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(Leadership in Energy & Environmental Design: http://www.usgbc.org/)

The LEED (Leadership in Energy and Environmental Design) Green Building Rating System^TM is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. Members of the U.S. Green Building Council representing all segments of the building industry developed LEED and continue to contribute to its evolution. LEED standards are currently available or under development for:

• New construction and major renovation projects (LEED-NC)
• Existing building operations (LEED-EB, Pilot version)
• Commercial interiors projects (LEED-CI, Pilot version)
• Core and shell projects (LEED-CS, Pilot version)
• Homes (LEED-H)
• Neighborhood Development (LEED-ND)

LEED was created to:

• define "green building" by establishing a common standard of measurement
• promote integrated, whole-building design practices
• recognize environmental leadership in the building industry
• stimulate green competition
• raise consumer awareness of green building benefits
• transform the building market

LEED provides a framework for assessing building performance and meeting sustainability goals. LEED emphasizes strategies for sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality. LEED recognizes achievements and promotes expertise in green building through a system offering project certification, professional accreditation, training and practical resources.

Click below to view the LEED Foundations documents:

• LEED Committee Charters - describes the purpose and scope of each LEED Committee
• LEED Foundations Policy Manual - describes USGBC policy for consensus based development of the LEED family of products
• LEED Product Development Handbook - describes the operating procedures for management and administration of LEED Products

Currently, more than 500 projects have been registered throughout the United States and six other countries, with over 50 being LEED-certified totaling more than 70 million square feet of commercial floor space.

LEED is flexible, enabling buildings to become certified according to their level commitment to green design, which is reflected in a points and labeling system:

Energy & Lighting
Energy and atmosphere is the largest part of the LEED program, providing the ability to earn 17, or 27% of all possible points. Out of these 17 possible points, optimization of energy performance can result in 10 points.

The first step prescribed by LEED is to achieve minimum energy performance, represented as either 1) an EPA Energy Star label score of 60 or 2) meeting the requirements of the ASHRAE/IES 90.1-1999 model energy code using the system/component method, or local energy code (whichever is more stringent).

Achieving the minimum requirement entails adoption of systems/components such as T8/T5 lamps, electronic ballasts, lower-wattage HID lamps, compact fluorescent lamps, more efficient fixtures, LED exit signs and other equipment.

If we can demonstrate compliance with the minimum requirements, now we can actually begin gaining LEED points by exceeding the Energy Star base of 60 or ASHRAE/IES 90.1-1999 (without amendments) code.

Savings must be demonstrable using either:
1. the Energy Star Label benchmarking tool or
2. the energy cost budget method included in ASHRAE/IES 90.1-1999, which entails building calculations that can demonstrate the energy savings potential of lighting controls. Control strategies, which can significantly reduce energy consumption, include:

• Daylight harvesting
• Peak shaving
• Lumen maintenance dimming
• Overlighting compensation
• Adaptive compensation

One obstacle toward LEED Certification is the cost. The most experienced teams submitting for LEED Certification can complete the documentation work for as low as $10,000 on a typical project. Less experienced teams have reported costs between $30,000 and $60,000 for LEED Version 2.0 documentation. Costs will also vary depending on the building's size and program.

LEED 2.1 includes the following notations on Light Pollution...

Light Pollution Reduction

Intent
Eliminate light trespass from the building and site, improve night sky access and reduce development impact on nocturnal environments.

Requirements
Meet or provide lower light levels and uniformity ratios than those recommended by the Illuminating Engineering Society of North America (IESNA) Recommended Practice Manual: Lighting for Exterior Environments (RP-33-99). Design exterior lighting such that all exterior luminaires with more than 1000 initial lamp lumens are shielded and all luminaires with more than 3500 initial lamp lumens meet the Full Cutoff IESNA Classification. The maximum candela value of all interior lighting shall fall within the building (not out through windows) and the maximum candela value of all exterior lighting shall fall within the property. Any luminaire within a distance 2.5 times its mounting height from the property boundary shall have shielding such that no light or brightness from that luminaire crosses the property boundary.

Submittals
Provide the LEED Letter Template, signed by an appropriate party, declaring that the credit requirements have been met.

Technologies & Strategies
Adopt site lighting criteria to maintain safe light levels while avoiding off-site lighting and night sky pollution. Minimize site lighting where possible and model the site lighting using a computer model. Technologies to reduce light pollution include full cutoff luminaires, low-reflectance surface and low-angle spotlights.

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