I am thrilled to report that the suite of three LEED pilot credits on resilient design, which the Resilient Design Institute has spearheaded, were approved yesterday by the LEED Steering Committee. This follows approval of the credits last week by the LEED Pilot Credit Committee.
RDI has been promoting such credits since January, 2013 and then led their development since September, 2014 with an active committee of practitioners facilitated by me and Mary Ann Lazarus, FAIA, a member of the RDI Advisory Board. Other key participants in the credit-development process are listed at the end of this article.
Overview of the credits
There are three credits in the new LEED pilot credits on resilient design. These fall into the Integrative Process category of LEED (thus the IP in the credit identities), and they are pilot credits (pc in the identities). In the LEED Rating System, they are applicable to all Building Design and Construction (BD+C) rating systems, along with Homes and Mid-Rise Residential rating systems.
In a nutshell, these three credits are designed to ensure that a design team is aware of vulnerabilities and addresses the most significant risks in the project design, including functionality of the building in the event of long-term interruptions in power or heating fuel.
The three pilot credits are described in greater detail below:
A schematic showing the basic structure of the three pilot credits. Graphic: Jessie Woodcock, ZGF
Credit IPpc98 – Assessment and Planning for Resilience
This credit encourages designers, planners and building owners or operators to assess and then plan for a wide range of natural disasters or disturbances as well as consider longer-term trends affecting building performance such as changing climate conditions. To earn this credit, one must satisfy a prerequisite and one of two optional measures.
The prerequisite is substantial: to complete a hazard assessment for the project site. This involves identifying the potential high risks associated with natural hazards that could affect the site. Specific requirements for such assessment are provided for the following hazard types:
- Tornado/high wind
- Landslide/unstable soils
The top three hazards (if there are that many) must be documented on a template that summarizes the hazard and provides references for determining priorities for addressing those. This analysis must be completed prior to beginning schematic design.
In addition to satisfying the prerequisite, above, to earn Credit IPpc98, the design team must implement one of the following:
Option 1 – Climate Resilient Planning
Recognizing that climate change will increase some vulnerabilities in the years and decades ahead, this option calls for completing a vulnerability assessment of impacts associated with climate change. For regions where state, regional, or local climate change studies have been conducted, those can be used for determining risks. For other areas, including outside the U.S., a climate scientist should be consulted if possible or relevant resources consulted.
Given these climate change vulnerabilities, the project team then must identify which are highest priority for planning and design, taking into account the expected service life of the project and changes expected during that period. This information is to be shared with the project team and client.
Option 2 – Emergency Preparedness Planning
This measure is designed to ensure that emergency preparedness has been considered. Compliance is provided by completing two forms, which are available through the American Red Cross Ready Rating program and available online at no cost. These two forms are the Red Cross 123 Assessment Form and the Red Cross Facility Description Form.
Specific requirements of Credit IPpc98 – Assessment and Planning for Resiliencecan be found using this link to the USGBC website.
Credit IPpc99 – Design for Enhanced Resilience
This credit is designed to ensure that each of the top hazards identified in Credit 1 are addressed through specific mitigation strategies. To earn Credit IPpc99, you have to, first of all, satisfy the hazard assessments in Credit IPpc98. Then you have to implement specific mitigation measures for the identified hazards. (If more than three hazards are identified for a particular site, only the top-three need to be addressed.) For projects outside the United States, either U.S. requirements or local equivalents, whichever is more stringent, may be followed.
A sampling of the specific requirements for these hazard types are listed below (this is not a comprehensive list):
FORTIFIED for Safer Business requirements may be followed for non-residential buildings, or flooding-specific design measures, including the flooding, must be incorporated:
- All flood resistant provisions of ASCE 24-14 must be followed.
- The lowest structural member of an occupied floor must be a minimum of five feet above the FEMA-defined base flood elevation, or dry floodproofing measures must be implemented for applicable commercial buildings.
- All sewer connections must include sewer backflow preventers.
- Mechanical and electrical equipment must be protected from flooding as per FEMA 55 guidelines.
Tornados and high wind (including hurricanes)
FORTIFIED for Safer Business requirements may be followed for non-residential projects, or the following wind-specific design measures are required:
- For projects in FEMA Wind Zones II, III or IV, all structures must incorporate wind design measures called for in ASCE/SEI 7-10.
- For projects in FEMA Wind Zones III and IV, safe rooms or refuge areas must be provided
There are two options for satisfying the seismic requirements. Either a Silver rating with the Arup REDi Rating System: Resilience-Based Earthquake Design Initiative for the Next Generation of Buildings must be earned, or FORTIFIED for Safer Business Design Criteria 3.5, Seismic Specific Design Requirements must be followed. The former is a robust seismic standard that provides for maintaining functionality of a building following an earthquake, rather than simply getting occupants out of the building, which is the goal of most seismic codes.
Projects must be designed and built according to standards detailed in the multi-agency publication Designing for Tsunamis: Seven Principles for Planning and Designing for Tsunami Hazards.
There are two options for projects in which wildfire is a top hazard:
- Demonstrate compliance with the ICC International Wildland-Urban Interface Code (2012) or with NFPA 1144 (2013); or
- Meet FORTIFIED for Safer Business Design Criteria 3.7: Wildfire Specific Design Requirements.
In areas deemed prone to drought through the vulnerability assessment (Credit IPpc98), the following must be achieved:
- Reduce the project’s landscape water requirement by at least 60% per the Outdoor Water Use Reduction Credit in LEED and use only non-potable or non-municipal water sources.
- Reduce the project’s indoor water use by at least 60% per the Indoor Water Use Reduction Credit in LEED.
Landslides and unstable soils
For sites with landslide-prone slopes and soils (either on the building site or uphill of the building site), a signed report from a geotechnical engineer is required showing that any steep-slope (≥ 15% or 6.75°) soils and underlying geology have been investigated and determined not to pose a landslide risk. A contour map of the site and surrounding area is required highlighting steep slopes (over 15%) and landslide-prone soils.
Terrorism and other direct human actions
While there are no specific requirements for addressing anthropogenic hazards, such as terrorism and accidents in Credit IPpc99, project teams are encouraged to address passive survivability measures in Credit IPpc100.
Specific requirements of Credit IPpc99 – Design for Enhanced Resilience can be found using this link to the USGBC website.
Credit IPpc100 – Passive Survivability and Functionality During Emergencies
The intent of this credit is to ensure that buildings will maintain reasonable functionality, including access to potable water, in the event of an extended power outage or loss of heating fuel. Power outages are often one of the primary impacts of natural disasters and there is growing concern about terrorist actions targeting energy infrastructure.
This credit includes three options, two of which are required to earn the LEED point.
Option 1 – Thermal Resilience
Of all the components of the suite of LEED pilot credits on resilient design, this one is the most groundbreaking. It requires thermal modeling to demonstrate that the building will maintain “livable temperatures” during a power outage lasting seven days during both peak winter and peak summer conditions.
Livable conditions are defined as SET temperature between 54°F and 86°F. SET is a temperature metric (standard effective temperature) that factors in relative humidity and mean radiant temperature. Deviations from this livability range are limited to a certain number of degree-days (or degree-hours) using SET temperature during winter and summer conditions.
For residential buildings (single-family and multifamily) during a one-week period during the summer peak, the building may not exceed 86°F SET for more than 9 SET °F degree-days (216 °F SET hours). During the winter, a residential building may not drop below 54°F SET for more than 9 SET °F degree-days during a one-week period.
For non-residential buildings, the winter requirements are the same as for residential, but in the summer, a greater deviation above 86°F SET is allowed: 18 °F SET degree-days (432 °F SET degree-hours) during a one-week period.
In other words, the project team has to demonstrate, through thermal modeling, that the building will maintain conditions within this “livability zone.” That level of performance is accomplished through a combination of a highly insulated building envelope, high-performance glazings, optimized orientation, passive solar design, vegetative shading, and other features.
Flexibility is provided with this option by allowing the design team to designate “habitable zones” in a building and ensure that these spaces, and not the entire building, achieves thermal resilience. There are also specific requirements for ventilation to ensure adequate fresh air.
Option 2 – Back-Up Power
The intent of this option is to provide access to electricity during widespread power outages. It is necessary to demonstrate that emergency power will be available to provide for the following functions, which are deemed critically important:
- Operation of electrical components of fuel-fired heating systems;
- Operation of a fan needed for emergency cooling if mechanical air conditioning equipment cannot operate;
- Operation of water pumps if needed in a building to provide access to potable water;
- Low-level lighting in all building spaces to define a path of egress—beyond the requirements provided for in building codes;
- One location with high-level lighting (minimum 30 footcandles measured 30 inches above the floor) for every 500 square feet;
- At least one functioning electrical receptacle per 250 square feet of occupied space;
- Operation of a cable modem and wireless router or other means of providing online access within the building; and
- Operation of one elevator in the building, if applicable.
These emergency power requirements can be met with either of the following:
- Fuel-fired, back-up generator(s) with fuel sufficient for 7 days in residential buildings and lodging or 72 hours in non-residential buildings. (Piped natural gas cannot satisfy this requirement.)
- A solar-electric system with battery storage sufficient for the above-mentioned critical loads, excluding elevators, assuming no sun. In this case, the duration requirements are lower than with fuel-fired generators—to encourage the use of renewable energy systems: residential building and lodging – 72 hours; non-residential buildings – 24 hours. With this option, the average daily wintertime production of the solar system in kWh must equal or exceed the dialing demand in kWh of all critical load circuits, assuming typical consumption and no elevator operation.
- A microgrid serving the building as part of a larger building cluster or region. In this case, the emergency power requirements do not apply. Islanding capability (an ability to operate when the regional power grid is down) is assumed with the microgrid.
Option 3 – Access to Potable Water
The intent of this option is to ensure that occupants of a building will have at least minimal access to potable water during a power outage—the most common situation in which access to potable water is lost.
There are different options for satisfying this requirement, depending on whether the building is on a municipal water system or not.
If the building is on municipal water, the assumption is that municipal water will remain accessible to the building, either due to gravity-flow from storage or due to back-up power at the municipal water department to operate pumps to pressurize the system. If pumps are needed within the building to deliver water to higher floors, either:
- There must be back-up power for those pumps with adequate fuel for the pumps to remain operational for seven days; or
- There must be an accessible faucet on a lower floor to which municipal water reaches without an onsite pump at a minimum of 10 psi; for larger multifamily buildings, there must be one such faucet for every 75 occupants.
For buildings that are not on municipal water, allowable options for maintaining access to potable water include the following:
- Back-up, fuel-fired generator that powers a deep-well or other pump with adequate fuel for at least seven days;
- A stand-alone, off-grid solar system providing power to the well pump;
- Access to gravity flow water from a spring or cistern (such as a cistern that is part of a rainwater harvesting system); if the water supply is a cistern, it must include adequate storage to provide a minimum of two gallons per building occupant per day for seven days;
- A hand pump serving a potable water well on the property that is accessible to building occupants during power outages; or
- Potable water storage in the building providing a minimum of two gallons per occupant per day for seven days.
Specific requirements of Credit IPpc100 – Passive Survivability and Functionality During Emergencies can be found using this link to the USGBC website.
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These are challenging credits
We recognize that these are challenging LEED credits—they will be hard for many design teams to achieve. As pilot credits, the idea is to “test-drive” the credits. We want to get some experience and then figure out if there are ways to refine and simplify them.
We are also looking forward to input on the temperature metric we are using for Credit IPpc100 (SET, rather than simply dry-bulb temperature) and the livability zone we identify of 54°F to 86°F SET. Are these reasonable?
How pilot credits work in the LEED Rating System
In LEED, there are five “slots” in a project scorecard for either pilot credits or innovation credits. These three Resilient Design pilot credits are now available for use in these slots, along with dozens of other pilot credits that have been previously approved.
The education goal of these pilot credits
Perhaps most importantly, we want these LEED pilot credits to put resilient design on the radar screen for design teams going through LEED certification. Resilience is an important priority today—and will become more important in the years ahead as climate change advances.
It is our hope that these pilot credits will get more people talking about resilience and thinking about how to incorporate resilient design features into their buildings—whether or not they actually earn the LEED credits.
Getting your feedback
Our Resilient Design Pilot Credit Committee is very interested in any feedback you have on these credits. Feedback can be provided by commenting on this blog (there is a delay between when you submit a comment and when it is approved for posting), or by e-mailing me directly. So that others can benefit from your input, my preference would be that you post comments to this blog.
For those with experience outside North America, we would be interested in your input on standards related to resilient design in other countries around the world. Many countries face even more difficult challenges related to climate change than we face here in the U.S.; we want these credits to be applicable worldwide. What standards should we be referencing?
Thanks to an all-star team of contributors and advisors
To create these credits, Mary Ann Lazarus and I engaged a broad and highly skilled group of practitioners around the country. Key members of the Resilient Design Pilot Credit Core Committee include Valerie Walsh of Walsh Sustainability Group in Boulder, CO; Lona Rerick, AIA of ZGF Architects in Portland; Betsy del Monte, FAIA of the SMU Lyle School of Engineering in Dallas; Mark Meaders of HDR in Dallas; Rachel Minnery, FAIA, Director | Building Environment Policy at the American Institute of Architects in Washington, DC; and Ted van der Linden, director of sustainability at DPR Construction in San Francisco.
In addition, many other experts contributed to the discussions of specific credits, including Don Watson, FAIA, author of Design for Flooding: Architecture, Landscape, and Urban Design for Resilience to Climate Change and principal of EarthRise Design in Trumbull, CT; Erik Olsen, PE, the managing partner of Transsolar KlimaEngineering in New York; Brendon Levitt, RA of Loisos + Ubbelohde in Alameda, CA; Jim Newman of Linnean Solutions, LLC in Cambridge, MA; Gail Brager, Ph.D., director of the Center for the Built Environment in Berkeley, CA; Luke Leung, PE, LEED Fellow of Skidmore Owens & Merrill LLP in Chicago; Ibrahim Almufti, PE a structural engineer with the Advanced Technology + Research group in Arup’s San Francisco office; Ryan Colker Director, Consultative Council/Presidential Advisor at National Institute of Building Sciences; and Carl Sterner, the director of product marketing at the software company Sefaira, in New York.
All of these busy people—and others whom I couldn’t fit into this blog—deserve a hearty thanks.
Thanks also to Batya Metalitz, Jeremy Sigmon, Jason Hercules, and Emma Hughes at the U.S. Green Building Council, who have been very helpful in guiding us through this process, along with members of the LEED Pilot Credit Committee, who had invaluable input during out work on these credits.