ANSI/ASHRAE 185.1-2020: Test Method for UV-C Disinfection in Air-Handling Units and Air Ducts
The ANSI/ASHRAE 185.1-2020 standard defines a test method for evaluating UV-C technologies in HVAC systems to determine their effectiveness in inactivating airborne microorganisms. Airmid Healthgroup provides independent, accredited testing to this standard, with over a decade of experience evaluating in-duct air purification technologies.
Scope of ANSI/ASHRAE 185.1-2020
The standard outlines key parameters for testing UV-C disinfection systems in air-handling units (AHUs) and HVAC ductwork, including:
- Bioaerosol generation techniques
- Upstream and downstream air sampling for microbial analysis
- Environmental and airflow conditions necessary for standardised testing
At Airmid Healthgroup, we have over a decade of experience testing a wide range of in-duct air purification technologies, including:
- HEPA filters
- Electrostatic filtration
- UV-C disinfection systems
- Photocatalytic oxidation (PCO)
- Plasma-based air purification
Our testing capabilities cover a broad spectrum of contaminants including viruses, bacteria, mould, allergens, and volatile organic compounds (VOCs).
Test Overview
The ANSI/ASHRAE 185.1-2020 standard provides a rigorous test method to assess the effectiveness of UV-C lights in inactivating airborne microorganisms when installed in air-handling units or HVAC ductwork. The test simulates real-world conditions by introducing bioaerosols into a controlled test duct, where UV-C exposure is evaluated under defined airflow and environmental conditions.
How the ANSI/ASHRAE 185.1-2020 Test Works
- Test Duct Configuration: A sealed, controlled test duct is used — typically based on an ASHRAE 52.2 test rig or a customised duct system — allowing precise control of airflow, temperature, and humidity. The duct is equipped with a UV-C disinfection system positioned according to the manufacturer’s specifications.
- Bioaerosol Generation: Live airborne microorganisms (such as bacteria, viruses, or mould spores) are introduced into the duct using a nebuliser or bioaerosol generator. Target bioaerosols are selected based on standard pathogenic models or customised based on the client’s product claims.
- Airflow & Environmental Conditions: Airflow rates are set to mimic HVAC operational conditions, ensuring a realistic residence time for UV-C exposure. Temperature and humidity levels are monitored and controlled throughout, as these factors influence microbial viability and UV-C efficacy.
Our ANSI/ASHRAE 185.1-2020 Testing Capabilities
We conduct standardised and customised evaluations using our modified ASHRAE-type recirculation duct, designed to accommodate:
Single-Pass Testing
Evaluates immediate filtration and disinfection performance in a single air pass through the UV-C system.
Multi-Room Recirculation Testing
Simulates real-world performance across recirculating air systems to reflect conditions found in actual buildings and HVAC installations.
Custom Duct Configurations
Tailored duct setups designed to match specific product designs, installation configurations, and application environments.
Why Test with Airmid Healthgroup?
- Expertise in Microbiology & Aerobiology — we specialise in evaluating airborne contaminants and their interaction with HVAC technologies
- Custom Test Design — in addition to ANSI/ASHRAE 185.1-2020 compliance, we develop bespoke testing protocols to meet the unique needs of your product
- Industry Credibility — our results support product validation, regulatory submissions, and market claims for manufacturers worldwide
Partner With Airmid Healthgroup
We can test your product in full compliance with ANSI/ASHRAE 185.1-2020, or collaborate with you to develop a customised evaluation that aligns with your specific goals. Contact us today to discuss your testing requirements.
Frequently Asked Questions
What is ANSI/ASHRAE 185.1-2020 and what does it test?
ANSI/ASHRAE 185.1-2020 is an industry standard that defines the test method for evaluating the effectiveness of UV-C light systems installed in air-handling units and HVAC ductwork. It measures how well UV-C technology inactivates airborne microorganisms — including bacteria, viruses, and mould spores — under controlled, standardised conditions.
What types of UV-C systems can be tested to ANSI/ASHRAE 185.1-2020?
The standard applies to UV-C disinfection systems installed within air-handling units and HVAC ductwork. This includes in-duct UV-C lamps, UV-C modules integrated into AHUs, and combination systems that pair UV-C with other technologies such as HEPA filtration or photocatalytic oxidation.
What microorganisms are used in ASHRAE 185.1-2020 testing?
Standard pathogenic models are used as test organisms, with the specific microorganisms selected based on the product’s intended application and claims. Airmid can also customise the test organisms used to reflect the specific pathogens most relevant to your product’s target environment or market.
Why do temperature and humidity matter in UV-C testing?
Both temperature and relative humidity affect microbial viability and the efficiency of UV-C disinfection. Testing under controlled environmental conditions ensures that results are reproducible and accurately reflect performance under realistic HVAC operating conditions — rather than ideal laboratory conditions that may not reflect real-world use.
Can Airmid develop a custom test protocol for my UV-C product?
Yes. In addition to standard ANSI/ASHRAE 185.1-2020 testing, Airmid develops bespoke evaluation protocols for products with unique configurations, combination technologies, or specific application environments. Contact our team to discuss your product and testing requirements.
