Leadership in Energy and Environmental Design

What is LEED?

The Leadership in Energy and Environmental Design (LEED) Green Building Rating System is a nationally accepted benchmark for the design, construction, and operation of high performance "green buildings". LEED's rating system gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings’ performance. LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality. The LEED Rating System was developed by the U.S. Green Building Council.

The U.S. Green Building Council (USGBC), a 501(c)(3) nonprofit organization, is a community of more than 7,500 organizations from every sector of the building  industry united by a common purpose: to transform the building marketplace to sustainability.

Many other organizations recognize the value of using pervious concrete pavements as a "green" building material. See these articles: The EPA - Green Infrastructure - Statement of Intent, The Portland Cement Association (PCA) "Building Green with Grey Concrete"; The "Discover Center" - Gold-LEED Certification "Green Building Expansion"; and The California State University "The Greening of - Concrete?".

To obtain the maximum credits possible - think outside the box.

Pervious Concrete

Green Building Design should begin in the Parking Lot (Sustainable Sites). LEED-NC; the Green Building Rating System for New Construction and Major Renovations - Version 2.2, recognizes pervious paving and stormwater collection as integral parts in many of the Requirements in their application for Certification Credits. Please review the National Institute of Building Sciences (NIBS); "Federal Green Construction Guide for Specifiers" & the EPA Web Site Porous Pavement.)

The NRMCA has also produced a RMC-LEED Reference Guide.

Pervious concrete is recognized by the USGBC as a green building material. However, LEED points aren’t obtained just by using a specific product (such as pervious concrete). Pervious concrete, in conjunction with the dual-use system, can help to meet specific “green” goals that will gain one, or more points. Example: One specific Requirement for Sustainable Sites; SS Credit 6.1: "Stormwater Design: Quantity Control" states, in-part: "Implement a stormwater management plan that prevents the post-development peak discharge rate and quality from exceeding the pre-development peak discharge rate and quantity for the one-and two-year 24-hour design storms". The Potential Technologies & Strategies states, in-part: "Design the project site to maintain natural stormwater flows by promoting infiltration. Specify garden roofs and pervious paving to minimize impervious surfaces." Applying the strategy of using pervious concrete as a pervious paving in the design of the building parking lot can obtain one-point. Pervious concrete is also a rigid-pavement and does not deform under traffic loading as does some other permeable pavements such as precast paving blocks. In addition, there are no re-coating requirements as with asphalt pavements, and this helps to reduce pollution.

An additional point may be obtained by implementing a Requirement as stated in SS Credit 6.2. The strategy to obtain this credit is to design an infiltration system that captures 90% of the average annual rainfall, and removes 80% of the average post development total suspended solids (TSS). A properly designed and integrated dual-use system would meet these requirements and allow the applicant to collect an additional credit.

Designing for Sustainable Sites (SS), and Water Efficiency (WE) are two methods of obtaining points using pervious concrete pavement systems. Using pervious concrete, to include the dual-use system, using clean, re-cycled, crushed concrete as a base-material MR Credit 2.1, and observing the light-reflectance of pervious concrete pavements (high-albedo) SS Credit 7.1 can generate additional points.

In some applications, pervious concrete pavements may be more expensive per square yard than some non-permeable pavements. This cost can generally be offset by reducing or eliminating the need for drainage systems and/or retention ponds and their associated maintenance costs. In addition to the cost savings, elimination of retention ponds can also help meet the goal of reducing site disturbance found in SS Credit 5.1 under Sustainable Sites and therefore help earn another LEED point.

In general, the up-front development costs of the dual-use (Park in the Pond) systems are about half the cost of conventional asphalt pavements and associated stormwater infrastructure systems for most commercial projects.

Note: Even though it does not gain the applicant a point, a verifiable, mandatory maintenance program should be included in a program that combines the pavement with the stormwater storage/treatment system. This can be accomplished by extending the building commissioning program (as required under LEED Energy & Atmosphere - EA Prerequisite 1) to also include the parking lot/stormwater system. Even though not required, this should be considered under the "Whole-Building" concept.

The USGBC recommends LEED Project Teams be organized at the beginning of a project, and that each of the team members have the knowledge and experience of applying their discipline in meeting the project goals within the LEED Guidelines. Each member of the team should have: