This is a legacy version of the WELL Building Standard. Please check the latest version here.

Air filtration

Air filtration


To remove indoor and outdoor airborne contaminants through air filtration.

This requirement is applicable to unconditioned and non-regularly occupied spaces, unless it can be shown that the air from these areas cannot migrate to other spaces. This requirement is not applicable to spaces with no direct supply air from the outdoors with direct exhaust (no recirculation) to remove internally generated particles.

For Part 1, if the fan coil units are strictly local recirculation within a single ventilation zone (which may be different than a thermal zone) then Part 1 would not be required to be met at the fan coil unit. If the fan coils serve multiple ventilation zones, these would be functioning as a local air handling unit and the requirements of Part 1 would need to be met. The requirements of Feature 5, Part 2 would be applicable at any point where the outside air supply can be addressed before it is introduced into the project space. This could be at the 100% outside air unit at the roof, or within the individual fan coil units (in this design arrangement), depending on design consideration.

Please note that rack space needs to be available only in the main air ducts for recirculated air. (If there is no recirculated air as a part of the system, or if there are no main air ducts for recirculated air, then this feature may not apply.) If there is a recirculated air system and rack space is not available, then it is possible to submit an alternative adherence path (AAP) to suggest a different strategy for meeting the intent. Please review the published AAPs for this feature to see other strategies that have been approved.

IWBI recognizes that tenants often do not have control of base building mechanical systems. In such instances, feature 5 is considered outside the scope of the project, and therefore not applicable. The project team will need to provide documentation confirming the scope concern.

The project will still need to achieve the feature 1 air quality performance requirements, which may require the project to implement alternative design solutions, such as installing stand alone air purifiers within the space to filter air. Please note that achieving the air concept precondition features, such as feature 5 Air Filtration, will support the project in achieving feature 1 Air Quality Standards.

Feature 5 requirements do not distinguish between types of HVAC systems. Depending on the installed system, the team may be able to apply an alternative solution to meet the intent of feature 5.