by Christopher Green, AIA, and Ravi Shah, Assoc. AIA

It is past time for the construction and regulatory industries to establish minimum standards for the performance of buildings in relation to resource consumption including but not limited to water, energy, and land. A green construction code is the clearest way toward developing a strong foundation for this effort. That raises the question: What are the fundamental differences among rating systems, standards, and codes? This is a question we field frequently from architects and others in the building industry, and to help frame the rationale for creating the new International Green Construction Code, we’ve outlined a comparison of these three different concepts below.

Building codes
Building codes are an enforceable body of rules that govern the design, construction, alteration, and repair of buildings. Code books are an essential aid to architects, engineers, designers, and builders for creating buildings that comply with the code adopted by a jurisdiction. Such codes are based on requirements for the safety, health, and quality of life of building users and neighbors, and vary from city to city, state to state. Model codes developed by a consensus-based process of stakeholder groups are typically adopted by local communities, with local amendments respective of climate and regional construction practice.

Municipalities generally adopt codes on a three-year cycle and employ building officials to review and recommend code adoptions or revisions. The established review process allows a code to take into consideration appropriate local conditions affecting the sustainability of resources particular to the region. Once adopted, the code becomes a clear and unwavering guide to the architect with responsible control of the project until the next cycle of that code is adopted, and it becomes part of the standard of care an architect must follow. An established code development cycle provides architects and building officials with the opportunity to understand new code requirements and work together in applying these requirements, assuring the public of a reasonable level of and application to their project, ensuring the protection of health, safety, and welfare.

Building codes, as the governing body of rules over a jurisdiction for buildings, are not intended to be flexible and are enforceable to the letter of the code or, as code officials say, “compliant with the minimum standard.” Unlike standards and rating systems, codes are not optional or permissive once adopted. Building codes are written in precise language meant to be enforceable. An example of compliance language from the 2006 IRC:

N1101.2 Compliance. Compliance shall be demonstrated by either meeting the requirements of the International Energy Conservation Code or meeting the requirements of this chapter. Climate zones from Figure N1101.2 or Table N1101.2 shall be used in determining the applicable requirements from this chapter.

An ICC code effort is an important step in establishing accepted, uniform national minimum standards toward the creation of highly sustainable and resource-efficient architecture.

Building standards
Standards, for example the ICC 700 National Green Building Standard or ASHRAE 90.1, typically outline a series of options for performance of building systems and assemblies and are often referenced by codes but are not strictly enforceable due to the provisions for multiple options, unless adopted by a jurisdiction as its code, which is rare and presents problems, as they are not meant to be enforceable. Standards do not reference codes, whereas codes sometimes reference standards as options for compliance.

A standard is most appropriately applied to things that everyone does that are not quite regulation or are considered optional and then are agreed to by a consensus of stakeholders (see below). This use derives from the American National Standards Institute (ANSI) as well as the International Organization for Standardization (ISO) standards. Architects, consulting engineers, and builders are the most common audience for standards, looking to the documents for options when approaching the design and construction of code-compliant buildings.

Many of the mandatory measures found in the National Green Building Standard are consistent with the International Code Council's I-Codes. Additionally, the baseline for energy savings has been updated to the IECC 2006. To qualify for "Bronze" in the energy efficiency chapter of the ICC 700, a home must be at least 15 percent better than the 2006 IECC (ENERGY STAR™ equivalent).

An example of compliance language in a standard, in this case ICC 700:

701.1.1 Minimum Performance Path requirements. A building complying with Section 702 shall exceed the baseline minimum performance required by the ICC IECC by 15 percent, and shall include a minimum of two practices from section 704.

From ANSI’s Web site:

Building rating systems
Historically, a rating system, such as fire safety ratings of materials or other safety rating systems, was referenced in the code to describe acceptable minimum requirements for materials or systems in a building. Independent bodies test and rate the products or materials and an official label and documentation would be required for the product before offering it in the marketplace, subject to on-site inspection by a code official. Since the emergence of total or green building rating systems, the purpose has spread from safety to energy and environmental impact, and through the development of a complex series of prerequisites and options, rating systems strive to rate the overall performance of a building. Unlike product safety rating systems, green rating systems are intended to be voluntary. But in recent years, due to a lack of enforceable green codes, states have begun to incorporate them into requirements for public or state owned construction.

There are now two established building rating systems in the marketplace. In response to architects’ questions about how current rating systems in the marketplace stack up to the goal of reaching carbon neutral buildings by 2030, the AIA developed a position statement on rating systems outlining 16 major criteria. The AIA maintains a position of neutrality regarding rating systems currently available in the marketplace to promote the choice of the best tool for each individual project, act as a voice for its members to address concerns about those systems, and act as a collaborative critique for continuous improvement of all rating systems as tools for architects and the building, design, and construction industry. Rating systems can be modified on a more frequent and less regulated cycle, which can create a set of unique challenges to design professionals and owners seeking to use the rating system.

Rating systems are typically above and beyond code—they aspire to a set of criteria for construction and performance, not minimums. To use the carrot/stick metaphor, rating systems are a carrot system, rewarding above-and-beyond performance, while a building code enforces penalties for not meeting a minimum. The rating systems are owned by, administered for, or otherwise operated by nonprofit organizations or local governments and may generate profits either for the owner organization or for the rating body or individuals commissioning the building to that system. There is an emerging cottage industry associated with the rating of buildings that is independent of the licensing requirements for professionals such as engineers and architects.

If a jurisdiction calls for compliance with a rating system, it has been effectively codified. But enforcement of the requirement presents some challenges to the jurisdiction, introducing tremendous education and training hurdles for code officials, depending on the complexity of the rating system. If a rating system is tied to a code in some way, codifying the rating system effectively enforces that code. Building officials are able only to enforce a code and does so by plan review, inspections, and permits (with related fees) received by the municipality governing the project. A building official is not necessarily legally obligated trained to, or has the staff to enforce a rating system. Their time is sometimes not compensated, as fees are paid to a rating organization, not the municipality. Thirty-six states have public building requirements that call out at least one rating system. Examples of ratings systems include LEED, Green Globes, and Energy Star.

Below is an example showing how a rating system treats complying to a building performance line item in a standard, in this case EnergyStar:

To qualify for the ENERGY STAR, a building or manufacturing plant must score in the top 25 percent based on EPA's National Energy Performance Rating System. To determine the performance of a facility, EPA compares energy use among other, similar types of facilities on a scale of 1-100; buildings that achieve a score of 75 or higher may be eligible for the ENERGY STAR. The EPA rating system accounts for differences in operating conditions, regional weather data, and other important considerations.

Rating systems go beyond outlining an industry’s consensus on a topic by starting with standards-level definitions and outlining options that correlate to a rating level, such as LEED Silver or Energy-Star “compliant.” At times, because the system may be owned by an organization or governmental body, they may not be developed with consensus input of all stakeholder groups; rather a select group favorable to that organization. Next-generation rating systems, such as the Living Building Challenge, go beyond the options and set strict prerequisites for building performance.