Construction

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• Preparation Before Construction Begins

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• The general contractor (GC) should go over all LEED-specific issues—including IAQ management, the role of low-emitting materials, environmental materials tracking tools, construction waste management, and more—at an orientation meeting.

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• It’s a good idea for the GC to meet with subcontractors to reinforce the LEED responsibilities related specifically to their trades. This exercise helps to build trust and is crucial for obtaining buy-in from all participants in the process.

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• Enabling coordination and communication among the GC, subcontractors, and the design team early in the process can minimize scheduling delays and pushback from subcontractors.

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• The GC distributes the Indoor Air Quality plan outlining procedures and best practices to be distributed to subcontractors prior to the construction phase. The plan should clearly identify who is responsible for implementing each component of the plan—for example, “Wrapping installed open-ended HVAC ductwork is the responsibility of the mechanical contractor,” and “Quality control is the responsibility of the general contractor.” 

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• Develop a checklist for weekly activities that lists SMACNA guidelines, protection of absorptive material, and use of MERV 8 filters along with related to-do items, such as taking photographs to document the IAQ strategies. It’s a convenient way to stay on top of required tasks, and the checklist can be used at weekly meetings and posted around the site. See the Documentation Toolkit for a sample checklist.

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• During Construction

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• The contractor and subs should ensure that SMACNA practices are being followed. Each of the five major SMACNA areas is addressed in detail below.  

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• Decide whether HVAC units will be used during construction. If so, ensure that MERV 8 filters have been purchased and are used throughout the site. Remember that any filters used during construction must be replaced prior to occupancy.

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• Post copies of the IAQ plan in various places around the construction site to ensure that the plan is being followed. Hang signs that remind subcontractors to follow IAQ practices such as covering exposed ductwork with plastic, wet mopping regularly, and using low-VOC products and other SMACNA practices. See the Documentation Toolkit for sample signage.

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• Assign an IAQ manager to assist the GC. This person can run spot-checks for SMACNA and other best-practice compliance.  

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• HVAC Protection

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• Follow SMACNA strategies for HVAC protection that are appropriate to your project. These include items such as the following:

  • This ductwork was ordered wrapped, and was stored away from construction work until installation. Photo – YRG Sustainabilitywrapping ductwork and or ventilation equipment in plastic once it arrives on site;
  • ordering ductwork pre-wrapped in plastic before it is delivered to the site;
  • placing ductwork or ventilation equipment in a room away from construction work to protect it from dust until it is installed and covered;
  • covering exposed grilles with plastic once ductwork is installed;
  • and laying plastic over underfloor air systems to keep out construction debris.

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• Ordering ductwork pre-wrapped in plastic or having open grilles sealed once installed may add slightly to costs, but pre-wrapped ductwork, for example, makes HVAC protection easy to achieve.

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• Source Control

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• Follow SMACNA strategies for source control that are appropriate to your project. These include items such as the following.

  • For construction materials storage, do not use This project used low-emitting paints, sealants, and adhesives, and stored them in a closet to protect air quality. Photo – YRG Sustainabilitymechanical rooms or air-mixing rooms as many products give off gases that can be absorbed by other materials or could be distributed to other areas through the ventilation system.
  • Use only low-emitting adhesives; sealants; paints, coatings; flooring products; composite woods; and furniture, wall, and ceiling systems. 
  • When cleaning the construction space, use low-VOC cleaners.
  • Combustion-based construction equipment used in the interior of a building should be exhausted directly to the outside. Long-snake exhaust pipes can be attached to this type of equipment for easy exhausting out of windows.
  • When combustion-based, stand-alone heating units are used for supplemental heating during construction, it may be best to keep the heating units outdoors to exhaust and pump the heat to the indoors.

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• Using low-emitting materials helps projects gain the Low-Emitting Materials series of credits—IEQc4.1: Adhesive and Sealants, IEQc4.2: Paints and Coatings, IEQc4.3: Flooring Systems, IEQc4.4: Composite Wood and Agrifiber Products, and IEQc4.5: Furniture and Furnishings.

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• Using low-VOC construction materials and cleaning products helps to pass the air-quality test for IEQc3.2: Construction IAQ Management Plan Before Occupancy. 

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• Using low-VOC products—adhesives, sealants, paints, coatings, flooring systems, and composite wood—should add little to no extra cost. 

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• It is a good idea for the GC to set up a supervisory mechanism, such as designating an IAQ manager to run quality control checks and to ensure that the proper products and procedures are being used. 

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• The IAQ management plan should specifically state who is responsible for ensuring that low-VOC materials are used onsite, and the GC should verify that the products and procedures being used by each subcontractor are in compliance.

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• Pathway Interruption

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• Follow SMACNA strategies for pathway interruption that are appropriate to your project. These include items such as the following:

  • The base-building elevator shafts were sealed on this project to prevent movement of dust. Photo – YRG SustainabilityTemporary barriers and self-contained dustless apparatus, such as concrete grinders and drywall sanders, can be helpful to isolate and protect finished construction areas from areas that are still under construction. Isolate construction dust produced by activities like cutting drywall or wood. 
  • Separate construction zones from occupied zones.

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• Contain construction air pollution by exhausting air to create negative pressure in construction areas. 

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• Plastic barriers are the most inexpensive, but drywall or cloth partitions can be used as well.

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• Housekeeping

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• Follow SMACNA strategies for housekeeping that are appropriate to your project. These include items such as the following:

  • Wet mopping on a daily basis during construction keeps down dust. Photo – YRG SustainabilityWet mopping helps keep construction dust particles from becoming airborne.
  • Frequent sweeping helps control construction dust and keeps construction materials free of debris.

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• Housekeeping is a no- to low-cost measure and is simple to implement.  

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• These practices may be slightly time-consuming, but will help to create a healthier working environment for all the construction workers onsite on a daily basis. Communicating this point frequently to everyone on the site can help to build compliance. 

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• Scheduling

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• Carefully schedule construction and any necessary occupant moves in a manner that reduces occupant exposure to construction pollution. 

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• Carefully examine the sequencing of material installation before construction begins.  Schedule installation to protect absorptive materials from construction pollution. For example, do not store or install acoustic ceiling tiles before painting occurs or flooring products are installed because the ceiling tiles will absorb the off-gassing paint or floor adhesives and will contaminate the air over a longer time period. This could also compromise the project’s ability to attain IEQc3.2: Construction IAQ Management Plan—Before Occupancy. 

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• Scheduling is a no-cost measure but needs to be coordinated before construction begins.

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• Wrap-Up and Documentation

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• Take photos throughout the construction process to demonstrate that your IAQ plan has been followed. There is no specific number of photos required, but they must be taken at two or more different stages of the project. For reference, prior to 2009 this credit required at least 16 photos—see the Documentation Toolkit for examples.

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• All five SMACNA control measures have to be documented in a photo log. It is easy to take pictures of covered ducts, but don’t forget to also take photos of more process-oriented strategies such as housekeeping and pathway interruption. The pictures should clearly show all the control measures adopted during construction. Photos should be submitted with a brief description, the time and date, and an indication of what SMACNA practice is demonstrated. 

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• These MERV 8 filters were installed prior to initial system start-up, and replaced prior to occupancy. Photo – YRG SustainabilityIf the building’s air handlers are used, replace all filters (MERV 8) required during construction with new filters—after construction and before occupants move into the space.

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• Replace construction filters with MERV 13 filters if the project is also attempting to earn credit for IEQc5: Indoor Environmental Pollutant Source Control.

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• It is usually a good idea to do a “mini air flush” (if your project is not attempting IEQc3.2) before occupancy to help remove any lingering VOCs from the construction process. This can be as simple as putting industrial sized fans in the window and pumping in fresh air overnight or running the HVAC exhaust on high for a few days. (See IEQc3.2: Construction Indoor Air Quality Plan—Before Occupancy if the team wants to do a full flush-out for an additional LEED point.)

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• Fill out the LEED Online form and upload the IAQ plan, photos with SMACNA descriptions, and cut sheets of MERV filters used onsite during construction, if air handlers were used.

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• Alternatives to installing MERV 8 filters include not using the building HVAC units, bringing in a stand-alone temporary system, or using natural ventilation.