USDA Forest Products 

Laboratory’s Debris 

Launcher

James J. Bridwell

Robert J. Ross

Zhiyong Cai

David E. Kretschmann

Forest

Products

Laboratory

Research

Note

FPL–RN–0329

United States Department of Agriculture

Forest Service
Bridwell, James J.; Ross, Robert J.; Cai, Zhiyong; Kretschmann, David E. 

2013 (revised 2017). USDA Forest Products Laboratory’s debris launcher. 

Research Note FPL-RN-0329. Madison, WI: U.S. Department of 

Agriculture, Forest Ser-vice, Forest Products Laboratory. 14 p.

A limited number of free copies of this publication are available to the 

public from the Forest Products Laboratory, One Gifford Pinchot Drive, 

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Abstract

Throughout the United States, hundreds of tornados and 

several hurricanes affect people’s livelihoods each year. 

These natural disasters not only cause structural damage 

to property, they also cause numerous injuries, and regrettably, far too many deaths of people caught in their path. In 

an effort to increase the probability of surviving the strong 

winds and associated flying debris of these ferocious storms, 

a number of Americans are installing safe rooms in their 

homes.

In recent years, researchers at the U.S. Forest Service, 

Forest Products Laboratory (FPL), in Madison, Wisconsin, 

conducted a series of studies to examine the effectiveness 

of various materials and wall designs for use in such safe 

rooms. A key element of the research was the use of an airpressure debris launcher that is capable of firing 2-in. by 

4-in. lumber missiles into wall sections at speeds of

approximately 100 miles per hour. This research note

presents details of the launcher, summarizes test methods

and results, and prescribes recommendations for future

testing.

Keywords: Safe rooms, cross laminated timber, debris 

launcher

June 2013

Revised September 2017

Contents

Introduction......................................................................... 1

Debris Launcher Design Details......................................... 1

Missile Details .................................................................... 3

Panel Design ....................................................................... 3

Test Method ........................................................................ 4

Test Results......................................................................... 5

Concluding Comments........................................................ 6

References........................................................................... 6

Appendix—Panel Description, Mounting Configuration, 

Missile Velocity, and Damage Report................................. 8

Conversion Table

English unit Conversion factor SI unit

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

miles 1.6093 kilometers (km)

pounds (lb) 0.45359 kilograms (kg)

Acknowledgment

The authors acknowledge Dr. Joseph Murphy, who 

performed early tests, and his contribution to developing 

the equipment and test protocols.
USDA Forest Products Laboratory’s 

Debris Launcher

James J. Bridwell, General Engineer

Robert J. Ross, Supervisory Research General Engineer

Zhiyong Cai, Supervisory Research Materials Engineer

David E. Kretschmann, Research General Engineer

Forest Products Laboratory, Madison, Wisconsin

Introduction

Throughout the United States, hundreds of tornados and a 

number of hurricanes affect people and homes each year, 

causing injury, death, and structural damage. Nearly every 

state east of the Rocky Mountains faces the possibility of 

devastating tornados, with the Midwest being particularly 

at risk (Fig. 1). Living along the gulf and east coasts offers 

little respite, as powerful hurricanes are apt to cause similar, 

and potentially more widespread, damage.

One particular danger of tornados and hurricanes is flying 

debris. When the envelope of a structure is punctured by debris, pressure changes from the wind can cause the structure 

to rapidly fail. In many areas, buildings were not built with 

resistance to debris in mind. However, with the impressive 

media coverage of recent disasters such as the devastating 

tornados in Joplin, Missouri, and Moore, Oklahoma, as well 

as Hurricanes Katrina and Sandy, greater numbers of home 

and small business owners are seeking to increase their 

probability of surviving a storm by voluntarily installing 

a “safe room” to shelter in.

A safe room is defined by the Federal Emergency Management Agency (FEMA) as “a space where you, your family, 

or friends and employees can survive a tornado or hurricane 

with little to no injury.” Guidelines for safe room design are 

detailed in FEMA P-361, Design and Construction Guidance of Community Shelters, and FEMA P-320, Taking Shelter from the Storm: Building a Safe Room Inside Your Home

(FEMA 2008a,b). 

There are two main criteria for safe room design. The first is 

that the room’s structural components must be able to withstand the basic wind load of the tornado or hurricane. The 

FEMA guidelines follow other major building codes such as 

International Building Code (IBC) 2006 and International 

Residential Code (IRC) 2006 in using American Society 

of Civil Engineers (ASCE) ASCE 7-05 criteria to establish 

wind loads. A map showing the four main wind zones specified in ASCE 7-05 is shown in Figure 2. 

The second design criterion is that the safe room must have 

resistance to flying debris. A number of test criteria are used 

for debris impact resistance of overall building assemblies, 

for instance, the Florida Building Code (FBC), IBC, and 

ASCE 7-05 all reference large missile impact testing for 

building structures. FEMA P-320 and P-361 attempt to standardize safe room design by stipulating that testing of safe 

rooms shall be done in accordance with ICC-500, Standard 

for the Design and Construction of Storm Shelters (ICC: 

NSSA 2008). Table 1 is a list of design wind speed scenarios 

and corresponding missile speeds for tornado safe rooms 

according to ICC-500. With regard to hurricanes, ICC-500 

requires a missile speed of 0.4 × design wind speed, 

whereas FEMA P-361 suggests a higher velocity value 

of 0.5 × design wind speed.

As part of their ongoing efforts to improve safe room design, researchers at the U.S. Forest Service, Forest Products 

Laboratory (FPL), conducted performance tests on a series 

of materials and wall designs that might be used in the construction of safe rooms. These tests were performed using a 

specially designed debris launcher that meets ICC-500 

criteria of launching 2-in. by 4-in. lumber missiles at speeds 

of approximately 100 miles per hour (Fig. 3). 

Debris Launcher Design Details

The main components of FPL’s debris launcher are the 

pressure tanks, control valve, barrel, muzzle (Fig. 4), and 

instrument panel (Fig. 5b).

The pressure tanks are made of 52-in. long, 6-in. diameter 

schedule 40 PVC pipe and house the air needed to propel 

the missile to the target panel. The tanks are connected to 

the barrel by means of an electric solenoid control valve 

system (Fig. 5a). The control valve is a modified sprinkler 

valve that, via the instrument panel (Fig. 5b), allows the operator to remotely regulate air pressure in the tanks to ensure 

safety during testing.

The barrel of the debris launcher is made from a 150-in. 

long piece of 4-in.-diameter schedule 40 PVC pipe, which 

when housed in the mobile firing platform (Fig. 3), is supported every 24 in. by an aluminum block that is attached to 

the frame. These supports limit recoil and ensure accurate 

placement of the missile on the test target. Prior to firing, 
Research Note FPL–RN–0329

2

Figure 1. Map from FEMA P-320 showing the number of “Severe,” “Devastating,” and 

“Incredible” (categories EF3, EF4, and EF5, respectively) tornados in the United States 

from 1950–2006. Note the concentration in the Midwest, though many states are affected 

(FEMA 2008b).

Figure 2. Design wind zones from FEMA P-320 based on ASCE 7-05 criteria. The zones 

mirror the locations of high intensity storms from Figure 1, with the addition of higher 

design requirements along the coasts due to hurricanes (FEMA 2008b).
USDA Forest Products Laboratory’s Debris Launcher

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Missile Details

The typical missile used in the impact tests was a nominal 

2-in. by 4-in. Southern Pine board that weighed between

15 and 15.5 lb and was between 144 and 146 in. long. No 

specifications were made on the desired grade of the missile; 

however, FEMA-361 (2008a) stipulates that missiles should 

contain no knots within 12 in. of the leading edge. Before 

being loaded into the barrel, each missile had a sabot of approximately the same circumference as the inside of the cannon barrel attached to its end to minimize the amount of air 

pressure lost (Figs. 6a,b). The sabot weighed 0.4 lb.

Panel Design

Test panels were designed to mimic the retrofitting of existing building structures to provide increased impact resistance to the debris propelled by tornados and hurricanes. 

The tests presented in this note used a wide array of materials including oriented strandboard (OSB), plywood, hardwood paneling, fiber-laminated hardboard, cross laminated 

timber (CLT), and bamboo composite panels. 

OSB, plywood, hardwood, and CLT are common materials to the U.S. building industry and were chosen for their 

widespread use and availability. Bamboo was chosen for 

some panels because of its widespread availability, high 

strength–weight ratio, and superior ductility. The flexure and 

ductility characteristics of bamboo composites allow them 

to absorb high-impact energy while limiting catastrophic 

damage. Specific sizing and details of each panel can be 

found in the table in the Appendix.

Along with a variety of materials tested, there were four 

main configurations of panels. In the first configuration, 

panels were mounted to the front of a 6-in.-deep laminated 

lumber wall so that the missile impacted the panel first. In 

the second configuration, panels were mounted to the rear of 

the wall so that the missile struck the wall first. In the third 

configuration, panels were attached to a partially sheathed 

2-in. by 4-in. stud frame, which itself was mounted to the

wall (Fig. 7). The fourth configuration had the panel

mounted to a steel frame in front of a laminated lumber

backstop (Fig. 8).

Table 1. ICC-500 physical missile criteria for tornado 

shelters 

Design wind 

speed (mph) 

Missile dimensions 

(Nominal, in.) 

Missile 

weight (lb)

Missile 

speed (mph)

130 2 by 4 sawn lumber 15 80 

160 2 by 4 sawn lumber 15 84 

200 2 by 4 sawn lumber 15 90 

250 2 by 4 sawn lumber 15 100 

Figure 3. Debris launcher housed in the mobile firing 

platform.

each lumber missile is inserted all the way to the rear of 

the barrel. 

Attached to the front end of the barrel is the muzzle, which 

houses two electro-optical sensors. As the missile passes 

through the muzzle, the light across the first and then the 

second sensor is interrupted, sending electrical signals back 

to a conditioner in the instrument panel. The signal conditioner then computes and outputs a velocity measurement to 

the operator based upon the calibrated distance between the 

sensors and the time between signals.

Besides computing missile velocity, the instrument panel 

also serves as the control center for FPL’s debris launcher. It 

enables the operator to route air to the pressure tanks, monitor tank air pressure, and activate the control valve to fire 

each missile all while maintaining a safe distance from any 

possible safety concern. 

Figure 4. Details of the dimensions of the FPL debris launcher.
Research Note FPL–RN–0329

4 

Figure 5. Debris launcher’s (a) control valve and 

(b) instrument panel.

Test Method

During testing, the muzzle of the debris launcher was positioned approximately 16 ft from each target specimen. 

This distance protected the instrument from any rebound 

of the missile off of the panels and minimized loss of 

initial velocity as measured at the muzzle.

Even though the muzzle is 16 ft from the panel, the missile 

is only unsupported by the barrel over about a 4-ft 

horizontal distance, which is approximately 0.03 s of flight 

time. This results in a minimal vertical displacement 

(Fig. 9).

Figure 6. (a) Sabot and (b) missile with sabot attached at 

the trailing end.

(a)

(b)

(a)

(b)
USDA Forest Products Laboratory’s Debris Launcher

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Figure 7. (a) Model of overall test setup and two panel configurations–Configuration 3 on the left and Configuration 1 

on the right. (b) Model of Configuration 2 setup. (c) Detail 

of Configuration 3 setup.

Figure 8. Configuration 4–CLT panel with high-speed 

photography.

Unless otherwise noted, in each test the missile struck the 

horizontal and vertical center of the target panel. If the panel 

was fastened across studs, such as a multi-layer panel specimen, the missile contacted the panel between the studs. It 

was also assumed that the missile impacted the target within 

5° of normal to the panel surface per requirements of ICC500. This was later verified through pictures from the highspeed cameras. The general procedure for panel tests at FPL

was as follows:

1. Mounted target panel.

2. Used a laser sight to aim the debris launcher barrel at the

vertical and horizontal center of the panel. Laser sight was

removed prior to loading each missile.

3.Loaded a sabot-attached missile into the barrel of the debris launcher. Positioned the missile all the way to the rear

of the barrel.

4.Closed the control valve and pressurized the tanks to the

desired air pressure.

5. From the instrument panel, activated the control valve and

released pressure into the barrel.

6.Recorded missile velocity at the muzzle and panel results.

Test Results

Panel descriptions, mounting configurations, missile velocity, and damage reports obtained from testing of 30 individual panel sections can be found in the table in the Appendix. 

The figures below are examples of the results observed. 

Figure 10a shows a cross section of a panel that has been 

perforated by the lumber missile. Figure 10b shows a panel 

section that was able to withstand the force of the missile, 

although it did sustain considerable damage. 

(a)

(b)

(c)
Research Note FPL–RN–0329

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Figure 9. Model of Configuration 4 showing the distance from muzzle to panel and the 

trajectory of the missile.

Figure 10. (a) Example of a missile perforating a sandwich 

panel section of bamboo and insulation. (b) Example of a 

bamboo panel damaged, but not perforated, by a missile.

Concluding Comments

The debris launcher at FPL has been shown to be an effective tool to simulate the flying debris produced by tornados 

and hurricanes. The cannon was capable of performing all 

ranges of testing sizes and speeds to meet building codes 

and FEMA guidelines. With further testing and refining of 

safe room design, home and small business owners will be 

more confident in their ability to survive the extreme weather events that threaten such a large portion of the country. 

The following are some possible improvements to debris 

impact testing at FPL that would make the system even 

more effective:

• Continue efforts toward overall standardization of the impact test method.

• Include more detailed measurements and characteristics of

panels and missiles for comparison.

• Develop and refine impact load modeling to better verify

results.

• Include new materials and guidelines for designing target

panels.

• Improve placement of high-speed cameras and implement

strain-imaging systems in the contact area to better study

the impact region.

References

ASCE. 2005. Minimum design loads for buildings and other 

structures: SEI/ASCE 7-05 (ASCE Standard No. 7-05). Reston, VA: American Society of Civil Engineers. 424 p.

(a)

(b)
USDA Forest Products Laboratory’s Debris Launcher

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FEMA. 2008. Design and construction guidance for community safe rooms. Second Edition. FEMA P-361. Washington, D.C.: Federal Emergency Management Association. 

374 p.

FEMA. 2008. Taking shelter from the storm: building a 

safe room for your home or small business. Third Edition. 

FEMA P-320. Washington, D.C.: Federal Emergency Management Association. 46 p.

ICC: NSSA. 2008. ICC/NSSA Standard for the design and 

construction of storm shelters. Washington, D.C.: International Code Council: National Storm Shelter Association. 

42 p.
Research Note FPL–RN–0329

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Table 1. Test results from FPL debris impact study 

Test

No. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

1 No panel 

(The first missile was launched 

at the wall only.) 

Wall only Front 104 Full perforation, with 5-in. protrusion out 

of the back of the wall section. Wood 

shards airborne on impact. 

2 Layer 1: 1⁄2-in. oriented strandboard (OSB) 

Layer 2: 1-in. foam insulation 

Mounted to the wall with nails every 6 in. 

on the perimeter. 

Wall only Front 102 2-in. indentation in OSB, insulation, and 

face of the wall. The rear of the wall 

cracked and showed about 2-in. 

deformation. Wood shards airborne on

impact.

3 Layer 1: 1⁄2-in. OSB 

Layer 2: 1-in. foam insulation 

Layer 3: 1⁄2-in. wire mesh 

Mounted to the wall with nails every 6 in. on the 

perimeter. 

Wall only Front 104 2-in. indentation in OSB, insulation and 

face of the wall. The rear of the wall was

cracked.

Appendix—Panel description, mounting configuration, missile velocity, 

and damage report
USDA Forest Products Laboratory’s Debris Launcher

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Table 1. Test results from FPL debris impact study (continued) 

Test

No. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

4 Layer 1: 1⁄2-in. plywood panel 

Layer 2: 1-in. foam insulation standoffs inside the 

squares of a chain link fence 

Mounted to the wall with nails every 6 in. on the 

perimeter. 

Wall only Front 87 The missile pushed in the chain link and made a 2-

in. indentation on the face of the wall. The rear of 

the wall was cracked and showed about a 2-in. 

deflection. Wood shards airborne on impact. 

 

5 4-in. by 4-in. by 1⁄4-in. ballistic fiber-coated hardboard.

Mounted to the wall with 2-1/2-in. deck screws and 1-

in. fender washers spaced at 4 in. on the perimeter and 

6 in. in the interior. 

Wall only Rear 103 The missile caused a 2-in. indentation in the front 

of the wall, but there was no deflection at the rear. 

The ballistic panel appeared undamaged. No 

debris; some screws loosened. 

 

6 4-ft by 4-ft by 1/4-in. tempered hardboard. 

Mounted to the wall with 2-1/2-in. deck screws and 1-

in. fender washers spaced at 4 in. on the perimeter and 

6 in. in the interior. 

Wall only Rear 103 The missile caused an indentation of about 2 in. in 

the front of the wall. A crack was present in the 

hardboard panel, but the deflection was less than 3 

in. No debris; some screws loosened. 

 

   
Research Note FPL–RN–0329

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3

Table 1. Test results from FPL debris impact study (continued)

Test

no. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

7 1-in. by 12-in. by 48-in. bamboo panel. 

Mounted to the support frame with screws to all 

support studs. 

16-in. on-center 

(OC) wall frame 

with 2-1/2 in. 

of foam 

insulation

in the void. 

Front 103 The missile bounced off the panel but made an 

indentation in the face of the wall. No damage was 

seen on the rear of the wall. 

 

8 (2nd shot) 4-ft by 4-ft by 1/4-in. tempered hardboard. 

Mounted to the wall with 2-1/2-in. deck screws and 

1-in. fender washers spaced at 4-in. on the perimeter 

and 6 in. in the interior. 

Wall only Rear 109 The rear of the wall deformed over 3 in. and 

dislodged the hardboard panel. 

 

9 2-ft by 2 ft by 1/2-in. plywood panel. 

Mounted to the wall with 2-1/2-in. deck screws and 

fender washers spaced at 4 in. on the perimeter and 

6 in. in the interior. 

Wall only Rear 104 The missile caused a 2-in. indentation in the face of 

the wall. Cracks were present in the plywood panel. 

The rear of the wall had 1 in. or less deflection. No 

debris; some screws loosened. 

 

   
USDA Forest Products Laboratory’s Debris Launcher

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Table 1. Test results from FPL debris impact study (continued)

Test

no. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

10 2-ft by 2-ft by 1⁄2-in. OSB panel. 

Mounted to the wall with 2-1/2-in. deck screws 

and fender washers spaced at 4 in on the 

perimeter and 6 in. in the interior. 

Wall only Rear 105 The missile caused a 2-in. indentation in the 

face of the wall. Cracks were present in the 

OSB panel. The rear of the wall had 1 in. or 

less deflection. No debris; some screws 

loosened. 

 

11 3⁄4-in. by 12-in. by 48-in. bamboo panel. The 

panel was machine made with generally 

uniform thickness. 

Mounted to the support frame with three 

rows of screws, 16-in. spacing. 

4-ft by 8-ft 

frame of 

2-in. by 6-in. studs, 

16-in. OC. The frame was 

mounted to the wall with 4-

in. by 4-in. blocks at the top 

and bottom. The frame 

had OSB sheathing above 

and below the target panel.

Front 105 The missile penetrated the panel and made 

an indentation in the face of the wall. No 

visible damage was done to the back side of 

the wall. 

12 3⁄4-in. by 12-in. by 64-in. bamboo panel. The 

bamboo panel was humanmade with longer 

fibers and had a varied thickness. 

Mounted to the support frame with three 

rows of screws, 16-in. spacing. 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target panel. 

Front 105 The missile perforated the panel and 

impacted the wall in the same area as 

Missile #14. There was damage to the back 

side of the wall in the form of a large crack. 

 
Research Note FPL–RN–0329

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Table 1. Test results from FPL debris impact study (continued)

Test

no. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

13 (2nd shot) 4-ft by 4-ft by 1⁄4-in. ballistic fiber 

coated hardboard. 

Mounted to the wall with 2-1/2-in. deck screws 

and 1-in. fender washers spaced at 4 in. on the 

perimeter and 6 in. in the interior. 

Wall only Rear 104 The missile caused a 2-in. indentation in the face 

of the wall, but there was no deflection at the 

rear of the wall. The ballistic panel appeared 

undamaged. No debris; some screws loosened. 

14 (2nd shot) 2-ft by 2-ft by1/2-in. plywood panel. 

Mounted to the wall with 2-1/2-in. deck screws 

and fender washers spaced at 4 in. on the 

perimeter and 6 in. in the interior. 

Wall only Rear 107 Missile was fired 2 in. to the right of initial 

impact. Missile perforated the wall and blew out 

the plywood panel, protruding over 2 ft. 

15 (2nd Shot) 2-ft by 2-ft by 1⁄2-in. OSB panel. 

Mounted to the wall with 2-1/2-in. deck screws 

and fender washers spaced at 4 in. on the 

perimeter and 6 in. in the interior. 

Wall only Rear 105 The missile caused a 2-in. indentation in the wall 

face. Damage in the OSB panel along the seam 

lines of the wall. The wall and OSB had less 

than 3-in. deflection. 

16 5-in. by 5-in. by 36-in. live oak beam. 

Mounted to the support frame with rope and 

placed on supporting 2-in. by 4-in. extensions. 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target beam. 

Front 109 The missile indented the front of the beam and 

cracked the rear, opposite of the impact area. 

Some of the frame studs were cracked and 

twisted. 

17 12-in. by 1-1/2-in. by 60-in. laminated bamboo 

panel.

Mounted to the support frame with screws to 

the supporting wall studs. 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target panel. 

Front 104 The missile perforated the bamboo panel and the 

wall. It protruded 24 in. through the back of the 

wall with lots of fraying on the panel. The wall 

had been weakened by previous strikes in the 

area. 

18 12-in. by 1-in. by 60-in. laminated bamboo 

panel.

Mounted to the frame with screws to the 

supporting wall studs. 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target panel. 

Front 107 The missile perforated the bamboo panel and the 

wall. The bamboo panel had a cleaner 

penetration hole and less frayed fibers than the 

panel used with Missile #17. 

19 4-ft by 7-ft by 1⁄2-in. OSB panel. 

Mounted to the wall with 2-1/2-in. deck screws 

and fender washers spaced at 4 in. on the 

perimeter and 6 in. in the interior. The panel was 

fastened in the center 3-ft by 4-ft section only. 

Wall only Rear 104 The missile caused a 1-1/2-in. indentation in the 

face of the wall. Cracks in the OSB panel were 

present. The rear of the wall had 1 in. or less 

deflection. 

20 Layer 1: 12-in. by 1-in. by 60-in. pressed 

bamboo board 

Layer 2: 2-in. by 4-in. stud frame, 16-in. OC 

with Styrofoam insulation in the voids 

Layer 3: 12-in. by 1-in. by 60-in. pressed 

bamboo board 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target panel. 

Front 103 The missile perforated both of the bamboo 

boards and the Styrofoam. The penetration 

created a clean entrance hole while the rear had 

fibers frayed 8 in. from either side of the hole. 

21 Layer 1: 12-in. by 1-in. by 60-in. pressed 

bamboo board with nylon cargo straps on the 

rear face 

Layer 2: 2-in. by 4-in. stud frame, 48-in. OC 

with Styrofoam insulation in the void 

Layer 3: 12-in. by 1-in. by 60-in. pressed 

bamboo board 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and 

bottom. The frame had 

OSB sheathing above and 

below the target panel. 

Front 102 The missile perforated the front bamboo board, 

pulled the cargo straps, and crushed the 

Styrofoam. The rear bamboo board was 

undamaged. Three of four frame studs were 

damaged. 

   
USDA Forest Products Laboratory’s Debris Launcher

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Table 1. Test results from FPL debris impact study (continued)

Test

no. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

22 Layer 1: 12-in. by 3⁄4-in. by 48-in. highquality (HQ) laminated plywood board 

Layer 2: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

Layer 3: 2-in. by 4-in. stud frame, 16-in. OC 

Layer 4: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and bottom. 

The frame had OSB 

sheathing above and below 

the target panel. 

Front 102 The missile perforated all three of the plywood 

boards. The penetration created a clean 

entrance hole through all three plywood 

boards. 

23 Layer 1: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board with nylon cargo 

straps on the rear face 

Layer 2: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

Layer 3: 2-in. by 4-in. stud frame, 48-in. OC 

Layer 4: 12-in.by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

The frame was mounted to 

the wall with 4-in. by 4-in. 

blocks at the top and bottom. 

The frame had OSB 

sheathing above and below 

the target panel. 

Front 103 The missile perforated the front plywood 

board, pulled the straps, and broke the second 

board. It did not damage the rear board. The 

frame sustained major damage to the two 

center studs. 

24 Layer 1: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood with nylon cargo straps 

on the rear face 

Layer 2: 2-in. by 4-in. stud frame, 16-in. OC 

Layer 3: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

Double studs were used in 

the center two wall cells and 

single studs on the perimeter. 

The top and bottom 3 ft were 

sheathed with 3⁄4-in. OSB. 

Front 105 The missile perforated the front plywood 

board, pulled the cargo straps, and protruded 

through the second board. The frame itself had 

no significant damage. 

25 Layer 1: 12-in. by 2/3-in. by 48-in. 

Laminated Storm Blocker® board 

Layer 2: 2-in. by 4-in. stud frame, 16-in. 

on center 

4-t by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

Double studs were used in 

the center two wall cells and 

single studs on the perimeter.

The top and bottom 3 ft were 

sheathed with 3⁄4-in. OSB. 

Front 102 The missile perforated the Storm Blocker® 

panel in the strike zone, struck the wall, and 

bounced back. The frame did not appear to 

suffer any significant damage. 

26 Layer 1: 12-in. by 1-in. by 48-in. bamboo 

composite board with nylon cargo straps on 

the rear face 

Layer 2: 2-in. by 4-in. stud frame, 48-in. 

OC

Layer 3: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood board 

4-in. by 8-in. frame of 2-in. 

by 6-in. studs, 16-in. OC. 

Double studs were used in 

the center two wall cells and 

single studs on the perimeter.

The top and bottom 3 ft were 

sheathed with 3⁄4-in. OSB. 

Front 103 The missile perforated the bamboo board, 

pulled the straps in the strike zone, broke 

through the plywood board, and struck the 

wall. The frame did not appear to suffer any 

significant damage. 

27 Layer 1: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood with nylon cargo straps 

on the rear face 

Layer 2: 12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood 

Layer 3: 2-in. by 4-in. stud frame, 48-in. 

OC

Layer 4:12-in. by 3⁄4-in. by 48-in. HQ 

laminated plywood 

4-ft by 8-ft frame of 2-in. 

by 6-in. studs, 16-in. OC. 

Double studs were used in 

the center two wall cells and 

single studs on the perimeter.

The top and bottom 3 ft were 

sheathed with 3⁄4-in. OSB. 

Front 105 The missile perforated all layers of the 

plywood boards and pulled the straps in the 

strike zone and struck the wall. The frame did 

not appear to suffer any significant damage. 

28 Five ply Douglas-fir cross laminated timber 

panel. Each lamination was 1-in. thick. 

2-in. by 8-ft panel attached 

to steel frame 

Front 103.5 The 15.3-lb., 2-in. by 4-in. missile caused a 1-

1/2-in. indentation in the front of the panel. The 

fourth lamination failed perpendicular to grain. 

There was some deflection at the rear but it 

was not permanent and no debris flew from the 

back side of the panel. 

   

   
Research Note FPL–RN–0329

14

7

Table 1. Test results from FPL debris impact study (continued)

Test

no. Panel description 

Wall/support 

frame 

Panel

location

Missile speed 

(mph) Damage description 

29 Five ply Douglas-fir cross laminated timber 

panel. Each lamination was 1-in. thick. 

2-ft by 8-ft panel attached to 

steel frame 

Front 102.0 The 15.4-lb, 2-in. by 4-in. missile caused a 

15/16-in. indentation in the front of the panel. 

The fourth lamination failed perpendicular to 

the grain. No debris flew from the back of the 

panel, but there was a permanent deflection on 

the rear of the panel. 

 

30 Five ply Douglas-fir cross-laminated timber 

panel. Each lamination was 1-in. thick. 

2-ft by 8-ft panel attached to 

steel frame 

Front 103.4 The 15.6-lb., 2 by 4 missile caused a 15/16-in. 

indentation in the front of the panel. The fourth 

lamination failed perpendicular to grain. There 

was limited deflection at the rear but it was not 

permanent and no debris flew from the back of 

the panel. Missile shattered.