Tips for Mitigating Influenza in Commercial Buildings

With cold and flu season coming up, spending time reviewing HVAC systems and their major components as well as air and water distribution can help mitigate the spread of type A (H1N1) and other types of influenza. Adopting simple common-sense measures, following proper maintenance protocols, and performing upgrades can reduce risks.

Following is a list of tips to consider during cold and flu season:

• Monitor facilities to ensure that no warm, stagnant water is present as it can provide an environment conducive to the growth of problematic microbes, such as Legionella, which causes Legionnaire’s disease.

• Monitor areas, such as cooling towers, pooled water on roofs, and clogged drains, that can harbor unhealthy contaminants that can be introduced into a building and circulated by air-distribution systems into occupied spaces.

• One simple upgrade facilities can implement is to upgrade air-filter efficiency. As filter efficiency increases, airflow resistance also increases. Be sure the fan system can handle the resistance being imposed by the filters and other components in the system. Also, select replacement filters based on the specific particles being collected. Viral droplets or droplet nuclei of influenza, for instance, are very small but typically are surrounded by a mucus shell, making them larger and easier to remove.

• It may be necessary to re-evaluate how and when filters should be changed. Rather than use a simple schedule, it may be prudent to measure pressure drop through filter banks and set up basic performance metrics to determine the best filter-change model.

• Simple measures are the first line of defense. Technicians should wear cut-resistant gloves when performing filter changes or basic maintenance to air dampers and commonly exposed system components. Also, respirators should be fit properly to ensure that the risk of exposure while working above the ceiling or in poorly ventilated areas is minimized.

• A common service and maintenance procedure is to verify correct outside-air intake-damper settings and operation. Trane recommends that most commercial spaces operate at a slightly positive pressure relative to the outdoors to reduce the likelihood that contaminants will infiltrate into occupied areas.

• Check and validate restroom and other critical-area exhaust fans to ensure they are removing contaminants from the building before they become mixed with indoor air. Perform preventive maintenance on small exhaust fans to ensure they have not accumulated dirt, reducing their effectiveness.

• Provide staff with basic training and increase overall awareness about the risks of influenza exposure and the likely ways to contract the virus. Also, conduct formal training with staff technicians and subcontract workers regarding how to work with building systems to reduce risk and increase health and safety as well as reduce exposure to other harmful airborne particles.

• Direct contact is the most common pathway for the spread of disease. Communicate influenza safety tips and precautions to all building departments—especially those that primary function includes visitor occupancy.

• Encourage hand washing among staff. If possible, add hand-cleaner and sanitizer supplies at air-handler locations, equipment controls, railings, and access doors.

Additional Resources
There are many resources to provide details and more complete planning recommendations, including:

• IFMA Foundation’s Pandemic Preparedness Manual (

• The Center for Disease Control and Prevention (

• The Federal Emergency Management Agency (

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