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The following document provides a summary and details of the current LEED Green Building Rating System revisions and refinements currently underway. The copy of the LEED Green Building Rating System (Version 2.0) that is part of this summary Is a DRAFT document. This draft is being presented at this time to demonstrate the current suggested revisions to LEED, and it will continue to be refined up until the planned USGBC member ballot process planned for the month of October.
Please take a few moments to read the information contained in this primer and summary before moving onto reviewing the revised LEED Green Building Rating System Version 2 DRAFT.
The summary document attached provides an introduction and background to the LEED development and refinement process, some description of the major refinements included in the Version 2.0 draft, and a table summarize the differences between LEED Version 1 .0 and the DRAFT LEED Version 2.0.
The LEED Technical Committee is in the process of continuing to refine the Rating System and components included in it. The committee is aware of and has documented several key issues and elements that need to be fully addressed before LEED Version 2.0 is ready for balloting process. For example, in the Improving Energy Efficiency section, peer review and pilot feedback have identified a need to provide information and guidance to LEED users on how to establish the base case for measuring a project's performance relative to ASHRAE 90.1.
In addition to documenting final decisions on issues like this, several of the credits included in LEED Version 2.0 are still under consideration for inclusion or exclusion. A summary of credits that are currently under consideration for inclusion or exclusion in the final are provided in the summary.
The LEED Green Building Rating System is in the final stages of its pilot program. In addition to the pilot program the LEED Green Building Rating System Version 1.0 has been reviewed by experts in the fields that it addresses. The development schedule and plan for the continued development of the LEED Green Building Rating System is to compile the results of both of these activities to create LEED Version 2.0.
Based feedback compiled from both the pilot program participants and the expert review process to date, we have completed a DRAFT LEED Green Building Rating System Version 2.0. Preparing the LEED Green Building Rating system for Its official launch in late March of the year 2000 is one component of developing all of the tools and resources necessary to support a successful launch and ongoing program.
In addition to refining and finalizing the LEED Green Building Rating system itself, supporting resources such as the LEED Reference Guide, the USGBC's supporting websites, and informational and educational materials must also be completed and refined in close coordination with the final LEED Green Building Rating System. These very important activities are also currently underway and are being developed end deployed in a way to compliment the final version of the LEED Green Building Rating system, For example, the revisions to the LEED Reference Guide will include a broad range of supporting documentation, references, technologies and strategies, case studies, and other critical guidance to practitioners and owners necessary to support the effective understanding and application of each LEED Green Building Rating System criterion.
In the process of refining the LEED Green Building Rating System, the goals, intent, and objective of the system have remain largely intact. Some of the more major refinements to the LEED Green Building Rating System include movement towards being a performance based rating system rather than a combination performance and prescriptive based rating system. The goal was to make LEED a more dynamic, comprehensive and easier to use rating system. For example, in the Improving Energy Efficiency section, some of the prescriptive measures such as heat recovery as an individual credit have been removed, and emphasis has been put an complying with and out performing ASHRAE's Standard 90.1. The technologies and or strategies the project uses to achieve energy efficiency at various levels above ASHRAE 90.1 is up to the designers and building owners.
As you review the revised LEED Green Building Rating System, you will notice the site credits and water credits have been combined into a section titled Sustainable Sites and Safeguarding Water. For each credit, the new version identifies the intent, principles of performance, targets for performance, and a summary of technologies and strategies to achieve the intent of the credit being addressed.
Because the majority of the Rating System credits are now performance based, and the scope and breadth of issues that the LEED Rating System addresses is wider, many of the bonus credits have either been incorporated as defined credits In the new system or have been eliminated. Instead of a variety of bonus credits, the rating system now includes a single (1) innovation credit which can be applied for LEED Rating System does not address.
Finally, the balance of prerequisites vs. credits has changed based on several factors. For example, In some cases where prerequisites were required by law, or, are already a widely accepted building design and construction practice, they were eliminated.
The total possible point tally for LEED Version 1 vs, LEED Version 2 has changed from 50 total points for LEED Version 1.0 to a total possible point score of 60 for LEED Version 2.0. The current proposed achievement level scorers for Version 2.0 are Bronze: 25 to 30 points. Silver 31 to 36 points, Gold: 37 to 42 points, and Platinum: 43 points or more.
The first pages of the LEED Green Building Rating System Version 2.0 draft at the end of this summary include a Version 2.0 score card and a Version 1.0 score card that demonstrates the point total differences in each category, and lists the credits in a table format.
The following table maps how the revisions included in Version 2.0 relate back to the original Version 1.0, and includes comments about the significance of the changes as they relate to the individual credits being discussed.
The last section of the table identifies new credits and indicates their status relative to inclusion in Version 2.0 final.
<table to be inserted here later>
Contents:
Intent: Control erosion to reduce negative impacts on water and air quality.
Performance Principles: Employ best management practices (BMP) for sediment and erosion control to reduce, prevent impacts to water, air and soil due to temporary construction disturbance.
Target: Meet local soil erosion standards with a locally approved sedimentation and erosion control plan, which would meet the following objectives:
Technologies/Strategies: Employ silt fencing & sediment traps, construction phasing and/or stabilization of steep slopes.
Intent: Reduce the environmental impact of the building as it relates to the necessity and placement on this or other sites.
Performance Principles: Seriously consider environmental criteria throughout the site selection process. Conduct an environmental alternative analysis.
Target: Conclude an immediate need for the project and document the selected site's justification from a need and reduced environmental impact perspective.
Technologies/Strategies: Summarize decision-process information from interviews with client and other decision makers.
During initial site selection, document:
Intent: Protect undeveloped, greenfield lands and therefore preserve natural habitats and resources.
Performance Principles: Place new construction on vacant land located in areas with existing development density, OR, rehabilitate an existing building. Develop the building and site to link into existing infrastructure, and fill "density gaps."
Target: Develop projects on sites which:
Technologies/Strategies: During the site selection process give preference to sites with infill potential.
Intent: To rehabilitate damaged sites and protect undeveloped land.
Performance Principles: Utilize land that is abandoned, idled or has under-used industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination.
Target: Develop on a site classified as brownfield by EPA's Federal brownfield certification requirements. To meet site contamination criteria, hazardous substances must be present or potentially present on the property.
Technologies/Strategies: TBD
Intent: Reduce automobile use and sprawl.
Performance Principles: Locate buildings near mass transit. Provide temporary storage of bicycles.
Target: Locate building within 1/2 mile of a rail station (commuter rail, light rail or subway) or within 1/4 mile of 2 or more bus lines AND provide pedestrian-friendly physical linkages to mass transit OR demonstrate that these linkages exist: 1 credit.
Provide suitable means for securing bicycles for at least 5% of building occupants AND provide changing facilities OR provide preferred parking for car pools: 1 credit.
Install refueling facilities for alternative-fuel vehicles that use, for example, electricity, natural gas, or methanol/ethanol: 1 credit.
Technologies/Strategies: Provide suitable means, such as covered or internal access to subway, bus, or trolley stops/stations for 1st credit or provide showers and changing rooms for 2nd credit.
Intent: Sustains land and water resources and promotes biodiversity.
Performance Principles: Incorporate reduced site disturbance strategies and document in site plans and specifications.
Target: Reduce the development footprint (including building, utilities, access and parking) to exceed the local zoning's open space requirement for the site by 25%. 1 credit.
On previously degraded sites or sites where degradation results from construction, restore a minimum of 50% of the degraded area by replacing topsoil and salvaged or new vegetation: 1 credit.
Limit size disturbances to 50 feet beyond the building and perimeter for earthwork and impervious coverage. 1 credit.
Preservation plan for topsoil and existing trees: 1 credit.
Technologies/Strategies: During site planning and preparation of site plans incomplete and note targets on plans and in specifications.
Intent: Mimic natural hydrology and limit disruption on natural water flow and infiltration.
Performance Principles: Minimize the generation and concentration of storm water runoff from the site. Minimize the concentration of contaminants. Minimize the burden on existing and future infrastructure. Promote rainwater catchment and on-site infiltration.
Target:
Technologies/Strategies: Low impact development to include: constructed wetlands (open water or subsurface), stormwater filtering systems, bioswales, bio-retention basins, vegetated filter strips, and green roofs.
Intent: Reduce or eliminate potable water use for landscape irrigation.
Performance Principles: Employ design strategies and landscaping techniques such that no potable water is used for landscape irrigation after establishment of plantings.
Target: Use only plants that are tolerant of climate, soils, and natural water availability, and that do not receive watering from municipal potable water after a period of establishment is complete.
Technologies/Strategies: Selection of water efficient plantings, native plantings and well adapted plantings to the climate that will not require irrigation after establishment period. For projects without a sizable landscape component (high-rise, etc.), use of plants in locations not typically landscaped, such as interior atriums with plants or roof gardens.
Intent: Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impact on microclimate and human and wildlife habitat.
Performance Principles: Employ design strategies, materials, and landscaping designs that reduce heat absorption of exterior materials.
Target: Two (2) measures for one (1) credit, three (3) for more measures for two (2) credits.
For every 1,000 SF of impervious surface on the building lot, including parking lots, walkways, plazas, etc., provide shade on at least 300 SF within 5 years, using native trees and large shrubs, vegetated trellises, or other exterior structures overgrown with native vegetation.
Preserve and/or plant at least one (1) tree on the site located within every 1,000 SF of impermeable grade surface on the building lot including parking, walkways, and plazas, etc.
Use light color/high albedo (with albedo reflectance of at least 0.3) for 50% of the building's roofing materials.
Use green, vegetated roofs or roof gardens for 50% of the total roof area.
Use light color/high albedo materials (with albedo reflectance of at least 0.3) for 30% of the property's non-parking impervious surfaces (e.g., sidewalks, plazas, etc.). OR use light colored aggregate without a final coat of blacktop for impervious surfaces of outdoor parking lots. OR, place a minimum of 50% of parking underground where feasible. OR, use open grid paving with vegetation in paving cells.
Technologies/Strategies: Substitute vegetated surfaces for hard surfaces, using green roofs, green walls, and/or grass paving systems with water efficient vegetation.
Select paving and roofing materials and systems that have an albedo rating that matches the target. Note albedo requirements sufficiently in the drawings and specifications.
Intent: Reduce wastewater loads on municipal systems by pre-treating and recycling of water on-site, to promote aquifer recharge and reduce site water use.
Performance Principles: Implement on-site wastewater treatment and diversion systems. Decrease the use of potable water for sewage conveyance, or purify wastewater after use, by employing innovative on-site technologies.
Target: Reduce the use of municipally treated water for sewage conveyance by at least 50% of the regional average use; OR treat 100% of wastewater on site to stage-3 standards.
Technologies/Strategies: Provide advanced treatment to wastewater and recycle for non-potable reuse in the supply system. Usually requires dual plumbing service capacity in structures (recirculating filters, biological/chemical units, etc.)
Eliminate direct discharge of wastewaters to surface streams; use hydric or non-hydric vegetative systems as medium. Allow full infiltration to recharge aquifers and where suitable construct wetlands, sub-surface flow systems, etc.
Dry systems totally eliminate water as the transport medium and are suitable in locations without other service, or in separate systems design.
Intent: Minimize unnecessary outdoor lighting and light trespass from the site to reduce interference with biological systems, improve night sky access, and reduce impact on night habitat.
Performance Principles: Design site lighting to have a minimal impact off-site.
Target: Zero direct-beam illumination leaving the site, and reflected illumination from exterior lighting shall be minimized. Lumen levels for exterior lighting shall not exceed IES guidelines.
Technologies/Strategies: Full cut-off luminaries, low-reflectance ground covers beneath outdoor lighting; top lighting of exterior signs; minimize lighting of architectural and landscape features.
Intent: Reduce burden on municipal water supply and waste water systems. Promote self-sufficiency in building water use.
Performance Principles: To minimize water consumption within buildings.
Target: Install fixtures that in aggregate use 20% less water than the water usage requirements in the Energy Policy Act of 1992. 1 point.
Technologies/Strategies: Water conserving plumbing fixtures, laundry, dishwashing equipment, landscape irrigation controls, use of drip/weep irrigation, waterless urinals, use-activated controls on lavatories/sinks.
Target: Exceed the potable water use reduction by an additional 20% (40% total efficiency increase). 1 point.
Technologies/Strategies: High efficiency equipment plumbing fixtures such as toilets, dishwashers and laundry equipment. Use alternatives to drinking water for fixture transport water such as rainwater, treated municipal effluent, or cooling tower blowdown.
Alternative cooling tower treatment technology that allows for an increase in concentration ratio from a baseline of 4 to 20 or greater. This could be in the form of ozonation, filtration, or other chemical treatment alternatives. Rigorous examination of the proposed technology should be performed before specification.
Ultra high efficiency or dry fixture technology such as waterless urinals and composting toilets.
Intent: Verify and ensure that buildings are designed, installed, and calibrated to be operated as intended.
Performance Principles: Implement fundamental best practice commissioning procedures.
Target: Comply with the required elements of the LEED Commissioning Requirements document as noted in the LEED Reference Guide.
Technologies/Strategies: TBD
Intent: Establish minimum level of energy efficiency designed and build into the base building systems and envelope.
Performance Principles: Design to and analyze expected building efficiency and performance using an accepted and maintained minimum standard.
Target: Comply with ASHRAE 90.1-1999 or local energy code, whichever is the more stringent.
Technologies/Strategies: Using ASHRAE 90.1-1999 or local standards, use building modeling and analysis techniques to establish and document compliance.
Intent: Reduce ozone depletion.
Performance Principles: Limit the use of CFC-based refrigerants in HVAC&R systems.
Target: New Buildings: Use no CFC-based refrigerants in HVAC&R systems. Existing Buildings: Develop, adopt, and fund a comprehensive CFC-phaseout plan with a specified period for implementation.
Technologies/Strategies: TBD
Intent: Achieve energy performance above the minimum standard to reduce operating costs and environmental impacts associated with excessive energy use.
Performance Principles: Measure and document the designed performance of the building and its systems using a standard that recognizes increasing levels of performance.
Target:
Exceed the building
requirements of ASHRAE/IES Standard 90.1-1999 by:
|
Level |
Points |
New Buildings |
Existing Buildings |
|
LEVEL 1 |
2 |
15% |
10% |
|
LEVEL 2 |
4 |
30% |
20% |
|
LEVEL 3 |
7 |
50% |
35% |
|
LEVEL 4 |
10 |
75% |
50% |
Intent: Encourage and recognize increasing levels of self-supply through renewable technologies to reduce operating costs and environmental impacts associated with excessive energy use.
Performance Principles: Employ the use of on-site non-polluting-source renewable technologies contributing to the total energy requirements of the project.
Target: Supply a fraction
of the building's total energy load through building-integrated or
directly connected renewable energy systems.
|
Level |
Points |
% of Total Energy Load in Renewables |
|
LEVEL 1 |
1 |
5% |
|
LEVEL 2 |
2 |
10% |
|
LEVEL 3 |
3 |
20% |
Intent: Verify and ensure that buildings are designed, installed, and calibrated to be operated as intended in order to improve energy performance and IEQ.
Performance Principles: Implement best practice commissioning procedures.
Target: Comply with the optimal elements in the LEED Commissioning Requirements document as noted in the LEED Reference Guide.
Technologies/Strategies: Introduce standards and strategies into the design process early. Incorporate and clearly state target requirements in the project commission documents. Tie contractor final payments to documented system performance.
Intent: Provide for ongoing accountability and optimization of building energy and IEQ performance over time.
Performance Principles: Design and specify equipment to be installed in the base building systems to allow for comparison, management, and optimization of actual vs. estimated energy performance over time.
Target: Comply with installed equipment requirements in order to satisfy the USDOE's IPMVP for energy consumption.
Technologies/Strategies: Introduce standards and strategies into the design process early. Incorporation and clearly state target requirements in the project construction documents. Tie contractor final payments to documented system performance. Provide for ongoing Measurement and Verification system maintenance and operating plan to be included in installers operations and maintenance manuals.
Intent: Facilitate the reduction of waste generated by building occupants that is hauled and dumped in landfills.
Performance Principles: Provide dedicated space for the collection and storage of materials, which maximizes diversion of materials congruent with markets for recycling within the community.
Target: Provide a centralized ground-floor location for collection and storage of materials separated from each other for recycling, including: newspaper, glass, metals, plastics, organic waste (food and soiled paper), and dry waste.
Technologies/Strategies: TBD
Intent: Incrementally conserve resources, retain cultural resources, reduce waste, and reduce environmental impacts of new buildings as they related to materials manufacturing and transport.
Performance Principles: Reuse large portions of existing structures during renovation of rebuild projects.
Target:
Technologies/Strategies: Facade preservation. Existing structure consideration during programmatic design and occupancy use and flow.
Intent: Conserve resources, reduce waste, reduce environmental impacts related to materials manufacturing and transport.
Performance Principles: Incorporate structural designs that will minimize material use.
Target: Analyze multiple structural designs and select one that requires the minimum structural elements by weight.
Technologies/Strategies: Tensile structures, trusses, etc.
Intent: Reduce waste generated during land clearing, demolition, and construction thereby reducing landfill use.
Performance Principles: Develop and implement a waste management plan and quantify materials diverted by weight.
Target:
Technologies/Strategies: Develop and specify a waste management plan that identifies licensed haulers and processors of recylables, identifies markets for salvaged materials, employs deconstruction, salvage, and recycling strategies and processes, and documents the cost for recycling, salvaging, and reusing materials. At a minimum, the plan shall address recycling of cardboard, metals, concrete brick, asphalt, land clearing debris (if applicable), beverage containers, clean dimensional wood, plastic, glass, gypsum board, and carpet, and evaluates the cost-effectiveness of recycling rigid insulation, engineered wood products and other materials.
Intent: Conserve resources, reduce waste, reduce environmental impacts related to materials manufacturing and transport.
Performance Principles: Specify salvaged or refurbished materials for a fraction of total building materials.
Target:
Technologies/Strategies: Calculate fractional percentages in terms of dollar value of installed salvaged material (including material, cleanup work, installation, and design effort associated with reuse), divided by the total installed material cost (materials, installation, design including mechanical and electrical).
Intent: Reduce the use or depletion of raw materials by replacing them with recycled materials and support the market and economic development of recycling.
Performance Principles: Specify building materials containing recycled content for a fraction of total building materials.
Target:
Technologies/Strategies: Calculate fractional building materials in terms of dollar value of installed recycled material (including material installation), divided by the total installed material cost (materials, installation, design including mechanical and electrical and excluding overhead and fees).
Intent: Reduce environmental impacts of transportation of building materials and support the local economy.
Performance Principles: Source regionally extracted, harvested, and manufactured building materials.
Target:
Technologies/Strategies: Calculate fractional percentage in terms of dollar value of installed local material (including material and installation) divided by the total installed material cost (materials, installation, including mechanical and electrical and excluding overhead and fees).
Intent: Reduce the use or depletion of finite raw materials by replacing them with renewable and rapidly renewable materials and encourage environmentally responsible forest management.
Performance Principles: Source renewable or rapidly renewable building materials for a fraction of the project materials for both permanent building applications and temporary construction applications.
Target:
Technologies/Strategies: Calculate fractional rapidly renewable materials in terms of dollar value of installed rapidly renewable materials (including material and installation) divided by the total installed materials cost (materials, installation, including mechanical and electrical and excluding overhead and fees). For certified renewable wood materials, calculated as a percentage of total wood-based materials.
Intent: Prevent or avoid the development of IAQ problems in buildings thereby contributing to the overall quality of the indoor environment affecting the health and well-being of the occupants.
Performance Principles: Include proactive design details that will eliminate some of the common causes of indoor air quality problems in buildings.
Target: Meet the minimum requirements of voluntary consensus standard ASHRAE 62-1989, Ventilation for Acceptable Indoor Air Quality and approved Addenda, as well as the design details listed in the LEED Reference Guide.
Technologies/Strategies: Introduce standards into the design process early. Incorporate references to targets in plans and specifications. Ensure ventilation system OA capacity can meet standards. Locate building fresh air intakes away from loading areas, building exhaust fans, cooling towers, and other sources of contamination.
Intent: Prevent exposure to ETS by nonsmoker occupants and avoid contaminating the building and systems with smoke.
Performance Principles: Prohibit smoking in the building. Where the owner/designer of the base building does not control the issue of smoking in tenant spaces, provide facilities to isolate smoking, using appropriate design that effectively contains, captures, and removes ETS from that space.
Target: Zero exposure of nonsmokers to ETS.
Technologies/Strategies: Prohibit smoking in the building and/or provide designated smoking areas outside the building to locations where ETS can not re-enter the building's ventilation system and away from high building occupant or pedestrian traffic. Provide properly engineered locations to contain and remove ETS at its source locations, validated by referenced test methods.
Intent: Provide for long term Indoor Air Quality monitoring to support sustained occupant health and comfort.
Performance Principles: Install and maintain a permanent carbon dioxide monitoring system that tracks the ventilation performance of the HVAC system and allows operators to make adjustments to maintain targets.
Target: Indoor carbon dioxide levels not to exceed outdoor levels by more than 530 parts per million at any time.
Technologies/Strategies: Install sensors in areas of the building with high occupant densities and at the ends of the distribution ductwork. Select system based on ease of calibration. Specify that system operation manuals required that calibration of all of the sensors be performed on a quarterly basis.
Intent: Deliver fresh air effectively to building occupants to support their health, safety, and well being.
Performance Principles: Employ architectural and HVAC design strategies to increase ventilation effectiveness and prevent short-circuiting of airflow.
Target: Effective distribution of filtered and conditioned outside air to all building occupants.
Technologies/Strategies: Techniques available include use of displacement ventilation and natural ventilation. Operable windows with an architectural strategy for natural ventilation and cross ventilation and using the stack effect are appropriate options.
Intent: Protect construction workers and building occupants by preventing IAQ problems arising from the construction process and/or improper handling of building materials during construction and renovation.
Performance Principles: Specify control and containment strategies including protecting the HVAC system, controlling sources, interrupting pathways for contamination, enforcing proper housekeeping and coordinating schedules to minimize disruption.
Target: Meet or exceed the minimum requirements of SMACNA IAQ Guideline for Occupied Buildings under Construction, 1995. Ventilate at a rate of one air change per hour minimum during construction OR flush out for one week after construction ends and before occupancy. Maximum of xxx ppm of VOCs at occupancy.
Technologies/Strategies: Achieve, and document, the construction sequencing for IAQ during construction. Sequence and coordinate construction activities (pre-occupancy) to minimize adverse impacts on indoor air quality including but not limited to:
After completion of construction and prior to occupancy specify cleaning requirements for ventilation system components and pathways exposed to contamination during construction.
Intent: Reduce the quantity of possible indoor air contaminants that are odorous or irritating to building occupants to protect their health.
Performance Principles: Evaluate and preferentially specify materials that are low emitting, non-toxic and chemically inert.
Target: Meet VOC limits for adhesives and sealants as specified below:
Select topcoat paints which meet VOC and chemical component limits of Green Seal, Inc. third party certification.
Restrict use of carpeting. Carpet systems must meet the Carpet and Rig Institute Green Label Indoor Air Quality Test Program.
Specify composite wood products which do not contain urea-formaldehyde or phenol-formaldehyde resins.
Technologies/Strategies: Request and evaluate emissions test data from manufacturers for comparative products. Ensure that VOC limits are clearly stated in specification, in General Conditions, or in each section where adhesives, sealants, and coatings are addressed.
Intent: Avoid exposures of building occupants to toxic or hazardous chemicals that adversely impact air quality.
Performance Principles: Design to physically isolate activities associated with chemical use from other locations in the building and/or provide properly engineered locations with dedicated ventilation systems to contain and remove chemical pollutants from source emitters at source locations. Employ strategies to capture dirt, pesticides, etc. from entering the building (e.g., through the use of grilles, mats, grates, etc.).
Target: No cross-contamination of areas. Elimination of hazardous chemical contamination. Isolation of high hazard areas where impossible to eliminate.
Technologies/Strategies: Design all chemical storage and mixing areas for housekeeping procedures (central storage facilities and janitors' closets, where appropriate) to allow for secure product storage in spaces that have water in chemical concentrate mixing areas, with drains plumbed for the appropriate disposal of liquid waste, separate outside venting, and negative pressure.
Include permanent architectural entryway system(s) (e.g., grilles, grates, etc.) to catch and hold particles to keep them from contaminating the building interior.
Intent: Increase occupant control of HVAC, natural ventilation, and lighting systems to support optimum health, productivity, and comfort in the workspace.
Performance Principles: Provide occupants with control over temperature, air movement and lighting.
Target: In office buildings, for 50% of the workstations, provide for individual or highly localized control of airflow, temperature and lighting, or, provide operable windows and lighting controls for all occupants at the perimeter.
Technologies/Strategies: TBD
Intent: Provide a thermally comfortable environment necessary to the productive and healthy performance of the building occupants.
Performance Principles: Integrated envelope and HVAC system design strategies that achieve thermal comfort conditions based on mean radiant temperature, local air velocity, relative humidity, and air temperature.
Target: Comply with ASHRAE Standard 55-1992, Addenda 1995.
Technologies/Strategies: TBD
Intent: Provide a connection to daylight and outdoors to increase occupant comfort and integrate the indoor space with the outdoor environment.
Performance Principles: Implement design strategies to provide access to daylight and views to the outdoors in a glare-free way.
Target: Design to allow daylight to reach 20 ft. in from the perimeter (where windows are possible). For interior areas with roof above, provide daylighting of 50% of the occupied space unless compelling reasons prohibit (e.g., security, historic preservation considerations, etc.).
Technologies/Strategies: Daylight monitors, clerestory, glazing, sun controls/shading devices, light shelves.
Intent: Provide for long term Indoor Air Quality monitoring to support sustained occupant health and comfort.
Performance Principles: Install and maintain a permanent humidity monitoring system that supplies operators with feedback on humidity performance in their buildings.
Target: Maintain 45% to 55% RH in all parts of the building at all times.
Technologies/Strategies: Install and maintain a humidity monitoring system for key areas of the building (i.e., at the perimeter, and spaces provided with humidity control). Select a system that is designed for ease of calibration. Specify that system operation manuals require calibration of all sensors be performed quarterly. Measure humidity to evaluate the effectiveness of humidification and/or dehumidification systems, and the existence of infiltration, presence of steam leaks and other internal sources of moisture.
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last updated 10/10/99
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