Bushfire Smoke & Commercial Buildings
Air filtration within commercial buildings typically includes both outside air and recirculated air handling systems to ensure air quality for building occupants. On days of poor air quality such as when bushfire smoke is present, the focus should be on improving air filtration of outside air handling systems (rather than recirculated air handling systems) to improve air quality for building occupants.
C
ommercial buildings are required to provide a constant flow of outside air to the inside of commercial buildings via outside air handling systems. If the air filters are not of a high enough efficiency to remove smoke particles, this will lead to a significant amount of smoke being noticed inside buildings. Smoke is one of the most difficult particles sizes to catch as it is 0.3 - 0.5 microns in size. Smoke fits within the PM2.5 category (which are particles with a diameter of 2.5 micrometres or less). These particles are so small they can get deep into the lungs and into the bloodstream, affecting the heart and lungs and potentially causing serious health effects.
TECHNICAL
Jonathan Bunge (M.ENG Chemical) and Shannon Roger (B.Ed) I Airepure Australia 2020
Bushfires produce smoke particles, which can be removed from the air stream within commercial HVAC systems using appropriately efficiency rated particulate air filters – which target and capture the smoke particles. Refer to table below. In addition to smoke, bushfires also produce odourous gases such as oxides of nitrogen (NOx) and volatile organic compounds (VOC). These odourous gases are often bound to smoke particles, which means that a significant amount of them can be removed along with the smoke with effective particulate filtration.
How to eliminate the presence of bushfire smoke in commercial buildings
To eliminate the presence of bushfire smoke and odour within commercial buildings via existing HVAC systems, an upgrade of the particulate air filters within outside air handling systems is the most important factor, followed by the addition of gaseous (carbon) filters. The particulate air filters (of appropriate efficiency) will capture the majority of the smoke particles and the odour attached to the smoke particles. This will improve air quality for building occupants. The addition of the gaseous filters placed after the particulate air filters will adsorb the remaining odourous gases. Please Note: A gaseous (carbon) filter alone will not remove smoke particles. A particulate air filter (of appropriate efficiency) is required to capture the majority of the smoke particles and the odour attached to the smoke particles.
How to reduce the presence of bushfire smoke in commercial buildings Odour Filters
To reduce the presence of bushfire smoke and odour within commercial buildings via existing HVAC systems, an
65
