Sustainability of the Building Envelope

Since the early 1990s, sustainability has become an increasing priority for facilities projects. It is no secret that building construction and operation have an enormous direct and indirect impact on the environment in terms of energy use, atmospheric emissions, use of raw materials, waste generation, water use, and many other factors. As the economy and population continue to expand, the design, construction and operation community will face increasing challenges to meet the new demands for facilities that are accessible, secure, healthy, and productive while minimizing their impact on the environment.

For the design, construction and operation of a facility, there is an especially important interface between the indoor and outdoor environments, that of the building envelope. The building envelope is comprised of the outer elements of a building—foundations, walls, roof, windows, doors and floors. The prime functions of the building envelope are to provide shelter, security, solar and thermal control, moisture control, indoor air quality control, access to daylight, and views to outside, fire resistance, acoustics, cost effectiveness and aesthetics. Because of the varied and sometimes competing functions associated with the building envelope, an integrated, synergistic approach considering all phases of the facility life cycle is warranted. This "sustainable" approach supports an increased commitment to environmental stewardship and conservation, and results in an optimal balance of cost, environmental, societal, and human benefits while meeting the mission and function of the intended facility.

Figure 1. Source: EPA, USGBC

Description

The main objectives of sustainable design are to avoid resource depletion of energy, water, and raw materials; prevent environmental degradation caused by facilities and their infrastructure throughout their life cycle; and create built environments that are accessible, secure, healthy, and productive.

While the definition of what constitutes sustainable building design, construction and operation is constantly evolving, there are six fundamental principles that nearly everyone agrees on.

Fundamentals

Following are sustainability recommendations pertaining to the design and construction of the building envelope.

Optimize Site Potential

Photo of high-reflectance, high emissivity roofing

Figure 2. Energy Star® Roof-compliant, high-reflectance, and high emissivity roofing can lower roof surface temperature by up to 100°F, decreasing the amount of heat transferred into a building.

Optimize Energy Use

Photo of a PV skylight entry

Figure 3. A PV skylight entryway
Courtesy of DOE/NREL

Figure 4. EnergyPlus™ Screen Captures
Courtesy DOE

Figure 5. Air Leakage through a Building Enclosure

While the LEED® Green Building Rating System requires buildings to undergo Fundamental Building Commissioning of systems to achieve certification, it merely recommends that some form of building envelope commissioning be incorporated. Lemieux and Totten have proposed a Building Envelope Commissioning process that could supplement the Fundamental Building Commissioning required for LEED® certification.

Protect and Conserve Water

Photo of rainwater harvesting for reuse in landscape irrigation

Figure 6. Rainwater harvesting for reuse in landscape irrigation
Courtesy of Texas Water Development Board

Use Environmentally Preferable Products

Figure 7. Viewed over a 30 year period, initial building costs account for approximately just 2% of the total, while operations and maintenance costs equal 6%, and personnel costs equal 92%.
Source: Sustainable Building Technical Manual

Enhance Indoor Environmental Quality

Graph of thermal environmental conditions for human occupancy from ASHRAE 55-2004

Figure 8.
Courtesy ASHRAE Standard 55-2004, Thermal Environmental Conditions for Human Occupancy.

Photo of the architectural entries of the EPA Kansas City Regional Office

Figure 9. The architectural entries of the EPA Kansas City Regional Office are designed to prevent undesirable air particles from entering the building. Originally conceived as a permanent grating "walk-off system," an easier to maintain stone floor with walk-off carpets was eventually utilized offering lower capital and operational costs.

Courtesy of GSA and Koll Construction

Optimize Operations and Maintenance Practices

Applications

The benefits of high performance, sustainable design, construction and operation are universal. All different types of buildings, including office buildings, schools, hospitals, libraries, courthouses, and research facilities, can and should incorporate sustainable and high performance strategies and systems that consider the entire building life cycle, above and beyond just the elements associated with the building envelope.

Emerging Issues

Balancing Security/Safety and Sustainability Objectives—Providing for sustainable designs that meet all facility requirements is often a challenge to the building design, construction and operation community. With limited resources it is not always feasible to provide for the most secure facility, the most architecturally expressive design, or energy efficient building envelope. From the concept stage through the development of construction documents, it is important that all project or design stakeholders work cooperatively to ensure a balanced design. Successful designs must consider all competing design objectives.

Integrated Design—Designers are moving away from the conventional building design approach that has historically resulted in little interaction between all parties involved in the project. There is a movement to embrace integrated building design, fostering communication amongst all parties that could be involved in the project, and facilitating working together from the start to coordinate and optimize the design of the site and the building.

Relevant Codes and Standards

Additional Resources

Publications

Organizations

Others