights for Use in Air Handling Units or Air Ducts to Inactivate Airborne Microorganisms.

— ISO 15714 'Method of evaluating the UV dose to airborne microorganisms transiting in-duct ultraviolet germicidal irradiation devices.

However, none of these are fully relevant for the wide variety of different technologies used for the removal and deactivation of airborne microorganisms : in the case of ASHRAE 185.1 and ISO 15714, the test is specified only for UV devices and does not include mechanical filtration and other technologies.

There is currently no internationally accepted method for measuring the inactivation/removal effectiveness of air disinfection devices that are mounted in HVAC (Heating, Ventilation and Air-conditioning) systems other than UV-based ones.

This document provides a laboratory test method for microorganism inactivation/removal. It builds on existing standards such as the ones listed above and broadens the scope to cover specific types of microorganism inactivation/removal devices in air ducts.

Test Method for Measuring in-duct Airborne Microorganisms Inactivation/Removal Effectiveness (AMIRE)

This document stipulates a method that evaluates inactivation/removal effectiveness against airborne microorganisms in air cleaning devices, such as air filters set up in a heating, ventilation and air-conditioning (HVAC) system in commercial, institutional and office buildings, also air-purifying systems, or air sterilizers in these buildings.

The airborne microorganism inactivation/removal effectiveness is based on an evaluation of the ability of the duct-mounted air-filtering devices to capture or inactivate bacteria, moulds or viruses with common particle sizes. By measuring the inactivation/removal effectiveness, the quality level of the product can be assessed.

This method includes detailed requirements for the test rig, which simulates the nominal air flow rate of the devices. The method also covers data acquisition, analysis, and reporting of results.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 15957:2015, Test dusts for evaluating air cleaning equipment

ISO 29464:2024, Cleaning of air and other gases — Vocabulary

ISO 16890‑2:2022, Air filters for general ventilation — Part 2: Measurement of fractional efficiency and air flow resistance

ISO 16890‑3:2023, Air filters for general ventilation - Part 3: Determination of the gravimetric efficiency and the air flow resistance versus the mass of test dust captured

For the purposes of this document, the terms and definitions given in ISO 29464 and the following apply.

3.1

airborne microorganism

particle of biological origin suspended in air

Note 1 to entry: Airborne microorganisms include bacteria, fungi and their spores, and viruses

[SOURCE: ISO 29464:2024, 3.6.12]

3.2

airborne microorganism inactivation/removal effectiveness (AMIRE)

degree of reduction of airborne microorganisms resulting from passage through an air cleaning device

3.3

bioaerosol

particles of biological origin suspended in a gaseous medium

Note 1 to entry: Bioaerosol particles include viruses, bacteria, fungi, pollen, plant debris, fragments of these and their derivatives such as endotoxins, glucans, allergens and mycotoxins.

Note 2 to entry: The size of a bioaerosol particle can be larger if it is encased within a liquid drop, for example a virus in sputum.

[SOURCE: ISO 29464:2024, 3.2.20]

3.4

biosafety level

BSL

designation used to specify the level of protection and containment necessary for dealing with dangerous microorganisms in a laboratory

Note 1 to entry: levels range from BSL 1 (least protection needed) to BSL 4 (maximum protection required)

Note 2 to entry: Classification depends on infectivity, disease severity, transmission risk, and work type. See the WHO Laboratory Biosafety Manual or CDC BMBL for details.

3.5

colony forming unit

CFU

unit for expressing the number of culturable bacteria or moulds present in a sample

Note 1 to entry: for microorganisms in air, concentrations are usually expressed as colony forming units per cubic metre of air sampled (CFU/m³)

3.6

nominal air flow rate

air flow rate specified by the manufacturer

Note 1 to entry: it is the volume of the air passing through the air cleaning device per unit time.

3.7

plaque forming unit

PFU

unit for expressing the number of culturable viruses present in a sample

Note 1 to entry: for viruses in air, concentrations are usually expressed as plaque forming units per cubic metre of air sampled (PFU/m³).

3.8

test device

air cleaner being subjected to performance testing

Note 1 to entry: Air cleaners indicates air filters set up in a heating, ventilation and air-conditioning (HVAC) system and commercial, institutional and office buildings air-purifying systems, or air sterilizers.

[SOURCE: ISO 29464:2024, 3.1.45, modified – Note 1 to entry has been added]

3.9

test rig

complete assembly of equipment used for determining performance of an air cleaner.

This test method determines the performance of an air cleaner capable of inactivating or removing airborne microorganisms in a duct or HVAC system by measuring the microorganisms upstream and downstream of the test device.

The test device may physically remove microorganisms from the air or may cause damage sufficient to prevent reproduction of sampled microorganisms (inactivation) or both in parallel.

This test is carried out in a large test rig of approximately 600 mm × 600 mm (2 feet × 2 feet). The test rig required for conducting this test is described in clause 5.

The test rig used for this standard shall comply with the requirements of the ISO 16890-2 test rig except as noted in this clause . A schematic of the test rig is shown in Figure 1.

Key

1 upstream HEPA filtration with turbulence damping grid to provide clean air

2 test microorganism generation

3 upstream microorganism sampling port

4 upstream test filter pressure tap

5 test device

6 downstream test filter pressure tap

7 downstream microorganism sampling port

8 downstream HEPA filtration with turbulence damping grid to prevent particle from escaping out of the duct

9 example of air flow measurement device location

Figure 1 — Schematic diagram of the test rig

Bioaerosol shall be injected at the same test rig location shown in Figure 1. The bioaerosol injection system shall produce an upstream challenge that meets the qualification criteria of clause 7.2. The injection system design is described in clause 7.2.

Installation of the test device shall be as designated by the manufacturer or equipment provider. The test device shall be sealed into the test rig in a manner that prevents leakage between the test device and the mounting frame.

One or more bioaerosol samplers shall be installed upstream of the test device, and downstream of the device. These samplers shall be collocated with the probes specified in ISO 16890-2. If multiple samplers are used, they shall be located so that the inlet air streams do not interfere with each other. The inlets of the bioaerosol samplers shall face into the airflow. Isokinetic sampling (to within 10 % of a measured target flow velocity as measured by the instruments indicated) shall be used. Flow rate through the sampling system shall be measured with volumetric devices such as orifice plates or rotameters having an accuracy of ±5 %. Samples and devices shall be located such that the air cleaning device does not influence the upstream sampling location. A light baffle or extra distance may be needed for some devices.

After completing the test, procedure for preventing microbial contamination of the test facility is necessary. Disconnect the nebulizer from the apparatus. Sterilize the remained microorganism suspension. Sterilize all apparatus and supplies that come into contact with the microorganism suspension to prevent exposure and reduce laboratory contamination. The inside of in-duct is exposed to a UV-C for at least 30 minutes and then the inside of in-duct is cleaned if necessary.

A duct leakage test shall be conducted as described in ISO 16890-2:2022, clause 8.2.8. This test detects leakage (air exchange) between the air inside the test rig and the room.

The velocity uniformity test shall comply with ISO 16890-2:2022, clause 8.2.9. This test measures differences in air velocity across the duct cross section using a nine-point traverse.

This test shall be performed in the same way as described in clause 8 but with no device in the test rig. The No Device test shall meet the specifications in Table 1. This test serves to detect, and allow correction for, any differences between upstream and downstream sampling.

Table 1 — System qualification measurement requirement

The bioaerosol tests shall be conducted using microorganisms that are safe to work with when aerosolizing enough for a full-scale test. Micrococcus luteus (American Type Culture Collection (ATCC) 10 240) is a gram-positive coccus that is often present in indoor air. It is a microorganism that can be handled in a biosafety level 1 laboratory. Bacillus subtilis (ATCC 6 633) is a gram-positive rod is a biosafety level 1 bacteria which is highly resistant to environmental stress and is commonly used in indoor aerosol research. For virus related research, MS2 bacteriophage (ATCC 15 597-B1 using Escherichia coli host ATCC 15 597) is relevant for use for representative studies of viruses in aerosol research. It is biosafety level 1 and easy to grow. For mould, it is recommended to use Aspergillus niger (ATCC 6 275) as representative of fungal species which may be an issue for indoor air quality. For specific questions, other organisms may be used provided that the laboratory can operate at the required biosafety level. It is recommended to follow ATCC product literature for specific considerations. All strains used shall be listed in the test report.

Table 2 — List of test organisms

Preparation of the test microbial suspension for the aerosolization requires culturing the test organism in the laboratory and preparing a suspension suitable for aerosol generation in the test duct. The microbial challenge suspensions are prepared by inoculating the test organism onto solid or into liquid media, incubating the culture until mature, wiping organisms from the surface of the pure culture (if solid media), and eluting them into sterile fluid to a known concentration to serve as a stock solution. The organism preparation is then diluted into the nebulizing fluid. The nebulizing fluid is quantified on agar plates to enumerate the number of test organisms in the suspension. The number of culturable organisms shall be at least 10⁶ CFU or PFU per ml.

The generation system may include a collision nebulizer that is based on air atomizing spray nozzles (nozzles size of 0,3 mm) in which a suspension of microorganisms is nebulized with compressed air(pressure of 3 bar). Other nebulizers are acceptable.

In order to prevent excessive water condensation in the operation of the bioaerosol generator, a Diffusion Dry unit shall be installed after the generator. The average upstream concentration shall be over 1,0 × 10⁴ cfu/m³ or pfu/m³. By adjusting the test microorganism concentration in suspensions and the setting of the generator, the microbe concentration in the air stream can be controlled.

The test shall be conducted using the air flow rate recommended by the air cleaning device manufacturer. Air flow rate, temperature and relative humidity shall be measured as indicated in ISO 16890-2. The temperature shall be (23 ± 3) °C and relative humidity shall be (50 ± 10) % R.H.

Bioaerosol sampling shall not be initiated until a steady-state bioaerosol challenge concentration has been established. This ensures that the conditions under which the test is performed are stable and that the data collected is representative of the system’s performance. Samples should be simultaneously (or sequentially) collected upstream and downstream of the test device, at specified locations where normal aerosol test equipment such as optical particle counters would be located. Samples should be conducted in triplicate for results repeatability and to statistically analyse any variances. Flow rates should be controlled by calibrating and stabilizing a flow rate, depending on method and device used, to ensure accurate representation of the bioaerosol concentration. Collection devices include viable cascade or cyclonic impactors, liquid impingers, or other equipment as identified by the researcher. Aerosol collection media should be specific for the growth requirements of the organism in the challenge solution (bacteria, mould, virus, etc.). Temperature, humidity and airflow should be monitored, recorded and maintained throughout the course of the study to avoid any extraneous influence of the aerosolization process or stability of bioaerosols. Using these guidelines as reference ensures that the bioaerosol sampling is done accurately and reliably, providing high-quality data for evaluating the effectiveness of the test device or system under investigation.

Sampling devices shall be the same type upstream and downstream. Impingers and impactors are acceptable samplers. The sampler should be selected according to the size of the bioaerosol being tested. When using MS2 bacteriophage virus as a test microorganism, the use of impinger is recommended. When sampling by the impactor method, use sampler with more than 300 holes. Samplers shall be covered to avoid exposure to light or external contamination. At least three replicate samples shall be taken both upstream and downstream. When sampling by the impinge method, there should be at least three liquid medium obtained from upstream and downstream. All procedures shall be the same for processing of the upstream and downstream samples. Good laboratory practices appropriate for the sampler type shall be used and documented in the test report.

The average upstream concentration shall be over 1,0 × 10⁴ cfu/m³ or pfu/m³. Standard deviations of the upstream and downstream concentrations shall be calculated based on the CFU or PFU counts from the triplicate plates. If no colony or plaque appears on the agar plates, the result is expressed as “< 1 cfu” or “< 1 pfu” in the sampled air volume.

The primary measure of performance within this test method is the single-pass bioaerosol microorganism inactivation/removal effectiveness. This effectiveness, η, shall be quantified by comparing the average bioaerosol concentration upstream and downstream of the device using the following general equation:

(1)

where:

This general equation is corrected for system biases according to 9.2.

The no device correlation (penetration) ratio is calculated by measuring the numbers of culturable organisms upstream and downstream without the device in the duct (or with the device off if the device does not block much of the cross-section of the test rig). The device-off option is allowed to aid in switching between the tests quickly and allow the possibility of using a single nebulizer solution for both tests. The same sampling methods are used in 8.3. The equation is:

(2)

where:

To remove this system bias, the Single-Pass airborne microorganism inactivation/removal effectiveness from Equation 1 shall be corrected using the No Deviceorrelation (Penetration) Ratio from Equation 2. Thus, the final corrected value for the Single-Pass airborne microorganism inactivation/removal effectiveness (AMIRE) becomes:

(3)

The summary section of the performance report shall include the following information:

a) Reference to this standard

b) Name and location of the test laboratory

c) Date of the test

d) Test operators’ names

e) Device manufacturer’s name (or name of the marketing organization, if different from the manufacturer)

f) How the device was obtained

g) Description of the test device, including the following:

1) brand and model number;

2) physical description of construction;

3) photos of device as positioned in the test rig.

h) Summary of Test data

1) test air temperature and relative humidity;

2) test airflow rate;

3) no-device test correlation (penetration) data;

4) type of organism used for bioaerosol test;

5) make and model number of bioaerosol sampler used for the test;

6) name and address of the laboratory analysing the samples;

7) table of upstream and downstream bioaerosol concentration from the efficiency test.

i) Calculated single-pass bioaerosol removal/inactivation efficiency

1) uncorrected removal/inactivation efficiency from Equation 1;

2) corrected removal/inactivation efficiency from Equation 3.

Inclusion of all test raw data in the report is required. Data shall include details of the bioaerosol samples analysis.

1. 
   (informative)
   
   Test method for measuring microorganisms filter media deactivation effectiveness (MFMDE)
   1. Scope

This annex specifies a method that evaluates deactivation effectiveness against airborne microorganisms in air filters set up in a heating, ventilation and air-conditioning (HVAC) system and commercial, institutional and office buildings in-duct air-purifying systems.

This annex applies to fibrous air filters treated with antimicrobial agents on the filter media, or to fibrous air filters antibacterial modules combined with antimicrobial technology such as high-pressure discharge, ultraviolet rays, and plasma. This document may not apply if the device fails to meet the criteria for general air filters as specified in ISO16890 or ISO 29463.

The test that this document focuses on aims to verify the airborne microorganism deactivation of the filter over time by capturing microorganism floating in the air on the filter media surface and along the media depth.

• 1. Principle

This testing method was developed to determine performance for an fibrous filter media capable of deactivating the airborne microorganisms captured in a duct or HVAC system. The equipment and test environment for this test are the same as the main body unless otherwise defined in this Annex A.

The test filter attached with airborne microorganisms are used as specimens by two pieces with a same size using a sterilized tool.

The one specimen leaves it under the stable environmental condition for a certain period of time so that the deactivation reaction can sufficiently occur on the surface of the test specimen. The deactivation reaction time is performed according to the conditions suggested by the manufacturer according to the sample characteristics. For other specimens, proceed immediately to the microbial elution procedure.

Each specimen is immersed in a solution for elution of microorganisms and shaken vigorously so that the attached microorganisms can sufficiently move into the liquid phase. The elution solution dilutes to appropriate level for colony counting. After inoculating the diluted solution on the nutrient agar, incubate for 24 hours in a 37 °C. The cultured colonies are counted and marked to calculate the deactivation effectiveness.

Key

1 cut test filter

2 elution of microorganism

3 deactivation in constant temperature and humidity

4 serial dilution

5 spreading on agar plate

6 incubation and CFU counting

a) without deactivation time

b) with deactivation time

Figure A.1 — Schematic diagram of the test

• 1. Test apparatus and materials
     1. Test filter

The test filter being tested shall show no signs of damage or any other irregularities. The test filter shall be handled carefully and shall be clearly and permanently marked with the following details:

— manufacturer’s identifications of the test filter (lot number, model number, nominal flow rate, etc.);

— upstream side of the test filter.

The environmental condition (temperature, relative humidity and etc.) of the test filter during the testing shall be the same as that of the test air.

For a test filter with additional accessories installed (or added) for the purpose of deactivation, accessories with the same characteristics as those actually used shall be operated during the test. The test filter shall be sealed into the test rig in a manner that prevents leakage.

• • 1. Test rig

The test rig for this test is the same as the ones used in the standard.

• • 1. Testing equipment
       1. Autoclave

Equipment capable of operating at a temperature of (121 ± 3) °C and a pressure of (103 ± 5) kPa to pasteurize or sterilize.

• • • 1. Shaking incubator

Equipment capable of providing constant agitation of organisms in solution and maintaining a temperature of (37 ± 2) °C.

• • • 1. Vortex mixer

Agitator producing a vortex shaking action.

• • • 1. Orbital shaker

Equipment capable of performing a range of 100 r/min to 250 r/min.

• • • 1. Refrigerator

Equipment capable of maintaining a temperature of 2 °C to 8 °C.

• • • 1. Colony counter

Instrument capable of automatically or manually counting 400 colonies/plate

• • 1. Testing materials

The following materials are used:

— flasks: 250 ml – 500 ml Erlenmeyer;

— Petri dishes: 15 mm × 90 mm;

— pipettes: 1 ml, 5 ml, 10 ml;

— test tube rack (stainless);

— bottles, sterile, glass, 100 ml – 500 ml capacity;

— inoculating loop;

— test tubes or bigger;

— micropipettes, capable of delivering 0,001 ml accurately and consistently;

— pH meter, capable of measuring to ±0,2 units.

• • 1. Preparation of test microorganisms and test reagent

The test microorganisms are same as the ones used in the main text(see table 1). Select the one microorganism and prepare microbial suspension diluted with peptone saline solution to the concentration of over 10⁶ CFU or PFU per ml.

• • • 1. Peptone saline solution

Dissolve 1 g of enzymatic digest of casein and 8,5 g of sodium chloride in 1 000 ml of deionized water. Adjust the pH with sodium hydroxide or hydrochloric acid. The final pH should correspond to 7,0 to 7,2 at 25 °C. Sterilize by autoclaving at (121 ± 3) °C for 15 min. Store at (5 ± 3) °C for no longer than 1 month.

• • • 1. Phosphate buffered saline

Add 34 g of potassium dihydrogen phosphate (KH2PO4) to 500 ml of conditioned water, add 175 ml of 1 N sodium hydroxide to adjust the pH to 7,2, and add deionized water to make 1 000 ml of phosphate buffer solution. This is sterilized at (121 ± 3) °C for 15 minutes and then stored in the refrigerator. When using, take 1 ml of this stock solution, add it to 800 ml of deionized water, and use it as a phosphate buffered saline solution.

• 1. Test procedure
     1. Generation of test microorganisms

Microorganism generation method is referred to 5.2 and 5.3 of main body.

• • 1. Cutting out the sample

After recovering the filter that has been adsorbed with airborne microorganism, cut at least 10 squares samples with a side of a minimum of 1 cm using tweezers and scissors disinfected with 70 % isopropanol or appropriate disinfectant. The five different locations should be selected in sampling the filter to represent the distribution overall the filter media, and two filter samples should be obtained with the same location. The sample size should be adapted to the biggest tube size available that will be used in clause A.4.3, and should be the biggest possible while allowing a good dispersion of the microorganisms during the procedure.

• • 1. Recovery of microorganism from test filter

Put a square filter into a test tube containing peptone saline solution enough to put the test sample. At this time, the filter is put into the tube in a direction in which the microorganism exposed surface can be contacted with peptone saline solution. Shake the tube with 150 r/min for 10 minutes so that microorganisms can be eluted into peptone saline solution.

Put the other square filter in constant temperature and humidity chamber with temperature of (23 ± 3) °C and a relative humidity of 70 % for 1, 2, and 4 hours. The amount of time the filter is exposed to constant temperature and humidity could be changed and not exceed 24 h. The exposure time should be recorded on test report.

After the exposure time passed, place the filter into the test tube containing peptone saline solution. Shake the tube with 150 r/min for 10 minutes so that microorganisms could be eluted into peptone saline solution.

• • 1. Incubation

Enumerate microorganism by performing 10-fold serial dilutions of the eluted solution in phosphate-buffered saline. Spread 0,1 ml of each dilution to agar medium. All plating shall be performed in triplicate. Replace the lids, invert the petri dishes and incubate them at (37 ± 1) °C for 24 h. The culture temperature and storage method could be changed according to the method provided by the provider and recorded.

After incubation, count the number of colonies in the Petri dishes containing 30 to 300 colonies. For each dilution series, record the number of colonies recovered to two significant figures, as well as the dilution factor for the plates used for counting. If the number of colonies in the plates is less than 30, then count and record the number of colonies in these plates. If there are no colonies recovered in any of the agar plates in the dilution series, record the number of colonies as “< 1”.

• 1. Expression of data and calculations
     1. Determination of the number of viable microorganisms

The calculation of the number of microorganisms immediately recovered from the filter is calculated by the following equation: .

(A.1)

where

N is the number of viable microorganisms recovered per cm² per test filter

B₀ is the average number of microorganisms from the test filter immediately after the airborne microorganism exposure, in CFU

D is the dilution factor for the plates counted

• • 1. Determination of Microorganisms Filter Media Deactivation Effectiveness

The overall deactivation effectiveness of the test filter is calculated according to the following equation:

(A.2)

where

B₀ is the average number of microorganisms from the test filter immediately after the airborne microorganism exposure, in CFU

B_T is the average number of microorganisms extracted from the test filter after the deactivation time(T), in CFU

It is also described as logarithm value:

(A.3)

where:

R is the common logarithm value of the MFMDE;

U₀ is the average of the common logarithm of the number of microorganisms, in CFU/0,1 ml, recovered from the test filter immediately after the airborne microorganism exposure;

A_T is the average of the common logarithm of the number of microorganisms, in cells/0,1 ml, recovered from the test filter after the deactivation time (T),

• 1. Reporting the results

In the test report for the MFMDE, the test information should be included referred to section 10.1, and the test results should include calculation procedure and results described in section A.5

1. 
   (Normative)
   
   Dust loading test for AMIRE and MFMDE
   1. Scope

This annex specifies a test method to determine the effect of dust loading on the airborne microorganism inactivation/removal effectiveness of air treatment devices. The procedure follows ISO 16890-3. The method is intended to simulate degradation in performance caused by particulate accumulation during real-life operation.

NOTE: Dust loading may alter the physical structure, surface exposure, or active components of antimicrobial devices, thereby impacting their effectiveness.

• 1. Test Apparatus

The same test rig, environmental conditions, test airflow and test airflow as specified in clause 5 shall be used. The device configuration shall be identical to the one tested in clause 5.

• 1. Test Dust

The synthetic loading dust specified as L2 in ISO 15957 shall be used as the loading dust.

• 1. Dust Feeder

The dust feeder shall conform to the requirements specified in clause 7 of ISO 16890-3.

• 1. Dust loading

The dust loading test shall be conducted in accordance with the procedure specified in clause 9 of ISO 16890-3:2024 under controlled and standardized laboratory conditions

• • 1. Preparation of Test Apparatus

The test apparatus and environmental conditions shall comply with the specifications defined in this standard.

• • 1. Dust Injection

Dust shall be injected using a calibrated dust feeding system at a concentration of (140 ± 14) mg/m³. An initial load of 60 g of dust shall be supplied. If the filter resistance to air flow has not exceeded 50 % increase from the initial value then apply more dust until 50 % increase has been reached. The dust shall be uniformly distributed across the entire surface of the filter or antimicrobial treatment area.

• 1. Performance Evaluation After Dust Loading (AMIRE and MFMDE)

Upon completion of dust loading, the performance of the device shall be evaluated without delay using the methodologies specified in clause 9 (AMIRE) and Annex A (MFMDE) of this document.

The test results shall be documented as the antimicrobial efficiency after dust loading and shall be compared to the initial (pre-loading) performance to assess any degradation due to dust accumulation.

Bibliography

[1] ISO 3696, Water for analytical laboratory use — Specification and test methods

[2] ISO 5167‑1, Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 1: General principles and requirements

[3] ISO 29643 (all parts), High efficiency filters and filter media for removing particles in air

[4] AHAM AC-5-2022, Method for assessing the reduction rate of key bioaerosols by portable air cleaners using an aerobiology test chamber

[5] ISO 15714, Method of evaluating the UV dose to airborne microorganisms transiting in-duct ultraviolet germicidal irradiation devices

[6] ISO 16000‑36, Indoor air — Part 36: Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber

[7] IEC/PAS 63086‑3-1, Household and similar electrical air cleaning appliances — Methods for measuring the performance — Part 3-1: Method for assessing the reduction rate of key bioaerosols by portable air cleaners using an aerobiology test chamber

[8] ASTM E2720, Standard practice for evaluation of effectiveness of decontamination procedures for air-permeable materials when challenged with biological aerosols containing human pathogenic viruses

[9] ANSI/ASHRAE 185.1, Method of testing UV-C lights for use in air handling units or air ducts to inactivate airborne microorganisms

[10] ANSI/ASHRAE 52.2, Method of testing general ventilation air-cleaning devices for removal efficiency by particle size

[11] EPA, Generic Verification Protocol for Biological and Aerosol Testing of General Ventilation Air Cleaners

[12] World Health Organization (WHO), Laboratory biosafety manual, 4^th Edition, Geneva:2020

[13] Centers for Disease Control and Prevention (CDC), Biosafety in Microbiological and Biomedical Laboratories (BMBL), 6th Edition

[14] ATCC, Bacillus spizizenii (Nakamura et al.) Dunlap et al. 6633TM Product Sheet

[15] ATCC, Micrococcus luteus (Schroeter) Cohn 10240TM Product Sheet

[16] ATCC, Escherichia coli (Migula) Castellani and Chalmers 15597TM Product Sheet

[17] ATCC, Escherichia coli bacteriophage MS2 15597-B1TM Product Sheet

[18] ATCC, Aspergillus niger van Tieghem 6275TM Product Sheet