During a wildfire, commercial buildings face significant drawbacks from poor indoor air quality (IAQ) caused by smoke, which can cause damage to property and equipment, and health issues for occupants.

During these events, a building’s best asset is its HVAC system. Not only does it keep the inside air cool, but it also provides clean air through the reuse of indoor air. Keeping your HVAC system functioning optimally requires preparation before and maintenance following the wildfire.

In this blog post, we illustrate how smoke affects indoor air quality and the steps to take to ensure your HVAC system functions properly before and after a fire advisory.  


How Does Smoke Affect IAQ? 

Depending on your building’s proximity to a wildfire and the density of the smoke, a wildfire can impact your IAQ differently. 

Your primary concern is the impact of the fine particles on a building’s interior, occupants and equipment. These fine particles can enter your building in the following ways:

  • Natural ventilation of open windows and doors
  • Mechanical ventilation devices, such as bathroom or kitchen fans that vent to the outdoors or HVAC systems that have a fresh air intake
  • Infiltration, when particles enter through small openings, joints, cracks and around closed windows and doors

With an overabundance of smoke particles, your IAQ can quickly degenerate, causing:

    • Odor infiltration, which occurs when smoke particles become infused in ceiling tiles and soft fabrics, creating unpleasant odors
  • Health issues when particles enter the eyes or respiratory system, causing burning eyes and runny nose, as well as illnesses, such as bronchitis; fine particles also can aggravate chronic heart and lung diseases, which can potentially be fatal to those affected
  • Damage to HVAC systems if enough ash and soot clog the ducts and coils, causing the system to overwork and motors to fail

To avoid infiltration, ventilation should be closed off and an inspection should be conducted to ensure that smoke is not entering small openings.

How to Prepare Your Facility for a Wildfire 

Successful preparation for a wildfire is contingent upon optimally functioning HVAC systems, precooling the building the day of the wildfire and clear communication with the occupants. 

Investment in Filters and Coil Cleaning Solutions 

Replace the filters, even if they have been replaced within the last few months. Because your HVAC system will filter in so many smoke particles, a brand new filter will capture more fine particles in the air, especially with high-performing filters, such as the Merv 8 and Merv 13 filters.

Similarly, a significant amount of smoke particles will build up in your HVAC system coils, and preliminary coil cleaning rids the coil of prior build-up from normal functioning. If the coils become overloaded with soot, they can cause false temperature readings, which can offset the interior temperature of the building. 


On the day of the wildfire, your engineers should execute a process called “precooling” that establishes a cooling mass. Doing so keeps temperatures cool while taking in the least amount of outside air.

Recirculating the inside air helps keep a high IAQ. However, cooling a building with inside air is more difficult, so precooling begins early in the morning, before external temperatures increase. 


Precooling often creates especially cold spaces during the morning. To avoid calls reporting the cooler temperatures, provide a clear line of communication with building occupants through text, email and phone calls. Inform them of the day’s procedures and the necessity of precooling to keep them safe.

 Interested in learning more? Request a quote!

HVAC System Maintenance After a Wildfire 

Because the smoke from a wildfire requires so much work from your HVAC system, your engineers should perform an inspection that looks similar to a quarterly maintenance inspection. This inspection should include: 

  • Changing filters again if the filter is too clogged; this can cause the motor to burn out
  • Performing a visual inspection to ensure no immediate or long term issues arise, such as corrosion and the beginning stages of rust
  • Cleaning ducts to remove lingering soot and dust 
  • Treating cooling tower condenser systems, which have an open loop system and will experience soot and ash build-up; treating the water with chemicals avoids draining the pipes, which is a significant cost 

Does preparing your commercial building for a wildfire seem like a daunting set of tasks? We have the right team for you.

Work with the Seasoned Engineers of Able Services 

In partnership with Able Services, we will perform preliminary and post-fire maintenance on your HVAC system to ensure your air quality is suitable and your equipment is in functioning shape, so you can keep your occupants safe and comfortable. 

The last few wildfire seasons have not been easy, so it’s more important than ever that your assets are operated and maintained by highly trained engineers, led by seasoned chief engineers with years of experience preparing facilities for wildfires.

Ready to take the first step with Able Services? Request a quote today.

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