Tips for Mitigating Influenza in Commercial Buildings

With cold and flu season upon us, spending time reviewing your HVAC system, its major components, and air and water distribution is time well spent to help mitigate the spread of type A (H1N1) and other types of Influenza. Some of the precautions may be based on adopting simple common sense measures, while others are related to proper maintenance protocols. In addition, there are system upgrades that can be performed to help mitigate risks. Below is a list of tips to consider during cold and flu season:

  • Monitor facilities to ensure that no warm, stagnant water is present (which can provide an environment conducive to the growth of problematic microbes such as Legionella, the cause of Legionnaire’s Disease).
  • Monitor areas including cooling towers, pooled water on roofs, or clogged drains that can harbor unhealthy contaminants that can be introduced into the building and circulated by the air distribution systems into occupied spaces.
  • One simple change facilities can implement is to upgrade the efficiency of the air filters. As filter efficiency increases, typically their resistance to air flow also increases. Always check to 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 you intend to collect. Viral droplets or droplet nuclei of influenza, for instance, are very small but are typically surrounded by a mucus shell making them larger and easier to remove.
  • It is necessary to re-evaluate how and when filters should be changed. Rather than set a simple schedule, it may be more prudent to measure the pressure drop through filter banks and set up basic performance metrics to determine the best model for filter changes.
  • 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, properly fit respirators may help 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 dampers settings and operation. Most commercial spaces should operate at a slightly positive pressure relative to the outdoors to reduce the likelihood of contaminants infiltrating into the occupied areas.
  • Check and validate restroom and other critical area exhaust fans to assure they are removing contaminants from the building before they become mixed with the 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 of staff technicians and subcontract workers in how to work with your building systems to reduce risk and increase health and safety as well as reducing 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 whose primary function includes occupancy of guests, visitors, and the general public.
  • Encourage hand washing among all staff. If possible, add hand cleaner and hand sanitizer supplies at air handler locations, equipment controls, railings and access doors.

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

These tips have been provided by Trane (although the image at the beginning of the article was supplied by Cathy Aste).


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