ASHRAE Journal - April 2024 - 20

COLUMN INFECTIOUS AEROSOL CONTROL
TABLE 1A Maintenance schedule changes between normal mode and IRMM for ventilation systems.
MINIMUM FREQUENCY IN
Check Filter Pressure Drop
Check P-Traps
Visually Inspect OA Intake
Verify Operation of Natural Ventilation Controls
Verify Operation of Mechanical Ventilation Controls
Check Filter Fit and Seal
Check for Proper Damper Operation
Verify Accuracy of Sensors That Control Outdoor
Airflow
Verify Minimum Outdoor Airflow
NORMAL MODE (PER 62.1/180)
Quarterly
Quarterly
Semiannually
Semiannually
Annually
Annually
BRIEF SUMMARY OF VENTILATION SYSTEM INSPECTION
TASKS IN STANDARD 241
MINIMUM FREQUENCY IN IRMM
Quarterly or When Replaced
Monthly
Monthly
Monthly
Quarterly
Annually or When Replaced Annually or When Replaced
Quarterly
Every 5 Years
Every 5 years
NORMAL MODE MINIMUM
FREQUENCY AND TASK
Ultraviolet (UV) Germicidal Irradiation
All Air Cleaning Systems
Separation Space
Semiannual Test
Semiannual Test
Semiannual Test
Semiannual Test
Every 2 Years
Every 3 years
TABLE 1B Maintenance schedule changes between normal mode and IRMM for additional engineering controls.
TYPE OF ADDITIONAL ENGINEERING CONTROL
IRMM MINIMUM FREQUENCY AND TASK
(BRIEF SUMMARY)
In-Room Air Cleaners
Monthly, Verify Location and Operating Setting
Quarterly, Verify Performance
Quarterly, Verify Performance
As Used, Test Negative Pressure
systems must receive more frequent attention.
Inspection tasks and frequencies are based on existing
requirements in ASHRAE Standards 180-201811 and
62.1-2022, with new requirements for engineering
controls like IRACs and UV. Tables 1A and 1B illustrate
maintenance interval differences between normal
mode and IRMM. Upon a transition to IRMM, any
tasks that have not been performed recently enough
to satisfy the IRMM maintenance interval must be
addressed. For example, ASHRAE Standard 62.12022
requires verifying the operation of ventilation
controls annually, while Standard 241 requires this
inspection quarterly in IRMM. When our example
school transitions to IRMM, it must be verified that
ventilation controls are operating properly if that
task has not occurred in the last three months. If the
school chooses to provide VECAi with IRACs, they must
be checked monthly for correct location, operating
setting and any airflow obstructions.
Building Readiness Plan
Documenting how your equipment will operate
and be maintained in IRMM is critical to ensuring
facility readiness for high infection risk. This concept
of documentation in a Building Readiness Plan
(BRP) is not new; it evolved from a recommendation
20
ASHRAE JOURNAL ashrae.org A P R I L 2024
in ETF guidance into a
fundamental requirement in
Standard 241. All engineering
and non-engineering controls
that will be used in IRMM,
including the operating
parameters and maintenance
schedules to achieve VECAi,
must be detailed in the BRP
(Section 8.1), and updated
as buildings and systems are
modified. A Building Readiness
Plan Template (Informative
Appendix E) will help users start
the documentation process. The
Standard 241 Committee will
continue to develop tools to assist
users, so they can more easily
assess, operate and maintain
HVAC systems that are ready to
reduce the risk of infection.
References
1. ASHRAE Standard 241-2023, Control of Infectious Aerosols.
2. ASHRAE. 2023. " Equivalent Clean Airflow Calculator. " ASHRAE
Standard 241-2023, Control of Infectious Aerosols. ASHRAE. https://
tinyurl.com/4avfafp9
3. ANSI/ASHRAE Standard 62.1-2022, Ventilation and Acceptable
Indoor Air Quality.
4. ASHRAE. 2021. " Building Readiness " ASHRAE Epidemic Task
Force. ASHRAE. https://tinyurl.com/4a2962b8
5. Santarpia, J.L., D.N. Rivera, V.L. Herrera, et al. 2020. " Aerosol
and surface contamination of SARS-CoV-2 observed in quarantine
and isolation care. " Sci Rep 10:12732. https://doi.org/10.1038/s41598020-69286-3
6.
Bushmaker, T., C.K. Yinda, D.H. Morris, M.G. Holbrook, et al.
2023. " Comparative aerosol and surface stability of SARS-CoV-2
variants of concern. " Emerg Infect Dis. 29(5):1033-1037. https://doi.
org/10.3201/eid2905.221752
7. ASHRAE. 2021. " Core Recommendations for Reducing Airborne
Infectious Aerosol Exposure. " ASHRAE Epidemic Task Force.
ASHRAE. https://tinyurl.com/2m9bmtd7
8. U.S. GAO. 2020. " Report to Congressional Addresses-K- 12
Education: Schools Districts Frequently Identified Multiple
Building Systems Needing Updates or Replacement. " GAO-20-494.
United States Government Accountability Office.
9. Katipamula, S., R. Underhill, N. Fernandez, W. Kim, et al. 2021.
" Prevalence of typical operational problems and energy savings
opportunities in U.S. commercial buildings. " Energy and Buildings
253:111544. https://doi.org/10.1016/j.enbuild.2021.111544
10. Katipamula, S. et al., 2020. " Improving Commercial Building
Operations Through Building Re-Tuning: Meta-Analysis (Updated
2020). " Pacific Northwest National Laboratory. https://tinyurl.com/
yh8xasrv
11. ANSI/ASHRAE/ACCA Standard 180-2018, Standard Practice for
Inspection and Maintenance of Commercial Building HVAC Systems.

http://tinyurl.com/4avfafp9 http://tinyurl.com/4avfafp9 https://tinyurl.com/4a2962b8 https://doi.org/10.1038/s41598-020-69286-3 https://doi.org/10.1038/s41598-020-69286-3 https://doi.org/10.3201/eid2905.221752 https://doi.org/10.3201/eid2905.221752 https://tinyurl.com/2m9bmtd7 https://www.doi.org/10.1016/j.enbuild.2021.111544 https://tinyurl.com/yh8xasrv https://tinyurl.com/yh8xasrv http://www.ashrae.org

ASHRAE Journal - April 2024

Table of Contents for the Digital Edition of ASHRAE Journal - April 2024