COMPOSITE MATERIAL FIRE FIGHTING RESEARCH

Federal AviationAdministrationCOMPOSITE MATERIAL

FIRE FIGHTING RESEARCH

ARFF Working Group October 8, 2010

Phoenix, AZ

Presented by:

Keith BagotAirport Safety Specialist

Airport Safety Technology R&D Section

John HodeARFF Research Specialist

SRA International, Inc.

Airport Safety Technology Research2Federal Aviation

AdministrationOctober 8, 2010

Presentation Outline

• FAA Research Program Overview

• Composite Aircraft Skin Penetration Testing

• Composite Material Cutting Apparatus

• Development of Composite Material Live Fire Test Protocol



FAA Research Program Overview

FAA Technical Center, Atlantic City, NJ Tyndall AFB, Panama City, FL

FAA HQ, Washington, DC




Program Breakdown:Program Breakdown:

• ARFF Technologies

• Operation of New Large Aircraft (NLA)

• Advanced Composite Material Fire Fighting

-




Past Projects: Past Projects:

- High Reach Extendable Turrets

- Aircraft Skin Penetrating Devices

- High Flow Multi-Position Bumper Turrets

- ARFF Vehicle Suspension Enhancements

- Drivers Enhanced Vision Systems

- Small Airport Fire Fighting Systems

- Halon Replacement Agent Evaluations



Advanced Composite Material Fire Fighting

Expanded Use of Composites

• Increased use of composites in commercial aviation has been well established– 12% in the B-777 (Maiden flight 1994)– 25% in the A380 (Maiden flight 2005)– 50% in both B-787 & A350 (Scheduled)

• A380, B-787 & A350 are the first to use composites in pressurized fuselage skin



Advanced Composite Material Fire Fighting

Research Areas

• Identify effective extinguishing agents.

• Identify effective extinguishing methods.

• Determine quantities of agent required.

• Identify hazards associated airborne composite fibers.



Composite Aircraft Skin Penetration Testing




3 Types of Piercing Technologies




Objectives

• Provide guidance to ARFF departments to deal with the advanced materials used on next generation aircraft.

• Determine the force needed to penetrate fuselage sections comprised of composites and compare to that of aluminum skins.

• If required forces are greater, will that additional force have a detrimental effect on ARFF equipment.

• Determine range of offset angles that will be possible when penetrating composites and compare to that of aluminum skins.




Phase 1: Small-Scale Laboratory Characterization of Material Penetration for Aluminum, GLARE and CRFP (Drexel University)

Phase 2: Full-Scale Test using the Penetration Aircraft Skin Trainer (PAST) Device (FAA-TC)

Phase 3: Full-Scale Test Using NLA Mock-Up Fire Test Facility (Tyndall Air Force Base)




• Test Matrix Developed

– Three Materials:• Aluminum (Baseline)

• GLARE

• CFRP

– Three Thickness’– Three Loading Rates– Two Angles of Penetration– Three Repetitions



ASPN Penetration/Retraction ProcessMaterial deformation & tip region penetration

Conical region penetration

Cylindrical region penetration

Retraction



ASPN Penetration and Retraction Forces

Constant force is required to perforate aluminum panels after initial penetrationIncreasing force is required to perforate CFRP and GLARE panels after initial penetration

PP NP

PR

NR



Maximum Plate Penetration (PP) and Plate Retraction (PR ) Loads at 0.001 and 0.1 in/s

PP

RR

• For Aluminum panels : Retraction load is higher than penetration load, caused by petals gripping the panel upon retraction (due to elastic recovery)

• For GLARE and CFRP panels: Penetration load is higher than retraction load - petals remain deformed (due to local damage of composite plies)



Maximum Nozzle Penetration (NP) and Nozzle Retraction (NR ) Loads at 0.001 and 0.1 in/s

PP

RR

• For Aluminum panels : Retraction load is higher than penetration load, caused by petals gripping the panel upon retraction (due to elastic recovery)

• For GLARE and CFRP panels: Penetration load is higher than retraction load - petals remain deformed (due to local damage of composite plies)



Petals FormationGLARE (Normal Penetration)Aluminum (Normal Penetration)

CRF (Normal Penetration)Aluminum (Oblique Penetration)



Composite Material Cutting Apparatus



Composite Material Cutting ApparatusPurpose

• Increased use of composite materials on aircraft

• Limited data available on cutting performance of current fire fighting tools on composite materials

• Aim to establish a reproducible and scientific test method for assessing the effectiveness of fire service rescue saws and blades on aircraft skin materials



Composite Material Cutting ApparatusObjectives

• Create an objective test method by eliminating the human aspect of testing

• Design a test apparatus that facilitates testing of 4’X2’ panels of aluminum, GLARE, and CFRP

• Measure:– Blade Wear– Blade Temperature– Blade Speed – Plunge Force– Axial Cut Force– Cut Speed

• Utilize computer software and data acquisition devices to monitor and log data in real time




Design Progression



Development of a Composite Material Fire Test Protocol




ALUMINUM CARBON/EPOXY GLARE

Norm for ARFF Unfamiliar to ARFF Unfamiliar to ARFF

Melts at 660°C (1220°F) Resin ignites at 400°C (752°F)

Outer AL melts, glass layers char

Burn-through in 60 seconds Resists burn-through more than 5 minutes

Resists burn-through over 5 minutes

Readily dissipates heat Holds heat May hold heat

Current Aircraft B787 & A350 2 Sections of A380 skin

What we knew before this testing…



FedEx DC10-10F, Memphis, TN

18 December 2003

Aluminum skinned cargo flight

Traditionally, the focus is on extinguishing the external fuel fire, not the fuselage.



Representative IncidentAir China at Japan Naha Airport, August 19, 2007

4 minutes total video

3 minutes tail collapses

ARFF arrives just after tail collapse




External Fire Control Defined

• Extinguishment of the body of external fire– Our question: Will the composite skin continue to burn after the

pool fire is extinguished, thereby requiring the fire service to need more extinguishing agent in the initial attack?

• Cooling of the composite skin to below 300°F– Our question: How fast does the composite skin cool on its

own and how much water and foam is needed to cool it faster?• 300°F is recommended in the IFSTA ARFF textbook and by Air

Force T.O. 00-105E-9. (Same report used in both)• Aircraft fuels all have auto ignition temperatures above 410°F.

This allows for some level of a safety factor.



Creation of a Test Method

First objective: • Determine if self-sustained

combustion or smoldering will occur.

• Determine the time to naturally cool below 300°F (150°C)

Second objective: Determine how much fire agent is needed to extinguish visible fire and cool the material sufficiently to prevent re-ignition.

Exposure times of Initial tests:• 10, 5, 3, 2, & 1 minutes

– FAR Part 139 requires first due ARFF to arrive in 3 minutes.– Actual response times can be longer or shorter.



Initial Test Set-up

FLIR

Color Video

Color Video at 45 ° Front view



Initial Test Set-up



Test 10 Video



Initial Results• Longer exposure times inflicted heavy damage on the panels.

– Longer exposures burned out much of the resin.– Backside has “hard crunchy” feel.– Edges however, seem to have most of the resin intact. Edge area matched 1 inch

overlap of Kaowool.

Test 6, 10 minute exposure

Front (fire side) Back (non-fire side)Edge View



Panel Temperatures

Air Force Composite Fire Test 14

0

200

400

600

800

1000

1200

1400

1600

0 2 4 6 8 10 12 14 16

Time (minutes)

Tem

per

atu

re (

F)

TC 1

TC 2

TC 3

TC 4

TC 5

BURNER OFF

FLIR

Air Force Composite Fire Test 16

0

100

200

300

400

500

600

700

800

900

0 2 4 6 8 10 12

Time (minutes)

Tem

pera

ture

(F)

TC1

TC2

TC3

TC4

TC5

BURNER OFF

FLIR



Other Test Configurations

• Tests 22 and 23– The panel was cut into 4 pieces and stacked with ¾ inch

(76.2mm) spaces between.– Thermocouples placed on top surface of each layer.– Exposure time; 1 minute.



Other Test Configurations cont.

• This configuration not representative of an intact fuselage as in the China Air fire.

• Measured temperatures in the vicinity of 1750°F (962°C).

• Wind (in Test 22) caused smoldering to last 52 seconds longer.



Initial Findings

1. Post-exposure flaming reduces quickly without heat source

2. Off-gassing causes pressurization inside the panel causing swelling

3. Internal off-gassing can suddenly and rapidly escape

4. Off-gas/smoke is flammable

5. Longer exposures burn away more resin binder

6. Smoldering can occur

7. Smoldering areas are hot enough to cause re-ignition

8. Smoldering temperatures can be near that of fuel fires

9. Presence of smoke requires additional cooling

10. Insulated areas cooled much more slowly than uninsulated areas



Further Development of Fire Test Protocol

• Data from first series of tests was used to further modify the protocol development.

• For example, larger panels and different heat sources were utilized in this round of development.

• Larger test panels will be needed for the agent application portion of the protocol.

• Lab scale testing conducted to identify burn characteristics.

• Testing was conducted by Hughes Associates Inc. (HAI).




Lab scale tests

– ASTM E1354 Cone Calorimeter• Data to support exterior fuselage flame propagation/spread modeling

– ASTM E1321 Lateral Flame Spread Testing (Lateral flame spread)

– Thermal Decomposition Apparatus (TDA)

– Thermal Gravimetric Analysis (TGA)

– Differential Scanning Calorimetry (DSC)

– Pyrolysis Gas Chromatograph/Mass Spectroscopy (PY-GC/MS)




• Secondary test configuration (agent application to be tested at this scale)– Three different heat sources evaluated

• Propane fired area burner (2 sizes)

• Propane torch

• Radiant heater

– Sample panels are 4 feet wide by 6 feet tall• Protection added to test rig to avoid edge effects.

– A representative backside insulation was used in several tests.




12 total tests conducted

• 9 with OSB– 1 uninsulated– 8 insulated

• 3 with CFRP– 1 uninsulated– 2 insulated

Hood Calorimeter

Non-Combustible Mounting Wall

Propane Burner (Exposure Fire)

Water Suppression System

Test Panel

Hood Calorimeter

Non-Combustible Mounting Wall

Propane Burner (Exposure Fire)

Water Suppression System

Test Panel



Large Area Burner On Burner Off – 0 seconds Burner Off – 30 seconds

Burner Off – 60 seconds Burner Off – 100 seconds

OSB Exposed to Large Area Burnerwith Insulation Backing



Torch Ignition 1 minute after ignition 1.5 minutes after ignition

2.5 minutes after ignition 4 minutes after ignitionTorches Out

15 seconds after torches out

CFRP Exposed to Torch Burner with Insulation Backing



Findings

• Ignition occurred quickly into exposure

• Vertical/Lateral flame spread only occurred during exposure

• Post-exposure flaming reduced quickly without heat source

• Jets of internal off-gassing escaped near heat source from the backside

• Generally, results are consistent with small scale data



Test Conclusions

OSB vs. CFRP

• Both materials burn and spread flame when exposed to large fire

• Heat release rates and ignition times similar

• The thicker OSB contributed to longer burning

Large Scale Implications• OSB can be used as a

surrogate for CFRP in preliminary large scale tests

• Flaming and combustion does not appear to continue after exposure is removed– Since there was no or very

little post exposure combustion, no suppression tests performed as planned

– Minimal agent for suppression of intact aircraft?



Qualifiers to Results

• Need to check GLARE– No significant surface burning

differences anticipated ( may be better than CFRP)

• Verify /check CFRP for thicker areas (longer potential burning duration)

• Evaluate edges/separations– Wing control surfaces– Engine nacelle– Stiffeners– Post crash debris scenario

Can a well established fire develop in a post-crash environment?

EXAMPLE COMPLEX GEOMETRY FIRE TEST

SETUP FOR CFRP FLAMMABILITY EVALUATION.



Summary

• Carbon fiber composite has not shown flame spread and quickly self-extinguish in the absence of an exposing fire.

• Carbon fiber can achieve very high temperatures depending on configuration through radiation.

• Initial lab tests and fire tests show similar results and are consistent.

• Smoke should be used as an indicator of hot spots that must be further cooled.

• OSB can be used for large scale testing to establish parameters to save very expensive carbon fiber for data collection.



Questions or Comments?

FAA Technical Center

Airport Technology R&D Team

AJP-6311, Building 296

Atlantic City International Airport, NJ 08405

[email protected] 609-485-6383

[email protected] 609-601-6800 x207

www.airporttech.tc.faa.gov

www.faa.gov/airports/airport_safety/aircraft_rescue_fire_fighting/index.cfm

COMPOSITE MATERIAL FIRE FIGHTING RESEARCH

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