California is notorious for wildfires, and as fire season approaches we are often asked, “What do we do when there is a local fire, should we shut down our building or continue operating as usual?” Well, here are 5 key tips to managing your building in the event of a wildfire:
- DO NOT TURN OFF HVAC SYSTEM! There is a common misconception that turning off the air handling units or shutting outside air intakes will reduce smoke and pollutant migration into the building. However, this will actually bring you building under a negative pressure and allow for unfiltered, much dirtier air to enter the building through doors and any other pathways into the building. Reducing the outside air dampers to their minimum set-points is fine as long as care is taken to ensure the total CFM of outside air is greater than the total CFM of exhaust for the building to maintain a positive overall pressure.
- FILTRATION IS KEY. Ensure that all filters are well fitted and not allowing for any air bypass into the air handling units. Consider adding temporary pre-filters where you can but make sure the system can handle the added pressure drop. Tackified polyester media filters typically work well for this purpose. Also, while excessively dirty filters should be changed, remember that filters that have a light loading of dust/dirt actually work more efficiently at removing pollutants from the air. Additional, supplemental air cleaners can also be placed in the building, especially in more sensitive spaces, to provide additional filtration. HEPA air scrubbers with carbon filters typically work best. These can usually be supplied by your remediation contractor.
- HOUSEKEEPING. Consider increasing the housekeeping frequency to remove settled dusts from occupied spaces. i.e. both before and after occupancy each day.
- THERE IS NO SAFER PLACE THEN INSIDE THE BUILDING. Generally speaking of course. Point being that, all things being equal, pollutant levels will be much lower in well managed commercial office buildings with much more efficient filters than in people’s homes, vehicles, outdoors, etc.
- CONTACT HEALTHY BUILDINGS TO “CLEAR THE AIR”. (shameless plug, but seriously…). We conduct many emergency response IAQ assessments for clients to help ensure work places are safe for occupancy. We have the instrumentation to provide real-time measurements for the common pollutants associated with wildfires to include respirable dust, carbon monoxide, formaldehyde, volatile organic compounds, and carbon dioxide to ensure adequate ventilation. We also conduct qualitative checks of the building differential pressure to the outdoors, inspect HVAC and filtration, and can collect samples for mold spores and allergenic particles with a quick turn around on the analysis (airborne mold spore counts actually increase in the event of a wildfire believe it or not). This can be done either during the times of greatest impact from the wildfire, as a means of post-verification after the fires subside, or both.
It should be noted that these tips are for buildings that are impacted by the pollutants associated with wildfires as they relate to air quality and occupant exposure. Of course there are evacuation and safety measures that should be considered in the event that a building is more severely impacted or “in the line of fire” shall we say. You can also find some helpful information here: https://www.osha.gov/dts/wildfires/, and http://www.epa.gov/wildfire/.