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

Air flush

An air flush or building flush is a technique whereby air is forced through a building after construction and prior to occupancy in order to remove or reduce pollutants, such as VOCs and particulate matter, inadvertently introduced indoors during construction. Air flushing improves indoor air quality by limiting the exposure to an intense contamination period.

This feature requires an air flush at the completion of construction activities in order to effectively remove pollutants from indoor environments. Given the time required to conduct a flush, emphasis should be placed on the management of construction pollution as the first priority.

Part 1: Air Flush

A building air flush is performed while maintaining an indoor temperature of at least 15 °C [59 °F] and relative humidity below 60%, at one of the following volumes:

a.1 A total air volume of 4,500 m³ of outdoor air per m³ of floor area [14,000 ft³ per ft³ of floor area] prior to occupancy.
b.1 A total air volume of 1,066 m³ of outdoor air per m³ of floor area [3,500 ft³ per ft³ of floor area] prior to occupancy, followed by a second flush of 3,200 m³ of outdoor air per m³ of floor area [10,500 ft³ per ft³ of floor area] post-occupancy. While the post-occupancy flush is taking place, the ventilation system must provide at least 0.1 m³ per minute of outdoor air per m³ of floor area [0.3 CFM fresh air per ft³ of floor area] at all times.
Cardiovascular
Respiratory
Immune

Applicability Matrix

Core & Shell New & Existing Buildings New & Existing Interiors
Part 1: Air Flush - O O
Commercial Kitchen Education Multifamily Residential Restaurant Retail
Part 1: Air Flush O O O O O

Verification Methods Matrix

Letters of Assurance Annotated Documents On-Site Checks
Part 1: Air Flush Contractor
1

U.S. Green Building Council. LEED v4: Reference Guide for Building Design and Construction. Washington D.C.: U.S. Green Building Council; 2013: 37, 43-44, 541-552, 567, 605, 623, 645-53, 658-61, 682-3, 685-6, 723-4.

13.1.a

USGBC's LEED v4 EQ Credit: Indoor Air Quality Assessment requires performance of a building flush-out by supplying a total air volume of 14,000 cubic feet of outdoor air per square foot of gross floor area.

13.1.b

USGBC's LEED v4 EQ Credit: Indoor Air Quality Assessment requires that the space may be occupied only after delivery of a minimum of 3,500 cubic feet of outdoor air per square foot of gross floor area.