ASHRAE 241 Standard Test | Control of Infectious Aerosols

Independent ASHRAE 241 Standard Test for Bioaerosols and Air Cleaning Technologies

Airmid Healthgroup specializes in the ASHRAE 241 standard test, providing manufacturers, developers, and regulators with independent, high-quality data on air cleaning system performance.

aerobiology chamber ASHRAE 241, infectious aerosols, airborne pathogens — GLP and ISO-accredited lab, with aerobiology chamber, purpose-built for ASHRAE 241 testing to evaluate airborne pathogen reduction and infectious aerosols for risk management.

ASHRAE 241 Standard Test Method: Key Requirements

ISO 17025 Compliant Testing: Airmid Healthgroup operates under ISO/IEC 17025 accreditation principles, ensuring rigorous quality control.
Biosafety Standards: All bioaerosol testing is conducted following CDC/NIH Biosafety in Microbiological and Biomedical Laboratories (BMBL) guidelines.Non-Pathogenic Surrogates: We utilize safe, EPA/ASHRAE-approved surrogate microorganisms like MS2 bacteriophage to model airborne virus removal.
Advanced Bioaerosol Chambers: Testing takes place in precisely controlled bioaerosol exposure chambers, designed to replicate real-world indoor air conditions.
Standardized Environmental Parameters: Temperature (70-75°F), humidity (50-60%), and sampling protocols meet ASHRAE 241 specifications.
Triplicate Sample Plating: ASHRAE 241 requires at least three replicates per test condition (system OFF vs. system ON), ensuring statistical reliability.

How We Conduct ASHRAE 241 Testing

Chamber Preparation: The bioaerosol chamber is thoroughly disinfected before testing.
Microbial Aerosolization: A known concentration of test microorganisms is aerosolized into the chamber under controlled conditions.
Baseline Air Sampling: Initial air samples are collected to determine microbial concentration before the air cleaning system is activated.
Air Cleaning System Activation: The test system is turned on, and air samples are taken at key time points (e.g., 5, 10, 15, and 30 minutes).
Sample Analysis & Enumeration: Samples are analyzed to measure microbial reduction and determine ASHRAE 241 equivalent clean airflow rate (V-ACS).
Control Runs: Identical tests are performed without the air cleaning system to establish baseline natural decay rates.

Get Your Air Cleaning System ASHRAE 241 Tested

ASHRAE 241, infectious aerosols, airborne pathogens, aerobiology test chamber — Lab researcher in full PPE evaluating MS2, bacteriophage, for ASHRAE 241 evaluation of infectious aerosols and airborne pathogens.

Ensure your air cleaning system meets ASHRAE 241 performance standards with Airmid Healthgroup’s expert testing services.

Industry Leadership and Collaboration on ASHRAE 241 Test Standard

Members of ASHRAE 241 review process, ASHRAE 185, and the Environmental Health Committee
Members of ISO air cleaner committees
Members of IEC air cleaner committees
Working closely with AHAM on AC-5 testing
Endorsed by patient organizations such as the Asthma & Allergy Foundation of America (AAFA) and ECARF
An accredited laboratory for the Verified Healthier Air program
Strong network of leading academics, medical schools, and applied research centers with high-impact publications
www.iAIR.Institute, a 501(c)(6) in Washington, DC
Working on ARPA-H BREATHE project

Why Choose the iAIR Group for your ASHRAE 241 Test

Proven Expertise in Bioaerosol Testing: With a strong history in aerobiology research, we offer deep scientific expertise in airborne pathogen studies.
Trusted by Industry Leaders: We work with HVAC manufacturers, building developers, and regulatory agencies to validate air cleaning technologies.
Independent & Accredited: As an ISO 17025-accredited laboratory, our testing meets the highest standards of accuracy and reproducibility.
GLP-based projects
Aerobiology Infection Control Chambers and Allergen Exposure Chambers (AECs)
Bio-safety Level 2 testing, including Flu-Virus, bacteria, and mould testing
Pre-clinical and clinical studies, CRO network
Facility for digital twins, computational fluid dynamics, and AI mathematical models to enhance real-time chamber testing

ASHRAE 241 Test Standard: Ensuring Healthier Indoor Environments

ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers) develops industry standards that shape the performance of HVAC and air cleaning systems. ASHRAE Standard 241 establishes a test method for biological aerosol removal and defines the minimum equivalent clean air requirements to reduce airborne disease transmission in indoor environment.