There are several environmental and facility level engineering controls that can be employed to help mitigate transmission risk. These operational improvements are often industry specific and reflect the lessons we have learned together and shared through the CWA's community calls and conversations with operators around the world.


The American Society of Heating, Refrigerating and Air-Conditioning (ASHRAE) has made the following statement: "Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures. Ventilation and filtration provided by heating, ventilating, and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air. Unconditioned spaces can cause thermal stress to people that may be directly life threatening and that may also lower resistance to infection. In general, disabling of heating, ventilating, and air-conditioning systems is not a recommended measure to reduce the transmission of the virus." (22) Climbing gyms are often set up with excellent ventilation systems to handle the difficult enviromental challenges faced by stratification, large voluminous spaces, and chalk dust. ASHRAE has made a set of actionable suggestions on how to optimize your HVAC system to minimize transmission risk in your facility. Their full set of mitigation suggestions contains a wealth of knowledge but the most immediate steps you can take are to:

  • Consult with your HVAC engineer or facilities team to review your control systems
  • Consider replacing your physical filters with at least MERV 13 or 14 filters. Make sure that your system can handle the increased pressures of such filters.
  • Make sure your system is using as much outside air as possible. This may involve resetting the dampers on your system, or if you have an automated system a reprogramming of your automation. In either case it is best to consult with an HVAC engineer to make sure that your system can accomodate these changes.
  • Reduce recirculation of air as much as possible. For simple systems this may be as adjusting your dampers to use mroe outside air, for more complex systems consult with an HVAC engineer.
  • There are a number of disinfection modules that can be added to HVAC systems. UVC filters have been demonstrated to be effective for coronaviruses other than SARS-COV-2 and may be a good option. Pay attention to the replacement costs and life span of the UV bulbs. Bipolar ionizers may be effective, but there is not as much documentation to support their effectiveness.
It is important to note that all of these measures will reduce the efficiency of HVAC systems, increase some of your costs, and require more energy. While none of those outcomes are desirable the increased risk mitigation carries significant value.


As we move through the COVID-19 pandemic we are constantly learning more and many of the local guidance you have to pay attention to may evolve. The capcity limits, allowed open hours, and rules that you see from your local health authorities may change at any time. It is important to note that many of the people writing these guidelines do not know what an indoor climbing gym looks like or how it operates. You can advocate for yourself and write letters to your local department of health, elected representatives, and other areas of government that are creating these guidelines. The CWA is here to help support you with these efforts. If you need assistance making suggestions on the reopening guidelines that you are navigating email info@climbingwallindustry.org for immediate help. We have seen groups of gyms in several states and provinces successfuly influence the rules that they are required to follow by providing information about what risks are present in climbing gyms and how our industry is uniquely suited to handle risky situations.