LEED: Building flush-out

Consider a building flush-out period to reduce possible indoor air quality contamination after construction completion and prior to occupancy. This involves running the mechanical system with tempered 100% outside air for an extended period of time (two weeks).

  • TIPS:

    • Flushing out the building may be particularly important when high VOC- and particle-emitting construction materials, furnishings, interior finishes and cleaning agents have been applied.

    • Care should be taken with regard to humidity levels and microbial growth depending on the seasonal weather conditions.

    • All ventilation air filters should be changed as a final step of building flush-out. [1]

After conducting the minimum two-week building flush-out with new Minimum Efficiency Reporting Value (MERV) 13 filtration media at 100% outside air, new MERV 13 filters must be replaced in all locations except those that have been processing only outside air during the flush-out. 100% outside air can be a challenge in some climates, so it is important to identify when construction will be complete as early as possible so it can be determined whether or not this point can be achieved in an economical manner.

Incorporating this point into the project's overall LEED credit strategy is usually a scheduling decision. The owner may or may not want to have a usable building sitting empty for two weeks before the occupants are permitted to move in.

IAQ Testing: As an alternative to the two-week flush-out, the project team may decide to conduct a baseline IAQ testing procedure. The advantages to this approach include the reduction or elimination of the two-week flush-out period and the associated hassles of doing so. But the IAQ test is very sensitive and may require the contractor to perform additional procedures if VOC levels are detected above the limits outlined by the LEED program. IAQ testing may also indicate the need for a flush-out. [2]

Sources: [2] McGraw Hill article on meeting LEED IAQ requirements and [1] US DOE