If you haven’t worked on a LEED® (Leadership in Energy and Environmental Design) project recently, chances are high that you will. Since its unveiling in 2000, LEED® has become an important and integral part of the green building construction vernacular in North America and around the world.

As market demand has increased, LEED® has evolved, leading the U.S. Green Building Council to develop LEED® v4. As of October 2016, LEED® v4 became the only system for attaining certification as a green building with the Canadian Green Building Council (CaGBC). LEED® v4 includes some major changes from the previous version. In response, the CPCI Sustainability Committee has prepared this guide for precast concrete manufacturers.

What changed?
Those familiar with previous versions of LEED® will recognize the same fundamental structure. There are still prerequisites and credit categories, 110 potential points, regional priority credits and pilot credits. LEED® v4, however, has a new credit category for Location and Transport and places more emphasis on CaGBC’ s goal of reducing carbon emissions, and this means increased energy efficiencies across the board. There’s also a greater emphasis on transparency in terms of the impact of materials.

LEED® v4 is technically more rigorous than its predecessor. This version expands the market sectors (21) able to use LEED® including data centers, warehouses and distribution centers, hospitality, existing schools, existing retail, homes, and multi-family low and mid-rise.

There are new prerequisites and credits across the LEED® categories and rating systems. Point values have also changed. Each rating system been weighted with LEED® points associated with each credit and option.

LEED® V4 Summary and Certification Levels

• 7 Credit Categories
• 3 Ways to get additional points
• Total of 110 possible points
• Certified: 40 to 49 points
• Silver: 50 to 59 points
• Gold: 60 to 79 points
• Platinum: 80 + points

Summary of where precast concrete can directly or indirectly contribute to LEED® v4 points

Credit Categories and Sections	Available Credit Points
A. Location and Transportation
Sensitive Land Protection	1
High Priority Site	2
Surrounding Density and Diverse Uses	5
B. Sustainable Sites
Site Development - Protect or Restore Habitat	2
Open Space	1
Rainwater Management	3
Heat Island Reduction	2
C. Energy and Atmosphere Credit
Minimum Energy Performance	Required
D. Materials and Resources Credit
Construction and Demolition Waste Management Planning	Required
Building Life Cycle Impact Reduction	5
Building Product Disclosure and Optimization:
1. Environmental Product Declarations	2
2. Sourcing of Raw Materials	2
E. Indoor Environmental Quality Credit
Material Ingredients	2
Low-Emitting Materials	3
Daylight	3
Quality Views	1
Acoustic Performance	1
F. Innovation Credit
Innovation	5
LEED® AP with specialty	1
G. Regional Priority Credits
Regional Priority: Specific Credit	4

A. Location & Transportation Credit Category

16 points

The intent of this credit category is to avoid development on inappropriate sites, reduce vehicle miles traveled, enhance livability and improve human health by encouraging daily physical activity. Projects pursuing credits in this category must include a range of sustainability features, such as walkability, transit access, sensitive land protection, connectivity, and shared infrastructure.

Credits (precast concrete opportunity categories are listed in Green Bold Type)

LEED® for Neighborhoods Development Location	Required
Sensitive Land Protection	1
High Priority Status	2
Surrounding Density and Diverse Uses	5
Access to Quality Transit	5
Bicycle Facilities	1
Reduced Parking Footprint	1
Green Vehicles	1

Sensitive Land Protection, High Priority Status and Surrounding Density and Diverse Uses Credits
The first three credit sections in this category have a common theme – to guide the selection of a construction site based on environmental impact. The credits reward projects that reduce their footprint by avoiding building on sensitive lands, building in locations with development constraints or building in areas with existing infrastructure. These requirements usually involve building on compact and challenging sites with little or no site storage during construction.

To meet this credit, the project may be located within the boundary of a LEED®-certified Neighborhood Development or pursue individual credits.

Precast Concrete Approaches:
Precast concrete is an excellent choice in these circumstances since its building and infrastructure components are versatile. Using precast concrete can help enable earning these credits because it is ideal for compact multi-story construction to increase housing density. Precast concrete is made-to-order, offsite, for the conditions at hand and can also be installed as soon as it’s delivered, contributing to reduced need for additional storage of manufacturing equipment and materials for congested construction sites such as brownfield or sensitive land locations. Precast concrete can also be used for shared infrastructure such as wastewater and storm water treatment, and to house utilities.

Reduced Parking Footprint Credit

Precast Concrete Approaches:
Another potential for increasing density is to locate parking areas within the building footprint to limit site disturbance. A parking garage built with precast/prestressed concrete can be located within a building footprint to help maintain adjoining natural areas that would otherwise be consumed by surface parking.

B. Sustainable Sites Credit Category

10 points

These credits are intended to minimize the impact on ecosystems and water resources on the chosen site. This is done by evaluating and exploring ways to:

1. manage or restore existing habitat and biodiversity,
2. use of physical, social and environmental space,
3. reduce stormwater runoff and manage or improve the hydrology of the site
4. reduce the heat island effect from the project to the site and surrounding areas, and
5. minimize light pollution from the project to protect the wildlife and improve viewing

Credits (precast concrete opportunity categories are listed in Green Bold Type)

Construction Activity Pollution Prevention	Required
Site Assessment	1
Site Development – Protect or Restore Habitat	2
Open Space	1
Rainwater Management	3
Heat Island Reduction	2
Light Pollution Reduction	1

Site Development – Protect or Restore Habitat:
The intent of this credit is to conserve existing natural areas and restore damaged areas to protect habitat and promote biodiversity. This credit is achieved by protecting 40% of the site greenfield area and restoring 30% (including the building footprint) of all portions of the site identified as previously developed with native or adapted vegetation. Projects that achieve a density of 1.5 floor area-to land area ratio may include vegetated roof surfaces in this calculation.

Precast Concrete Approaches:
Using underground precast concrete stormwater detention and retention systems to store and treat rainwater enables the project to protect and restore habitat and eliminates (or minimizes) land required for detention ponds. A multi-story building with a vegetated roof can also be constructed with precast concrete.

Open Space:
For this credit, the project must provide an outdoor space greater than or equal to 30% of the total site area (including building footprint). A minimum of 25% of that outdoor space must be vegetated or have an overhead vegetated canopy. The concept is to encourage interactions with the environment, social interactions and physical activities.

Precast Concrete Approaches:
Precast concrete multi-story buildings are well suited to support vegetated roofs. Precast concrete also lends itself to the incorporation of stormwater planters and retention areas.

Rainwater Management:
The intent of this credit is to reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of the site, based on historical conditions and undeveloped ecosystems in the region. The approaches and techniques in this credit involve minimizing disturbed areas on the project site, limiting the amount of impervious cover on a site, and then infiltrating, filtering, storing, evaporating or detaining rainwater runoff at or close to its source.

Precast Concrete Approaches:
Precast concrete systems such as filtration planters or bioretention cells mimic natural hydrology by infiltrating runoff water into the groundwater or enabling it to evaporate into the atmosphere. Through a variety of physical, biological and chemical processes, pollutants are removed from the stormwater before returning to underground aquifers or surface waters. The planters act as temporary storage for runoff water, helping minimize discharge rates. In addition, a percentage of captured water provides irrigation for the vegetation in the planters, reducing the volume of stormwater runoff. Versatile and efficient, precast concrete filtration planters can be installed in almost any urban space.

Heat Island Reduction:
The intent of this credit is to minimize effects on microclimates and human and wildlife habitats by reducing heat islands. The requirements include two options:

1. the use of site shading and reflective pavements and roofing materials or vegetative roofs, or
2. underground or shaded parking areas.

Precast Concrete Approaches:
Precast concrete can contribute to heat island reduction through highly reflective surfaces by incorporating white cement. For reflective pavements, the requirement is to use paving materials with a three-year aged solar reflectance value (SR) of at least 0.28, or an initial SR of at least 0.33. The requirement for SR can usually be met by using precast concrete rather than asphalt for hardscape areas, including sidewalks, parking lots, drives and other impervious surfaces. Solar reflectance, sometimes called albedo, is a measure of a material’s ability to reflect sunlight (visible, infrared and ultraviolet wavelengths) on a scale of 0 to 1. An albedo value of 0.0 indicates that the surface absorbs all solar radiation, and a 1.0 SR value represents total reflectivity. Generally, light-colored surfaces have a high SR. Conventional grey concrete generally has an initial SR of greater than 0.35. Concrete made with white cement can have an SR greater than 0.70. As a comparison, new asphalt generally has an SR of approximately 0.05. This option of the credit is worth 2 points. ASTM E1980, “Standard Practice for Calculating Solar Reflectance Index of Horizontal and Low-Sloped Opaque Surfaces,” can be used to calculate the SR Index.

A second candidate to reduce heat island effects of a multi-story building or covered parkade is to incorporate an engineered vegetated roof system. This precast concrete approach works well with the site rainwater management credit outlined earlier.

C. Energy and Atmosphere Credit Category

33 points

These credits promote better building energy performance:

Credits (precast concrete opportunity categories are listed in Green Bold Type)

Fundamental Commissioning and Verification	Required
Minimum Energy Performance	Required
Building-Level Energy Metering	Required
Fundamental Refrigerant Management	Required
Enhanced Commissioning	6
Optimize Energy Performance	18
Advanced Energy Metering	1
Demand Response	2
Renewable Energy Production	3
Enhanced Refrigerant Management	1
Green Power and Carbon Offsets	2

Minimum Energy Performance:
The intent here is to reduce the environmental and economic harms of excessive energy usage by achieving a minimum level of energy efficiency for the building and its systems. There are several precast concrete approaches for achieving this credit, but the most frequently used option is to demonstrate a 5% improvement over a baseline building by using ANSI/ASHRAE/IESNA Standard 90.1. Energy performance must be measured by a whole building simulation using the Building Performance Rating Method in Appendix G of the standard.

Optimize Energy Performance:
The intent of this credit is to achieve high levels of energy performance beyond the prerequisite standard. This includes establishing an energy performance target in early design phases.

Precast Concrete Approaches:
Buildings constructed with precast concrete can achieve high levels of energy efficiency due to precast concrete building envelope air tightness and concrete’s thermal mass. Thermal mass is defined as a material's resistance to change in temperature as heat is added or removed. Precast concrete has high thermal mass due to its material density which provides a longer thermal lag to change its temperature. Glass and wood have much lower thermal masses and thus higher heat exchange conductivity. With its high thermal mass, precast concrete acts like a thermal sponge. It absorbs heat on warm days, keeping the interior of the building cool, and stored heat is released slowly at night when temperatures fall. In many climates, these buildings consume less energy than non-thermally dense buildings with walls of a similar insulation value. The building’s reduced heating, ventilating and air-conditioning needs then require smaller capacity equipment, reducing overall energy load.

The use of concrete as a thermal storage medium allows passive cooling and heating when actively engaged. The active engagement of the concrete in thermal dynamics of the building system is best achieved by using hollowcore precast prestressed concrete planks (slabs) as a medium of distribution of air through their cores and thereby working as a thermal storage medium. Pairing it to work as ventilated ceiling and considering the reduction in greenhouse gas emissions enables significant environmental and cost savings of a building over its life through reduced energy use. From a broader sustainability perspective, it is important to consider the impact of climate change on the internal environment; the use of thermal mass is a key adaptation measure for mitigating the impact of rising temperatures and unstable weather patterns resulting from climate change.

When thermal mass of the buildings is actively engaged for energy transfer, the stored heat in the building mass from occupants and lights etc. can be used to compensate for night losses in winter. In summer the cool night air, when 10-15°C, can be circulated through the cores of the hollowcore slabs, which in turn are cooled to absorb the next day's heat gains without the need of refrigeration. In places where the night is not cool enough (as in some parts of the USA and Canada) off-peak refrigeration would be required to pre-cool the buildings, but the concrete with its energy storage capacity can still handle the daytime loads. Passing air through the cores results in approximately doubling the heat transfer area. Moreover, the convective heat transfer is increased due to forced convection in the cores of the slabs. Due to the effectiveness of coupling of the supply air and mass, the temperature of the air leaving the slab is almost independent of the temperature entering the slab. On average about 75% of the thermal energy available from the tempered ventilation air can be absorbed by the slab. Consequently, using floors and ceilings as active thermal mass is less expensive when compared to the cost of conventional mechanical systems and provides the needful resiliency in operation which is not available with conventional mechanical systems.

Demand Response:
The intent of this credit is to increase participation in demand response technologies and programs that make energy generation and distribution systems more efficient, increase grid reliability, and reduce greenhouse gas emissions. This can be achieved by developing and commissioning a comprehensive plan for shedding at least 10% of building estimated peak electricity demand.

Precast Concrete Approaches:
Concrete’s thermal mass delays its heating and cooling energy requirements. This in turn allows for the shift of energy use off of peak usage times, further reducing the demands on the grid. Furthermore, the use of [insert info on Termobuild here]

D. Materials and Resources Credit Category

13 points

These credits encourage using sustainable building materials and reducing waste. In past versions of LEED®, the focus of material impacts has been on single attributes such as recycled content, rapid renewability or regional materials. The new focus is on disclosing information on environmental, health, and social impacts associated with the extraction, processing, transport, maintenance, and disposal of building materials. The requirements are designed to support a life cycle approach that improves performance and promotes resource efficiency.

Credits (precast concrete opportunity categories are listed in Green Bold Type)

Storage and Collection of Recyclables	Required
Construction and Demolition Waste Management Planning	Required
Building Life Cycle Impact Reduction	5
Environmental Product Declarations	2
Building Product Disclosure and Optimization
Sourcing of Raw Materials	2
Material ingredients	2
Construction and demolition waste management	2

Building Life Cycle Impact Reduction:
This credit encourages reuse and optimization to enhance the environmental performance of products and materials. It offers several options for reducing the impact of buildings, mostly focused on existing building adaptation and reuse. However, for new buildings, building product disclosure and optimization requires the calculation of a whole building life cycle assessment to demonstrate lower environmental impact of the proposed building, by 10% over a baseline building. The project is awarded three points for conducting a whole building life cycle assessment of the project’s structure and enclosure of at least 60 years that demonstrates this 10% reduction in at least three of following six impact categories, including:

1. global warming potential (greenhouse gases),
2. depletion of the stratospheric ozone layer,
3. acidification of land and water sources,
4. eutrophication (a type of pollution that stimulates an explosive growth of algae),
5. formation of tropospheric ozone, and
6. depletion of nonrenewable energy resources.

One additional caveat is that no impact category assessed as part of the life cycle assessment may increase by more than 5% compared with the baseline building.

Precast Concrete Approaches:
Precast concrete structures are known for durability and long service life resulting in a decrease of the environmental impacts associated with reconstruction, repair and maintenance. Precast structures often demonstrate the lowest life cycle impacts. A third party verified precast concrete life cycle assessment for a typical 5-storey building is available at: http://www.sustainableprecast.ca/en/precast_sustainability/life_cycle_assessment/. This LCA can be used in the pursuit of this credit, or the Athena Impact Estimator is an accepted tool for calculation, http://www.athenasmi.org/our-software-data/ecocalculator/.

Building Product Disclosure and Optimization – Environmental Product Declaration:
This credit encourages the use of products and materials for which life cycle information is available and that have environmentally, economically and socially preferred life cycle impacts. This information can be found in an environmental product declaration (EPD). An EPD is an independently verified and registered document that communicates transparent and comparable information about the life cycle environmental impact of building products. It verifies the sustainable attributes of a product.

Option 1 (Disclosure) awards one point for using twenty permanently installed products sourced from at least five different manufacturers that have published EPDs. Under this credit, a product-specific EPD is more desirable (worth a full product) but industry-average EPDs (worth half product) can be used if product-specific EPDs are not available.

Option 2 (Optimization) awards one point if it can be demonstrated that 50% (by cost) of all products in the building perform better than the industry-average environmental impacts. The EPD enables comparisons that may help to attain this point.

Precast Concrete Approaches: North American industry-wide EPDs are now available for a variety of precast concrete products at www.cpci.ca/en/resources/technical_publications/.

Note: Only manufacturers who are listed as contributors to the EPD in the appendix, use this for the credit. Contact individual precast manufacturers about product specific EPDs to achieve the full point.

Building Product Disclosure and Optimization – Sourcing of Raw Materials. The intent is to encourage the use of products and materials that have life cycle information and have environmentally, economically and socially preferred life cycle impacts.

Option 1 (Disclosure) awards one point for selecting from at least five manufacturers twenty products verified to have been extracted or sourced in a responsible manner. The credit requires Corporate Sustainability Reports (CSR) from twenty different products, which means precast concrete producers with a CSR can contribute a significant number of products to this option. Responsible sourcing precast concrete approaches include commitments to long-term ecologically responsible land use, reducing environmental harms from extraction and/or manufacturing processes, and meeting applicable standards or programs voluntarily that address responsible sourcing criteria.

Option 2 (Optimization) awards one point if 25% (by cost) of all products in the building have demonstrated leadership in the sourcing of raw materials. Several pathways are provided to meet this option, including material reuse and recycling. Recycled content is the sum of postconsumer recycled content plus one-half the pre-consumer recycled content, based on cost. Products meeting recycled content criteria are valued at 100% of their cost for credit achievement calculation.

For credit achievement calculation, products sourced (extracted, manufactured, purchased) within 100 miles of the project site are valued at 200% of their base contributing cost.

Precast Concrete Approaches:
Precast concrete products can contribute to the recycled content option since most concrete contains recycled materials such as fly ash, slag and silica fume. The portion of the recycled content is calculated for the submission.

Since precast plants are often located near project sites, this additional benefit may be useful to the project team. A caveat is that structure and enclosure materials may not constitute more than 30% of the value of all compliant building products.

Building Product Disclosure and Optimization – Material Ingredients:
This item encourages using products and materials that have environmentally, economically and socially preferred life cycle impacts. The intent is to reward project teams for selecting products for which the chemical ingredients are inventoried using an accepted methodology and for selecting products that minimize the use and generation of harmful substances.

Option 1 (Disclosure) provides one point if twenty products in the building disclose chemical ingredients in their products using an accepted methodology. Option 1 requires reporting of chemical ingredients of products to at least 1% (or 1,000 ppm). Other disclosure options are a Health Product Declaration, GreenScreen™, Cradle-to-Cradle™, Declare™ or other USGBC approved programs.

Option 2 (Optimization) provides one point if 25% (by cost) of all products in the building are verified to have improved life cycle impacts by optimizing their material ingredient chemistry.

Option 3. Provides one point if 25% (by cost) of the total value of products installed are sourced from manufacturers who document at least 99% (by weight) of the ingredients used to make the building product or material. They must also use a third-party system that validates the Environmental Health and Safety program as it pertains to the chemical ingredients in the product.

For credit achievement calculation of options 2 and 3, products sourced (extracted, manufactured or purchased) within 100 miles of the project site are valued at 200% of their base contributing cost.

Precast Concrete Approaches:
Precast concrete is an inert material and has one of the lowest levels of volatile organic compounds and off-gassing when compared with other commonly used building materials, such as cross laminated wood, and can help to meet the credit requirement. See also “low emitting materials” in section ‘E’ of this document.

E. Indoor Environmental Quality Credit Category

16 points

Indoor environmental quality credits promote better indoor air quality and access to daylight and views.

Credits (precast concrete opportunity categories are listed in Green Bold Type)

Minimum Indoor Air Quality Performance	Required
Environmental Tobacco Smoke Control	Required
Enhanced Indoor Air Quality Precast Concrete Approaches	2
Low-Emitting Materials	3
Construction Indoor Air Quality Management Plan	1
Indoor Air Quality Assessment	2
Thermal Comfort	1
Interior Lighting	2
Daylight	3
Quality Views	1
Acoustic Performances	1

Low-Emitting Materials:
The intent of this credit is to reduce concentrations of chemical contaminants that can damage air quality, human health, productivity and the environment. The focus is on eliminating volatile organic compound emissions from indoor air and removing the VOC content of materials in ceilings, walls and floors.

Precast Concrete Approaches:
Precast concrete is an excellent choice for interior finish material, eliminating the need for additional material to be applied on the interior. Precast concrete is defined as an “inherently non-emitting source” of VOCs in LEED® v4 and therefore can demonstrate compliance to this credit without any VOC emissions testing. This credit is worth three points.

Daylight and Quality Views:
The intent of these credits is to provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building. Up to three points can be achieved in the Daylight category through simulation, calculation or measurement. For Quality Views, a point can be achieved with a direct line of sight to the outdoors via vision glazing for 75% of all regularly occupied floor area.

Precast Concrete Approaches:
The precast concrete approach is to design the building to maximize interior daylighting and views to the outdoors through building orientation, shallow floor plates and increased building perimeter. Precast concrete floor systems can span large distances with shallow floor plates and column free spaces to help achieve these credits. Precast concrete can also be exposed on ceilings to reflect light deep into interior spaces, thus increasing the illuminance of the space.

Acoustic Performance:
The intent of this credit is to provide workspaces and classrooms that promote occupants’ well-being, productivity and communication through effective acoustic design. Unwanted noise can be a major distraction. Project teams must meet the Composite Sound Transmission Class ratings referenced or local building code (whichever is more stringent) and meet the reverberation time requirements referenced.

New - Total Precast ASTC Guide, RR-333

New - NRC - The ASTC Rating of Constructions with Precast Concrete Hollowcore Floors

New - NRC - The Transmission Loss of 203 mm Thick Prestressed Concrete Hollowcore Floors

New - NRC - Measurement of the vibration reduction index between concrete masonry walls and precast hollow core floors Hollow Core Concrete Floors with Concrete Walls with Rigid Junctions

Precast Concrete Approaches:
Precast concrete offers excellent noise control in two ways. First, precast concrete floors and walls effectively block airborne sound transmission over a wide range of frequencies. Second, precast concrete effectively absorbs noise, thereby diminishing noise intensity. This means that precast concrete can demonstrate compliance to this credit either through calculation or measurement. This credit is worth one point.

F. Innovation Credit Category

6 points

These credits address sustainable building expertise as well as design measures not covered under the other six LEED® credit categories.

Credits (precast concrete opportunity categories are listed in Green Bold Type)

Minimum Indoor Air Quality Performance	5
LEED® Accredited Professional	1

Up to five points can be applied to the project for innovative green design using precast concrete approaches that do not fit into the point structure of the six major credit categories, or if a credit achievement goes significantly beyond the requirement in one of the existing credit categories, thereby demonstrating exemplary performance.

Another option in this credit is for the project team to adopt a Pilot Credit from the USGBC’s Pilot Credit Library.

Precast Concrete Approaches:
Previous examples have been to reduce carbon dioxide embodied in concrete by 40%. One way to accomplish this is by using high volumes of secondary cementitious materials in concrete such that the result is a decrease in embodied carbon dioxide by 40% over typical mixes. Another potential innovation is to use exposed precast concrete. This precast concrete approach would eliminate a significant quantity of wall and floor coverings along with ceiling materials. This precast concrete approach could significantly improve indoor air quality [See Energy and Atmosphere Credit Category]

Note: Credit innovations must be applied for and once used by many over a length of time are no longer considered innovative. Pilot Credits are always a good place to look.

G. Regional Priority Credit Category

4 points

This credit addresses regional environmental priorities for buildings in different geographic regions.

Credits

Regional Priority: Specific Credit	1
Regional Priority: Specific Credit	1
Regional Priority: Specific Credit	1
Regional Priority: Specific Credit	1

Regional priority credits are identified by CaGBC chapters for each “environmental zone.” A maximum of four points are available for project teams to pursue in this credit category. Each CaGBC chapter has the authority to create six potential regional priority credits, of which an applicant may pursue a maximum of four. This allows for the "regional authority" to designate target credits that are of particular importance for a region and potentially give additional credits for projects that meet criteria in existing credit categories. For example, in a region where urban heat island reduction is identified as an important goal, the CaGBC chapters could increase the points available for Sustainable Sites: Heat Island Reduction creating greater incentive for design teams to employ heat island reduction through precast concrete approaches. Since precast concrete contributes to most credit categories, it will play a significant role in achieving Regional Priority credits.

Summary

LEED® is an opportunity. The green building industry is continuing to grow, and LEED® has been a big part of that growth. Expand your AEC business by educating yourself on the LEED® v4 program. Request information from precast concrete suppliers with regard to Recycled Content, Life Cycle Assessment (LCA) Environmental Product Declaration (EPD) and ask for any other documentation that may assist you in pursuing LEED® credits under the new v4 version.

For more help with understanding Precast Concrete and LEED® v4, contact CPCI help desk support and CPCI customer support program. Please email us at helpdesk@cpci.ca or call us at 1.877.YES.CPCI (1.877.937.2724).