IHST's Quick Guide to LEED IAQ Testing

LEED Credits for IAQ Testing



The Leadership in Energy and Environmental Design (LEED) Green Building Rating System® allows newly constructed buildings to earn credits, either by flushing the building air or performing air testing prior to occupancy. To earn these credits, EQ Credit 3.2, Construction IAQ Management Plan Before Occupancy requires completion of either of two procedures to ensure good indoor air quality.

The first option is to perform a flushing of the building's interior air, as follows:

After construction ends and prior to occupancy and with all interior finishes installed, perform a building flush-out by supplying a total air volume of 14,000 cubic feet of outdoor air per square foot of floor area while maintaining an internal temperature of at least 60 degrees F, and relative humidity no higher than 60%.

Alternatively, air testing may be performed instead of a building flush-out. The air testing must meet the following criteria:

  • Use test protocols consistent with the USEPA Compendium of Methods for the Determination of Air Pollutants in Indoor Air;
  • All measurements must be completed prior to occupancy, but during normal occupied hours, with the building ventilation starting at the normal daily start time and operated at the minimum outside air flow rate for the occupied mode throughout the duration of the testing;
  • All interior finishes (millwork, doors, carpet, acoustic tiles, etc.) must be in place at the time of testing. Non-fixed furnishings, such as workstations and partitions are encouraged, but not required to be installed at the time of testing;
  • Samples must be collected for each portion of the building served by a separate air handling system. In each area served by a single air handler, samples must be collected for each 25,000 square feet of floor space, or each contiguous floor space, whichever is larger. Samples must be include areas presumed to have the least ventilation, and the strongest presumed source strength; and,
  • Samples must be collected for a minimum duration of four (4) hours, 3' - 6' above the floor.

What Are the Passing Criteria for Air Samples?



LEED criteria specified five contaminant classes for sampling. These contaminants, and their maximum acceptable concentrations are listed as follows:

  • Formaldehyde - 50 ppb
  • Paticulates (PM10) - 50 ug/m3
  • Total Volatile Organic Compounds (TVOC) - 500 ug/m3
  • 4-Phenylcyclohexene (4-PCH) - 6.5 ug/m3 (Required only if carpets or fabrics with styrene butadiene rubber (SBR) latex backing are used in building materials)
  • Carbon monoxide - 9 ppm, and no greater than 2 ppm above outdoor levels

What Should I Know About Air Sampling?


First, you should understand that simply performing the air sampling does not guarantee earning of EQ credit. The samples must be properly collected and analyzed, and the sample results must all fall below the maximum allowed concentrations. To help ensure your sample results fall within the acceptable ranges, you should plan the sampling to occur after all installs are complete, paints and adhesives are dry, and the building has been cleaned of dust and construction debris. Ensure that all building systems are operating properly. Finally, ensure that no unusual sources of contamination are present (i.e., equipment exhaust, move-in activities or furniture assembly, installation, miscellaneous sawing, cutting activities, etc.)

Second, budget and schedule appropriately for the air sampling from the outset of your project. Consider the following when planning for sampling:

  • The onsite portion of the air sampling will typically take at least one full day (8 hours). If the building is large or complex, sampling may take more than one day. If possible, construction, finishing and move-in activities should be suspended during air sampling.
  • The number of samples and onsite time required will vary, based on building size, configuration and HVAC design. IHST will be happy to discuss your project, review building plans, and provide you with reliable air sampling cost estimates.
  • It usually takes about ten (10) business days to receive air sample analysis results from the laboratory. Shorter turnarounds are available at increased cost. In many cases, you may not have to delay occupancy until sample results are received. You may still be able to receive credit, provided the sample collection occurred after installation was complete and prior to occupancy. Check with your LEED consultant and project managers to determine the best scheduling for air sample collection.
  • It is possible that one or more air samples may exceed allowed maximums. Decide before-hand if you will want to try again for the EQ credit in such a case, by repeating the sampling. If so, allow enough time for re-testing prior to occupancy. Normal turnaround for sample analysis is usually ten (10) business days. Shorter turnaround times are available at increased cost.

More Questions?


If you have more questions, IHST will be happy to talk with you and/or your LEED consultant. Call IHST at (972) 478-7415 for more information!