8.3 Construction IAQ Management and Assessment
Key Takeaways
- Construction Indoor Air Quality Management Plan (1 point) requires implementing the SMACNA IAQ Guidelines for Occupied Buildings Under Construction, 2nd Edition, 2007 during all construction phases.
- All absorptive materials stored on-site must be protected from moisture damage, and any filters used during construction must be replaced with new filters before occupancy.
- Indoor Air Quality Assessment Option 1 (Flush-out) requires 14,000 cubic feet of outdoor air per square foot of floor area, delivered while maintaining ≥60 deg F and ≤60% relative humidity.
- IAQ Assessment Option 2 (Air Testing) measures formaldehyde, particulate matter PM10 and PM2.5, ozone, TVOC, and target contaminants including carbon monoxide against published concentration limits.
- Both IAQ Assessment options earn 1 point for Option 2 air testing or 2 points for a partial flush-out plus occupied flush-out combination, awarded separately from the construction plan credit.
EQ Credit: Construction Indoor Air Quality Management Plan (1 Point)
Intent: Promote the well-being of construction workers and building occupants by minimizing IAQ problems associated with construction.
Required Plan Components
Develop and implement an IAQ management plan that follows the control measures in the SMACNA IAQ Guidelines for Occupied Buildings Under Construction, 2nd Edition, 2007. SMACNA defines five categories:
| SMACNA Control | Field Action |
|---|---|
| HVAC protection | Seal duct openings; isolate return air; cover supply diffusers |
| Source control | Specify low-emitting products (paints, sealants, cleaners) used during construction |
| Pathway interruption | Pressurize clean areas; depressurize work areas; install temporary barriers |
| Housekeeping | Daily wet-wiping and HEPA vacuuming; control dust generation |
| Scheduling | Sequence dirty work (cutting, sanding, demolition) before installing absorptive finishes |
Absorptive Material Protection
Absorptive materials - gypsum board, carpet, ceiling tile, insulation, fabric panels - must be stored under cover, off the floor, and protected from rain, snow, and condensation. Wet absorptive materials grow mold and become an irreversible IAQ liability.
Filter Replacement Before Occupancy
If permanently installed air handlers are used during construction, install MERV 8 minimum filtration on each return grille. Immediately before occupancy, replace all filtration media with new MERV-rated filters that meet the project's normal operating spec (commonly MERV 13 if pursuing Enhanced IAQ).
Tobacco Smoke During Construction
The construction IAQ plan must also prohibit tobacco smoke use inside the building and within 25 ft of openings during the construction period, mirroring the ETS Control prerequisite.
EQ Credit: Indoor Air Quality Assessment (1-2 Points)
Intent: Establish better indoor air quality in the building after construction and during occupancy.
Choose Option 1 (flush-out) OR Option 2 (air testing). Projects may also combine a partial flush-out with a delayed flush-out for 2 points.
Option 1 - Flush-out (1 or 2 Points)
Path A (1 point): After construction ends and before occupancy, supply 14,000 cubic feet of outdoor air per square foot of floor area while maintaining an internal temperature of at least 60 deg F and relative humidity no higher than 60%.
Path B (2 points): Begin with 3,500 cf/sf of outdoor air before occupancy. Once occupants move in, continue ventilating with at least 0.30 cfm/sf of outdoor air during operating hours until the cumulative total reaches 14,000 cf/sf.
Exam math example: For a 50,000 sf project, the Path A target is 14,000 × 50,000 = 700 million cubic feet of outdoor air. The duration depends on the system's outdoor air capacity.
Option 2 - Air Testing (2 Points)
Test the air in each occupied space (or representative spaces) using approved EPA, ASTM, and ISO methods. Results must fall below the contaminant maximums published in LEED v4.1:
| Contaminant | Maximum Concentration |
|---|---|
| Formaldehyde | 9 ppb (≈11 µg/m³) |
| Particulates PM10 | 50 µg/m³ |
| Particulates PM2.5 | 12 µg/m³ (or 15 µg/m³ in some climates) |
| Ozone | 0.075 ppm |
| TVOC (Total VOCs) | 500 µg/m³ |
| Carbon monoxide (target contaminant) | 9 ppm AND no more than 2 ppm above outdoor |
| Target VOCs (e.g., benzene, naphthalene, formaldehyde) | Per CDPH v1.2 chronic reference exposure limits |
Test samples must be collected with HVAC running at normal occupied flow rates, doors and windows in normal positions, and at the breathing zone (3-6 ft above the floor). Resample any failed locations after corrective action.
Choosing Between Options
- Flush-out is simple and reliable when the schedule allows, but consumes time and energy.
- Air testing is faster and gives objective data, but failures trigger expensive remediation right before move-in.
Most project teams plan Option 2 with Option 1 as a fallback if testing fails. Either way, the Construction IAQ Management Plan credit must already be in place - the assessment credit verifies that the plan worked.
Which document is the required reference for the Construction Indoor Air Quality Management Plan credit?
A 40,000 sf office wants to achieve Indoor Air Quality Assessment Option 1 (Flush-out, Path A) for 1 point. How much outdoor air must be delivered before occupancy, and what indoor conditions must be maintained during the flush-out?