August 27, 2021

Earning LEED Indoor Air Quality Assessment in v4.1

Stop and smell the roses, they smell great!

LEED Indoor Air Quality Assessment, IEQc4, is another throwback LEED credit. It was simply renamed from Construction IAQ Management, Before Occupancy, to the much more glamorous Indoor Air Quality Assessment. You’ve still got two options: either flush out the building with a whole bunch of outside air or hire someone to come and test the air. All in all, pretty straightforward for a LEED credit. For more LEED credit guidance, read our insight on earning Multi-Attribute Optimization.

LEED Requirements for IEQc4 - Indoor Air Quality Assessment for v4.1

Requirements for IEQc4 – LEED Indoor Air Quality Assessment for v4.1

Select one of the following two options, to be implemented after construction ends and the building has been completely cleaned. All interior finishes, such as millwork, doors, paint, carpet, acoustic tiles, and movable furnishings (e.g., workstations, partitions), must be installed, and major VOC punch list items must be finished. The options cannot be combined.

Option 1. Flush-Out (1 point)
Path 1. Before Occupancy

Install new filtration media and perform 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 while maintaining an internal temperature of at least 60°F and no higher than 80°F  and relative humidity no higher than 60%. 


Path 2. During Occupancy

If occupancy is desired before the flush-out is completed, 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 while maintaining the same temperature and humidity requirements as Path 1. 

 Once the space is occupied, it must be ventilated at a minimum rate of 0.30 cubic foot per minute (cfm) per square foot of outdoor air or the design minimum outdoor air rate determined in EQ Prerequisite Minimum Indoor Air Quality Performance, whichever is greater. During each day of the flush-out period, ventilation must begin at least three hours before occupancy and continue during occupancy. These conditions must be maintained until a total of 14,000 cubic feet per square foot of outdoor air ( has been delivered to the space.


Option 2. Air Testing (1-2 points)

After construction ends and before occupancy, but under ventilation conditions typical for occupancy, conduct baseline IAQ testing in occupied spaces for the contaminants listed in each path. 

Path 1. Particulate Matter and Inorganic Gases (1 point)

Test for the particulate matter (PM) and inorganic gases listed in Table 1, using an allowed test method, and demonstrate the contaminants do not exceed the concentration limits listed in the table.


Path 2. Volatile Organic Compounds (1 point)

Perform a screening test for Total Volatile Organic Compounds (TVOC). Use ISO 16000-6, EPA TO-17, or EPA TO-15 to collect and analyze the air sample. Calculate the TVOC value per EN 16516:2017, CDPH Standard Method v1.2 2017 section 3.9.4, or alternative calculation method as long as full method description is included in test report. If the TVOC levels exceed 500 µg/m3, investigate for potential issues by comparing the individual VOC levels from the GC/MS results to associated cognizant authority health-based limits. Correct any identified issues and re-test if necessary. 

Additionally, test for the individual volatile organic compounds listed in Table 2 using an allowed test method and demonstrate the contaminants do not exceed the concentration limits listed in the table. Laboratories that conduct the tests must be accredited under ISO/IEC 17025 for the test methods they use. Exemplary performance is available for projects that test for the additional target volatile organic compounds specified in CDPH Standard Method v1.2-2017, Table 4-1 and do not exceed the full CREL levels for these compounds adopted by Cal/EPA OEHHA in effect on June 2016.

Long story short – flush out your building for 1 point OR test for particulate matter, ozone and carbon monoxide for 1 point AND/OR a bunch of VOCs for a second point.

Strategies for Achieving IEQc4 - Indoor Air Quality Assessment for v4.1

Strategies for Achieving IEQc4 – Indoor Air Quality Assessment for v4.1

Honestly, this comes down to does the team really want this point and if so, do they want to pay for it or take a a few weeks for it.

If you’ve got the time before the building is occupied, its pretty straightforward – calculate how much outside air you’ll need (project square footage X 14,000 cubic feet), figure out how much outside air your HVAC system can provide (open up the dampers all the way for quicker turnaround) and let the system rock until you reach the thresholds. It will need to be conditioned somewhat, depending on location and time of year, so there may be a small energy penalty, but that’s about it. Just document flow rates, start/end times, to justify the flushout duration, and you’ll be good to go. Just make sure to reset any dampers that may have been changed back to original design settings, and to swap out all your filters, and you’re good to go.

If the building has to be occupied, you’ll do the same process to get at least 3,500 cubic feet before occupancy, then just dial it back and calculate how long you’ll need to run the system to reach 14,000 cubic feet.

For testing, honestly, just give the testing agency the requirements for the option(s) you want to pursue and they’ll give you a report detailing the results and hopefully you comply.  If you don’t, well, then you may have to dive into researching trouble areas or do a flushout and re-test. 

Version 4.1 is much better for Testing Option 2 for VOCs that v4. There are significantly fewer VOCs required to test for, so life will be easier. 

Let’s recap the strategy:

  1. Choose between flushout and hiring a testing company
  2. For flushout, try and implement before occupancy – either way, you’ll nee to calculate how long to run the systems to reach 14,000 cubic feet per square foot.
  3. For testing, send the exact LEED testing requirements to your chosen firm, and confirm they can meet them. The rest is on them
More Best Practices for Indoor Air Quality Assessment

More Best Practices for Indoor Air Quality Assessment

The strategies detailed will get you to the point, one way or the other. Here are a few other tips: 

  1. Making sure low-VOC products are used will help nip any off-gassing in the bud.
  2. Maintaining proper ventilation during the construction process will help dilute any contaminants. 
  3. Time of year might be an issue for flush-out – running 14,000 CF of air in the middle of a 100-degree humidity streak is a burden on the HVC system.
  4. Have a narrative for flush-out calculations and confirmation on system reset and filter change to documentation Path 1
  5. Have test results that show everything under the LEED limits for Path 2
Summary for Achieving IEQc4 - LEED Indoor Air Quality Assessment

Summary for Achieving IEQc4 – LEED Indoor Air Quality Assessment

Let’s recap how to earn 1 point for IEQc4:

  1. Make sure you have opted into LEED v4.1!
  2. Pick a path: flush-out or testing
  3. Calculate system requirements based on project size
  4. Verify your testing firm can test according to the LEED requirements and let them have at it.
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