CONCRETE

The Sustainable Choice

Concrete Facts

About Sustainability

The ready mixed concrete industry is dedicated to upholding the principles of sustainable development-development that meets the needs of the present without compromising the ability of future generations to meet their own needs-by attempting to balance social, economic and environmental impacts.

Sustainability has become part of the fabric of society. Corporations in every industry are shaped by their customers’ desire to be more environmentally responsible. Companies that adopt sustainable practices will become preferred suppliers. While environmental performance, including greenhouse gas emissions, will be increasingly monitored and regulated, voluntary initiatives such as the one presented here will help achieve ambitious sustainability goals.

Construction industry stakeholders-including project owners, designers, contractors and product manufacturers-are especially affected by the challenges of sustainable development since the built environment has significant environmental, social and economic impact on our lives and planet. On one hand, our built environment provides us with places to live and work and contributes to a robust economy and societal needs. On the other, operating our buildings, houses and infrastructure consumes enormous amounts of energy and valuable resources. Building products require natural resources and energy to produce and transport. New construction projects can burden natural habitats.

We are dedicated to continuous improvement through product and process improvements. The industry continues to increase the use of recycled materials, including industrial by-products, thus conserving valuable natural resources and reducing process energy required to manufacture concrete. The industry continues to explore new ways to further reduce the carbon footprint through the development of innovative cements and concrete mixtures. Concrete companies also strive to improve manufacturing processes, including the use of alternative energy sources, to minimize the energy of production and the associated greenhouse gas emissions. Finally, the industry continues to enhance transportation efficiency and delivery methods to reduce the environmental impact of the construction process.

EPDs

Environmental Product Declarations

LEED v4, Architecture 2030 Challenge for Products and the International Green Construction Code request building product manufacturers to submit Environmental Product Declarations (EPDs) to demonstrate environmental performance of their products. LEED v4 provides 2 points for a project that can document: 1) having 20 products and materials with EPDs and 2) having 50% of the products by cost demonstrating lower impacts than industry baselines through EPDs. LEED v4 values different types of EPDs as follows:

  • Self declared EPDs are worth 1/4 value (not third party verified)
  • Industry average EPDs (hotlink back to location with (CRMCA +EPE+20170317)) are worth 1/2 value (third party verified)
  • Product Specific EPDs are worth full value (third party verified)

In LEED v4, a “product” is defined by the distinct function it serves. That means concrete has the advantage of contributing significantly because of concrete’s wide range of applications or functions. For example, footings, foundations walls, shear walls, bearing walls, columns, beams, slabs, sidewalks and parking areas, each with a unique mix design, would all be considered different products in LEED v4 and therefore contribute significantly to the 20 required products or the 50% of products by cost used in a building.

Click here to download a guide to specifying concrete for LEED v4 projects.

This Environmental Product Declaration (EPD) covers concrete mixes produced by Canadian Ready-Mixed Concrete Association (CRMCA) members, including Concrete BC members. This EPD was independently verified by NSF International in accordance with ISO 14025 and ISO 21930. The life cycle assessment was independently reviewed in accordance ISO 14044 and the referenced PCR.

Here’s a step-by-step instructional regarding how to use an EPD

The National Ready-Mixed Concrete Association (NRMCA) periodically presents Environmental Product Declarations (EPDs). EPDs are third party verified (certified) reports published by product manufacturers that provide quality assured and comparable information regarding environmental performance of their products. Well established in other parts of the world, EPDs are starting to appear in the US as the common methodology for assessing environmental performance of a product. The upcoming LEED v4 Rating System and Architecture 2030 Challenge for Products are starting the demand for EPDs. Join us for an informative 1-1/2 hour webinar as we offer a brief overview of EPDs, the Life Cycle Assessment (LCA) that supports them and the Product Category Rules (PCRs) that sets the ground rules for them. In addition, the webinar will discuss NRMCA’s EPD Program and present the first certified EPD for concrete in North America.

NEW Watch a Recorded Webinar on EPDs

Concrete & LEED Canada

New Construction (NC) 1.0

The Canada Green Building Council (CaGBC) has released version 1.0 of Leadership in Energy and Environmental Design (LEED) for new construction (NC) in Canada. This version, LEED Canada – NC v.1.0, references relevant Canadian legislation, standards, and government programs.

Using concrete can facilitate the process of obtaining LEED Green Building certification. LEED is a point rating system to evaluate the environmental performance of a building. The system is credit based, allowing projects to earn points for environmentally friendly actions taken during the building process.

LEED was launched in an effort to develop a “consensus-based, market-driven rating system to accelerate the development and implementation of green building practices.” The program is not rigidly structured; i.e., not every project must meet identical requirements to qualify. The flexibility in the rating system allows each project team to “select the green strategies that will best meet the project’s goals.”

The LEED rating system has five main credit categories:

  • Sustainable Sites

  • Water Efficiency

  • Energy and Atmosphere

  • Materials and Resources

  • Indoor Environmental Quality

Each category is divided into credits. Detailed information on the LEED program and project certification process is available on the CaGBC website, www.cagbc.ca. The program outlines the intent, requirements, technologies, and strategies for meeting each credit. Credits are broken down into individual points. Additional points can be earned for innovation, exceptional environmental performance, and use of a LEED-accredited professional on the project team.

A building requires at least 26 points for certification. Silver, gold, and platinum levels are also available.

14pts – Sustainable Sites
5pts – Water Efficiency
17pts – Energy and Atmosphere
14pts – Materials & Resources
15pts – Indoor Environmental Quality
65pts – Total Core LEED Rating System Points
5pts – Innovation & Design Process Points

The following are suggestions for earning LEED points through the use of cement and concrete products. The designations correspond to LEED ratings system credit categories.

(Sustainable Sites Credit 3)

Cement can be used to solidify and stabilize contaminated soils and reduce leaching concentrations to below regulatory levels. Documentation is required indicating the site was contaminated and the remediation performed. This credit is worth 1 point.

(Sustainable Sites Credit 5.1)

Concrete parking garages on the lower floors of a building can be used to limit site disturbance, including earthwork and clearing vegetation. For example, one criterion is to limit site disturbance to 12m (40 ft) beyond the building perimeter. Parking garages within buildings help maintain existing natural areas that would be consumed by paved parking. This credit is worth 1 point.

(Sustainable Sites Credit 5.2)

Concrete parking garages on the lower floors of a building can be used to help reduce the footprint of the development. In this context the building footprint includes the building, access roads, and parking. Parking garages within buildings reduce the building footprint by reducing paved parking areas. This requirement can be met by exceeding the local zoning’s open space requirement for the site by 25%. This credit is worth 1 point.

(Sustainable Sites Credit 6.1)

The intent of this credit is to limit disruption and pollution of natural water flows by managing storm water runoff. Using pervious concrete will reduce the rate and quantity of storm water runoff because it increases infiltration of stormwater. Pervious concrete contains coarse aggregate, little or no fine aggregate, and insufficient cement paste to fill the voids between the coarse aggregate. It results in concrete with a high volume of voids (20% to 35%) and a high permeability that allows water to flow through easily. On building sites where the existing imperviousness is greater then 50%, the technical requirement for this credit requires reducing the rate and quantity of stormwater runoff by 25%. On building sites where the existing imperviousness is less than 50%, the requirement specifies that the post-development discharge rate and quantity from the site shall not exceed the pre-development rate and quantity. This credit is worth 1 point.

(Sustainable Sites Credit 7.1)

Use light-colored/high-albedo materials (reflectance of at least 0.3) for at least 30% of the site’s non-roof impervious surfaces. This requirement can be met by using portland cement concrete, rather than asphalt for 30% of all sidewalks, parking lots, drives and other impervious surfaces. Another option include placing a minimum of 50% of parking spaces underground or covered by structured parking.

Albedo, which in this context is synonymous with solar reflectance, is the ratio of the amount of solar radiation reflected from a material to the amount that shines on the material. Solar radiation includes the ultraviolet as well as the visible spectrum. Generally, light-colored surfaces have a high albedo, but this is not always the case. Surfaces with lower albedos absorb more solar radiation. The absorbed radiation is converted into heat and the surface gets hotter. Where paved surfaces are required, using materials with higher albedos will reduce the heat island effect—consequently saving energy by reducing the demand for air conditioning—and improve air quality. As the temperature of urban areas increases, so does the probability of smog and pollution. Smog episodes rarely occur when the temperature is below 21°C.

Portland cement concrete generally has a reflectance of approximately 0.35, although it can vary. Measured values are reported in the range of 0.4 to 0.5. For “white” portland cement, values are reported in the range of 0.7 to 0.8. New asphalt concrete generally has a reflectance of approximately 0.05, and asphalt concrete five or more years old has a reflectance of approximately 0.10 to 0.15. This credit is worth 1 point.

(Energy & Atmosphere Prerequisite Credit 2)

All new buildings must demonstrate energy savings using a whole building energy simulation program. The two compliance paths for new buildings are (1) to show that the building complies with Natural Resources Canada’s Commercial Building Incentive Program (CBIP) requirement by reducing energy consumption by at least 25% relative to the Model National Energy Code for Buildings 1997 (MNECB), or (2) to reduce energy cost consumption of the building by at least 18% relative to ASHRAE/IESNA 90.1-1999.

The 2 compliance paths for major renovations to existing buildings are to (1) reduce energy consumption by at least 10% relative to the MNECB, or (2) comply with ASHRAE/IESNA 90.1-1999.

Many engineering consulting firms have the capability to perform whole building energy simulations to determine energy consumption and costs as required using computer-based programs such as CBIP-EE4, DOE2 or EnergyPlus. When concrete is considered, it is important to use programs like these that calculate yearly energy use on an hourly basis. Such programs are needed to capture the beneficial thermal mass effects of concrete.

Components constructed of concrete generally are considered “mass.” This means the components have enough heat-storage capacity to moderate daily temperature swings. Buildings constructed of cast-in-place, tilt-up, and insulating concrete forms (ICF) possess thermal mass which helps moderate indoor temperature extremes and reduces peak heating and cooling loads. Thermal mass can make a significant contribution to energy savings; this is demonstrated when mass is incorporated into an energy consumption simulation program. When buildings are properly designed and optimized, incorporating thermal mass can lead to a reduction in heating, ventilating, and air-conditioning equipment capacity. Reduced equipment capacity can represent energy and construction cost savings. This item is required and is not worth any points.

(Energy Credit 1)

This credit is allowed if energy cost savings can be shown compared to a base building that meets the requirements of MNECB or ANSI/ASHRAE/IESNA 90.1-1999. Insulated concrete which exhibits the prerequisite thermal mass characteristics noted above, will most likely be eligible for points when used in conjunction with other energy savings measures,. The number of points awarded will depend on the building, climate, fuel costs, and minimum requirements of the standards.

When using MNECB, from 1 to 10 points are awarded for energy cost savings of 24% to 64% for new buildings and 15% to 55% for existing buildings. When using ASHRAE/IESNA 90.1-1999, from 1 to 10 points are awarded for energy cost savings of 15% to 60% for new buildings and 5% to 50% for existing buildings.

(Materials Credit 1)

The purpose of this credit is to leave the main portion of the building structure and shell in place when renovating. The building shell includes the exterior skin and framing but excludes window assemblies, interior walls, floor coverings, and ceiling systems. This credit should be obtainable when renovating buildings with a concrete skin, since concrete in buildings generally has a long life. This is worth 1 point if 75% of the existing building structure/shell is left in place, 2 points if 95% is left in place, or 3 points if 50% of non-shell areas are maintained.

(Materials Credit 2)

This credit is received for diverting construction, demolition, and land clearing waste from landfill disposal. It is awarded based on diverting at least 50% by weight or volume of the above listed materials. Since concrete is a relatively heavy construction material and is frequently crushed and recycled into aggregate for road bases or construction fill, this credit should be obtainable when concrete buildings are demolished. This credit is worth 1 point if 50% of the construction, demolition, and land clearing waste is recycled or salvaged and 2 points for 75%.

For concrete, either the credit for building reuse or the credit for construction waste management can be applied for, but not both, because the concrete structure is either reused or recycled into another use.