Earning the LEED IAQ Credit – Building Flush-out or IAQ Testing?
Will Wade | July 15, 2019
Building flush-out or IAQ testing? This is the question many project teams ask when trying to determine how to successfully achieve the LEED IAQ credit under Version 4. In this post we’ll take a look at the key requirements and the pros and cons of these two options.
LEED v.4 IAQ Assessment Overview
Leadership in Energy and Environmental Design® (LEED) Version 4 (v.4) from the U.S. Green Building Council (USGBC) went into effect for all projects in October 2016. The construction process introduces a number of contaminants into the indoor environment, which if not avoided or properly controlled could negatively impact occupant comfort, health, and productivity. The Indoor Environmental Quality (EQ) – Indoor Air Quality (IAQ) Assessment Credit verifies acceptable IAQ in newly constructed or renovated buildings by either flushing the building with outdoor air or conducting baseline IAQ testing after construction and before occupancy. When applying for LEED Certification every point counts making the IAQ Credit well-worth pursuing.
Key Requirements of the LEED IAQ Assessment Credit
Four significant modifications were made to this credit in LEED v.4. The most significant modification involves the number of points awarded to verify IAQ. Under v.4, two points are awarded for IAQ testing, and only one point is awarded for building flush-out. This makes IAQ testing the more attractive approach for many projects. A second noteworthy change is that several new measurements were added to the IAQ testing option related to volatile organic compounds (VOCs). In previous versions of LEED, baseline IAQ testing was required for Total VOCs (TVOCs). In v.4, expanded testing for specific VOC chemicals is required in addition to the test for TVOCs. Changes were also made to the number of sampling locations required for testing, which are determined by the size of the building, heating, ventilation, and air conditioning (HVAC) distribution, and the uniformity of space types. Further, additional testing for ozone and fine particles (PM2.5) are required for buildings located in areas of the country that do not meet US Environmental Protection Agency (EPA) regional air quality goals.
Evaluating the Options
While each construction project has unique characteristics that may influence whether building flush-out or IAQ testing is the best route, under Version 4 the scales are tipped in favor of IAQ testing. Under LEED v.4, IAQ testing earns a project two credits compared with only one from building flush-out. A single point can often be the difference in which level of certification a project achieves.
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There are many other advantages to IAQ testing as opposed to building flush-out. One of the main reasons IAQ testing is often selected by project teams is because the testing can be performed during the brief window of time between construction completion and occupancy. Having the IAQ sampling completed within one to two days is significantly preferable to the one to two weeks (or more) often needed to complete a building flush-out. For many buildings the time required to complete the flush-out process is prohibitive.
Another critical advantage of the IAQ testing is that the test results provide objective data that can be used for documentation and communication purposes. By getting a baseline metric of pre-occupancy IAQ conditions, the owner has scientifically sound data that proves the success of the multiple measures used to enhance IAQ in LEED buildings. This is an effective tool to communicate project success and the acceptability of IAQ in the new facility with occupants and other stakeholders. With building flush-out, essentially the building is purged with outdoor air and the assumption is made that IAQ is acceptable. This does not provide any measurable air quality data that can be used as a baseline or referenced by building managers in the future.
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IAQ testing can be performed in a timely manner, provides hard data, and earns an extra point, so it is often the more attractive option. The expanded sampling program required in v.4 makes it imperative for project teams to enlist a qualified expert to develop and conduct the testing. The additional testing for specific VOCs, ozone parameters, and PM2.5 that are required under the revised credit make the testing program more complex. Depending on the contaminant being tested, the USGBC specifies that specific test procedures be used. An experienced company will design the testing program to help ensure that the correct methodology is used, that all the testing parameters are met, and that laboratories analyzing the samples are properly accredited for the methods used. A strong understanding of built environments and the construction process is necessary in order to determine the number of samples needed and when and where they should be collected. Additionally, the testing company must now be knowledgeable about regional air quality conditions and EPA regulatory compliance to determine what additional measurements are required. Using a qualified consultant significantly optimizes the chances of obtaining the two points for IAQ testing.
Knowledge of the Credit, Indoor Environments, and Construction are Critical
Having a full understanding of requirements of the LEED IAQ Assessment Credit is imperative in determining the most appropriate approach for your specific project. While the IAQ testing option is attractive because two points will now be awarded, the new testing requirements require diligent application and that a compliant sampling program be implemented. To ensure that the additional points for IAQ sampling are earned and to avoid additional costs from re-testing, be certain to work with a qualified expert to develop and execute the IAQ testing program.