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It’s about the plan, not the waste amount diverted

Effective waste diversion on the jobsite starts with an effective CWM plan.

Photo – Tristan Roberts
This prerequisite, which is new in LEED v4, requires all teams to develop and implement a construction and demolition waste management (CWM) plan. Teams must establish waste diversion goals by identifying at least five material or waste streams targeted for diversion. In addition, teams must specify the means and methods of diversion for each of the five selected materials streams. 

Upon completion of the project, the general contractor should provide a waste report detailing all major waste streams generated and include disposal and diversion rates. Teams pursuing the corresponding Construction and Demolition Waste Management credit should be aware of additional requirements for the final waste report.

All teams must plan for five different waste streams under this prerequisite. To earn points under Option 1 of the related credit, teams must implement plans for at least three waste streams.

Image – USGBC
This prerequisite does not have any performance requirements in terms of the amount of waste diverted. But all teams must develop a plan and produce a final report—even if the project location does not have recycling services and/or if teams are not going to pursue the corresponding credit.

Look at the companion credit before developing your plan

Teams are rewarded for the implementation of the plan developed in this prerequisite through meeting diversion or reduction of total waste material thresholds. Teams will benefit from studying the requirements of the Construction and Demolition Waste Management credit before developing their plan to verify which option, if any, they will use for that credit.

What are material streams? 

The LEED Reference Guide defines streams as flows of materials coming from a job site into markets for building materials.

Typically a single material goes to a single waste stream.

Image – USGBC
The online LEED Reference Guide video “Defining Waste Streams” provides additional information and states that a waste stream is defined by where the waste goes. Typically a single material goes to a single waste stream; however, there are cases where a single type of material could go to multiple waste streams and conversely, where multiple materials go to a single waste stream.

An example of two waste streams for a single material type would be wood waste that is sent to both a power generation facility as fuel and to local building supply to be reused. An example of multiple materials counted as a single waste stream would be crushing site-separated asphalt, concrete, and masonry together for aggregate, which is considered onsite waste diversion.

An easy way to understand your streams is to focus on the heaviest waste or the waste that generates the most volume. As a best practice, a material stream should constitute at least 5% by weight or volume of total diverted materials. Teams must divert multiple material streams to earn Option 1 of the corresponding credit.

Onsite separation vs. commingled collection

Teams must include collection and sorting methods as part of their CWM plans. Depending on what is appropriate, projects may use a combination of onsite separation and commingled collection. In addition, teams may consider other waste stream diversion tactics like deconstructed materials sent to reuse markets, reuse of deconstructed materials, and take back programs from manufacturers.

In onsite separation, materials are sorted in dumpsters before they leave the site and are each counted as separate waste streams.

Image – USGBC
For onsite separated (aka source separation) materials, each type of material sent to a separate recycling facility counts as single stream. If, however, a single material is being diverted to several streams, each stream is counted separately. An example of two waste streams for a single material would be wood waste that going to a power generation facility as fuel and to local building supply to be reused.

To count toward the corresponding credit, commingled recycling facilities must be able to provide project-specific diversion rates or an average diversion rate for the facility that is regulated by the local or state authority. Visual inspection is not an acceptable method of evaluating diversion rates.

If the commingled recycling facility can track and produce documentation of specific materials recycled for your project, you can count commingled waste as multiple waste streams.
Otherwise, commingled waste that is average diversion rate for a regulated facility sent to the same recycling sorting facility is counted as a single waste stream regardless of how many different materials are included. The average recycling rate for the facility must exclude alternative daily cover (ADC).

Source reduction now counted as a viable option

The credit addresses a new way of achieving CWM—via source reduction. Source reduction eliminates project waste through prefabrication, modular construction, or incorporating standard material lengths or sizes into the project’s design to eliminate waste.

To get the most benefit, this option requires teams to plan for source reduction during design and implement it during construction. Teams planning to utilize source reduction as the credit achievement option should address its use in their CWM plan.

Alternative Daily Cover (ADC) is out

There’s a big change in CWM from previous versions of LEED. Alternative daily cover (ADC) no longer qualifies as diversion. Any materials that are used for ADC must be counted as landfilled and your CWM plan must account for this. 

Land-clearing debris and hazardous materials are still out but must be accounted for

Similar to LEED 2009, land-clearing debris materials that are natural (like rock, soil, stone, and vegetation) are not considered construction, demolition, or renovation waste. Consequently, teams should not include these materials in their calculations, although their CWM plans must account for these materials.

Similarly, teams must document the safe removal and disposal of hazardous materials in their CWM plans but exclude these materials in their calculations.

Incineration can be considered diversion in certain cases

In a new development for LEED v4, incineration can be diversion, but only if reuse and recycling methods are not readily available in the project’s location and a team can demonstrate they exhausted these strategies before sending waste material to energy facilities.

In those cases, waste-to-energy incineration may be considered diversion and it must be included in the CWM plan. Teams must follow European Commission Waste Framework and Incineration Directives and the waste-to-energy facility must meet the applicable European standards based on fuel type.

Note: The combustion of waste wood (“wood-derived fuel” or biofuel) is considered diversion and not subject to the additional requirements for waste-to-energy incineration.

Waste report can be by weight or volume

Teams can calculate the diversion rate by weight or volume as long as they are consistent. The diversion rate is calculated by dividing the total waste diverted from the landfill by the total waste generated by the project and multiplying the result by 100.

Solid waste conversion factors

LEED Reference Guide
As the LEED v4 Reference Guides for BD+C and ID+C do not include a solid waste conversion factors tables, teams may want to utilize Table 2: Volume-to-Weight Conversion for Construction and Demolition Debris for the Construction Waste Management credit in the LEED BD+C: Multifamily Midrise in the Credit Library as a resource.

Other waste diversion tactics

Teams may consider other waste stream diversion tactics like sending deconstructed materials to reuse markets, reuse of deconstructed materials, and take back programs from manufacturers.

Deconstructed materials can be donated to charity or sent to another project site. Much like commingled waste, donation also counts as a single waste stream unless the receiving organization can verify and track the individual materials that are donated. This is another example of a multiple material types constituting a single waste stream when additional documentation is not available.

For deconstructed materials that are reused onsite, no distinction is made between whether the materials are serving their original function or not. In this case, each material reused onsite for each purpose counts as a single waste stream.

Take back programs for single material types are single waste streams.

Image – USGBC
Take back programs are offered by product manufacturers who will accept shipments of materials removed during renovation and/or purchased overruns of their products. This type of waste stream is defined by the specific material type. For example, you would have two distinct waste streams if you had carpet sent to a take back program from a carpet manufacturer, and ceiling tile sent to a take back program from a ceiling tile manufacturer.

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