What precaution is necessary when installing ultrahigh efficiency filters?

What precaution is necessary when installing ultrahigh efficiency filters?

• A. They must not be installed upside down
• B. They must bypass primary air
• C. They must be grounded
• D. They must be sealed around the edges to prevent air leakage

Answer: (D)

The key idea is that the edges of ultrahigh efficiency filters must be sealed to prevent air from bypassing the filter media. When there are gaps around the perimeter, some of the airstream can flow through these gaps rather than through the filter material, dramatically reducing the overall effectiveness of the filtration. A proper seal around the edges ensures the entire airflow passes through the filter, preserving the rated efficiency and preventing unfiltered air from reaching occupied spaces. The other considerations—orientation, bypassing primary air, or grounding—are not the essential precaution for achieving the filter’s performance; sealing around the edges is the critical step.

The key idea is that the edges of ultrahigh efficiency filters must be sealed to prevent air from bypassing the filter media. When there are gaps around the perimeter, some of the airstream can flow through these gaps rather than through the filter material, dramatically reducing the overall effectiveness of the filtration. A proper seal around the edges ensures the entire airflow passes through the filter, preserving the rated efficiency and preventing unfiltered air from reaching occupied spaces. The other considerations—orientation, bypassing primary air, or grounding—are not the essential precaution for achieving the filter’s performance; sealing around the edges is the critical step.