Recently a swim school facilities owner contacted Desert Aire to ask about ventilation of indoor pools and air quality in light of COVID-19. The owner wanted to know if any changes in their pool dehumidification system were needed to maintain or improve indoor air quality of the pool room to help prevent the spread of COVID-19 and the potential risk to swimmers.
To answer this facility owner’s question, let’s take a closer look at indoor pool ventilation in a typical indoor pool room.
Local authorities establish the rules on opening indoor pool facilities and nationally the rules are very inconsistent. Each swim facility owner or manager needs to consult and follow local authorities’ rules that govern its facility.
Desert Aire team members have served on several indoor pool facility ventilation committees, including the CDC’s Model Aquatic Health Code and have kept current on the on-going discussion of the impact of COVID-19 on indoor pools. We've kept up to date to respond to the question, "Are indoor pools safe during COVID-19?"
The following is from the CDC’s “Considerations for Public Pools, Hot Tubs, and Water Playgrounds During COVID-19” regarding ventilation from the CDC.gov website updated July 15, 2020.
There is no evidence that COVID-19 can be spread to humans through the use of recreational waters. Follow safe swimming practices along with social distancing and everyday preventative actions to protect yourself.
As public aquatic venues open in some areas, the CDC offers the following considerations for the safety of those who operate, manage, and use public pools, hot tubs, and water playgrounds.
Maintaining Healthy Environments
To maintain healthy environments, operators of public aquatic venues may consider:
- Ensuring that ventilation systems of indoor spaces operate properly.
- Increasing introduction and circulation of outdoor air as much as possible by using a 24-hour ventilation cycle rather than just during occupied hours.
- However, do not open windows and doors if doing so poses a safety risk to staff, patrons, or swimmers.
ANSI/ASHRAE Standard 62.1
One aspect of the realities of how indoor pools are ventilated is air turnover rate. The guide that mechanical engineers use to determine how much ventilation air the dehumidification equipment for an indoor pool must be designed for is ANSI/ASHRAE Standard 62.1-2020: Ventilation for Acceptable Indoor Air Quality. This ASHRAE swimming pool ventilation standard is updated every three years and is adopted as is by the International Building Codes.
Indoor swimming pools are required to have a very high ventilation rate to assist in removing the byproducts of the chlorine that is added to the pool water.
Compare the ventilation rate of an indoor pool area with 3 other building types:
· 8 times more than an office space
· 4 times more than an elementary classroom
· 2.6 times more than a science laboratory
In fact, there is no other building type listed in the standard that comes close to the required ventilation rate of an indoor pool. In general, swimmers and coaches are at more risk in other approved buildings than an indoor pool, due to the high ventilation rate requirements of an indoor pool facility. In addition, as mentioned above, the CDC indicated that pool water itself will not support the COVID virus due to the level of chlorine content required by code. The COVID risk to swimmers indoors is low.
In addition to ventilation, indoor pool humidity control is another consideration to maintain good indoor air quality and pool user health. Studies have shown that relative humidity between 40-60% is ideal to create a healthy indoor space and minimize the spread of airborne viruses (see Sterling Chart courtesy of 40to60rh.com).
Indoor pools are designed with HVAC systems to maintain air humidity within this range. Proper air handling for indoor pools helps ensure healthy, appealing places to have fun, compete and maintain good health.
For more information about selecting dehumidification units to achieve a desired ventilation requirement, see our Technical Bulletin 5 “Ventilation Air for Indoor Pools” or see our Technical Bulletin 9 "Interaction of Pool Water and Air Chemistry”
You can contact Desert Aire at www.desert-aire.com/contact or go to www.desert-aire.com/find-a-tech to find a local service technician in your area, or submit a service request at www.desert-aire.com/dehumidifier-service/repair.
Desert Aire extends thanks to Counsilman-Hunsaker for collaborating on this blog. View the Counsilman Hunsaker video: “CHAirQuality: How does air quality play a part in the overall condition of a facility?”