The Case for Green Neighborhood Developments
Green neighborhoods are an integral part of the solution to the environmental challenges facing the planet.
Today we use the equivalent of 1.5 Earths to meet the resource needs of everyday life and absorb the resulting wastes. This measure of our planet’s carrying capacity means that it takes Earth 18 months to regenerate what is used in only 12 months. If current trends continue, estimates suggest, by the year 2030 we will need the equivalent of two planets.1 Turning resources into waste faster than they can be regenerated puts the planet into ecological overshoot, a clearly unsustainable condition that we all must address.
The forces driving this situation are numerous. Human population has increased exponentially in the past 60 years, from about 2.5 billion in 1950 to more than 7 billion today. Our linear use of resources, treating outputs as waste, is responsible for the toxins that are accumulating in the atmosphere, in water, and on the ground. This pattern of extraction, use, and disposal has hastened depletion of finite supplies of nonrenewable energy, water, and materials and is accelerating the pace of our greatest problem—climate change.
The challenges are especially acute in cities, which also face issues like food security, economic competitiveness, and fiscal austerity. More than half of the world’s population now lives in urban rather than rural areas, and the urban share is predicted by the United Nations to rise to 70% by 2050, with the emergence of megacities of 10 million to 20 million people.2 Rapid urbanization and natural resource stresses will significantly shape urban redevelopment and greenfield growth in the decades ahead, and the problems must be effectively addressed if communities are to become more sustainable.
The impetus behind development of the Leadership in Energy and Environmental Design (LEED) rating systems was recognition of those problems, coupled with awareness that the design and construction industry already had the expertise, tools, and technology to transform buildings and make significant advances toward a sustainable planet. LEED projects throughout the world have demonstrated the benefits of taking a green design approach that reduces the environmental harms of buildings and restores the balance of natural systems.
Since the bulk of urban growth is forecast to occur in communities of 100,000 to 250,000 people, neighborhoods will be the fundamental units of urban change and innovation. At the neighborhood level, these “drawing boards” can catalyze LEED for Neighborhood Development (ND) strategies, such as affordable housing, climate protection, and improved public health. Rapid urbanization requires community planning processes that are ideal for green intervention and transformation. Opportunities for sustainable solutions range from small green business start-ups to large-scale ecosystem services.
Growing evidence points to a strong public preference for sustainable built environments, including LEED ND’s core elements of traditional neighborhood design and multimodal travel. The National Association of Realtors recently found that two-thirds of households would prefer a smaller home within walking distance of restaurants, shops, and schools over a large-lot property farther away.3 With tools like LEED ND, neighborhoods can become exemplars of innovative leadership in achieving sustainability goals.
Developed by the U.S. Green Building Council, LEED is a framework for identifying, implementing, and measuring green building and neighborhood design, construction, operations, and maintenance. LEED is a voluntary, market driven, consensus-based tool that serves as a guideline and assessment mechanism. LEED rating systems address commercial, institutional, and residential buildings and neighborhood developments.
LEED seeks to optimize the use of natural resources, promote regenerative and restorative strategies, maximize the positive and minimize the negative environmental and human health consequences of the construction industry, and provide high-quality indoor environments for building occupants. LEED emphasizes integrative design, integration of existing technology, and state-of-the-art strategies to advance expertise in green building and transform professional practice. The technical basis for LEED strikes a balance between requiring today’s best practices and encouraging leadership strategies. LEED sets a challenging yet achievable set of benchmarks that define green building for interior spaces, entire structures, and whole neighborhoods.
LEED for New Construction and Major Renovations was developed in 1998 for the commercial building industry and has since been updated several times. Over the years, other rating systems have been developed to meet the needs of different market sectors. The LEED ND rating system was launched in May 2009 after four years of development and pilot testing by a partnership of the USGBC, the Natural Resources Defense Council, and the Congress for the New Urbanism.
Since its launch, LEED has evolved to address new markets and building types, advances in practice and technology, and greater understanding of the environmental and human health effects of the built environment. These ongoing improvements, developed by USGBC member-based volunteer committees, subcommittees, and working groups in conjunction with USGBC staff, have been reviewed by the LEED Steering Committee and the USGBC Board of Directors before being submitted to USGBC members for a vote. The process is based on principles of transparency, openness, and inclusiveness.
The LEED rating systems aim to promote a transformation of the construction industry through strategies designed to achieve seven goals:
- To reverse contribution to global climate change
- To enhance individual human health and well-being
- To protect and restore water resources
- To protect, enhance, and restore biodiversity and ecosystem services
- To promote sustainable and regenerative material resources cycles
- To build a greener economy
- To enhance social equity, environmental justice,community health, and quality of life
These goals are the basis for LEED’s prerequisites and credits. In the LEED ND rating system, the major prerequisites and credits are categorized as Smart Location and Linkage (SLL), Neighborhood Pattern and Design (NPD), and Green Infrastructure and Buildings (GIB).
The goals also drive the weighting of points toward certification. Each credit in the rating system is allocated points based on the relative importance of its contribution to the goals. The result is a weighted average: credits that most directly address the most important goals are given the greatest weight. Project teams that meet the prerequisites and earn enough credits to achieve certification have demonstrated performance that spans the goals in an integrated way. Certification is awarded at four levels (Certified, Silver, Gold, Platinum) to incentivize higher achievement and, in turn, faster progress toward the goals.
BENEFITS OF USING LEED
LEED is designed to address environmental challenges while responding to the needs of a competitive market. Certification demonstrates leadership, innovation, environmental stewardship, and social responsibility. LEED gives building owners and operators the tools they need to immediately improve both building performance and the bottom line while providing healthful indoor spaces for a building’s occupants.
LEED-certified developments are designed to deliver the following benefits:
- Lower operating costs and increased asset value
- Reduced waste sent to landfills
- Energy and water conservation
- More healthful and productive environments for occupants
- Reductions in greenhouse gas emissions
- Qualification for tax rebates, zoning allowances, and other incentives in many cities
In particular, LEED ND benefits are distinguished by the following:
- Scale. The sheer quantity of green benefits is magnified when captured at the neighborhood scale, often including dozens or hundreds of buildings and thousands of occupants.
- Comprehensiveness and synergies. Neighborhood planning is inherently comprehensive, and that all-inclusive scope enables unique opportunities to capture synergistic benefits. An example is rainwater management accomplished, in part, at an outdoor civic space that infiltrates runoff.
- Longevity. Once designed and constructed, neighborhoods may persist for hundreds of years. A sustainable neighborhood design, therefore, pays green dividends for generations, cumulatively a much larger return than on most other green investments.
By participating in LEED, owners, operators, designers, and builders make a meaningful contribution to the green building industry. By documenting and tracking resource use, they contribute to a growing body of knowledge that will advance research in this rapidly evolving field. This will allow future projects to build on the successes of today’s designs and bring innovations to the market.
LEED CERTIFICATION PROCESS
The process begins when the owner selects the rating system and registers the project (see Rating System Selection). The project is then designed to meet the requirements for all prerequisites and for the credits the team has chosen to pursue. After documentation has been submitted for certification, a project goes through preliminary and final reviews. The preliminary review provides technical advice on credits that require additional work for achievement, and the final review contains the project’s final score and certification level. The decision can be appealed if a team believes additional consideration is warranted.
LEED has four levels of certification, depending on the point thresholds achieved:
- Certified, 40–49 points
- Silver, 50–59 points
- Gold, 60–79 points
- Platinum, 80 points and above
CERTIFICATION OPTIONS FOR LEED ND
The LEED for Neighborhood Development rating system comprises two adaptations, LEED ND: Plan and LEED ND: Built Project, which have certification options unique to this rating system.
Smart Location & Linkage (SLL) and Neighborhood Pattern & Design (NPD) prerequisite review. If the project team has any doubts about the project’s ability to achieve the SLL or NPD prerequisites, this optional review can be a useful official determination before investing further in submission preparation. It is available to both LEED ND: Plan and LEED ND: Built Project registered projects.
Letter of Support optional review. This full review of all prerequisites and credits is available to projects registered under LEED ND: Plan that have not earned all land-use entitlements. Applicants seeking an early design-phase award from USGBC to assist with local approvals may elect to undergo this review and will receive a letter of support if successful.
1 Global Footprint Network, footprintnetwork.org/en/index.php/gfn/page/world_footprint/, accessed September 11, 2012.
2 UN Habitat Global Report on Human Settlements, 2009.
3 National Association of Realtors, 2011 Community Preference Survey.
How to use this Reference Guide
This reference guide is designed to elaborate upon and work in conjunction with the rating system. Written by expert users of LEED, it serves as a roadmap, describing the steps for meeting and documenting credit requirements and offering advice on best practices.
Within each section, information is organized to flow from general guidance to more specific tips and finally to supporting references and other information. Sections have been designed with a parallel structure to support wayfinding and minimize repetition.
PROJECTS OUTSIDE THE U.S.
The International Tips section offers advice on determining equivalency to U.S. standards or using non-U.S. standards referenced in the rating system. It is meant to complement, not replace, the other sections of the credit.
Helpful advice for projects outside the U.S. may also appear in the Step-by-Step Guidance section of each credit. When no tips are needed or available, the International Tips heading does not appear.
Units of measurement are given in both Inch-Pound (IP) and International System of Units (SI). IP refers to the system of measurements based on the inch, pound, and gallon, historically derived from the English system and commonly used in the U.S. SI is the modern metric system used in most other parts of the world and defined by the General Conference on Weights and Measures.
Where “local equivalent” is specified, it means an alternative to a LEED referenced standard that is specific to a project’s locality. This standard must be widely used and accepted by industry experts and when applied, must meet the credit’s intent leading to similar or better outcomes.
Where “USGBC-approved local equivalent” is specified, it means a local standard deemed equivalent to the listed standard by the U.S. Green Building Council through its process for establishing non-U.S. equivalencies in LEED.
TAKING AN INTEGRATIVE APPROACH TO NEIGHBORHOOD DEVELOPMENT
An important starting point for project certification is the formulation of overarching goals to guide the project team’s work toward successful certification. To set valid goals, start by expressing objectives that are derived from or responsive to the following:
- The developer’s mission. One of the strongest motivations for project certification should be the developer’s values and organizational aims. Whether the project is undertaken by for-profit investors or nonprofit community interest organizations, LEED ND strategies can be tailored to make a strong triple-bottom-line case for certification.
- The project’s environmental setting. The degree of environmental sensitivity on and around a project site creates both responsibilities and opportunities for leadership and innovation. LEED ND offers a full set of natural resource measures for demonstrating stewardship and helping achieve local environmental goals.
- The project’s community context. The social and economic conditions of the surrounding community, and its overall sustainability goals, are factors that should influence project goal-setting and credit selection. LEED ND strategies can be applied to such community issues as jobs and housing balance, affordable housing, and universal visitability.
TEAM MEMBERS AND RELEVANT ORGANIZATIONS
For the purposes of LEED ND, the project team has three major components: the applicant acting as team leader, a multidisciplinary group of design professionals, and local supporting partners. The applicant is the entity that decides to certify a project under LEED ND. This can be a property owner or developer composed of individuals or companies that control a majority of the area within a project boundary, either through ownership and/or options to purchase. A property owner or developer can join with any combination of the following as joint applicants: another property owner or developer, a nonprofit organization, a homeowners association, or a public or quasi-public agency, such as a housing authority, redevelopment authority, or business improvement district.
Because the rating system integrates smart growth, new urbanism, social equity, and green building practices, a successful LEED ND submission draws on the diverse skills of a comprehensive team of professionals. The rating system can require expertise in many professions, depending on project characteristics and credits attempted. Ensuring that a team has appropriate technical skills is crucial for successful projects and certifications, and the owner or developer should consider which of the following professions need to be represented on the project team:
- Urban planning
- Civil engineering
- Transportation planning
- Mechanical and electrical engineering
- Landscape architecture
- Biology and botany
At least one member of the project team should be a LEED ND Accredited Professional experienced in certifying the kind of project being proposed. Having qualified LEED ND knowledge and insight on the team will aid considerably in efficient and accurate preparation of submission documentation.
In addition to assembling a multidisciplinary and LEED ND–experienced project team, it is also important to consider local partners—the public agencies with authority or services that affect certain credits, or interested nonprofits with allied goals—when starting a submission. Project teams should identify local partners during credit selection, make them aware of the project, and seek their assistance with submission documentation where appropriate.
Devising a LEED Work Plan
It is recommended that LEED applicants follow a series of steps to certification.
STEP 1. IDENTIFY PROJECT SITE AND PREPARE PRELIMINARY DEVELOPMENT PROGRAM
Site selection is normally done with general development objectives in mind, along with information about available properties and market conditions in a given area. USGBC encourages the informal use of LEED ND location criteria in the site selection process. Properties chosen with LEED ND in mind and sites that already align with LEED ND principles will be easier to certify. Standard protocol is to prepare a preliminary development program once a prospective site is identified, and if a financial assessment of that program indicates project feasibility, control of the site is acquired through purchase, option to purchase, lease, or equivalent agreements.
STEP 2. SELECT RATING SYSTEM
The LEED system comprises 21 adaptations designed to accommodate the needs of a variety of market sectors (see Rating System Selection Guidance). The project team leader should confirm that LEED ND is the most suitable LEED rating system for the project. Some projects pursue LEED ND as well as several LEED building rating systems simultaneously. Certain multiple-building projects may want to investigate the USGBC Campus Program, which is not a rating system but a certification process.
Assuming LEED ND is the appropriate choice, the project team leader should also confirm which of two LEED ND rating systems is applicable to the project:
- LEED ND: Plan. A project must use the LEED ND Plan rating system if it is in a planning stage or has constructed less than 75% of its total building floor area.
- LEED ND: Built Project. If a project is at full build-out, it must use the LEED ND rating system.
The LEED ND: Plan and LEED ND: Built Project rating systems have identical credit requirements but differing documentation requirements and awards.
STEP 3. ASSEMBLE PROJECT TEAM AND IDENTIFY RELEVANT ORGANIZATIONS
Site acquisition and the preliminary development program will define the project type (residential, nonresidential, mixed-use), physical setting (e.g., urban infill versus suburban greenfield), and scale (amount of land, buildings, infrastructure). These characteristics influence the professional disciplines required for a LEED ND project team. If possible, the team should include a LEED ND Accredited Professional with experience certifying the kind of project envisioned for the site. This step should also identify public agencies with authority over the site and nongovernmental organizations with interests in the area or the project’s goals. As credit selection and documentation proceed, having a working relationship with these entities is likely to be valuable.
STEP 4. CHECK MINIMUM PROGRAM REQUIREMENTS AND PREREQUISITES
Review the prerequisites and the minimum program requirements (see Minimum Program Requirements) against the project site and preliminary development program. Ensure that there are no obvious obstacles to project eligibility or prerequisite achievement.
STEP 5. FINALIZE PROJECT BOUNDARY AND DEVELOPMENT PROGRAM
Two fundamental descriptors of a LEED ND project must be finalized at this point:
- Project boundary. This boundary determines the land area of a project, including its buildable and nonbuildable portions. Review the minimum program requirement regarding the delineation of a project boundary.
- Development program. This is a summary of project land and subareas and the number of buildings by type and construction timing. The preliminary program initiated at site selection is finalized at this point for LEED ND purposes. Although development programs sometimes change over time, an operative set of land and floor area quantities needs to be used for documenting and verifying credit achievement. If a change occurs during certification review, the team should provide USGBC with amended values as soon as they are available.
STEP 6. RECONFIRM MINIMUM PROGRAM REQUIREMENTS AND PREREQUISITE COMPLIANCE
Return to Step 4 prerequisites and confirm the project’s compliance with certainty, now using the final project boundary and development program. For project teams that have any doubts about meeting the SLL or NPD prerequisites, this is the point at which a formal prerequisite review can be useful.
STEP 7. DEVELOP LEED SCORECARD
Use the project goals to identify the credits and options that should be attempted by the team. The Behind the Intent sections offer insight into what each credit is intended to achieve and may help teams align goals with credits that bring value to the owner, environment, and community of the project.
This process should focus the team on those credits with the highest value for the project over the long term. Once the high-priority credits have been selected, identify related credits that reinforce the priority strategies and provide synergistic benefits.
Finally, establish the target LEED certification level (Certified, Silver, Gold, or Platinum) and identify additional credits needed to achieve it. Make sure that all prerequisites can be met and include a buffer of several points above the minimum in case of changes during design and construction.
STEP 8. ASSIGN ROLES AND RESPONSIBILITIES
Itemize required documentation and calculations and assign responsibility for their preparation to team members.
STEP 9. DEVELOP CONSISTENT DOCUMENTATION
Submission work begins with two critical tasks that underpin the balance of the submission:
- Base mapping. A submission typically requires several credit-specific maps on one of two required base maps: (1) the project site, and (2) the vicinity within a mile of the project site. Land development projects often use standardized maps and drawings, and USGBC encourages project teams to adapt them for LEED ND base mapping purposes.
- Cross-cutting calculations. The rating system has multiple credits that require the same calculations. Performing them at the outset of submission preparation improves consistency and speeds up subsequent credit work. See the next section, Maintaining Consistency in the Application.
With base mapping and cross-cutting calculations in hand, team members will be able to complete the balance of the submission. If feasible, teams should adapt and reuse project information compiled for other purposes. However, when adapting such materials, it is best to highlight or excerpt only the portions relevant to LEED certification.
STEP 10. PERFORM QUALITY ASSURANCE REVIEW AND SUBMIT FOR CERTIFICATION
A quality assurance review is an essential part of the work program. A thorough quality control check can improve clarity and consistency of the project’s LEED documentation, thereby avoiding errors that require time and expense to correct later in the certification process. The submission should be thoroughly proofread and checked for completeness. In particular, numeric values that appear throughout the submission (e.g., site area) must be consistent across credits.
Maintaining Consistency in the Application
The project boundary defines the land and water area that is reviewed for certification (see Minimum Program Requirements).
Figure 1 illustrates how a project boundary may encompass a parcel, a parcel plus adjacent rights-of-way, or multiple parcels and rights-of-way. If a project team elects to include rights-of-way, the entire width of the rights-of-way must be within the boundary (Figure 1).
Figure 1. Example project boundary
When drawing the project boundary, teams should consider the impact of boundary location in relation to credit requirements. Inclusion or exclusion of features on the periphery of a project site may affect credit applicability and scoring. For example, the distances between through-connections on a project boundary under NPD Credit Connected and Open Community can be affected by the inclusion or exclusion of adjacent street rights-of-way. Because some credit requirements apply to existing uses as well as new construction (see Table 6), carefully consider whether the inclusion of existing areas will help or hinder the project’s achievement.
A project is categorized by site type depending on where its boundary is set, the status of land inside the boundary, and the status of properties surrounding the boundary. The following site types may apply: previously developed, infill, adjacent. The subsections below define these terms and explain their use.
previously developed altered by paving, construction, and/or land use that would typically have required regulatory permitting to have been initiated (alterations may exist now or in the past). Land that is not previously developed and landscapes altered by current or historical clearing or filling, agricultural or forestry use, or preserved natural area use are considered undeveloped land. The date of previous development permit issuance constitutes the date of previous development, but permit issuance in itself does not constitute previous development.
previously developed site a site that, prior to the project, consisted of at least 75% previously developed land
LEED ND project teams may consider platted lots of less than 1 acre (0.4 hectares) previously developed if a building was constructed somewhere on the lot. The purpose of this allowance is to prevent teams from having to individually assess small home lots to determine the amount of land under the building footprint versus the yard space. For any lots larger than 1 acre, the team must separate the land into previously developed and undeveloped portions.
Previously developed property status can apply to a project site itself, which carries benefits under several credits, and to surrounding properties. Assessing properties with few buildings present may be confusing, however. If the land previously had buildings, it is considered previously developed even if those buildings have since been torn down. Another frequently confusing situation is parkland. Improved parks with manicured landscaping and constructed features like playgrounds (e.g., a city park) are considered previously developed. Land that has only been cleared or graded, with no additional improvements, is not considered previously developed. Land maintained in a natural state (e.g., a forest preserve) is not considered previously developed, even if minor features like walking paths are present.
Figure 2. Example map of previously developed area within project
infill site a site that meets any of the following four conditions:
- At least 75% of its boundary borders parcels that individually are at least 50% previously developed, and that in aggregate are at least 75% previously developed.
- The site, in combination with bordering parcels, forms an aggregate parcel whose boundary is 75% bounded by parcels that individually are at least 50% previously developed, and that in aggregate are at least 75% previously developed.
- At least 75% of the land area, exclusive of rights-of-way, within 1/2 mile (800 meters) of the project boundary is previously developed.
- The lands within 1/2 mile (800 meters) of the project boundary have a preproject connectivity of at least 140 intersections per square mile (54 intersections per square kilometer).
The circulation network itself does not constitute previously developed land; it is the status of property on the other side of the segment of circulation network that matters. For conditions (a) and (b) above, any fraction of the perimeter that borders a water body is excluded from the calculation.
As defined above and illustrated in the accompanying diagrams, there are four circumstances in which a LEED ND project can be considered an infill site. In all instances, the characteristics of land around the project are important. Conditions (a) and (b) involve the parcels bordering or close to the LEED ND project boundary; conditions (c) and (d) involve characteristics of the area within a 1/2-mile (0.8 km) distance of the project boundary. For a parcel to qualify as “bordering,” it must share a linear section of boundary; a parcel that adjoins the project at only a single point (e.g., kitty-corner) is not considered bordering.
Calculations for condition (a): Previous development on adjacent parcels
Step 1. On a vicinity map, identify parcels adjacent to the project perimeter. For each parcel, calculate the area that is previously developed. Determine the percentage of the parcel that is previously developed by dividing the previously developed area by the entire parcel area and multiplying by 100 (Equation 1). Each adjacent parcel that is at least 50% previously developed is then considered a qualifying parcel in these calculations.
Step 2. Sum the previously developed land area of each qualifying parcel identified in Step 1, divide by the total land area of all qualifying parcels (Equation 2), and multiply by 100. The result must be 75% or higher.
Step 3. Measure the total project perimeter, any portion adjacent to waterfront, and the length of portions adjacent to qualifying parcels, from Step 1. After subtracting waterfront length from the total perimeter length, divide the perimeter length adjacent to all qualifying parcels by the total net perimeter length, and multiply by 100 to obtain the percentage of the perimeter bordering previously developed parcels (Equation 3). The result must be 75% or more.
Calculations for condition (b): Previous development on adjacent parcels using aggregate method
This is the same as condition (a) except that the expanded boundary is used in place of the project boundary. The boundary can encompass the project plus any parcels that directly border the project site.
Calculations for condition (c): Previous development in surrounding area
Calculations for condition (d): Connectivity in surrounding area
Projects need to meet only one of the four conditions to qualify as an infill site, but for the sake of illustration, the following example project is tested against (and meets) all four criteria. The calculations are presented in IP units but are the same for project teams using SI.
A 35-acre project site is evaluated for its status as an infill parcel. The project team evaluates each parcel of land adjacent to the project boundary and collects information about the land uses within 1/2-mile of the project boundary (Table 1).
The project meets infill condition (a) (previous development on parcels adjacent to site perimeter) because the portion of the perimeter that borders parcels that are more than 50% previously developed is 86% (Equation 3):
In addition, the adjacent parcels are in aggregate 78% previously developed (Equation 2):
The project meets infill condition (b) (previous development on parcels adjacent to the project site and any number of bordering parcels “borrowed” to create the “aggregate parcel”) because the aggregate parcel’s perimeter portion adjoining parcels that are more than 50% previously developed is 84% (Equation 3):
In addition, the parcels adjacent to the aggregate parcel are in total 84% previously developed (Equation 2):
The project meets infill condition (c) (previous development on surrounding land) because the land within 1/2 mile of the project perimeter is 78% previously developed.
The project meets infill condition (d) (connectivity of surrounding land) because the land within 1/2 mile of the project perimeter has more than 140 intersections per square mile:
adjacent site a site having at least a continuous 25% of its boundary bordering parcels that are previously developed sites. Only consider bordering parcels, not intervening rights-of-way. Any fraction of the boundary that borders a water body is excluded from the calculation.
To be an adjacent site (Figure 7), the project site needs to border previously developed land along at least 25% of its boundary.
A LEED ND project site can be considered adjacent even if a narrow greenway or undeveloped, permanently protected land separates it from previously developed parcels. The greenway or undeveloped land may average no more than 400 feet (125 meters) in width and be no more than 500 feet (155 meters) wide in any one place. The undeveloped land must be protected from residential and nonresidential construction by easement, deed restriction, or other enforceable legal instrument.
For a project site to qualify as an adjacent site for SLL Prerequisite Smart Location, Option 2, the greenway or other protected open space must allow through-connections to the previously developed land.
When determining infill and adjacent status, if the project site is next to a street right-of-way, the team must consider the previous development status of property on the other side. Parks with physical improvements are considered previously developed; legally dedicated land in its natural state is considered undeveloped. When waterfront occurs on the other side of a street right-of-way, the length of that waterfront may be excluded from the calculation.
Once a project boundary has been established, the project team should assemble information on the type and location of previous development within the boundary to determine whether the site itself qualifies as a previously developed site.
buildable land the portion of the site where construction can occur, including land voluntarily set aside and not constructed on. When used in density calculations, buildable land excludes public rights-of-way and land excluded from development by codified law or LEED for Neighborhood Development prerequisites.
Buildable land (Figure 8) is an important element of a project because it is the denominator in the calculation of land-use densities. First, determine the base amount of buildable land in the project. Then, if additional land is voluntarily set aside and protected from development, it may be moved into the nonbuildable category, not to exceed 15% of the base amount of buildable land. To be considered nonbuildable under this provision, the land must be protected from construction by easement, deed restriction, or other enforceable legal instrument. Any additional land that is voluntarily set aside and not built on, such as open space, must be considered buildable (after the first 15%) because it was available for construction but set aside voluntarily.
For example, in a 20-acre project with a 4-acre park required by local government code, the base buildable land would be 16 acres. Should the developer wish to set aside additional land for permanent protection, up to 15% of the base 16 acres (i.e., up to 2.4 acres) could be set aside and also considered nonbuildable.
The development program is a tabular presentation typically prepared by a developer detailing land uses and the demolition, construction, renovation, or retention of buildings within the project boundary. The development program should account for all land and water within the boundary according to the buildable and nonbuildable categories, discussed above. In preparing the development program, teams should consider the following:
New construction. A majority of a project’s square footage should be new construction or major renovation. When an existing building undergoes major renovations as part of a project, it is typically considered new construction, but the determination varies by credit. For example, GIB Prerequisite Indoor Water Use Reduction lumps major renovations in with new construction because replacing water fixtures is common practice in a major renovation. Please refer to individual credit sections of this guide for more information. Major renovation is defined as follows:
Major renovation. Extensive alteration work in addition to work on the exterior shell of the building and/or primary structural components and/or the core and peripheral MEP and service systems and/or site work. Typically, the extent and nature of the work is such that the primary function space cannot be used for its intended purpose while the work is in progress and where a new certificate of occupancy is required before the work area can be reoccupied.
Existing buildings. As used in LEED ND, existing refers to buildings undergoing no alterations and those undergoing minor renovations. If existing buildings are included in a project, the project team should carefully review each prerequisite and credit for its applicability: some credit calculations include existing buildings and some do not. Table 6 summarizes treatment of existing and planned project features by credit.
Several provisions of the rating system are tied to milestone dates on a project’s development timeline, beginning with property acquisition and extending through build-out and occupancy. Some rating system provisions must be applied in perpetuity. It is critical that the project team understand the timeline concepts within LEED ND. The following milestone dates should be carefully considered in the LEED ND context:
- Property acquisition is the date that the project developer purchased or took equivalent control of a majority of the land area inside the project boundary.
- Preproject conditions are those present on the date the developer acquired rights to a majority of its buildable land through purchase or option to purchase.
- Existing conditions are those present on the date of certification submission. However, a built feature is not considered existing if it was constructed by the project developer as part of the LEED ND project (this will come into play only for projects under construction).
- Build-out is the time at which all habitable buildings on the project are complete and ready for occupancy.
Tables 2–4 show major milestones for credits on a timeline that assumes concurrent build-out and occupancy.
Because of the numerous geographic provisions and calculations in the rating system, mapping is an important part of documenting project characteristics and verifying credit achievement. Project teams should use the following types of maps (Figure 9):
Project site. A standardized project site base map should be used throughout the submission to illustrate sitelevel features relevant to individual credits.
Vicinity. A standardized vicinity base map should be used throughout the submission to illustrate relevant surrounding features for up to 1 mile (1.6 km) around the project boundary.
Special maps. Certain credits require information that is more feasibly shown on special maps instead of the standard base maps. For example, maps of the high-priority redevelopment areas under Option 3 of SLL Credit Preferred Locations may cover large parts of communities.
Visual verification of credit documentation is an important element of LEED ND certification. Each map should have a title with the applicable credit name, northpoint, scale, and the relevant features clearly labeled and dimensioned in sufficient detail to enable verification of credit compliance. Maps and other drawings should be concise, clear, and of sufficiently high resolution to allow detailed review of project features. Overly large documents, however, are difficult to manage; create concise maps that document only the relevant credit requirements.
WALKING AND BICYCLING DISTANCES
The second most common set of metrics in the rating system is the distances traveled by pedestrians and bicyclists from origins, such as dwellings, to destinations, such as schools. Walking and biking distances must be measured along pedestrian and bicycle networks that comply with the following LEED definitions:
walk distance the distance that a pedestrian must travel between origins and destinations without obstruction, in a safe and comfortable environment on a continuous network of sidewalks, all weather-surface footpaths, crosswalks, or equivalent pedestrian facilities. The walking distance must be drawn from an entrance that is accessible to all building users.
bicycle network a continuous network consisting of any combination of the following: (1) off-street bicycle paths or trails at least 8 feet (2.5 meters) wide for a two-way path and at least 5 feet (1.5 meters) wide for a one-way path, (2) physically designated on-street bicycle lanes at least 5 feet (1.5 meters) wide, and (3) streets designed for a target speed of 25 mph (40 kmh)
Sometimes known as shortest path analysis, the measurement is the distance a pedestrian or bicyclist would travel from an origin point to the closest destination of a given type, such as the closest bus stop (Figure 10). The term walkshed denotes an area created from a compilation of walk distances from an origin, such as a polygon encompassing all possible pathways within 1/4-mile walking distance. Walksheds can sometimes be used as a way to assess compliance with credits.
Dwellings or businesses accessed through common building entries are counted according to the number of dwelling units or business establishments reached through such entrances. For example, a multifamily building entrance used to access 20 dwelling units counts as 20 origin points. A nonresidential building entrance leading to 10 office tenants and two retail tenants counts as 12 origin points.
The rating system measures land-use density in two categories, residential and nonresidential. Density is calculated according to the following definitions:
density the amount of building structures constructed on the project site, measured for residential buildings as dwelling units per acre of buildable land available for residential uses, and for nonresidential buildings as the floor-area ratio of buildable land area available for nonresidential uses. In both cases, structured parking is excluded.
floor-area ratio (FAR) the density of nonresidential land use, exclusive of structured parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential buildings.
To be considered a dwelling unit (for the purpose of inclusion in a residential density calculation), the space should be intended for long-term occupancy and provide facilities for cooking, sleeping, and sanitation. Hotel rooms, for example, are not dwelling units.
Determine densities as follows:
Step 1. Sum the amounts of buildable land area by these categories:
- Mixed-use (a combination of residential and nonresidential)
- Other (e.g., voluntary set-asides of open space)
The total must equal 100% of the project’s buildable land.
Step 2. For mixed-use buildings, assign proportional shares of the associated land area to residential and nonresidential categories using the following equations:
Step 3. Add the land area of the “other” buildable land category to the nonresidential land category.
Step 4. Sum the residential and nonresidential land areas from above to obtain their respective total land areas for the entire project.
Step 5. Divide the project’s total dwelling units or total nonresidential floor area by the total residential or nonresidential land area, respectively. This gives residential density as dwelling units per acre (hectare) of residential buildable land, and nonresidential density as a floor area ratio for nonresidential buildable land.
The project’s base land-use densities may be adjusted in two instances: (1) the buildable land adjustment when extra protected areas are set aside (see Buildable Land, above), and (2) under SLL Prerequisite Agricultural Land Conservation, where provision of a community garden enables a density increase. The latter adjustment applies only to that prerequisite.
A project’s development footprint is essentially all of its impervious surfaces. The footprint calculation is used in seven credits where imperviousness is a consideration, such as GIB Credit Rainwater Management. Development footprint is defined as follows:
development footprint the total land area of a project site covered by buildings, streets, parking areas, and other typically impermeable surfaces constructed as part of the project.
Surfaces paved with permeable pavement (at least 50% permeable) are excluded from the development footprint.
Another common cross-cutting metric is transit service, expressed in daily trips at stops. An important partner in projects with a transit component is the transit agency serving the site. Transit-related credits should be reviewed with the agency during goal setting and credit selection, and if possible, submission documentation should be reviewed with the agency before submission.
Steps for calculating and documenting transit service are as follows (including some special procedures depending on the prerequisite or credit):
Step 1. Identify dwelling units and nonresidential use entrances within project boundary
On a site map, indicate the location of all building entrances and dwelling units.
- See Walking and Bicycling Distances.
Step 2. Determine whether any new transit is planned
Research transit plans for the area to determine whether any new transit is planned near or within the project. Stops along the planned routes qualify only if they meet one of the three criteria outlined in the rating system:
- A funding agreement with the Federal Transit Administration (or equivalent national-level agency for projects outside the U.S.)
- Approval in an agency budget
- Preliminary engineering for a rail line and allocated funding
Step 3. Identify transit stops within 1/4 mile (400 meters) or 1/2 mile (800 meters)
On a map, identify the locations of existing and planned transit stops (planned stops must meet the requirements in Step 2) that are within a 1/4-mile (400-meter) or 1/2-mile (800-meter) walking distance of the project’s dwelling units or nonresidential use entrances, based on vehicle type. Bus, streetcar, or rideshare stops qualify if they are within 1/4 mile of at least one project building entrance. Bus rapid transit, light or heavy rail, commuter rail, or ferry stops qualify if they are within 1/2 mile of at least one project building entrance.
Each point at which a transit vehicle stops to receive or discharge passengers is considered a separate transit stop; this includes stops facing each other on opposite sides of a street. This method of counting is specific to LEED for Neighborhood Development; the LEED Building Design and Construction rating system uses another method.
Step 4. Identify transit vehicle types
Identify the type of transit vehicles that serve each qualifying transit stop: bus, streetcar, bus rapid transit, rail, or ferry.
Step 5. Create walk route and distance map
Calculate walk routes and distances from the project’s dwelling units and nonresidential use entrances to transit stops. The routes must comply with the rating system’s requirements for pedestrian facilities. See Walking and Bicycling Distances.
- Count the number of dwelling units and nonresidential use entrances within a 1/4-mile (400-meter) walk of a bus or streetcar stop or within a 1/4-mile (800-meter) walk of a rail, bus rapid transit or ferry stop.
- Confirm that at least 50% of the project’s dwelling units and nonresidential use entrances are within the required walking distance of one or more transit stops.
Step 6. Count trips at each qualifying transit stop
A trip is defined as the moment a transit vehicle stops at a stop. If a single vehicle stops at multiple stops along a route, each stop is considered a trip.
For each transit stop that is within the required walking distance, review transit service schedules to determine the following:
- The number of transit vehicle rides on a weekday. If service varies by weekday, count the weekday with the lowest number of trips.
- The number of transit vehicle trips on each weekend day. If counts per weekend day are different, use an average; however, no day may have zero trips.
- An individual transit stop can be counted only once, regardless of the number of dwelling units or nonresidential use entrances within walking distance of it.
- Total the trips provided at all qualifying transit stops and determine whether the number meets the daily transit service threshold for both weekday and weekend trips, as noted in the credit requirements.
Step 7. Assess achievement of relevant prerequisites and credits
Transit service thresholds vary by prerequisite and credit. The following credits contain transit calculations:
- SLL Prerequisite Smart Location
- SLL Prerequisite Agricultural Land Conservation
- SLL Credit Access to Quality Transit
- NPD Prerequisite Compact Development
- NPD Credit Mixed-Use Neighborhoods
- NPD Credit Transportation Demand Management
Transit service example for SLL Prerequisite Smart Location
A 5-acre project involves new construction of 75 dwellings and 10 businesses plus two existing nonresidential buildings. Twenty-five of the dwellings are in a multifamily building, and the remainder are detached single-family units. Of the businesses, five share a building, and the others are in their own buildings. This gives a total of 51 residential buildings and eight nonresidential buildings, for a project total of 59 buildings. For the sake of brevity, it is assumed that each of the 59 buildings has a single entrance and that the project and vicinity pedestrian networks comply with rating system requirements.
The project team does a preliminary assessment of transit service in the area and finds one rail station with two platforms (essentially two stops) and six bus lines near the project. The six bus lines have a total of 20 stops near the project.
Closer assessment reveals that four of the bus stops cannot be reached by any existing or planned project building within a 1/4-mile walking distance, so these are eliminated from consideration. For the remaining two rail stops and 16 bus stops, all qualify because at least one existing or planned project building entrance is within the allowed walking distances.
Additionally, a new bus line is planned that has the required funding commitments. Six new bus stops will be within walking distance of the project, bringing the total to 22 qualifying bus stops.
The team calculates the number of dwelling and nonresidential entrances within walking distance of at least one of the 22 bus stops. Using shortest path analysis, the team finds that 40 of the 59 building entrances are within the required distance of at least one bus stop, then calculates the percentage: 40 / 59 = 0.68%. Because 68% of the entrances have access to transit, the project exceeds the required threshold (50% of total origin points).
Next, the team counts the number of daily transit trips at the 22 stops for each day of the week. Based on timetables, the team finds that the stops, in aggregate, have 400 trips per weekday, 250 Saturday trips, and 100 trips on Sunday. Because Saturday and Sunday trip numbers are different, the team must use their average: 250 + 100 = 350, and 350 / 2 = 175. (Although the Saturday and Sunday trips can be different, neither can be zero.)
With 400 daily weekday trips and an average 175 daily weekend trips, the project exceeds the prerequisite’s thresholds of 60 and 40, respectively.
Another rating system metric is connectivity, expressed as intersections per square mile (square kilometer). Connectivity is an important objective of LEED ND because it enables multimodal travel that, in turn, reduces energy use and emissions of pollutants, including greenhouse gases, while improving public health and equitable access.
Connectivity can be calculated internally (within the project boundary) or in the area surrounding the project (within a specified distance of the project boundary).
For both internal and surrounding connectivity, eligible and ineligible intersections are as follows (Figure 12):
- Count publicly accessible intersections of the circulation network, including intersections of streets with dedicated alleys and transit rights-of-way, and intersections of streets with nonmotorized rights-of-way.
- If one must both enter and exit an area through the same intersection, exclude that intersection and any intersections beyond that point; intersections leading only to culs-de-sac are also not counted.
Assemble maps of existing and planned streets and rights-of-way inside the project boundary (internal connectivity) or existing streets and rights-of-way in the vicinity (surrounding connectivity). Use mapped street data from GIS or CAD files of right-of-way centerlines, normally available from the local government.
Exclude ineligible intersections (as listed above) and count the remaining qualifying intersections. Sum the number of qualifying intersections for the project site area (internal connectivity) or the area within a 1/4-mile (400-meter) distance of the project boundary (surrounding connectivity).
When determining area, include street rights-of-way. Exclude the area of water bodies, parks larger than 1/2 acre (0.2 hectare), public facility campuses, airports, rail yards, slopes over 15%, and areas nonbuildable under codified law or the rating system.
Finally, prorate the eligible intersections in the area to the equivalent of a square mile or square kilometer. For example, 50 intersections in a 0.75-square-mile (1.9-square-kilometer) project site equates to 67 intersections per square mile (174 intersections per square kilometer).
The results of Equation 9 determine compliance with the connectivity prerequisite and credit.
PROJECT GEOGRAPHIC CENTER
Several credits require measuring the distance from a project’s geographic center to certain features, such as farmers markets. In CAD or GIS terms, the project’s geographic center is the “centroid” of the polygon created by the project boundary.
THROUGH CONNECTIONS AND RIGHT-OF-WAY INTERSECTS
SLL Prerequisite Smart Location and two NPD credits require the measurement of distances between the points where internal right-of-way centerlines pass through or terminate at the project boundary. Figure 13 shows how rights-of-way may intersect a project boundary. NPD Prerequisite Connected and Open Community and NPD Credit Connected and Open Community allow rights-of-way to terminate at the project boundary, as well as pass through it. As shown in Figures 15–18, the points where the centerlines of rights-of-way intersect the project boundary are the points used to measure interval distances between those points along the boundary. Maximum allowable distances between intersect points are stipulated in each credit.
CIRCULATION NETWORK AND BLOCK FRONTAGES
Three NPD credits stipulate requirements for circulation networks, block length, and building frontages. Circulation network and block length are defined as follows:
circulation network all motorized, nonmotorized, and mixed-mode travel ways permanently accessible to the public, not including driveways, parking lots, highway access ramps, and rights-of-way exclusively dedicated to rail. It is measured in linear feet.
block length the distance along a block face; specifically, the distance from an intersecting right-of-way edge along a block face, when that face is adjacent to a qualifying circulation network segment, to the next ROW edge intersecting that block face, except for intersecting alley ROWs.
The applicability of these terms to a typical streetscape is shown in Figure 19.
Sidewalks are usually (but not always) located within the circulation network right-of-way. When measuring the length of the circulation network using the above definition, count a right-of-way only once, regardless of how many travel modes or lanes use it. For example, a street segment containing four vehicular lanes, a bicycle lane, and a bordering sidewalk is considered a single length of circulation network. If, however, a pedestrian-only right-of-way does not occur along a street but stands alone, its length is counted separately for the circulation network.
The dividing line between the right-of-way and block frontage is the property line, regardless of sidewalk location.
Some elements of a project, such as a plaza or square, may occasionally allow vehicular passage but are not part of the circulation network. For example, a plaza serving primarily as a public meeting space is not considered part of the dedicated circulation network, even if emergency vehicles are allowed to drive through it.
Many kinds of people use a typical LEED building, and the mix varies by project type. Occupants are sometimes referred to in a general sense; for example, “Publicize the availability of subsidized transit passes to project occupants.” In other instances, occupants must be counted for calculations. Definitions of occupant types are general guidelines that may be modified or superseded in a particular credit when appropriate (such changes are noted in each credit’s reference guide section). Most credits group users into two categories, regular building occupants and visitors.
Regular Building Occupants
Regular building occupants are habitual users of a LEED project. All of the following are considered regular building occupants.
Employees include part-time and full-time employees, and totals are calculated using full-time equivalency (FTE).
A typical project can count FTE employees by adding full-time employees and part-time employees, adjusted for their hours of work (Equation 10).
For buildings with more unusual occupancy patterns, calculate the FTE building occupants based on a standard eight-hour occupancy period (Equation 11).
Staff is synonymous with employees for the purpose of LEED calculations.
Volunteers who regularly use a building are synonymous with employees for the purpose of LEED calculations.
Residents of a project are considered regular building occupants. This includes residents of a dormitory. If actual resident count is not known, use a default equal to the number of bedrooms in the dwelling unit plus one, multiplied by the number of such dwelling units.
Primary and secondary school students are typically regular building occupants (see the exception in SLL Credit Bicycle Facilities).
Hotel guests are typically considered regular building occupants, with some credit-specific exceptions. Calculate the number of overnight hotel guests based on the number and size of units in the project. Assume 1.5 occupants per guest room and multiply the resulting total by 60% (average hotel occupancy). Alternatively, the number of hotel guest occupants may be derived from actual or historical occupancy.
Inpatients are medical, surgical, maternity, specialty, and intensive-care unit patients whose length of stay exceeds 23 hours. Peak inpatients are the highest number of inpatients at a given point in a typical 24-hour period.
Visitors (also “transients”) intermittently use a LEED project. All of the following are considered visitors.
Retail customers are considered visitors. In water-related credits, retail customers are considered separately from other kinds of visitors and should not be included in the total average daily visitors.
Outpatients visit a hospital, clinic, or associated health care facility for diagnosis or treatment that lasts 23 hours or less.
Peak outpatients are the highest number of outpatients at a given point in a typical 24-hour period.
Volunteers who periodically use a building (e.g., once per week) are considered visitors.
Higher-education students are considered visitors to most buildings, except when they are residents of a dorm, in which case they are residents.
In calculations, occupant types are typically counted in two ways:
Daily averages take into account all the occupants of a given type for a typical 24-hour day of operation.
Peak totals are measured at the moment in a typical 24-hour period when the highest number of a given occupant type is present.
Whenever possible, use actual or predicted occupancies. If occupancy cannot be accurately predicted, use one of the following resources to estimate occupancy:
- Default occupant density from ASHRAE 62.1–2010, Table 6-1
- Default occupant density from CEN Standard EN 15251, Table B.2
- Appendix 2 Default Occupancy Counts
- Results from applicable studies.
If numbers vary seasonally, use occupancy numbers that are a representative daily average over the entire operating season of the building.
If occupancy patterns are atypical (shift overlap, significant seasonal variation), explain such patterns when submitting documentation for certification.
The following LEED ND credits reference occupancy:
- SLL Credit Bicycle Facilities
- NPD Credit Transportation Demand Management
- NPD Credit Local Food Production
- GIB Prerequisite and Credit Indoor Water Use Reduction
- GIB Credit Solid Waste Management
Minimum Program Requirements
The Minimum Program Requirements (MPRs) are the minimum characteristics or conditions that make a project appropriate to pursue LEED certification. These requirements are foundational to all LEED projects and define the types of buildings, spaces, and neighborhoods that the LEED rating system is designed to evaluate. View the Minimum Program Requirements
Rating System Selection Guidance
Projects are required to use the rating system that is most appropriate. However, when the decision is not clear, it is the responsibility of the project team to make a reasonable decision in selecting a rating system before registering their project. This guidance helps project teams select a LEED rating system. View the Rating System Selection Guidance
Credit Category Overviews
Smart Location and Linkage (SLL) Overview
Smart Location and Linkage focuses on selection of sites that minimize the adverse environmental effects of new development and avoid contributing to sprawl and its consequences. Typical sprawl development—low-density, segregated housing and commercial uses located in automobile-dependent outlying areas—can harm the natural environment: it can consume forestland, destroy or fragment wildlife habitat, degrade water quality by draining wetlands and increasing rainwater runoff, pollute the air and emit greenhouse gases through increased automobile travel, and often displace agriculture from prime farmland to locations where food production requires more energy and chemical inputs. In addition to these direct environmental effects, leapfrog development (a land-use pattern in which new development does not connect coherently to existing development, often leaving haphazard tracts of undeveloped land) can also harm the environment indirectly by promoting additional development in previously undeveloped areas.
Increased automobile travel is one of the most damaging consequences of sprawl. People living and working in outlying areas tend to drive greater distances, spend more time driving, own more cars, face a greater risk of traffic fatalities, and walk less. Vehicle emissions contribute to climate change, smog, and particulate pollution, which all are harmful to human health and natural ecosystems. In addition, the parking and roadway surfaces required to support vehicular travel consume land and nonrenewable resources, disrupt natural rainwater flow, and enlarge urban heat islands.
Choosing a smart location can make a substantial difference. Transportation surveys conducted by many metropolitan planning organizations across the country show that residents of close-in locations may drive only a third to half as much, on average, as residents of the most far-flung locations in a metro region.
To reduce the effects of sprawl and create more livable communities, preference should be given to locations close to existing town and city centers, sites with good transit access, infill sites, previously developed sites, and sites adjacent to existing development. Selecting these sites avoids development of outlying greenfield sites. In addition, these sites often have utilities, roads, and other infrastructure in place, reducing the need to build new infrastructure and minimizing the expansion of impervious surfaces that increase harmful rainwater runoff. In the locations that perform better environmentally, the benefits can often be multiple and reinforcing: convenient transportation choices, such as buses, light rail, heavy trains, car and van pools, bicycle lanes, and sidewalks, are generally more available near downtowns, neighborhood centers, and town centers, which are also the locations associated with shorter automobile trips. Research has shown that living in a mixed-use environment within walking distance of shops and services encourages walking and bicycling, which improve cardiovascular and respiratory health and reduce the risk of hypertension and obesity.
An additional benefit of locations that require less driving is that households may be able to own fewer automobiles and cut transportation expenses. For commercial development, fewer automobiles may mean less investment in parking infrastructure, which can reduce the amount of land needed for a project and lower construction costs. Abundant transportation choices can increase the value and marketability of a neighborhood development as well. More than 14.6 million households are expected to prefer housing within a half-mile of rail transit stops by 2025—more than double the number of households living in such locations today1.
Beyond the environmental damage caused by increased automobile dependence, fragmentation and loss of habitat to sprawl are major threats to many imperiled species. Selection of sites that are within or adjacent to existing development can minimize habitat fragmentation and also help preserve areas for recreation. Wetlands and floodplains tend to be biologically rich, and their conversion presents particularly serious environmental challenges: in addition to altering wildlife habitat, it can reduce water quality and increase the likelihood of flooding and associated consequences, such as erosion and loss of property. Left alone, these natural areas retain rainwater and floodwater for slow release into river systems and aquifers, and they protect lakes and streams by trapping sediment.
Another important concern is development intrusion onto prime agricultural lands, which typically require less fertilization and irrigation and are therefore the most resource efficient and environmentally sound locations for farming. Leapfrog patterns of development not only take these lands out of agricultural production but can also fragment farming communities and consequently reduce the economic viability of the local agricultural economy.
Many potential building sites in urban locations have been abandoned because of real or potential contamination from previous industrial or municipal activities. Remediation and reclamation of contaminated brownfield sites make them safer for the community and can also contribute to social and economic revitalization of depressed or disadvantaged neighborhoods. Development of these sites spares greenfields and makes use of existing infrastructure.
Finally, smart location choice also offers opportunities to repair the fabric of communities that are disjointed and sprawling. Suburban locations typically contain excellent redevelopment opportunities on grayfield sites, such as old airports, abandoned or underutilized shopping malls, and closed factories.
1 Center for Transit-Oriented Development, Hidden in Plain Sight: Capturing the Demand for Housing Near Transit (2004).
Neighborhood Pattern and Design (NPD) Overview
Neighborhood Pattern and Design emphasizes the creation of compact, walkable, mixed-use neighborhoods with good connections to nearby communities. These vibrant neighborhoods provide many important benefits to residents, employees, and visitors and to the environment.
In particular, because compact neighborhoods use land and infrastructure efficiently, they avoid fragmentation of wildlife habitat and farmland loss, conserve economic resources, and slow the spread of low-density development across a region’s landscape. Residents enjoy convenient access to shops, services, and public spaces within walking and bicycling distance, and when people choose to drive, they take shorter automobile trips, saving time and avoiding emissions. Compact development also facilitates access to public transportation because transit becomes more economically viable when supported by higher concentrations of population.
In addition, the small block sizes associated with compact neighborhoods encourage walking and bicycling because of increased connectivity, shorter travel distances, slower automobile traffic, and a more inviting pedestrian environment. The slower traffic speeds typically found in dense developments also can reduce injury rates. The environmental and public health benefits that accompany increased transportation choices and reduced rates of driving are further discussed in the introduction to Smart Location and Linkage.
Features such as sidewalks and trails, street trees, inviting building façades, small setbacks, minimal parking lot area, and measures to slow automobiles also increase pedestrian activity. Public spaces, such as parks, plazas, and playing fields, can encourage social interaction and active recreation while helping control rainwater runoff and reducing urban heat island effects. Community gardens also promote social interaction and physical activity while increasing access to fresh, locally grown produce.
Communities with diverse housing types that accommodate a range of incomes, ages, and physical abilities permit residents to live closer to their workplaces, help the community retain residents, and allow families to remain in the neighborhood as their circumstances change over time.
A community’s involvement in project design and planning can help the project complement adjacent neighborhoods, meet the needs of residents and workers, and nurture a cooperative relationship with the project’s neighbors.
Green Infrastructure and Buildings (GIB) Overview
Green Infrastructure and Buildings focuses on measures that can reduce the environmental consequences of the construction and operation of buildings and neighborhood infrastructure. In the U.S., buildings account for large shares of energy consumption and water use. Globally, construction consumes a major part of the stone, gravel, sand, and virgin wood used in the world. Sustainable building technologies reduce waste and use energy, water, and materials more efficiently than conventional building practices.
Including certified green buildings in projects is one way to reduce negative environmental effects. These buildings achieve substantially better performance across a range of environmental measures, and in many cases the cost per square foot can be comparable to that of conventional buildings.
Energy efficiency is an essential strategy for reducing pollution and greenhouse gas emissions, which are possibly the most negative environmental consequences of building and infrastructure operation. Production of electricity from fossil fuels is responsible for air pollution, water pollution, and more than one-third of U.S. greenhouse gas emissions; hydroelectric generation plants can degrade river habitats; and nuclear power presents waste disposal problems and safety concerns. Building systems—electrical, lighting, heating, ventilation, air-conditioning, and others—can be designed to significantly reduce energy consumption compared with conventional designs and practices. The same gains are possible with neighborhood-scale infrastructure components like street lights, traffic signals, and water and wastewater pumps.
District heating and cooling systems are an example of neighborhood-scale infrastructure that can improve energy efficiency because large plants are typically more efficient than building-based equipment. District systems can also take advantage of waste heat from on-site energy generation, improving efficiency. On-site power generation is another energy management strategy for either individual buildings or neighborhood-scale installations. These systems reduce transmission losses, and they may increase power reliability and decrease energy costs by supplementing or replacing utility-supplied electricity. Use of renewable energy in onsite generation further reduces environmental harms.
Solar orientation can also reduce energy consumption in buildings through passive or active systems. And applications like photovoltaic systems can be scaled up to neighborhood levels. The environmental consequences of building construction can be lessened through the reuse of existing buildings. Reuse avoids the environmental effects associated with the extraction, manufacture, and transportation of raw materials, and it reduces the volume of construction and demolition waste, lowering disposal costs and extending landfill life. Reuse of existing components and infrastructure systems can also reduce the cost of construction.
Using materials with recycled content conserves raw materials and supports recycling of construction wastes so that they can be diverted from landfills. Many commonly used products are now available with recycled content, including metals, concrete, masonry, acoustic tile, carpet, ceramic tile, and insulation. Most recycled-content products exhibit performance similar to products containing only virgin materials and can be easily incorporated into building projects at little or no additional cost.
Conventional building practices typically alter watershed hydrology and impair local water resources and ecosystems. Changes to hydrology may deplete aquifers, reduce stream base flow, and cause thermal stress, flooding, and stream channel erosion. New developments can be designed to minimize changes to natural hydrology and stream health by reducing the velocity, volume, temperature, and pollutant content of rainwater runoff.
Urban heat islands are another consequence of standard development patterns and practices. The use of dark, nonreflective materials for parking, roofs, walkways, and other surfaces raises ambient temperatures when radiation from the sun is absorbed and transferred through convection and conduction back to surrounding areas. As a result, ambient temperatures in urban areas can be artificially elevated by more than 10°F (5.5°C) compared with surrounding undeveloped areas. This increases cooling loads in summer, requiring larger HVAC equipment and consuming additional electricity, which in turn exacerbates air pollution and contributes to the formation of smog.
Heat islands are also detrimental to wildlife habitat: plants and animals are sensitive to high temperatures and may not thrive when temperatures increase. Water use can also be reduced through improved design and technologies that conserve water and ease demands on water supply. Indoors, potable water consumption can be reduced by using low-flow plumbing fixtures and waterless urinals. Outdoor water use, primarily for landscape maintenance, accounts for a large share of U.S. water consumption and can be reduced through careful plant selection and landscape design. Wastewater can also be reused for landscape maintenance.
Water conservation protects the natural water cycle and saves water resources for future generations by reducing amounts withdrawn from rivers, streams, underground aquifers, and other water bodies. Another benefit of water conservation is reduced energy and chemical use at wastewater treatment facilities. In addition to conserving precious potable water, wastewater reuse reduces the amount of wastewater released into environmentally stressed streams and rivers and lessen demands on overburdened wastewater treatment systems.
Site design provides another opportunity to reduce the environmental consequences of development. Site plans should preserve the existing tree canopy and native vegetation to the extent possible while accommodating compact development. Preserving existing vegetation can reduce rainwater runoff, mitigate the urban heat island effect, reduce the energy needed for heating and cooling, and reduce landscaping installation and maintenance costs. Trees also reduce air pollution, provide wildlife habitat, and make outdoor areas more pleasant for walking and recreation.
The construction process itself is often damaging to site ecology, indigenous plants, and animal populations. This problem can be minimized by confining construction activities to certain areas on the site and restricting the development footprint. Protection of open space and sensitive areas through the use of strict boundaries reduces damage to the site ecology and preserves trees, native vegetation, and wildlife habitat. Construction can also cause soil erosion by wind and water, and soil that leaves the site can cause water and air pollution. Loss of topsoil may increase rainwater runoff, which pollutes nearby water bodies, and may necessitate use of more irrigation, fertilizer, and pesticides. These problems can be prevented by implementing an erosion and sedimentation control plan.
Innovation (IN) Overview
Sustainable design strategies and measures are constantly evolving and improving. The purpose of this LEED category is to recognize projects for innovative planning practices and sustainable building features.
Occasionally, a strategy results in a project’s performance that greatly exceeds what is required in an existing LEED credit. Other strategies may not be addressed by any LEED prerequisite or credit but warrant consideration for their sustainability benefits. In addition, LEED is most effectively implemented as part of a cohesive team, and this category addresses the role of a LEED Accredited Professional in facilitating that process.
Regional Priority (RP) Overview
Because some environmental issues are particular to a locale, volunteers from USGBC chapters and the LEED International Roundtable have identified distinct environmental priorities within their areas and the credits that address those issues. These Regional Priority credits encourage project teams to focus on their local environmental priorities.
USGBC established a process that identified six RP credits for every location and every rating system within chapter or country boundaries. Participants were asked to determine which environmental issues were most salient in their chapter area or country. The issues could be naturally occurring (e.g., water shortages) or man-made (e.g., polluted watersheds) and could reflect environmental concerns (e.g., water shortages) or environmental assets (e.g., abundant sunlight). The areas, or zones, were defined by a combination of priority issues—for example, an urban area with an impaired watershed versus an urban area with an intact watershed. The participants then prioritized credits to address the important issues of given locations.
The ultimate goal of RP credits is to enhance the ability of LEED project teams to address critical environmental issues across the country and around the world.