NIST Special Publication 1111 

Summary of Workshop on Research 

Needs for Full Scale Testing to 

Determine Vulnerabilities of Siding 

Treatments and Glazing Assemblies to 

Ignition by Firebrand Showers 

Samuel L. Manzello 

Sayaka Suzuki 

 
NIST Special Publication 1111 

Summary of Workshop on Research 

Needs for Full Scale Testing to 

Determine Vulnerabilities of Siding 

Treatments and Glazing Assemblies to 

Ignition by Firebrand Showers 

Samuel L. Manzello 

Sayaka Suzuki 

Fire Research Division 

Building and Fire Research Laboratory 

June 2010 

U.S. Department of Commerce 

Gary Locke, Secretary 

National Institute of Standards and Technology 

Patrick D. Gallagher, Director
ii

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 1111 

Natl. Inst. Stand. Technol. Spec. Publ. 1111, 45 pages (June, 2010) 

CODEN: NSPUE2 
iii

Table of contents 

1. Introduction 1 

 1.1 Objective of this workshop 1 

 1.2 Session Agenda 1 

2. Results of Discussion 2 

2.1 Exposing siding treatments to firebrand showers 2 

2.2 Exposing window assemblies to firebrand showers 5 

2.3 Summary 6 

3. NIST Research Plan 7 

4. References 8 

5. Acknowledgements 9 

 Appendix1 Workshop Attendee List 10 

 Appendix 2 NIST Presentation 12 
1

1. Introduction 

1.1 Objective for this workshop 

Anecdotal evidence as well as post-fire damage assessment studies suggests that wind driven 

firebrand attack is responsible for the majority of structure ignitions in Wildland-Urban Interface 

(WUI) fires. A unique experimental apparatus, known as the NIST Firebrand Generator (NIST 

Dragon), has been constructed to produce a controlled and repeatable firebrand attack [1]. The 

experimental results generated from the marriage of the NIST Dragon to the Building Research 

Institute’s (BRI) Fire Research Wind Tunnel Facility (FRWTF) in Japan are being used by 

standards organizations to guide/develop new standards and provide the scientific basis for new 

requirements with the intent to make structures more resistant to firebrand attack. An 

experimental database is also being created to support NIST’s Wildland Fire Dynamics 

Simulator (WFDS) [2]. 

NIST planning is underway for a new experimental campaign scheduled for the fall of 2010 to 

determine vulnerabilities of siding treatments and glazing assemblies to firebrand bombardment 

using the NIST Dragon installed in the Fire Research Wind Tunnel Facility (FRWTF) at the 

Building Research Institute (BRI) in Japan. Input is desired for this testing series from interested 

parties in California (e.g. building officials, OSFM, code consultants, industry) since large WUI 

fires have occurred in this state recently. Specifically, guidance is desired in order to conduct 

experiments that will have the potential to provide the scientific basis for code change that can 

significantly reduce WUI fire losses. 

1.2 Session Agenda 

• Overview of the NIST Firebrand Generator (NIST Dragon) and prior application to 

determine vulnerabilities of roofing assemblies and building vents to firebrand showers 

(Presentation is provided in Appendix 2). 

• NIST summary of planned experiments to determine vulnerabilities to siding treatments 

and glazing assemblies to firebrand bombardment using the NIST Dragon installed in the 

Fire Research Wind Tunnel Facility (FRWTF) at the Building Research Institute (BRI) in 

Japan. (Presentation is provided in Appendix 2). 

• Group input, discussions, and exchange of information. 
2

2. Results of Discussion 

2.1 Input related to importance of exposing siding treatments to firebrand showers. 

The NIST presentation about siding treatments is summarized in the following four slides: 

Input from attendees: 

• Siding treatments applied in corners are very important and should be considered for 

testing (See Fig. 1).

• In addition to corners, siding treatments installed on the face of a vertical wall should also 

be used for testing. 

Siding

• Vinyl and wood siding

• Install siding horizontally – Single, Double, 

Triple? 

• Vertical installation? 

• Placed on wall – 3 m x 3 m

Materials for Siding

• Siding materials

– Vinyl and Wood

• Sheathing/backboard 

– OSB

• Weather-resistant barrier 

– Tyvak Drain Wrap

• (Strapping/furring strip, for 

wood)

Wood Frame

Sheathing (OSB)

Wood Siding

Fastener (Nail)

Weather Resistant Barrier

(Tyvek- House wrap or Drain wrap)

Strapping

Wood Frame

Sheathing (OSB)

Weather Resistant Barrier

(Tyvek- House wrap or Drain wrap)

Vinyl Siding

Fastener (Nail)

Wood siding

Vinyl siding

3m

3m

4m

Siding here

Structure Placed Inside FRWTF

Corner

• Use vinyl siding and vinyl corner 

materials

• Placed in front of structure
• Polypropylene should be included as a material to be used for experimentation, in 

addition to wood and vinyl siding since it is widely used as a siding material. 

• Many siding treatments have some possibility to be ignited because the assembly has 

many gaps where firebrands may become lodged within these gaps and cause ignition. It 

was felt that wood siding has big gaps. 

• Experiments of walls fitted with eaves should be included as part of the experimental 

planning. A very important long standing question is whether firebrands may become 

lodged within joints between walls and eave overhang (See Fig. 2). 

• A detailed discussion was held in regard to the type of eaves that should be used for the 

tests. Namely, a gable end eave or standard eaves (run along the base of the roof - See 

Fig. 3). 

• It was decided by the group that for the purposes of these experiments, a gable end eave 

is less important and testing should be done for standard eaves (See Fig. 2) 

• A simple vertical wall should be constructed with an eave attached the top 

• Architectural drawings were requested from the group of typical eave construction. An 

example of these are shown in Fig.3 

3

Fig.1 Schematic of Example of Corner 
Figure 2 Schematic of eave configurations. 

Fig. 3 Side view of standard eave assemblies. 

4
2.2 Input related to importance of exposing window assemblies to firebrand showers. 

The NIST presentation about window assemblies is summarized below: 

Note that the dimensions of the window assembly (right slide) are for illustration purposes only. 

5

Input from attendees: 

• The group felt that double hung window assemblies would be more susceptible to 

firebrand showers since there is more space for firebrands to become lodged within the 

framing. 

• Many types of materials are used for window frames: vinyl, wood, aluminum clad wood, 

and vinyl clad wood. 

• It is important to know how to properly install window assemblies. The joint requires 

some sealing (flashing material) and firebrands may become lodged within the seal. The 

group felt that the flashing used should be paper not metal. Paper is a common flashing 

material and would be more dangerous to firebrand penetration. 

• Window assemblies that are double hung with single pane glass may be more vulnerable 

than other type of window assemblies. 

Glazing

Wood Glazing

Vinyl Glazing

• Consider both vinyl framed 

glazing and wood framed glazing

• Interest: accumulation of 

firebrands inside corner of 

framing

• Can accumulated firebrands 

cause window breakage? 120cm 60 cm 120cm

90 cm

300cm

300 cm

130 cm

80 cm

170cm

Front view of structure

Glazing Location
6

2.3 Summary 

Anecdotal evidence exists related to vulnerabilities of siding treatments and glazing to firebrand 

attack yet standard test methods are not available to evaluate the ability of siding treatments and 

glazing assemblies to resist firebrand showers. Before the development of the NIST Firebrand 

Generator and the subsequent coupling of this device to the Fire Research Wind Tunnel Facility 

(FRWTF) at the Building Research Institute (BRI) in Japan, there was no method to actually 

generate firebrand showers in a controlled, laboratory setting to quantify these vulnerabilities. 

Therefore, full scale tests are planned to quantify the vulnerabilities of siding treatments as well 

as glazing assemblies to firebrand showers using the coupling of the NIST Dragon to BRI 

facilities. The results of the full scale tests will be reported to CALFIRE and ASTM and will 

serve as the basis for guiding reduced scale test methods for siding treatments and glazing 

assemblies as well as providing code change. A workshop was held in June, 2010 by NIST to 

provide input on the type of siding treatments and glazing assemblies most common and 

important to test. The focus has been placed on the state of California since many large WUI 

fires have occurred there over the past 10 years [3]. This document provides a succinct summary 

of the workshop results. The input from this workshop will be considered as NIST/BRI finalize 

their experimental plans. 
7

3. NIST Research Plan 

A detailed list experiments that are being considered is provided below: 

1. Siding Treatment Experiments (Vertical Wall and Corner)

Three kinds of siding materials: 

• Wood siding 

o Cedar shake shingle (both untreated and fire treated) 

• Vinyl siding 

o Polyvinyl chloride 

o Polypropylene 

2. Window Assembly Experiments

Two kinds of window frames: 

• Wood frame 

• Vinyl frame 

Window assemblies used will be double hung, either single or double pane with flashing paper. 

3. Vertical Wall Experiments Fitted With Eaves

• Eave overhang: 24 inches 

• Eave slope: 12 inches by 4.5 inches 

• Vertical wall fitted with wood and vinyl siding 
8

4. References 

1. S.L. Manzello, Y. Hayashi, T. Yoneki, and Y. Yamamoto, Quantifying the Vulnerabilities of 

Ceramic Tile Roofing Assemblies to Ignition during a Firebrand Attack, Fire Safety Journal, 

45:35-43, 2010. 

2. W.E. Mell, A. Maranghides, R. McDermott, and S.L. Manzello, Numerical Simulation and 

Experiments of Burning Low-Moisture Douglas-Fir Trees, Combustion and Flame, 156:2023-

2041, 2009. 

3. W.E. Mell, S.L. Manzello, A. Maranghides, B. Butry, and R. Rehm, Wildland-Urban Interface 

Fires: Overview and Research Needs, Int’l J. Wildland Fire, 19: 238-251, 2010. 
9

5. Acknowledgements 

Mr. Ethan Foote, Assistant Chief, Wildland Protection Building Construction – CALFIRE 

OSFM, organized this workshop and his assistance in greatly appreciated. The valuable input of 

all participants is warmly appreciated. 
10

Appendix 1 

 Workshop Attendee List 

Name Affiliation 

1 Ali Fattah (via conference call) PE Senior Research Engineer –Division of Building 

and Safety 

2 Bill Hendricks (representing) Cedar Shake & Shingle Bureau 

3 Cal Lewis Building & Fire Code Consultant –C. A. Lewis and 

Associates 

4 Darren Drake Fire Marshal, Napa City Fire Department 

5 Dave Sapsis Wildland Fire Scientist – CALFIRE OSFM 

6 Donn Harter President & Director of Technical Service, Americas 

Glass Association 

7 Ethan Foote Assistant Chief, Wildland Protection Building 

Construction – CALFIRE OSFM 

8 Howard Stacy Vice President- Western Fire Center, Inc. 

9 Jeff White Building Official, Calaveras County Building 

Department 

10 Jon S Traw PE, Traw Associates Consulting 

11 Joseph B Zicherman PhD, SFPE, Fire Cause Analysis 

12 Kuma Sumathipala Senior Manager, Fire Research, American Wood 

Council, AF&PA 

13 Mike Dobson (representing) Hoover Treated Wood Products 

14 Mike Mentink Fire Marshal, Moraga-Orinda Fire District 

15 Ray Zachau Fire Marshal, South Lake Tahoe Fire Department 

16 Rick Thornberry PE Building & Fire Code Consultant – The Code 
11

Consortium, Inc. 

17 Samuel L. Manzello NIST 

18 Sayaka Suzuki NIST 

19 Scott Alber PE, Fire Marshal, Marin County Fire Department 

20 Steve From Western Red Cedar Lumber Association(WRCLA) 

21 Steve Quarles (via conference 

call) 

UC Corporative Extension Advisor 

22 Steven R. Winkel FAIA, PE, The PREVIEW Group, Inc. (Architect 

Member Calif Bldg. Stads. Commission ) 

23 Vahid Toosi Fire Protection Engineer-Orange County Fire 

Authority 
12

Appendix 2 

Presentation Delivered at Workshop. 
Dr. Samuel L. Manzello

Mechanical Engineer

Fire Measurements Group

Building and Fire Research Laborato

National Institute of Standards and Tech

Gaithersburg, MD 20899-8662 

samuelm@nist.gov; +1-301-975-689

Input for Future Full Scale Te

Siding Treatments and Glazing A
Experiments Conducted Ye

• Determine firebrand production from burning stru

• Proof-of-concept testing• Heat flux; firebrand size/mass• Temperature/humidity• IR; visual imagery• Experiment in Dixon, California • Collaboration with Northern California Fire 

• Vacaville Fire Department• Dixon Fire Department

Mr. Matt Lage and Mr. George Lain
Gaithersburg, MD Boul

• 2,800 employees• ~2,500 associates and facility users• 3 Nobel laureates

NIST At A Glance
The NIST Laboratorie

NIST’s work enables

• Science• Technology innovation• Trade• Public benefit

NIST works with

• Industry• Academia• Other agencies• Government agencies• Measurement laboratories• Standards organizations

Mission: Promote U.S. innovation and industrial competitmeasurement science, standards, and technology in ways economic security and improve our quality of life.
Wildland-urban Interface (WU

• Current approach:

– Wildland-fuel and residential-fuel treatments– Not the outcome of a well coordinated scientific 

Of the 10 largest fire loss incidents (> $1Bhistory, 5 were WUI fires - all within the la

Proven risk assessment and mitigation to

Wildland fires spread into WUI comm

Annual Insurance Claim

Structure Lost in WUI 
Structure Ignition 

Pre- and Post-Fire Data Collection & Anal

.

Large Scale Fire Behavior and 

Wind Measurements

Integrated Approach to Red

Losses in the WUI

Lab Scale Fire Beha

Measurements
Collaborators

• Building Research Institute (BRI)• Dr. Yoshihiko HayashiBFRL-NIST

Structure Ignition

• Dr. Sayaka Suzuki (Japan)• Dr. Seul-Hyun Park (Korea)• Mr. John R. ShieldsWUI Program• Dr. William ‘Ruddy’ Mell• Mr. Alexander Maranghides• Dr. David Butry
Structure Ignition in Urban and 

• Firebrands major cause of ignition• Understanding firebrand ignition of stru

important to mitigate fire spread Japan/

Objective: Investigate ignition of s

to firebrand showers

2007 Southern California Fire Wa
Partnerships

• BRI - Japan • US Department of Homeland Security

Customers

• CALIRE• ASTM (Manzello voting member)

– Subcommittee E14.06 Vents– Subcommittee E14.08 WUI Exposu

• Results useful for: 

– ASTM, CALFIRE, ICC, NFPA, ISO, Insura
International Collabora

BRI (Japan) and BFRL-NIS

• Research focused on how far firebrands tr• Nice Academic Problem – Not helpful to de

• Vulnerable points where firebrands may e

• Unknown/guessed!

• Difficult to replicate firebrand attack!

• Entirely new experimental methods neede

• Firebrands: generation, transport, ignition

Goals

Science - Building Codes/Standards; Retro

Design structures to be more resistant to fire
Douglas-Fir Tree Burns at N

– Firebrand Collection using water pa

• Range of crown heights: 2.4 m – • Different moisture regimes

– Mass loss using load cells

4.5 m Douglas Fir, MC = 25%
Firebrand Generator 

Side View

Firebrand Generator 

Front View

Firebrand Generator (NIST 

Capable of producing controlled and repeatable 

distribution of firebrands
Building Research Institute 

• Fire Research Wind Tunnel Facility (FR• Unique facility – investigate influence o

BRI

Fire Research Win

(FRW
NIST Dragon

First Generation Device
Ceramic Roofing

U

∞ (m/s) OSB/TP/CT

No Bird 

Stops

OSB/TP/CT

With Bird 

Stops

OSB/CT

No Bird 

Stops

7 SI NI SI to F9 SI NI SI to F

Aged Roofing Simulated: OSB, then tiles (no ta

New Roofing Construction: OSB, Tar Paper, then 
Ceramic Roofing

U

∞ (m/s) OSB/TP/CT

No Bird 

Stops

OSB/TP/CT

With Bird 

Stops

OSB/CT

No Bird 

Stops

7 SI SI SI to F

9 SI SI SI to F

Aged Roofing Simulated: OSB, then tiles (no ta

New Roofing Construction: OSB, Tar Paper, then 

Pine Needles/Leaves Under Tiles
Vent Placement

Experiments simulate severe expos

Conducted using FDS
BRI/NIST Full Scale Exper

20 x 20 mesh (1.04 mm) is sho
NIST Dragon’s LAIR (Lofting and Igni

NIST Baby Dragon

Couple ‘Baby Dragon’ with wind 

Compare to BRI/NIST full scale r
Firebrand Accumulati

in Front of Obstacle
Firebrand Accumulati
Firebrand Accumula

W

Ea
Obstacles in Flow

1 m by 2 m 
Siding

• Vinyl and wood siding• Install siding horizontally – Single, 

Double, Triple? 

• Vertical installation? • Placed on wall – 3 m x 3 m
Materials for Siding

• Siding materials

– Vinyl and Wood

• Sheathing/backboard 

– OSB

• Weather-resistant barrier 

– Tyvak Drain Wrap

• (Strapping/furring strip, for 

wood)

Wood Frame

Sheat

F

Wood Frame

S

Wood siding

Vinyl siding
3m

Siding here

Structure Placed Inside 
Corner

• Use vinyl siding and vinyl corner 

materials

• Placed in front of structure
Glazing

Wood Glazing

Vinyl Glazing

• Consider both vinyl framed 

glazing and wood framed glazing

• Interest: accumulation of 

firebrands inside corner of framing

• Can accumulated firebrands 

cause window breakage?
120cm 60 cm 120cm

300cm

170cm

Front view of structu

Glazing Location