Maintaining Indoor Environmental Quality for a Healthy & Safe Holiday Travel Season
By Tim Visutipol
As we head into the holiday season, it is inevitable that there will be an increase in travel despite COVID-19 travel warnings. Some holiday travelers may choose to stay with family while others may choose a hotel. Whether this holiday season is used visiting family or vacationing, hotels will need to ensure a safe and healthy environment for their guests and staff. The CDC has recently issued guidance on how to protect hotel staff and guests from COVID-19 transmission.
Hotel guests can also play an active role in protecting themselves and others by opening windows, sanitizing high-touch objects in their room, and avoiding shared public spaces such as elevators and common areas. The American Hotels & Lodging Association’s hotel guidelines and The Wall Street Journal’s recent article on travel tips are just a few of the many resources available to assist with traveling during a pandemic.
However, what is less apparent, as well as less visible, is the importance of maintaining and monitoring a hotel’s indoor air quality. Even though hotel guests will not see HVAC filters or the amount of fresh outside air being brought into a hotel, an optimized HVAC system can help to mitigate the transmission of COVID-19.
While the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has not specifically issued guidelines for the hospitality sector to mitigate the spread of COVID-19, there are many strategies and tactics that can be utilized from their published commercial and residential building guidelines.
First and foremost, ASHRAE recommends all commercial buildings conduct a thorough HVAC system evaluation of all major equipment and maintenance. It is crucial that operators are able to control the building as it was originally designed while automating their responses to mitigate system downtime. While a physical inspection is always a good first step, monitoring system data, such as ongoing commissioning programs, would enable automated alerts and increase situational awareness. Whenever necessary conditions, such as airflow setpoints or commanded damper positions, are not met the proper action can then be immediately taken.
Figure 1: Monitoring Air Flow and flagging units not meeting setpoint
The next consideration is air ventilation. While there can be a combination of passive or mechanical ventilation depending on the building’s design and climate, the general recommendation is to always allow the highest possible amount of outside air to enter the building. This is done to increase the air changes per hour and dilute the indoor air. However, with cold winter weather, high amounts of outside air may not be a viable solution during the winter. Other metrics such as CO2 or occupancy levels may be better suited for regulating ventilation in colder climates.
In regards to air filtration, ASHRAE recommends upgrading HVAC filters to MERV-13 or the highest rating the system can accommodate. Data monitoring of active systems can then be used to ensure static pressure and flows are adequate after any filter changes. Building teams typically install a small number of new filters to test the equipment capacity before deploying new filters across the entire HVAC system. A further filter consideration would be using standalone air purifiers in high traffic hotel common areas or in guestrooms where MERV-13 filters may not be an option.
Figure 2: Supply Fan Points after Filter replacement compared to the prior week (Dotted Lines)
As always, it is essential to maintain thermal comfort with recommended humidity levels between 40% and 60%. With colder weather and increased ventilation, hotels are likely to see higher energy consumption this winter, especially as internal heat in the building may decrease due to fewer hotel guests and events. Automated BAS/HVAC systems monitoring and analysis can be used to not only optimize comfort conditions but also to identify opportunities to improve energy efficiency while alerting teams of real-time system anomalies.
Figure 3: Monitoring Return Air Humidity and flagging units out of the recommended range
By following these general guidelines and using data already available to building operators, hotels can ensure the best possible environment for their guests and staff during this holiday season.
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