Joan L. Pellegrino

Nelson P. Bryner

Erik L. Johnsson

NIST Special 

Publication 

1150

Wildland-Urban

Interface Fire

Research Needs

Workshop 

Summary Report

http://dx.doi.org/10.6028/NIST.SP.1150

NIST Special Publication 1150

Wildland-Urban Interface 

Fire Research Needs

Workshop Summary Report

August 15-16, 2012

Boulder, Colorado

Joan L. Pellegrino

Energetics Incorporated

Nelson P. Bryner

Erik L. Johnsson

Fire Research Division

Engineering Laboratory

http://dx.doi.org/10.6028/NIST.SP.1150

May 2013

U.S. Department of Commerce

Rebecca Blank, Acting Secretary

National Institute of Standards and Technology

Patrick D. Gallagher, Undersecretary of Commerce for Standards and Technology and Director
Certain commercial entities, equipment, or materials may be identified in this

document in order to describe an experimental procedure or concept adequately. Such

identification is not intended to imply recommendation or endorsement by the

National Institute of Standards and Technology, nor is it intended to imply that the

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Special Publication 1150 

Natl. Inst. Stand. Technol. Special Publication 1150, 117 pages (May 2013)

http://dx.doi.org/10.6028/NIST.SP.1150

CODEN: NSPUE2
Acknowledgments 

This report summarizes the results of the “Workshop on Wildland-Urban-Interface Fire Research Needs” held 

August 15–16, 2012, in Boulder, Colorado. The workshop was organized and funded by the National 

Institute of Standards and Technology. Thanks are extended to the Steering Committee co-chairs and 

members for their extensive efforts in guiding this workshop. Thanks also go to Energetics Incorporated’s 

team of Laurie Aldape, Paget Donnelly, Susan Kaczmarek, Ridah Sabouni, Katie Shay, Yannick Tamm, and

co-leaders Joan Pellegrino and Anand Raghunathan for their assistance in facilitating the workshop and 

preparing this report. Of course, this report would not have been possible without the specialized 

knowledge and insight contributed by the recognized experts in various aspects of the wildland-urban 

interface who took time from their busy schedule to participate in the workshop and review the results. 

These individuals are listed in Appendix A.

Steering Committee Co-Chairs

Nelson Bryner (National Institute of Standards and Technology)

Erik Johnsson (National Institute of Standards and Technology)

Steering Committee Members

Dan Bailey (International Code Council)

Nelson Bryner (National Institute of Standards and Technology)

Erik Johnsson (National Institute of Standards and Technology)

Alexander Maranghides (National Institute of Standards and Technology)

Nancy McNabb (National Institute of Standards and Technology)

Joan Pellegrino (Energetics Incorporated)

Anand Raghunathan (Energetics Incorporated)

Matt Rahn (San Diego State University)

Disclaimer

This report was prepared as an account of work sponsored by NIST. The views and opinions expressed herein do not 

necessarily state or reflect those of NIST. 

Contents | vi

CONTENTS

1 WORKSHOP OVERVIEW .................................................................................................................... 1

1.1 WILDLAND-URBAN INTERFACE FIRE PROBLEM ............................................................................................ 1

1.2 SCOPE AND OBJECTIVES.......................................................................................................................... 2

1.3 WORKSHOP FORMAT............................................................................................................................. 2

1.4 WORKSHOP REPORT.............................................................................................................................. 3

2 MITIGATING WUI FIRES .................................................................................................................... 4

2.1 OVERVIEW OF CURRENT ISSUES AND CHALLENGES ....................................................................................... 4

2.2 EXPOSURE QUANTIFICATION ................................................................................................................... 4

2.3 IGNITION-RESISTANT MATERIALS ............................................................................................................. 5

2.4 FIRE-RESISTANT DESIGN......................................................................................................................... 5

2.5 RESPONSE............................................................................................................................................ 6

2.6 RECOVERY ........................................................................................................................................... 6

2.7 PUBLIC EDUCATION, OUTREACH, AND PERCEPTION...................................................................................... 8

2.8 OTHER ................................................................................................................................................ 9

3 HARDENING THE WUI COMMUNITIES ..............................................................................................11

3.1 OVERVIEW......................................................................................................................................... 11

3.2 IMPORTANT WUI FIRE RESISTANCE RESEARCH NEEDS................................................................................ 11

3.3 EXPOSURE QUANTIFICATION ................................................................................................................. 11

3.4 MATERIALS ........................................................................................................................................ 12

3.5 FIRE-RESISTANT DESIGN....................................................................................................................... 13

3.6 RESPONSE.......................................................................................................................................... 14

3.7 RECOVERY ......................................................................................................................................... 15

3.8 EDUCATION........................................................................................................................................ 15

3.9 PRIORITIZED RESEARCH NEEDS AND IMPLEMENTATION PLAN....................................................................... 15

4 SUMMARY.......................................................................................................................................27

APPENDIX A: CONTRIBUTORS .................................................................................................................29

APPENDIX B: ACRONYMS .......................................................................................................................31

APPENDIX C: REFERENCES ......................................................................................................................33

APPENDIX D: WORKSHOP AGENDA.........................................................................................................37

APPENDIX E: OVERVIEW BRIEFINGS........................................................................................................39

I. BRETT LACEY, FIRE MARSHAL, COLORADO SPRINGS – WALDO CANYON FIRE.................................................. 40

II. HYLTON HAYNES, NATIONAL FIRE PROTECTION ASSOCIATION...................................................................... 52

III. RICK SWAN, CALIFORNIA DEPARTMENT OF FORESTRY, INTERNATIONAL ASSOCIATION OF FIRE FIGHTERS .............. 60

IV. KUMA SUMATHIPALA, AMERICAN WOOD COUNCIL ................................................................................... 63

V. STEVE QUARLES, INSURANCE INSTITUTE FOR BUSINESS AND HOME SAFETY .................................................... 72

VI. MARK DIETENBERGER, US FOREST SERVICE ............................................................................................. 81

VII. ALEX MARANGHIDES & NELSON BRYNER, NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY .................... 97
WUI FIRE RESEARCH NEEDS 

Workshop Summary Report

vii | Contents

Figures

Figure 3-1: Hardening of Structures...........................................................................................................17

Figure 3-2: Performance Standards and Needs..........................................................................................18

Figure 3-3: Understanding the Ignition Phenomena ..................................................................................19

Figure 3-4: Education of Stakeholders on Ignition Prevention...................................................................20

Figure 3-5: Improved Tools for Post-Fire Evaluation..................................................................................21

Figure 3-6: Unified and Efficient Response Teams.....................................................................................22

Figure 3-7: Fuels Management...................................................................................................................23

Figure 3-8: Realistic and Material-Neutral Test Methods ..........................................................................24

Figure 3-9: Codified Class A Fire-Rated Roofs ............................................................................................25

Tables

Table 3-1: Prioritized WUI Research Needs................................................................................................16
Introduction | 1

1 WORKSHOP 

OVERVIEW

1.1 WILDLAND-URBAN INTERFACE FIRE PROBLEM

The wildland-urban interface (WUI) encompasses housing and other structures that are either colocated or abut wildland vegetation and forest.1 WUI communities are especially susceptible to 

destruction from wildland fires. Several causes of WUI fires include the upsurge of structures in 

the WUI, long-term drought, climate change, and build-up of wildland fuel.2 In the last 100 years, 6

of the top 10 fire loss incidents occurred in WUI areas (5 of the 6 occurred in California).

2 In the 

United States, more than 45 million homes in 70000 communities are at risk of WUI fires—which

have destroyed an average of 3000 structures annually over the last decade—and this risk is

rapidly increasing.3

WUI fires can also generate huge response and recovery costs. For example, the 1991 Oakland 

and 2007 Witch Creek fires in California resulted in property losses of $2.7 billion and $1.5

billion, respectively.4 Federal funding for suppression and wildland fuel treatment has also risen 

significantly. In the period from 1996 to 2000 to the period from 2001 to 2005, this funding 

increased from $1.3 billion annually to $3.1 billion annually.5 In addition, an average of 70 % more

area was burned from 2000 to 2005 as compared to the 1990s.6 Recent increases in funding, area 

burned, and fire occurrences in WUI communities imply an intensification of the WUI fire 

dilemma and require a review of the approaches to mitigating the issue.7

A traditional approach to mitigating WUI fires that has its roots in a series of massive wildfires

in the early 1900s* has been to control or suppress a wildland fire as quickly as possible.8 

Wildland fire suppression operations successfully control 97 % to 99 % of all wildfires at initial 

attack.9 Typically, the 1 % to 3 % of wildland fires that are not quickly suppressed involve 

extreme fire behavior such as high winds, prolonged dry conditions, and accumulated fuels.

Although extreme fire behavior only occurs in a very limited number of fires, it can overwhelm 

firefighters and cause near simultaneous ignition of multiple structures within a community.

Under extreme fire conditions, the suppression approach to mitigating the impact of WUI fires 

is less effective than under non-extreme conditions.

Another approach to mitigating WUI fires has been to improve the fire resistance or harden the 

structures within WUI communities.10 Using principles of ignition and fire spread in the WUI, 

standards development organizations such as the National Fire Protection Association (NFPA)11, 

the International Code Council (ICC)12, and ASTM International13 have developed building 

codes and standards for WUI communities. However, the range of actual exposures possible 

under different conditions has not been fully characterized or quantified. This has resulted in a 

very limited coupling between the potential exposure that a structure might experience and the 

 * Including Hinckley, Minnesota 1894; Adirondack, New York 1903; and Big Blowup, Montana-Idaho 1910.
2 | Introduction

performance requirements in building codes and standards. For example, as a wildfire moves 

from the forest and into a community, direct flame contact may play a dominant role in the 

ignition of structures on the periphery of a community, but once a fire moves into a community, 

it is not clear whether direct flame contact or embers/firebrands† are causing most of the 

ignitions. Structures on the edge of a community may require increased resistance to ignition by 

flame contact while structures inside the community may need improved ignition resistance to 

embers. Other assessments include: 1) how wind and terrain affect ignition and fire spread 

within WUI communities, and 2) how to develop a representative performance test when the 

exposure has not been well characterized. 

Realistic WUI fire and ember exposures over a wide range of fuel types (vegetative and 

structural), terrain, and weather conditions must be determined in order to consistently 

quantify the expected severity of WUI fire events. Once established, these technically based 

ember and fire exposures for the WUI will form a stronger technical foundation for the 

development of a realistic set of performance-based building code provisions aimed at providing 

a level of structure ignition protection commensurate with the expected fire and/or ember 

exposure.

Strategies or methodologies to improve the fire performance or hardening of structures and 

communities include ignition-resistant‡ materials and construction, engineered fire-resistant§

design, passive and active fire protection, risk assessment tools, implementable codes, 

stakeholder education and compliance, and firefighter safety and effectiveness.

1.2 SCOPE AND OBJECTIVES

The “Workshop on Wildland-Urban-Interface Fire Research Needs,” held August 15–16, 2012, in 

Boulder, Colorado, provided a forum for WUI experts to discuss challenges, identify research 

needs, and establish research priorities to improve the fire resistance of WUI communities.

Participants included professionals in WUI fire behavior, engineered fire protection technologies, 

ignition-resistant materials, wildfire-resistant design, standard test methods for building materials,

fire suppression and response, and WUI building and fire codes, as well as representatives of

authorities having jurisdiction.

1.3 WORKSHOP FORMAT

Discussions focused on identification and prioritization of current issues in mitigating WUI fires, 

ignition prevention ideas, and potential fire resistance improvements through implementation of 

measurement science to develop innovative technological solutions. Those ideas considered as 

the highest impact and highest priority were further explored and developed.

The workshop began with a series of overview presentations from stakeholders:

• Authorities having jurisdiction: 

o Brett Lacey – Fire Marshal, Colorado Springs and Waldo Canyon Fire

• Standards development organizations:

o Dan Bailey – International Code Council 

o Hylton Haynes – National Fire Protection Association

 † Embers or firebrands are glowing or flaming fragments of fuel; these terms will be used interchangeably in 

this report. These fragments, which are lofted into the air and carried more than a mile by wind, may 

originate from either vegetative or structural fuel sources. 

‡ Ignition-resistant materials and construction incorporate material properties, chemicals, or configuration 

to prevent or limit ignition by embers or flame contact. 

§ Fire-resistant design utilizes material properties, construction, and assembly features to prevent or limit 

fire spread within design component and to other exposed structural and vegetative fuels. 
Introduction | 3

• Fire service:

o Rick Swan – International Association of Fire Fighters, California Department of 

Forestry and Fire Protection

• Industry: 

o Kuma Sumathipala – American Wood Council

• Research laboratories:

o Steve Quarles – Insurance Institute for Business & Home Safety

o Mark Dietenberger – U.S. Forest Service Forest Products Laboratory

o Alex Maranghides – National Institute of Standards and Technology

These overview presentations laid the foundation for the workshop participants to split into three 

breakout discussion groups. Each of the three groups was charged with first identifying current 

issues and challenges of current WUI fire mitigation techniques, and secondly with identifying 

research needs to address those issues and challenges. After the breakout groups finished 

identifying issues and research needs, they reassembled to present their findings.

After consolidating similar issues and research needs, the workshop participants prioritized the 

research needs. The research needs that participants labeled as “high-priority” were then assigned 

to each breakout group for the group members to complete more detailed implementation plans.

1.4 WORKSHOP REPORT

This workshop report describes and documents the contributions** of the workshop participants

regarding issues in mitigating WUI fires (Section 2), research needs to address existing challenges 

to hardening communities (Section 3), prioritized research needs (Table 3-1), and implementation 

plans for selected research needs (Figures 3-1 through 3-9). The workshop contributors are listed 

in Appendix A. Acronyms and references are listed in Appendix B and Appendix C, respectively.

Appendix D provides the workshop agenda. Appendix E provides overview presentations from 

the workshop.

 ** Contributions represent output of workshop participants and do not necessarily state or reflect those of 

the National Institute of Standards and Technology.
Mitigating WUI Fires | 4

2 MITIGATING 

WUI FIRES

2.1 OVERVIEW OF CURRENT ISSUES AND CHALLENGES

The risk for forest fires spreading across the WUI increases year by year as communities continue 

to grow and more and more people build in forested areas. In 2007, “the WUI occupied 9 % of 

the surface and contained approximately 39 % of all housing units within the conterminous United 

States.”14 While there are a number of strategies in place to address wildland fires, including rapid 

fire containment and suppression and fuels management, wildfire mitigation strategies do not 

necessarily target WUI communities. It should not be surprising that these wildland fire strategies 

are less than effective in mitigating fires in WUI communities.15 Fire protection is usually 

addressed by local fire service, which is often limited due to available resources and training.

Educating the homeowners living in the WUI is essential to preventing fires and fire spread.16

The workshop discussed and identified current issues in mitigation techniques for WUI fires.

These issues have been grouped into common themes or approaches: exposure quantification, 

ignition-resistant materials, fire-resistant design, response, recovery, public education, and other.

Each of the major themes for mitigating WUI fires is discussed below. The corresponding 

challenges identified at the workshop are presented in each section6.

2.2 EXPOSURE QUANTIFICATION

Exposure quantification seeks to measure the vulnerability of structures to ignition by fires. An 

exposure concept or scale17 can be used to quantify expected fire and ember exposure and is 

applicable throughout new and existing WUI communities. A WUI exposure-scale can be used 

not only to identify WUI areas that may be exposed to wildfire, but also characterize the intensity 

of the exposure. This scale would link the potential exposure to a structure or community as 

opposed to the more traditional approach of identifying areas that simply meet housing density 

and wildland vegetation requirements for WUI areas. The scale can therefore be used to provide 

the boundaries where specific land use and/or building construction regulations would apply.

Improving the exposure quantification tests will ostensibly lead to more effective building codes 

and reduced risk of structural ignition.18 Currently, standards development organizations (such as 

ASTM International, International Code Council, National Fire Protection Association, and 

others) are actively advancing WUI-related building and construction standards by compiling, 

organizing, and harmonizing the limited understanding of WUI fire exposure conditions for 

structures and communities. Better characterization of exposure conditions includes measuring 

 6 Text generated during the workshop sessions was formatted and placed inside highlighted boxes within Section 2 of 

this report. This text which describes the challenges was a product of workshop participants working in different 

breakout groups. For a specific topic, text from different sessions was grouped together within a single box. Text was 

not edited for consistency between different breakout groups.
Mitigating WUI Fires | 5

the critical roles played by burning embers, flame contact, and thermal radiation in structure 

ignition as well as understanding the importance of fuel package, terrain, and weather.

• Unknowns in ignition exposure

o Susceptible ignition points/locations 

o Fire exposure on structures

• Limited comprehensive data and voluntary reporting – ignition, exposure, and related 

statistics

• Lack of representative exposure test methods inhibits innovation*

• Inadequate consideration of ember ignition as fire cause

o Lack of effective coordination of research into codes

o Lack of analysis on effectiveness

o Lack of research and unbiased research funding; initiation bottle neck 

o Limited attribution of ember-cause ignition event in building/fire codes

*A set of exposure conditions that does not replicate realistic exposures will not encourage development of products/technology 

that will perform well under real exposure conditions (i.e., conditions not captured by the exposure test).

2.3 IGNITION-RESISTANT MATERIALS

Reducing the ignition potential and increasing the survivability of structural materials diminishes 

the severity of WUI fires. Through research, structural materials are constantly evolving to 

prevent ignition of the buildings and to slow fire propagation once the building is ignited.

However, it will be critical to develop an effective implementation plan for incorporating advanced 

materials into both existing and new construction. Relevant laboratory-scale standard test 

methods for building materials also require an improved understanding of the exposure 

conditions faced by WUI structures. Effective WUI building materials (e.g., siding) or assemblies 

(e.g., vented eaves) require standard test methods that simulate exposure conditions that are as, 

or more, severe than those in an actual WUI fire.

• Incomplete characterization and performance discrimination among combustible materials

• Limited new construction design and materials (e.g., roofs, decks, and siding)

• Inadequate knowledge of construction materials: combustible or noncombustible

• Limited research and development and use of new technologies (e.g., nanotechnology)

2.4 FIRE-RESISTANT DESIGN

In concert with ignition-resistant material improvements, engineered wildfire-resistant design and 

construction of WUI communities can improve fire performance by reducing exposure to the fire 

and decreasing the likelihood of fire spread. The geometry of the building may play a role. If a 

corner or seam allows embers to accumulate, a group of embers may transfer enough energy to 

cause the fire to spread to the exposed component and, subsequently, the structure. A fireresistant design strategy would minimize the accumulation of embers through layouts that reduce 

or eliminate geometries with internal corners, for example, which allow thermal radiation to be 

re-radiated from one surface to another. For communities, thermal radiation exposure and flame 

contact exposure to an adjacent surface can be reduced by designing noncombustible zones 

between adjacent structures or vegetation. These design principles can be incorporated in the 

initial development phases of a community or during retrofitting or home improvements. 
6 | Mitigating WUI Fires

• Inconsistent recommendations regarding adequate defensible space (e.g., walls or retaining 

walls)

• Defining standards allowing the use of new/economical products or vegetation clearing

• Limited community-wide fuels treatments: surrounding versus within 

• Current focus is fire suppression instead of mitigation in the built environment

• Limited intermediary solutions (e.g., removing mulch)

• Aesthetics of overgrown land

• Inappropriate landscaping choices: vegetation in relation to homes/windows

• Legacy infrastructure parcels and land use

• Inadequate vegetation and forest management

o Vegetation burns hotter and faster these days

• Inadequate WUI design codes and poor enforcement of them 

• Focus on protection, not design: fire blankets, water external systems, etc.

• Fuels reduction: need to reduce supply

o Use of non-native vegetation for landscaping

o Reliance on irrigation in arid or semiarid areas

o Code enforcement and ensuring compliance

o Need information based on type of vegetation and location from structure

• Limited consistent resources for effective long-term management

2.5 RESPONSE

Destructive WUI fire events usually occur in severe conditions (e.g., high winds or dry fuels) 

resulting in large, rapidly spreading fire perimeters. WUI fires differ from structural fires; they are 

more complex and require different equipment and operating procedures. The ability to suppress 

a wildfire depends on the energy release rate of the fire, the availability of fire service and 

equipment, staff training, quality of communications and organization efforts, and response times.

Limited resources—manpower and infrastructure—are the norm and can be easily overwhelmed 

during WUI events. Because existing standards are directed to either wildland or structural 

firefighting scenarios, WUI-specific standard equipment and operating procedure standards need 

to be developed to effectively fight fires in the WUI.

• Poorly established firefighting tactics for WUI

• Inadequate access for response 

• Limited understanding of the impact of engine crew size on initial attack effectiveness 

• Unified command on WUI fires is lacking

• Fire response capacity is limited

• Evacuations are not optimal

• Too much emphasis and money on suppression strategies

2.6 RECOVERY

Guidelines for rebuilding communities need to incorporate advanced ignition-resistant materials, 

improved methods of construction, and enhanced fire-resistant designs. As previously described, 

the limited exposure information currently available does not address the full range of realistic 

WUI exposures and offers little context for the design and construction of ignition-resistant 

landscapes and buildings. It is difficult to implement a more fire-resistant design if one does not 

understand whether the exposure is to embers, radiant heat, and/or flames. In addition to a lack 

of understanding regarding the exposure threat, the performance of current structural and 
Mitigating WUI Fires | 7

community designs is not well documented. Standardized post-fire data collection methods are 

not widely implemented. Post-fire (and pre-fire) WUI community data collection could also 

identify shortcomings or unnecessary redundancies in recommended mitigation actions for ease of 

implementation or clarity. This would help determine what improvements are needed in terms of 

community education and incentives. Analysis of post-fire data and sufficiently accurate WUI fire 

behavior and economic models could also support the development of rehabilitation guidelines 

(e.g., site planning, landscaping, vegetation choice and maintenance, building placement, and 

construction choices and prioritization) for damaged communities.

Rebuilding homes also requires homeowners to overcome the emotional response to the loss of 

their home and belongings, find competent design professionals to prepare housing plans that 

adhere to existing codes and planning requirements, navigate the permit process for rebuilding, 

and find an acceptable builder, among other details.19

• Rebuilding a community after a WUI fire without determining effectiveness of existing

mitigation strategy

o Unclear long-term impacts: lacking a holistic evaluation of long-term impacts

• Post-event mitigation tactics are seldom maintained – communities, legislation, etc.
8 | Mitigating WUI Fires

2.7 PUBLIC EDUCATION, OUTREACH, AND PERCEPTION

Education and effective information delivery is essential to the implementation of homeowner and 

community guidelines. Education and outreach must include the residents of WUI communities, 

government officials, community developers, firefighters, and other stakeholders. Each of these 

groups requires tailored and targeted information on regular intervals through a variety of venues 

and vehicles. There are a number of existing web-based resources that can be used to promulgate 

improved guidelines. Public education and awareness programs such as Fire Safe;20 Firesmart;21

Firewise;22 Fire Free;23 Ready, Set, Go;24 Fire Adapted Communities;25 and Living with Fire26

educate communities where potential hazards exist and provide steps to minimize those hazards.

These programs typically draw on the requirements and recommendations in WUI building codes 

such as the ICC International Wildland-Urban Interface Code (IWUIC)27 and standards such as 

Reducing Structure Ignition Hazards from Wildland Fires.28 Although the Ready, Set, Go program 

does mention the importance of hardening structures and the Fire Adapted Communities and 

Living With Fire programs present information on embers, typically embers are either not 

discussed or when discussed, not presented as a major ignition source.. The approaches described 

by these programs need to be expanded to more adequately describe the role of embers in 

structure ignition and need to include additional risk factors based on the attributes of adjacent 

structures and surrounding vegetation. Communities differ in the amount of financial resources 

available for landscape and residential fuel treatments. 

• Limited/inadequate outreach education of homeowners on wildfire risks

o Large lots (low number of homes/acre)

o Neighborhood (lower density housing)

• Multiple public education initiatives are not clearly differentiated

• Lack of community awareness/planning (local government and citizens) regarding WUI fire 

risks

• Homeowner desires conflict with best practices (e.g., rustic cabin look inconsistent with 

best practices)

• Lack of community motivation until the event happens 

• Politics

o Inadequate communication with politicians on the problem

o Weak political will/apathy – government officials and citizens

o Culture shift required: required codes versus lack of cooperation from some homeowners 

• Lack of personal accountability and responsibility

• Homeowner often unaware of benefits of implementing fire prevention best practices

o Cost – unwilling to pay

o Lack of initiative by homeowners and communities
Mitigating WUI Fires | 9

2.8 OTHER

There are many other issues that are challenging to categorize but are valid considerations in the 

attempt to mitigate WUI fires. These issues are no less important than those previously 

mentioned. In this report these issues have been grouped into one category that includes social, 

economic, jurisdictional, and environmental factors, among others.

• Inadequate definition of adequate clearance for diverse materials, topographies, and 

regional conditions

• Poor attitudes: wildfires are capricious, so hard to justify time, effort

• Economic limits

o Cost of special building materials and fuels management. Cost to responsible parties executing 

mitigation strategies.

o Lack of cost-benefit analysis for fire mitigation

o Best practices are not always cost effective for homeowners to implement

o Owner buy-in to WUI protective action through reduced insurance rates

• Government issues

o Jurisdictional issues – problem is complex combination of publicly owned wildlands where a 

wildfire may start and WUI communities where privately owned structures are destroyed. 

Cost and responsibility for fuels management, response, and recovery must be apportioned 

across involved public and private parties

o Multi-jurisdictional problems

o Limited funding at all levels – local, state, and federal (should be predominantly a federal 

concern)

• Environmental constraints 

o Invasive species

o Sensitive habitats

o Endangered species

o Erosion and sedimentation, nutrients, climate change, etc. 

• Beyond “replace wood shake roofs” and other simple tasks, the importance of subsequent 

mitigation measures in unknown

• Duplication of efforts by different authorities and parties

• Mitigation efforts are fragmented – the entire system needs consideration
10 | Mitigating WUI Fires

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.
Hardening t he WUI Communities | 11

3 HARDENING THE 

WUI COMMUNITIES

3.1 OVERVIEW

The Waldo Canyon fire near Colorado Springs, Colorado, in the summer of 2012 was the most 

destructive in state history—the wildfire decimated more than 18,247 acres(7380 ha or 2990 m2), 

killed two people, and destroyed nearly 350 homes. The total property damage is estimated at 

more than $110 million; the cost to fight the blaze is approximated at more than $16 million.29

The myriad of issues in mitigating WUI fires identified in the previous chapter suggests that 

wildland fires will continue to inflict a high level of destruction unless new science-based fire 

protection strategies are developed and existing mitigation tactics are fully implemented. 

Concepts to prevent ignition and retard fire spread, as well as methods to increase wildfire

resistance in WUI structures and regions—all ways to harden the WUI community against fire—

are presented below.

3.2 IMPORTANT WUI FIRE RESISTANCE RESEARCH NEEDS

Workshop participants identified a number of important research needs to aid in hardening the 

WUI community and address existing challenges; these needs are summarized below. The needs 

have been grouped into the following areas: exposure quantification, materials, fire-resistant 

design, response, recovery, and education.

3.3 EXPOSURE QUANTIFICATION

Test methods that represent realistic problems: The limited characterization of actual 

exposures coupled with an incomplete understanding of the roles played by fuels, weather 

conditions, and terrain makes developing performance-based and material-neutral test methods 

more difficult. Although WUI communities have a limited number of standard test methods and

design requirements such as California State Fire Marshal standards and several ASTM 

International standards, most are not performance based and material neutral. These methods 

should be more representative of realistic exposures. Standards should provide a path to 

discriminate performance of materials and increase the resistance of buildings to wildfire by 

providing a systematic and exposure-based method of evaluating the performance of vulnerable 

designs, materials, and constructions features. Because it would be too costly and impractical to 

conduct full-scale tests on every design and material combination, a more limited set of standard 

test methods must be developed. This set of exposure-based test standards will still need to 

capture the full range of potential exposure to flames, thermal radiation, and embers. Current test 

standards largely focus on fire resistance. Future test standards must emphasize ignition resistance 

applied at the building and community levels. New software may aid in the development and 

implementation of new testing. Design requirements must be developed and incorporated into 

new codes that are effectively enforced.
12 | Hardening the WUI Communities

Understand ignition phenomena: A key part of increasing the fire resistance of WUI 

communities includes augmenting the existing knowledge of ignition and fire spread (underlying 

and primary causes). Although WUI fires are initiated (started) by either “human caused” actions 

or lightening, these fires can be propagated or spread in a number of ways—embers, heat 

radiation from a nearby fire, direct fire contact, and/or fire jump.30 In addition, there are a number 

of points/locations on or near a building where ignition can occur. These points could also be a

vulnerable component that could facilitate fire spreading to other components or the interior of 

the structure. These locations include the roof, windows, vents, eaves, soffits, siding, trees,

bushes, and combustible mulch, among many more points.31 A comprehensive knowledge of how 

fires initiate in different building materials, building components, and communities is necessary.

Further, causes can be organized into a hierarchy by their severity or impact, enabling 

prioritization of mitigation or prevention strategies.

Specification of performance standards and needs: While hardening of the structures is an 

important part of WUI fire prevention and defense, specific ignition resistance and fire 

propagation considerations need to be further explained and clarified based on relevant 

circumstances and materials. With a more fully developed understanding of these interactions, 

WUI standards can be updated and/or created against which materials and methods of 

construction can be tested using relevant conditions.

3.4 MATERIALS

Research ignition-resistant and noncombustible materials: Even though some 

noncombustible and ignition-resistant building materials exist—stucco, fiber cement, wall siding, 

fire-retardant-treated lumber, and fire-retardant-treated wood shakes and shingles32—research 

and development (R&D) into improving existing designs, materials, and methods of construction 

and increasing the number of wildfire-resistive choices should be continued. This will add to the 

options available to designers, builders, and residents when constructing structures in the WUI 

communities, thereby reducing the chance for fire ignition.

Classifications for combustible materials to complement WUI exposures: National 

Institute of Standards and Technology (NIST) researchers are currently augmenting their 

definitions for building exposure to embers, radiant heat, and flames, leading to an exposure 

classification system (ECS) as a common industry resource.33 To design more wildfire-resistant 

buildings, designers will also need a clear, science-based understanding of the relative efficacy of 

construction material treatments (the combustibility of various materials and the relative 

combustibility of the same materials with different coatings or treatments). To complement the 

ECS, research is needed to develop (via consistent methodology and terminology) a similar 

classification system for specific materials with various treatments or coatings and methods of 

construction. In addition, there is a need to better understand the exposure thresholds posed by 

various types of vegetative embers that could land on or near a structure, taking into account 

expected variations by region and climate.

Effective accelerated weathering protocol for materials and coatings: The choice of 

materials and coatings can significantly affect the fire resistance of homes and other structures in 

WUI communities, yet the relative efficacies of the various treatment options, particularly their 

durability over time, are not well understood. Some coatings provide more lasting protection on 

some surfaces than others, depending upon the design and application as well as moisture and 

ultraviolet exposure. Research is needed to evaluate the accuracy of existing accelerated

weathering models for these materials and coatings and determine how closely these models 

match long-term “aging” conditions in each climate type. Ultimately, a clear and accurate protocol 

is needed to effectively guide design professionals, homebuilders, homeowners, standards 
Hardening the WUI Communities | 13

developing organizations, and others in a position to influence critical choices affecting fire 

resistance.

3.5 FIRE-RESISTANT DESIGN

Hardening of structures (exteriors including decks, siding, roofs, windows, and vents,

as well as interiors, and intra- and inter- community features): Hardening of structures 

entails reducing the potential for ignition from direct flame, firebrand showers, and radiant heat 

coming from outside of the defensible zone.34 Furthermore, hardening also entails the ability to 

slow the propagation of the flame should ignition occur. Ignition resistance and retarded firespreading structures and communities can be achieved with careful building planning, selection of 

fire-resistance construction materials, active and passive barriers, reflective materials, nonlouvered shutters, sprinkler installations, and inclusion of quality defensible space surrounding 

individual houses and neighborhoods.35 Where relevant standards exist they need to be enforced, 

and new standards are needed where none currently exist. For many measures, however, 

maintenance is critical. Homeowners should be held accountable for keeping roofs and gutters 

free of debris; maintaining defined defensible spaces; and not storing firewood on, near, or under 

decks.

New codes that focus on ignition resistance and fire resistance independently: Novel 

codes must continue to be developed that focus on ignition resistance and fire resistance as 

separate, but complementary approaches. The majority of past studies, knowledge, and codes are 

based on the fire resistance, heat release rate, propensity to drop burning debris, ability to selfextinguish, flame spread rating, ability to generate embers, or endurance a material possesses 

rather than the issue of how easily that material will catch fire or ignite. Additional research 

cognizant of this distinction is required for the development and implementation of appropriate,

effective WUI codes.

Ecosystem health and fuel management: Various fire jurisdictions conduct regular and 

prescribed fuels management activities, but these are most often done on publicly accessible lands.

An emphasis on controlling and reducing fuels on other lands, such as private residences and 

businesses and parkland, would benefit the fire resistance of communities and aid in retaining a 

healthy ecosystem. Creating more fuel breaks, implementing more controlled burns, harvesting 

timber, expanding chipping programs, and clearing brush and invasive species would improve the 

chances of survival for the WUI community during a wild fire event. Better planning and design to

limit the availability of fuels within the community is another approach that could impact 

survivability.

Codification of Class A fire-rated roofs as a system, including vulnerabilities of 

complex roofs: After WUI fires, firefighters have found Class A roofs lying on the ground—

while the homes they once covered were largely destroyed. Such occurrences highlight the 

importance of looking at a roof not as a standalone unit but as part of a larger system designed to 

protect the home. WUI code provisions that regulate roof construction and replacement should 

take into account the entire assembly system, including construction and joining techniques, 

materials, attics, crawl spaces, and vent systems. In addition, codes should contain requirements 

to mitigate the various vulnerabilities created by some complex designs and systems, including 

gutters, vents, fans, dormers, and other junctures between roof sections.

Simulation software to compare trade-offs between vegetation and structure 

hardening options: Development of this software tool will likely require considerable initial 

research, yet the effort holds significant promise as a way to help homeowners make informed 

decisions and move forward with investments to harden their homes and properties against WUI 

fires. Many homeowners today have balked at the multitude of protective devices, equipment, and 
14 | Hardening the WUI Communities

other approaches available on the market with varying price tags—putting off any action until they 

better understand the options. The proposed tool would enable them to weigh the costs and 

benefits and to prioritize the available strategies, approaches, and products in terms of 

effectiveness for a given level of investment. It should be designed for use by owners of both 

existing and new homes in WUI areas as well as other stakeholders.

Strategic incorporation of greenbelts, parks, and defensible spaces into new 

developments: Regulations, codes, and community design standards should require that WUI 

communities strategically plan and locate open space and recreational areas so that they can also 

serve as defensible spaces—where WUI fires can be stopped before they reach a community.

Placed around the outside of a community and between adjacent sections of a community, golf 

courses, ball fields, parks, walking/bike paths, and similar spaces can be developed and maintained 

as firebreaks to effectively limit fire spread. Appropriate dimensions and relative distance from the 

community should be determined by taking into consideration the terrain, climate, prevailing 

winds, and other relevant factors. Designers may need to be innovative in their designs and 

materials to optimize these spaces to serve the dual purpose. Depending on water pressure, 

hydrants (or surface water sources) may be strategically placed on the outer perimeter of these 

areas.

Standardization of defensible spaces in wildfire-prone states: All states with existing or 

new developments within or encroaching on areas prone to wildfire should clearly define 

“defensible space” so that homeowners, firefighters, government agencies, and other key 

stakeholders have a uniform understanding of the term. The definition would specify how the 

space will be maintained to serve its intended purpose and be consistent with the climate, type of 

terrain, and dominant type of vegetation. Wherever defensible space is an issue, housing densities 

should be strictly limited.

3.6 RESPONSE

Standards for unified command and cooperative tactics to improve attack 

effectiveness: An effective response to WUI fires requires swift and coordinated action by all 

available firefighting units and other emergency responders. Multiagency and multi-jurisdiction 

responses have sometimes led to significant initial confusion and the loss of valuable time in 

getting control of the fire. Some WUI areas have greatly enhanced the ability of diverse units to 

quickly coordinate by conducting joint training exercises and establishing a single point of 

command to issue orders, order resources, make plans and decisions, and serve as a 

clearinghouse for updates and information. Pre-planning across agencies to establish roles, 

priorities, evacuation routes, and other essential procedures saves valuable time in a real event.

This concept can be effectively expanded across all response agencies by creating standards for 

unified command and cooperative tactics. Further, response methods can be standardized as 

much as possible while incorporating proven cutting-edge technologies (e.g., foams) when 

relevant. Older, less-effective techniques (e.g., “throwing dirt on fire”) can provide additional 

response as appropriate.

Expanded fire engine crews to vastly increase efficiency: Restricting the initial spread of a 

wildfire to 10 acres or less can significantly reduce the final damage, underscoring the importance 

of launching an effective initial attack. Analyzed firefighter staffing data suggests that the efficiency 

of a three-person crew in fighting a wildfire increases 50 % with the addition of a fourth crew 

member.36 On this evidence, a clear economic case can be made for expanding all three-person 

fire crews to four members.
Hardening the WUI Communities | 15

3.7 RECOVERY

Improved tools for post-fire evaluation: Implementation of improved post-fire evaluation 

tools is necessary for forensic purposes in order to understand exactly what transpired during a 

WUI fire event. This can improve scientific understanding of how fires ignite structures and move 

throughout a community. Armed with this knowledge, building and community design can be 

engineered to restrict future ignition and fire spread.

3.8 EDUCATION

Public education for improved ignition prevention: More and more families are relocating 

into WUI communities;37 however, these residents may not understand the steps and proven 

measures they should undertake to protect themselves and their property from WUI fires. A 

recommitment to educating the public on ignition prevention techniques is necessary.

Homeowner education efforts can play a key role in fostering compliance, and homeowner 

associations and community boards can assist in enforcement. “Smokey the Bear – Only you can 

prevent forest fires,”38 was an effective public outreach tool to educate and instill a feeling of 

accountability in the public for preventing ignitions. Revamping the Smokey Bear campaign would 

be simple, straightforward, and effective. In addition, any education plan should also include the 

tried and tested practices in fire mitigation. This same knowledge should be shared with elected 

and appointed officials, with a focus on the local jurisdictions.

Social/local grassroots inspections and self-enforcement: Rules, regulations, and codes 

exist to help reduce the potential for fires in WUI communities. However, inspectors that 

enforce such rules are few in number and are often overwhelmed due to workload and/or budget 

constraints. The rise of social networking and the use of grassroots initiatives to empower citizen 

activists to act locally could be used to encourage neighbors to abide by regulations without 

engaging the authorities.

3.9 PRIORITIZED RESEARCH NEEDS AND IMPLEMENTATION PLAN

The previous sections provided a list and short summary of the important desired research topics 

for WUI fire resistance. Of those, the most pressing research needs or those that will have the 

most impact in mitigating the hazards associated with WUI fires were selected and designated as 

research priorities. The selection results are presented in Table 3.1 below. The implementation of 

the high-prioritized research needs was explored in depth with respect to specific tasks, timing, 

milestones, and performance targets. Figures 3-1 through 3-9 outline the results of these 

discussions7.

 7 Text generated during the workshop sessions was formatted and placed inside highlighted boxes within Figures 3-1 

through 3-9 within Section 3. This text which describes possible implementation plans was a product of workshop 

participants working in different breakout groups. Text was not edited for consistency between different breakout 

groups. 
16 | Hardening the WUI Communities

TABLE 3-1:PRIORITIZED WUI RESEARCH NEEDS

Rank Topics Areas Votes

1. Hardening of structures  (19)

2. Specify performance standards and needs  (16)

3 Understand ignition phenomena  (13)

4. Educate stakeholders on ignition prevention  (11)

4. Improve tools for post-fire evaluation  (11)

4. Unify and improve effectiveness of response teams  (11)

4. Enhance fuels management  (11)

8. Develop realistic and material-neutral test methods  (9)

8. Codify Class A fire-rated roofs  (9)

10. Strategically build greenbelts, parks, and defensible spaces 

into new developments

 (8)

11. Develop accelerated weathering protocol for materials and

coatings 

 (7)

12. Create simulation software to model trade-offs between 

vegetation and structure hardening options

 (6)

13. Develop and adopt classifications for combustible materials  (5)

13. Produce new codes focused on both ignition and fire 

resistance 

 (5)

13. Increase fire engine crew size to vastly increase efficiency  (5)

13. Standardize defensible spaces in wildfire-prone states  (5)

17. Research fire-resistive materials  (3)

18. Organize social or local grassroots inspections and selfenforcement (0)

Note: Each dot represents a participant-identified priority with the greatest potential to improve the fire resistance of 

WUI communities. 

 Blue represents a research (academic and federal agency) participant vote. 

 Green represents a standards development organizations and authorities having jurisdiction participant vote. 

 Orange represents a fire service participant vote. 

 Red represents an industrial participant vote.
Hardening the WUI Communities | 17

FIGURE 3-1: HARDENING OF STRUCTURES

A hardened building is one that can resist wildfire exposures including ember/firebrand, radiant heat,

and direct flame contact. When home spacing is close, extended exposures to radiant heat and flames 

must be considered. An effective structure hardening program must have viable defensible space and a 

vegetation management component (parcel level and community). An effective community hardening 

program will consider existing defensible space (including topography) and building spacing.

Short- or Long-Term Priority

Both short and long term: Homes are an important financial investment for homeowners.

•Review existing documents related to hardening buildings (NFPA, Chapter 7A[CA], IWUIC 

[ICC], other research) for adequacy and deficiencies

•Review and evaluate adequacy of current defensible space requirements in minimizing 

radiant heat exposure and opportunity for flame contact exposure 

•Separate mitigation issues specifically related to new versus existing homes

•Improve building, lot, and community design

•Enhance construction material

Major Tasks

•Conduct critical review of key publications: current codes, standards, and defensible 

space requirements (0 to 3 years)

•Define exposures (0 to 3 years)

•Slow propagation by improving new subdivision separation distances and greenbelts (0

to 3 years) 

•Identify and collect baseline data on building ignition and fire spread in the community 

(0 to 3 years)

•Decrease ignition of lot vegetation by embers (0 to 3 years) and by flame (>3 years)

•Reduce ignition of building exterior by embers and flame (>3 years)

Major Milestones

•Reviewed building codes and standards

•Vetted homeowner document (for existing homes)

•Vetted new home or building document in use

•Educational materials in hands of end users

•Reduced building ignition by 25 % in 3 years; 50 % in 5 years

•Slowed propagation rate by 25 % in 3 years; 50 % in 5 years

Performance Targets
18 | Hardening the WUI Communities

Short- or Long-Term Priority

Long term: New development and structural retrofitting are longer-term projects. 

•Involve public in code development and review

•Develop building code specifications to meet outcome

•Design materials that comply with the set performance standard

Major Tasks

•Increase the percentage of survival of structures exposed to WUI event (>10 years)

Major Milestones

•Increased survival to multiple exposures over time under various conditions over the life 

of the structures

•Improved survivability without suppression efforts

Performance Targets

FIGURE 3-2: PERFORMANCE STANDARDS AND NEEDS

Increase the possibility that structures within the WUI will survive exposure to wildfire by creating and 

implementing ignition and fire-resistance needs that can be translated into testing standards. These 

standards are applicable for new development and remodeling of existing structures within the WUI. 
Hardening the WUI Communities | 19

FIGURE 3-3: UNDERSTANDING THE IGNITION PHENOMENA

The knowledge surrounding the generation and propagation of embers is incomplete. Additional 

research will advance understanding of how vegetation, topography, climate, and construction cause 

structure ignition and spread of fires.

Short- or Long-Term Priority

Short term: Short-term action is needed to develop codes and standards, catch the coding wave of 

development, and decide where research is needed.

•Develop data gathering methods

•Initiate interaction between topography, climate, and fuel causes

•Determine the contribution of burning structures to fire spread (e.g., wind, location, 

materials, configurations)

Major Tasks

•Complete testing to determine ember generation based on vegetation and from structure 

fuels (0–3 years)

•Develop a fire model to validate behavior (>3 years)

•Determine contribution of landscaping (>3 years)

Major Milestones

•Changed use of building material and building configuration based on findings

•Acceptance of findings to change codes, standards, and acceptance by authorities having 

jurisdiction and community

Performance Targets
20 | Hardening the WUI Communities

FIGURE 3-4: EDUCATION OF STAKEHOLDERS ON IGNITION 

PREVENTION

Education is a critical component of WUI fire prevention. Increased educational outreach to the general 

public and officials at all levels, especially in local jurisdictions, will help reduce WUI fire occurrence.

Short- or Long-Term Priority

Long term: Cultural change such as this does not happen easily. In addition, politics plays a critical 

role in successfully resolving WUI fire issues, but the role and impact of politics has not been 

adequately addressed.

•Identify target audience

•Use social research to define media

•Develop media based on available technology

•Research and develop relevant and applicable content and delivery methods

Major Tasks

•Increase number of jurisdictions adopting WUI risk reduction codes (3 to 5 years)

•Raise the number of communities developing wildfire protection plans (3 to 5 years)

•Grow and expand the use of existing educational programs (5 to 8 years)

Major Milestones

•Adoption of WUI codes by more homes; possibly 50 % of new construction in WUI areas 

in 10 years

•Better survivability of structures after a WUI event; possibly 99 % of new construction

Performance Targets
Hardening the WUI Communities | 21

FIGURE 3-5: IMPROVED TOOLS FOR POST-FIRE EVALUATION

After abatement of the wildfire, the post-fire evaluation provides much information that is useful for 

future planning, reduction of fire risk, and comparison between fires. Improving tools and standardizing 

methodology will enhance the amount and quality of data collected and response timing.

Short- or Long-Term Priority

Both short and long term: Short-term activities include informing research initiatives. Long-term 

commitments are needed to maintain value and the integrity of data.

•Identify initial priorities

•Find local contacts

•Produce software, hardware, training, and standard operating procedures for post-fire 

methodology

•Develop consistent methodology

•Create standards for continuing education deployment

•Provide incentives for timely completion of evaluation

Major Tasks

•Develop and test tool kit (0–3 years)

•Test software/hardware on three fires (2 years)

•Establish performance targets and incentives (3 years)

•Train local and regional teams ready to deploy (5 years) 

Major Milestones

•Completed a satisfactory number of drills (3 to 4 per year)

•Enlisted additional participating agencies (25 %, 1 to 2 years)

•Collected acceptable amount of useful data (3 years)

Performance Targets
22 | Hardening the WUI Communities

FIGURE 3-6: UNIFIED AND EFFICIENT RESPONSE TEAMS

To improve the effectiveness of WUI response resources and technology, standards should be developed 

for a unified command. 

Short- or Long-Term Priority

Short term: The fire departments must be able to communicate and have the standard operating 

procedures during WUI fire events.

•Continue analysis of cost effectiveness

•Develop and streamline training standards

•Establish common terminology

Major Tasks

•Usage of the Incident Command System (ICS) by all departments (3 years) 

Major Milestones

•Trained fire departments with respect to WUI fires

•Properly staffed fire engines

•Common radio communications

•Nationwide buy-in to the ICS

Performance Targets
Hardening the WUI Communities | 23

FIGURE 3-7: FUELS MANAGEMENT

Managing the fuel available to fires at the WUI serves to reduce the potential fire intensity. Fuel 

management should be integrated into the design and planning of communities through strategic 

placement of greenbelt parks and golf courses. Ongoing maintenance of these vegetation management 

areas inside and outside the community is essential.

Short- or Long-Term Priority

Short-term: The activity is able to directly impact the intensity of the fires when they occur.

•Identify benchmark (geographically selected) communities that have implemented fuel 

management practices

•Evaluate NFPA standards and determine available regulatory mechanisms

•Observe the mechanical fuel reduction efficacy and prescriptive burn efficiency in relation to the 

community 

•Determine critical distances relative to the community where implementation of fuel management 

would be most effective

•Understand how different practices give different results—potentially using modeling and 

simulations to inform decision making

•Reduce fire intensity in the wild lands, community, and lot vegetation

Major Tasks

•Conduct literature review with respect to fuel management in relation to structures (0 to 2 years)

•Identify federal land management policy that restricts community resilience (0 to 2 years)

•Identify benchmark communities (0 to 2 years)

•Collect baseline data on wildland fire intensity, community, and lot vegetation (0 to 3 years)

•Reduce the fuel loading in the wildland, communities, and lots through prescribed burns, fuel 

mosaics, mastication projects, and healthy forest programs (0 to 3 years)

•Identify areas where fuel management or community planning has worked (1 to 2 years)

•Develop best management practices and adaptive management programs based on unique 

circumstances (2 to 5 years)

•Develop model(s) for designing fuel breaks based on fire history and fuel modeling (>3 years)

•Effectively maintain fuel management programs (>3 years)

•Evaluate ember generation and ignition properties of different fuel types (>5 years)

•Identify community design and planning strategies for WUI (>5 years)

Major Milestones

•Better synergy among state, local, and federal regulations promoting community resilience

•Established guidelines 

•Increased number of benchmark communities

•Reduced fuel loading by 15 % in 3 years and 30 % in 5 years and in 20 % of target (i.e., maintained) 

areas

•Creation of a model to design fuel breaks that incorporate fire history and lot vegetation

•Identification of saved communities

•Decreased homes lost per year

Performance Targets
24 | Hardening the WUI Communities

FIGURE 3-8: REALISTIC AND MATERIAL-NEUTRAL TEST 

METHODS

Repeatable standardized test methods are needed that realistically simulate WUI events and conditions, 

irrespective of material. Standardized test methods would ensure scientific and statistical rigor.

Short- or Long-Term Priority

Both short and long term: Short-term activities include investigating current standards and 

identifying gaps within those standards. Long-term challenges involve filling in the identified gaps.

•Engage all relevant parties

•Investigate existing WUI codes and standards

•Centralize collected data

•Develop an iterative and adaptive process that encourages an open process

Major Tasks

•Create a clearinghouse of testing information (1 to 2 years)

•Identify gaps in testing methods (2 to 3 years) 

•Fill gaps (2 to 3 years)

•Develop testing protocols (3 to 5 years)

•Conduct testing (ongoing) 

Major Milestones

•Increased understanding of ignition resistance versus fire resistance

•Protocols to test WUI standards

Performance Targets
Hardening the WUI Communities | 25

FIGURE 3-9: CODIFIED CLASS A FIRE-RATED ROOFS 

Class A fire-rated roofs offer the highest resistance to fire. The codes and tests to classify roofs should 

view the roof as a system, including other assemblies and components. To incorporate and evaluate the 

roof’s performance, vulnerabilities of complex roofs should be considered.

Short- or Long-Term Priority

Short term: The roof component of a structure is deemed the most vulnerable to ember exposure.

•Identify vulnerabilities

•Evaluate solutions for vulnerabilities

•Develop recommendations

•Retrofit guidelines

•Recommend intermediary measures (without changing the whole roof)

Major Tasks

•Establish retrofit guidelines (3 years)

•Propose intermediary recommendations without changing the whole roof (3 years)

Major Milestones

•Creation of a Class A roof rating based on a systems approach

Performance Targets
26 | Hardening the WUI Communities

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Summary | 27

4 SUMMARY

In response to the increasing losses due to WUI fires and to ensure that measurement science 

keeps pace with needed improvements in materials, fire-resistant design, mitigation response, and 

building and fire codes, NIST sponsored the Workshop on Wildland-Urban Interface Fire Research 

Needs on August 15–16, 2012, in Boulder, Colorado. The workshop provided an opportunity for 

experts in WUI fire behavior, protection, codes, and mitigation to collectively determine the 

areas of research that will have the most impact in mitigating the hazards associated with WUI 

fires. 

Workshop participants identified the following high-priority research areas for WUI fires: 

• Hardening of structures

• Specifying performance standards and needs

• Understanding ignition phenomena

• Educating stakeholders on ignition prevention

• Improving tools for post-fire evaluation

• Unifying and improving effectiveness of response teams

• Enhancing fuels management

This report summarizes the results of the workshop and will serve to guide NIST in pursuing a 

portfolio of programs that are focused on providing the measurement science needed to enable 

communities that are exposed to WUI fires to become more fire resistant. It can also be used by 

both the public and private sectors to guide policy, R&D, and other decision making relevant to 

this important area.
28 | Summary

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.
Appendix A: Contributors | 29

APPENDIX A:

CONTRIBUTORS

Dan Bailey

International Code Council

Phyllis Banducci

California Department of Forestry and Fire 

Protection

Curtis Brown

San Diego State University Research Foundation

Nelson Bryner

National Institute of Standards and Technology

David Bueche

Hoover Treated Wood Products

Mark Dietenberger

U.S. Department of Agriculture/Forest Service, 

Forest Products Laboratory

Paget Donnelly

Energetics Incorporated

Timothy Edwards

California Department of Forestry and Fire 

Protection/California Department of Forestry

Firefighters

Ali Fattah

City of San Diego Development Services 

Department

Charles Gangluff

Arkansas Association of Resource Conservation and 

Development Councils

Mark Gray

Washington Department of Natural Resources

Kenneth Hale

California Department of Forestry Firefighters

Hylton Haynes

National Fire Protection Association

Joseph Holland

Hoover Treated Wood Products

Tanya Hoover

California State Fire Marshal

Rik Johnsson

National Institute of Standards and Technology

Brett Lacey

Colorado Springs Fire Department

Jeff Linville

Weyerhaeuser

Alexander Maranghides

National Institute of Standards and Technology

Will May

International Association of Fire Chiefs

Nancy McNabb

National Institute of Standards and Technology

Steve Quarles

Insurance Institute for Business & Home Safety

Anand Raghunathan

Energetics Incorporated

Matt Rahn

San Diego State University

Christina Randall

Colorado Springs Fire Department

Cheryl Renner

Renner Associates, Planners
Appendix A: Contributors

Ridah Sabouni

Energetics Incorporated

Katie Shay

Energetics Incorporated

Michael Smaldino

International Association of Fire Fighters

Woody Stratton

U.S. Fire Administration

Kuma Sumathipala

American Wood Council

Rick Swan

International Association of Fire Fighters, 

California Department of Forestry and Fire 

Protection
Appendix B: Acronyms | 31

APPENDIX B:

ACRONYMS

ECS Exposure classification system

ICC International Code Council

ICS Incident Command System

IWUIC International Wildland-Urban Interface Code

NFPA National Fire Protection Association

R&D Research and development

NIST National Institute of Standards and Technology

WUI Wildland-urban interface
32 | Appendix B: Acronyms

DRAFT

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.
Appendix C: References | 33

APPENDIX C:

REFERENCES

 1 Roger Hammer, et al., “Wildland–Urban Interface Housing Growth during the 1990s in 

California, Oregon, and Washington” International Journal of Wildland Fire 16 (2007): 255–265.

2 William E. Mell, et al., “The Wildland–Urban Interface Fire Problem – Current Approaches and 

Research Needs,” International Journal of Wildland Fire 19 (2010): 238–251,

http://www2.bfrl.nist.gov/userpages/wmell/PUBLIC/TALKS_PAPERS/Mell_etal_WUI_research_ij

wf10.pdf.

3 “U.S. Communities Dealing with WUI Fire Fact Sheet (ICC) 1.1.2011,” Headwaters Economics, 

accessed September 21, 2012, www.headwaterseconomics.org.

4 Mark Fischetti, “How Much Do Wildfires Cost in Terms of Property Damage?” Scientific 

American, May 27, 2011, http://www.scientificamerican.com/article.cfm?id=graphic-science-howmuch-do-fires-cost-property-damage. 5 William E. Mell, et al., “The Wildland–Urban Interface Fire Problem – Current Approaches and 

Research Needs,” International Journal of Wildland Fire 19 (2010): 238–251, 

http://www2.bfrl.nist.gov/userpages/wmell/PUBLIC/TALKS_PAPERS/Mell_etal_WUI_research_ij

wf10.pdf.

6 William E. Mell, et al., “The Wildland–Urban Interface Fire Problem – Current Approaches and 

Research Needs,” International Journal of Wildland Fire 19 (2010): 238–251, 

http://www2.bfrl.nist.gov/userpages/wmell/PUBLIC/TALKS_PAPERS/Mell_etal_WUI_research_ij

wf10.pdf.

7 William E. Mell, et al., “The Wildland–Urban Interface Fire Problem – Current Approaches and 

Research Needs,” International Journal of Wildland Fire 19 (2010): 238–251,

http://www2.bfrl.nist.gov/userpages/wmell/PUBLIC/TALKS_PAPERS/Mell_etal_WUI_research_ij

wf10.pdf.

8 S. J. Pyne, Fire in America: A Cultural History of Wildland and Rural Fire (Princeton: Princeton 

University Press, 1982), 199–218.

9 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf. 10 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf. 11 National Fire Protection Association, 1 Batterymarch Park, Quincy, MA, www.nfpa.org 12 International Code Council, 500 New Jersey Avenue, NW, 6th Floor, Washington DC, www.iccsafe.org 13 ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA, www.astm.org
34 | Appendix C: References

 14 V. Spyratos, et al., “Development at the Wildland–Urban Interface and the Mitigation of ForestFire Risk” PNAS 104, No. 362007 (September 4, 2007), 

www.pnas.org/cgi/doi/10.1073/pnas.0704488104.

15 “Fire Mitigation Work in U.S. West is Misplaced, According to New Study Led by CU-Boulder,” 

University of Colorado-Boulder, June 8, 2009,

http://www.colorado.edu/news/releases/2009/06/08/fire-mitigation-work-us-west-misplacedaccording-new-study-led-cu-boulder.

16 Wildland Fire Lessons Learned Center homepage, accessed August 25, 2012, 

http://www.wildfirelessons.net.

17 A. Maranghides and W. Mell, Framework for Addressing the National Wildland Urban Interface Fire 

Problem- Determining Fire and Ember Exposure Zones using a WUI Hazard Scale, NIST Technical 

Note 1748 (Gaithersburg, MD: National Institute of Standards and Technology, July 2012).

18 Engineering Laboratory, “Reduced Ignition of Building Components in Wildland-Urban Interface 

(WUI) Fires Project,” National Institute of Standards and Technology, updated December 8, 

2011, http://www.nist.gov/el/fire_research/wildland/project_wuireducedignition.cfm.

19 Maria St. Louis-Sanchez, “Waldo Canyon Fire: First Rebuilt Home Begins to Take Shape,” The 

Gazette, September 1, 2012, http://www.gazette.com/articles/canyon-144033-rebuild-fire.html. 20 The Fire Safe Council homepage, accessed November 15, 2012, http://www.firesafecouncil.org/. 

21 FireSmart Canada homepage, accessed November 15, 2012, https://www.firesmartcanada.ca/; 

FireSmart homepage, accessed November 15, 2012, http://www.firesmartproject.eu/Go_home.action.

22 “Homeowners,” Firewise, accessed November 15, 2012, 

http://www.firewise.org/information/who-is-this-for/homeowners.aspx.

23 Firefree homepage, accessed November 15, 2012, http://www.firefree.org/. 

24 Ready, Set, Go Program homepage, accessed November 15, 2012, 

http://www.wildlandfirersg.org/.

25 Fire Adapted Communities Coalition homepage, accessed November 15, 2012, 

http://www.fireadapted.org/.

26 Living With Fire Program homepage, accessed November 15, 2012, 

http://www.livingwithfire.info/.

27 International Code Council homepage, accessed November 15, 2012, http://www.iccsafe.org.

28 National Fire Protection Association, NFPA 1144 Standard for Reducing Structure Ignition Hazards 

from Wildland Fire, 2008 Edition (Quincy, MA: National Fire Protection Association, 2008), 

http://www.nfpa.org; National Fire Protection Association, NFPA 1141 Standard for Fire Protection 

Infrastructure for Land Development in Suburban and Rural Areas, 2012 Edition (Quincy, MA: 

National Fire Protection Association, 2012), http://www.nfpa.org.

29 Jeremy P. Meyer, “Waldo Canyon Fire Investigation Results to be Revealed Sept. 12,” The 

Denver Post, August 29, 2012, http://www.denverpost.com/wildfires/ci_21429478/waldo-canyonfire-investigation-results-be-revealed-sept. 30 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf.

31 “Hardening Your Home,” California Department of Forestry and Fire Protection, accessed 

August 25, 2012, http://www.readyforwildfire.org/hardening_your_home. 32 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf.
Appendix C: References | 35

 33 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf.

34 “Defensible Space Planning and Preparation,” NAPA Firewise, accessed September 7, 2012, 

http://www.napafirewise.org/defensable-space-live/13_defensiblespace.html. 35 J. Cohen, “The Wildland-Urban Interface Fire Problem,” Forest History Today (Fall 2008): 20–26, 

http://nvfsc.org/index/wp-content/uploads/2010/03/10.01.08-The-Wildland-Urban-Interface-FireProblem-Jack-Cohen-Forest-History-Today.pdf.

36 Matt Rahn, Initial Attack Effectiveness: Wildfire Staffing Study (San Diego, CA: San Diego State 

University, Summer 2010), http://fire.sdsu.edu/docs/Rahn-Fire-Report-2010-2009-sm.pdf.

37 Amy Vaerewyck, “Wildfire Expert - Public Affairs Professor Studies Fire Mitigation Legislation” 

(Denver, CO: University of Colorado, July 2, 2012), 

http://www.ucdenver.edu/about/WhoWeAre/spotlight/faculty/Pages/Lloyd-Burton,-WildfireExpert.aspx.

38 Smokey the Bear homepage, accessed September 17, 2012, http://www.smokeybear.com/.
36 | Appendix C: References

 

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Appendix D: Agenda | 37

APPENDIX D:

WORKSHOP 

AGENDA

Wednesday, August 15, 2012

 8:00 am Registration Opens

 8:30 am OPENING PLENARY SESSION – Room 1107

Welcome and Introductions ~ Nelson Bryner, National Institute of Standards and 

Technology

 9:00 am Wildland-Urban-Interface Fire Overview Presentations

• Authorities Having Jurisdiction

Brett Lacey, Fire Marshal, Colorado Springs – Waldo Canyon Fire

• Building and Fire Codes

Dan Bailey, International Code Council

Hylton Haynes, National Fire Protection Association

• Fire Service 

Rick Swan, California Department of Forestry, International Association of 

Fire Fighters

Dan Bailey, International Association of Wildland Fire

• Industry, Testing Labs, & Users

Kuma Sumathipala, American Wood Council

Steve Quarles, Insurance Institute for Business and Home Safety

10:50 am Break

11:00 am Current Research Initiatives

Mark Dietenberger, US Forest Service

Woody Stratton, US Fire Administration

Alex Maranghides & Nelson Bryner, National Institute of Standards and 

Technology

12:00 pm Lunch 

 1:10 pm Charge for Breakout Sessions and Instructions ~ Anand Raghunathan, 

Energetics Incorporated
38 | Appendix D: Agenda

 1:20 pm Move to Concurrent Breakout Sessions: •Smokey •Blaze •Sparky

 1:30 pm BREAKOUT SESSION I

Focus: 1) Shortcomings of current WUI fire mitigation 

2) Ignition prevention/limiting fire spread 

Session agenda:

• Stage-setting discussions

• Facilitated brainstorming on current limitations and development areas

 2:50 pm Break

 3:05 pm BREAKOUT SESSION II

Focus: Discussion on developing of new codes, materials, designs, technologies, 

and response to improve WUI communities’ fire resistance

Session agenda:

• Facilitated brainstorming of development areas

• Prioritization of ideas for plenary report out

 4:10 pm Break

 4:30 pm PLENARY SESSION – Room 1107

Breakout Session Day 1 Group Reports: •Smokey •Blaze •Sparky

Q&A

 5:00 pm Day 1 Closing Remarks ~ Nelson Bryner, National Institute of Standards and 

Technology

 5:10 pm Day 1 Adjourns

Thursday, August 16, 2012

 8:10 am DAY 2 OPENING PLENARY SESSION – Room 1107 ~ Nelson Bryner, National Institute of 

Standards and Technology

 8:15 am GROUP PRIORITIZATION OF RESEARCH NEEDS

Instructions for Plenary Prioritization ~ Anand Raghunathan, Energetics 

Incorporated

 8:50 am Return to Original Breakout Sessions for Small Group Work: •Smokey •Blaze 

•Sparky

 9:00 am BREAKOUT SESSION III

Focus: Expound selected development priorities identified at the start of Day 2

Session agenda:

• Small group work 

10:15 am Break

10:35 am CLOSING PLENARY SESSION – Room 1107

Breakout Session Day 2 Group Reports: •Smokey •Blaze •Sparky

Q&A 

11:15 am Closing Remarks ~ Nelson Bryner, National Institute of Standards and Technology

11:30 am

-12:00

pm

Tours of National Institute of Standards and Technology Atomic Clock (Optional)
Appendix E: Overview Briefings | 39

APPENDIX E:

OVERVIEW 

BRIEFINGS 
40 | Appendix E: Overview Briefings

I. BRETT LACEY, FIRE MARSHAL, COLORADO SPRINGS – WALDO 

CANYON FIRE
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42 | Appendix E: Overview Briefings
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44 | Appendix E: Overview Briefings
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46 | Appendix E: Overview Briefings
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48 | Appendix E: Overview Briefings
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50 | Appendix E: Overview Briefings
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52 | Appendix E: Overview Briefings

II. HYLTON HAYNES, NATIONAL FIRE PROTECTION 

ASSOCIATION
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54 | Appendix E: Overview Briefings
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56 | Appendix E: Overview Briefings
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58 | Appendix E: Overview Briefings
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60 | Appendix E: Overview Briefings

III. RICK SWAN, CALIFORNIA DEPARTMENT OF FORESTRY,

INTERNATIONAL ASSOCIATION OF FIRE FIGHTERS
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62 | Appendix E: Overview Briefings
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IV. KUMA SUMATHIPALA, AMERICAN WOOD COUNCIL
64 | Appendix E: Overview Briefings
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66 | Appendix E: Overview Briefings
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68 | Appendix E: Overview Briefings
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70 | Appendix E: Overview Briefings
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72 | Appendix E: Overview Briefings

V. STEVE QUARLES, INSURANCE INSTITUTE FOR BUSINESS AND 

HOME SAFETY 
Appendix E: Overview Briefings | 73
74 | Appendix E: Overview Briefings
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76 | Appendix E: Overview Briefings
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78 | Appendix E: Overview Briefings
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80 | Appendix E: Overview Briefings
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VI. MARK DIETENBERGER, US FOREST SERVICE
82 | Appendix E: Overview Briefings
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84 | Appendix E: Overview Briefings
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86 | Appendix E: Overview Briefings
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88 | Appendix E: Overview Briefings
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90 | Appendix E: Overview Briefings
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92 | Appendix E: Overview Briefings
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94 | Appendix E: Overview Briefings
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96 | Appendix E: Overview Briefings
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VII. ALEX MARANGHIDES & NELSON BRYNER, NATIONAL 

INSTITUTE OF STANDARDS AND TECHNOLOGY
98 | Appendix E: Overview Briefings
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100 | Appendix E: Overview Briefings
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102 | Appendix E: Overview Briefings
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104 | Appendix E: Overview Briefings
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106 | Appendix E: Overview Briefings
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