Note: This is the first article of a three-part series covering green building plastics (1) trends, (2) material/process advances and (3) applications.

The construction and operation of buildings has a significant impact on the environment. In the U.S., buildings account for 39 percent of total energy consumption and 38 percent of carbon dioxide emissions. Buildings also use a tremendous amount of natural resources to construct and operate.

Constructing green buildings that consume resources more efficiently has become one of the primary goals in the industry. In turn, this will minimize pollution that can harm renewable natural resources that are crucial to a sustainable future.

"Green building," the practice of minimizing the impact a building has on the natural environment, has several clear goals:

• Select building materials and methods that conserve resources and materials required to construct a building
• Create a healthy indoor environment for occupants, free from volatile organic compounds (VOCs), mold or other harmful airborne pollutants.Studies have shown that healthy indoor environments can improve employee and student productivity
• Reduce energy consumption and fossil fuel use to heat, cool and illuminate the building. In addition to benefiting the environment, energy-efficient buildings cost less to operate
• Incorporate water-conserving systems that limit the use and prevent water pollution of this important natural resource

Green building regulatory trends

At the recent Greenbuild International Conference and Exhibition in New Orleans, several important global regulatory trends influencing plastics use in building and construction were highlighted.

Green building legislation, regulation and certification is here to stay in plastic building and construction applications. Significant potential cost-effective energy savings and CO₂ emissions reductions exist in new and existing buildings.

The Directive on Energy Performance in Buildings (EPBD), Directive 2010/31/EU, has been the main legislative instrument affecting energy use and efficiency in the EU building sector. It tackles both new construction and existing building stock in all sectors. This recast directive significantly increases energy efficiency ambition levels in EU buildings well into this future decade.

Major provisions of Recast Directive 2010/31/EU:

• As of Dec. 31, 2020, new buildings in the EU will have to consume "nearly zero" energy, and the energy will be "to a very large extent" from renewable sources (Dec. 31, 2018 for public buildings)
• No specific target is set for existing buildings renovation, but EU member states are advised to take measures for stimulation of low-energy refurbishments
• Minimum requirements for components are introduced for renovations and replacements

Individual goals set by member states are:

• United Kingdom: Zero-carbon homes by 2016 (heating and lighting)
• Hungary: Zero-emission buildings by 2020 (Climate Change Strategy)
• Netherlands: Energy-neutral buildings by 2020
• France: Energy-positive buildings by 2020

Returning to the U.S., the CALGreen Code is the first mandatory statewide standards code in the U.S. that addresses green construction to fight climate change. Formerly a voluntary standard, CALGreen was substantially modified and reissued as a statewide mandatory code for state-owned buildings, low-rise residential buildings, qualified historical buildings, general acute care hospitals, and public elementary and secondary schools. This code has been effective since Jan. 1, 2011.

California Green Building Standards Code (CALGreen) requires that every new building constructed in California:

• Install low pollutant-emitting materials
• Divert 50 percent of construction waste from landfills
• Reduce water consumption by 20 percent
• Install separate water meters for nonresidential buildings' indoor and outdoor water use
• Include mandatory inspections of energy systems (furnace, air conditioner, mechanical equipment) for nonresidential buildings greater than 10,000 square feet to ensure operating efficiencies relative to design

Leadership in Energy and Environmental Design (LEED) is an internationally-recognized green building certification system developed by the U.S. Green Building Council (USGBC). LEED is intended to provide building owners/operators a concise framework for identifying and implementing practical and measurable green building design, construction, operations and maintenance solutions.

LEED promotes sustainable building and development practices through a suite of rating systems. Categories include:

• Green Building Design & Construction
• Green Interior Design & Construction
• Green Building Operations/Maintenance
• Green Neighborhood Development
• Green Home Design and Construction

Plastics Institute of America
Green building energy flows.

Buildings as consumers of energy can implement technology for improving energy efficiency of buildings:

• Green design/green materials
• Improved insulation
• Heat recovery
• No thermal bridges — a thermal bridge is the penetration of the insulation layer by a highly conductive or noninsulating material that occurs in the separation between the interior (or conditioned space) and exterior environments of a building assembly or envelope. The main thermal bridges in a building are found at the junctions of facings and floors, facings and cross walls; facings and roofs, facings and low floors. They also occur each time there is a hole (doors, windows, electrical connections, etc.)
• District heating

Buildings as producers of energy can implement technology for producing energy and increasing the share of renewable energy:

• Photovoltaic solar cells
• Solar collectors
• Combined heat and power generators
• Wind turbines

Key green building plastics trends

Composite masonry

• Patented technology transforms post-consumer recycled rubber and plastics into naturally appearing, strong, durable environmentally friendly composite masonry
• The injection molded composite masonry is composed of 95 percent post-consumer PVC (polyvinyl chloride), HDPE (high density polyethylene), tire crumb rubber and compatibilizers
• The bricks are supplied with an underlying grid system that automatically aligns and spaces them, significantly reducing installation time
• Compared to molded concrete and traditional clay bricks and pavers, the composite masonry:
  • Weighs two-thirds less
  • Requires 85 percent less energy in manufacturing
  • Needs no water in the production process
  • Emits 95 percent less CO₂
  • Has inherent resistance to mold or mildew
  • Has excellent strength with a lifetime warranty against cracking in residential applications
  • Is slip resistant

AZEK Pavers
Composite masonry.

Next generation structural insulated panel systems (SIPs)

• Patented Thermocore SIPs use polyurethane foam with an R-Value of 7.0-7.5 per inch versus EPS (expanded polystyrene) with an R-Value of 3.5-4.0 per inch
• The newly patented Thermocore SIPs are the first in the industry to accommodate standard door/window jambs while providing maximum energy efficiency
• Compared to EPS panels, PUR (polyurethane) panels also offer:
  • Better fire resistance
  • Better moisture and chemical resistance
  • Greater density for greater strength
  • Less environmental impact

Thermocore Panel Systems
Structural insulated panel systems.

Heat-stopping acrylic sheet

• Infrared-reflecting Acrylite Heatstop sheet limits heat entering a building by reflecting a large portion of incident solar radiation
• By using proprietary Heatstop acrylic sheet in place of traditional acrylic glazing material, average annual air conditioning costs can be reduced by as much as 33 percent
• When replacing a standard skylight white diffusing material with the performance-formulated Acrylite Heatstop sheet, heat buildup indoors was cut nearly in half while light transmission stayed the same

Evonik
Heat-stopping acrylic sheet.