Understanding and implementing LEED practices is not just for architects and engineers. Contractors also contribute significantly to a building becoming LEED-certified. Under the current LEED Reference Guide for Green Building Design and Construction, a contractor directly manages and is responsible for 13 LEED points, with an additional four possible points for Innovation in Design (ID) credits. That number of points can take a building past the Silver level and up to Gold level certification. Contractors are responsible for managing the following credits.
Construction Waste Management (1–2 points, with the possibility of 1 ID point).
Meeting this credit’s criteria typically requires setting up several dumpsters at the construction site to segregate the waste (e.g., wood, metal, drywall, concrete and general trash), and then sending those segregated dumpsters to the proper recycling centers or landfills. Diverting 75 percent of waste from landfills to gain the two points for this credit is certainly achievable if the contractor is diligent in segregating all the waste.
Almost every bit of waste that comes from a construction site can be recycled; the challenge is finding a local recycling center that accepts the material. Usually only the above-mentioned four materials can be recycled easily.
The amount of recycled waste usually is measured in weight, so recycling concrete waste can have a large positive impact on the waste recycling percentage. For example, one dumpster of recycled concrete weighs about the same as five dumpsters of recycled wood.
Recycled Content and Regional Materials
From a documentation standpoint, the Recycled Content and Regional Materials credits are the most time-consuming and paperwork-intensive credits for the contractor to earn. There are a couple ways to calculate these percentages, but the method that usually yields a higher percentage is the Actual Materials Value method.
This method involves the large administrative task of gathering the individual cost for every piece of material that goes into a building. Once these individual costs are added together to get the total actual material value, it is compared to the total recycled materials cost and regional materials cost to calculate the recycled materials percentage and the regional materials percentage.
Another large task is gathering the documentation that confirms the recycled content of a material and where it was manufactured or harvested. Many materials don’t have this information readily available, and contractors may need to call the material manufacturer to gather it.
Recycled Content (1–2 points, with the possibility of 1 ID point).
The percentage for recycled content is related to the materials cost. Many of the more expensive building materials already have a high recycled content, which greatly helps the percentage. For example, structural steel is expensive and has a high recycled content, typically 50 percent to 85 percent.
Regional Materials (1–2 points, with the possibility of 1 ID point).
To get credit for being regional, a material must be manufactured or harvested within 500 miles of a project site. Fortunately, most heavy and bulky building materials are usually purchased from regional manufacturers to reduce shipping costs.
Contractors should work with architects in the pre-construction phase of a project to identify high-dollar materials and ensure those materials are specified from regional manufacturers. Examples of expensive materials that have a large impact include:
• concrete;
• masonry;
• stone;
• structural steel; and
• landscaping.
Certified Wood (1 point, with the possibility of 1 ID point).
To earn this credit, contractors must ensure the certified wood comes from a vendor that is Forestry Stewardship Council (FSC) Chain of Custody-certified. FSC wood can be bought off the shelf at most major home improvement stores, but only FSC wood that comes with the Chain of Custody certificate from a certified vendor counts in the certified wood calculation to earn the point(s).
Construction IAQ Management Plan — During Construction (1 point).
Many normal construction activities create poor air quality in the building that can persist even after construction is completed and the occupants have moved in. This credit consists of developing, following and documenting compliance with an indoor air quality (IAQ) management plan that outlines practices to follow during construction to ensure a high level of air quality throughout and after the construction process. Many IAQ management plans can be easily found online and adapted to fit a specific project.
Construction IAQ Management Plan — Before Occupancy (1 point).
Earning this credit might require running the HVAC equipment for an extended period of time to flush out the building with fresh air before occupancy. This impacts the schedule and possibly the owner’s move-in date. Contractors should keep the whole project team, especially the owner, aware of the flush-out period’s impact.
Low-Emitting Materials
Four credits fall under the general heading of Low-Emitting Materials: Adhesives and Sealants (1 point), Paints and Coatings (1 point), Flooring Systems (1 point), and Composite Wood and Agrifiber Products (1 point). Low-emitting refers to a material with a low level of volatile organic compounds (VOCs). The VOC limit for each of these materials can be found in the LEED Reference Guide.
The onsite project superintendent should keep a careful eye on all materials to ensure they are below the maximum VOC level for that material. Low-VOC materials have little or no odor. The project team should follow a quick rule of thumb as they walk the project site: If you can smell one of the products during installation, check its Material Safety Data Sheet immediately to see if it is below the VOC limit.
Contractors impact a relatively narrow percentage of the total LEED credits on a project, but the points associated with those credits can have a large sway on the level of certification a building earns.
Knowing what credits fall within the contractors’ responsibility, understanding the requirements, developing a plan to achieve those credits and diligently following the plan will ensure contractors do their part to help a building gain LEED certification.