U.S. Department 

of Transportation 

Federal Aviation 

Administration

Advisory 

Circular

Subject: AIRCRAFT FIRE EXTINGUISHING 

AGENTS 

Date: 7/08/04

Initiated by: AAS-100 

AC No: 150/5210-6D 

Change:

1. PURPOSE. This Advisory Circular (AC) provides guidance for reference material covering Aircraft

Fire Extinguishing Agents. 

2. CANCELLATION. Advisory Circular 150/5210-6C, dated January 28, 1985, is cancelled. 

3. APPLICATION. The Federal Aviation Administration (FAA) recommends the guidelines contained

in this AC for Aircraft Fire Extinguishing Agents. This AC is not mandatory and does not constitute a 

regulation. However, the information it contains provides an acceptable methodology for complying with 

Title 14 of the Code of Federal Regulations (CFR), part 139, Certification of Airports (Part 139). In the

event of a conflict, part 139 takes precedence over the other documents identified in this AC. 

4. APPLICABLE DOCUMENTS. 

The following documents are applicable to the extent specified in this AC: 

4.1 Code of Federal Regulations (CFR). 

14 CFR part 139, Certification of Airports (part 139).

4.2 National Fire Protection Association (NFPA). 

 NFPA 18, Standard on Wetting Agents, 1995 edition. 

NFPA 403, Standard for Aircraft Rescue and Fire-Fighting Services at Airports, August 7, 2003,

edition. 

NFPA 412, Standard for Evaluating Aircraft Rescue and Fire-Fighting Foam Fire Equipment,

2003 edition.

4.3 Military Specifications. 

MIL-F-24385F, Fire Extinguishing Agent, Aqueous Film Forming Foam (AFFF) Liquid 

Concentrate, for Fresh and Seawater, dated January 7, 1992. 
7/08/04 AC 150/5210-6D 

4.4 Underwriters Laboratory (UL) Standards. 

UL 162, Standard for Safety for Foam Equipment and Liquid Concentrate, dated March 30,

1994. 

5. HOW TO ORDER. 

a. Copies of part 139 may be purchased from:

Superintendent of Documents 

U.S. Government Printing Office 

Washington, DC 20402 

b. Copies of National Fire Protection Association (NFPA) Standard No. 403, Standard for 

Aircraft Rescue and Fire-fighting Services at Airports, and Standard No. 412, Standard for

Evaluating Aircraft Rescue and Fire-Fighting Foam Fire Equipment, may be ordered from:

National Fire Protection Association 

1 Batterymarch Park 

Quincy, MA 02269 

c. Copies of UL 162, Standard for Safety for Foam Equipment and Liquid Concentrates, can be 

purchased from: 

 Underwriters Laboratory, Inc. 

 Customer Service 

1285 Walt Whitman Road

Melville, NY 11747-3081 

d. A printed copy of this and other ACs can be ordered from: 

U.S. Department of Transportation 

Annmore East Business Center 

3341 Q 75th Avenue 

Landover, MD 20785 

e. Electronic copies of FAA ACs and part 139 may be obtained from:

Internet: http://www.faa.gov/arp 

David Bennett 

Director, Office of Airport Safety and Standards 

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AC 150/5210-6D 7/08/04 

TABLE OF CONTENTS

CHAPTER 1. BACKGROUND. ....................................................................................................1 

1.1 GENERAL.............................................................................................................. 1 

1.2 DEFINITIONS........................................................................................................ 1 

1.2.1 Primary Agents. .......................................................................................................1 

1.2.2 Supplementary Agents.............................................................................................2 

1.2.3 Other Agents. ...........................................................................................................2 

1.2.4 Theoretical Critical Fire Area (TCA). .....................................................................3 

1.2.5 Practical Critical Fire Area (PCA)...........................................................................3 

1.2.6 Control Time............................................................................................................3 

1.2.7 Extinguishment Time...............................................................................................3 

CHAPTER 2. QUANTITIES FOR AIRPORTS SERVING DOT-CERTIFICATED AIR 

CARRIERS/COMMERCIAL SERVICE. ...............................................................3 

CHAPTER 3. QUANTITIES FOR GENERAL AVIATION AIRPORTS. ...................................4 

CHAPTER 4. COMPATIBILITY OF AGENTS. ..........................................................................4 

CHAPTER 5. EXTINGUISHING AGENT SUBSTITUTES. .......................................................4 

CHAPTER 6. PERFORMANCE REQUIREMENTS....................................................................4 

CHAPTER 7. TESTING AND QUALITY ASSURANCE. ..........................................................4 

7.1 QUALITY CONTROL........................................................................................... 4 

7.2 RESPONSIBILITY FOR INSPECTION. .............................................................. 4 

CHAPTER 8. ENVIRONMENTAL...............................................................................................5 

8.1 ENVIRONMENTAL ISSUES................................................................................ 5 

APPENDIX A. Related FAA Advisory Circulars. .........................................................................7 

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AC 150/5210-6D 7/08/04 

CHAPTER 1. BACKGROUND. 

1.1 GENERAL. 

This AC provides reference information on the following agents: 

• Primary aircraft fire extinguishing agents

• Supplementary aircraft fire extinguishing agents 

• Other aircraft fire extinguishing agents 

1.2 DEFINITIONS. 

The following definitions do not include numerical quantities. These can be found in NFPA 403, Table

5.3.1 (b), as well as additional agent quantities to be carried. 

1.2.1 Primary Agents. 

Foam used for extinguishing aircraft fires should consist of an aggregation of bubbles of a lower specific 

gravity than that of hydrocarbon fuels or water. The foam should have strong cohesive qualities and be

capable of covering and clinging to vertical and horizontal surfaces. Aqueous foam cools hot surfaces by

its high water retention ability and must flow freely over a burning liquid surface to form a tough, airexcluding blanket that seals off volatile flammable vapors from access to air or oxygen. Good-quality

foam should be dense and long lasting, capable of resisting disruption by wind or draft, stable to intense 

thermal radiation, and capable of re-sealing in event of mechanical rupture of an established blanket. 

1.2.1.1 Aqueous Film Forming Foam (AFFF). 

These liquid concentrates consist of perfluorinated surfactants(s) with a foam stabilizer and viscosity

control agents. The AFFF acts both as a barrier to exclude air or oxygen and, in addition, produces an

aqueous film on the fuel surface capable of suppressing the evolution of fuel vapors. Ideally, the foam

blanket produced by the AFFF should be of sufficient thickness so as to be visible before fire fighters rely

on its effectiveness as a vapor suppressant. 

1.2.1.2 Fluoroprotein Foam (FP). 

Fluoroprotein Foam is simulated foam that is manufactured from protein foam concentrates to which

fluorochemical surfactants have been added. This increases the fluidity of the foam and offers a good 

burn back resistance. The manufacturer of the foam-making equipment should be consulted as to the 

correct concentrate to be used in any particular system (the proportioners installed must be properly 

designed and/or set for the concentrate being used). 

1.2.1.3 Film Forming Fluoroprotein (FFFP) Foam. 

These agents are also based on protein foam formulations. They are produced by increasing the quantity

and quality of the fluorocarbon surfactants added to the protein hydrolyzate. By doing this, the surface 

tension of the resulting solution that drains from the expanded foam is reduced to the point that it can

spread across the surface of a liquid hydrocarbon fuel. 

1.2.1.4 Protein Foam. 

These liquid concentrates consist primarily of hydrolysis products of various proteinaceous materials.

They also contain stabilizing additives and inhibitors to protect against freezing, to prevent corrosion of 

equipment and containers, to resist bacterial decomposition, to control viscosity, and to assure readiness

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7/08/04 AC 150/5210-6D 

for use in emergencies. Foam liquids of different types or different manufacturers should not be mixed

unless it is determined that they are compatible and/or completely interchangeable. 

1.2.2 Supplementary Agents. 

Supplementary agents are also referred to as secondary agents. Agents that fit into this category are 

carried on rescue vehicles to handle unique fire fighting requirements most common to airport fire

fighting use. Supplementary agents are employed either singly or in combination with foam to 

accomplish particular aircraft fire fighting operations such as a three dimensional running fuel fires 

(reference NFPA 403, Annex A, § A.5.2 (1)). 

This class of agents include: 

• Dry Chemical 

• Halotron® I 

• Carbon Dioxide 

1.2.2.1 Dry Chemical. 

The earliest use of dry chemical in aircraft fire fighting included the use of sodium bicarbonate-based

products. Today, the U.S. airport fire fighting industry relies almost exclusively on the use of potassiumbased chemicals as auxiliary extinguishing agents due to their compatibility with AFFF agents and their

reliable fire performance. 

1.2.2.2 Halotron® I. 

Subsequent to the U.S. decision to halt production of halon as part of the Montreal Protocol (reference 

NFPA 403, Appendix A, §A.5.2 (2)) and the use of halon-based agents (e.g., Halon 1211) in live fire 

training because of its environmental effects, the FAA teamed with other agencies and industry and 

identified an acceptable alternative to using halon-based agents in airport rescue firefighting vehicles. 

Several potential agents were evaluated. Only the Halotron® I product has completed the full-scale fire 

test performance evaluation and was approved as an alternative fire fighting agent to Halon 1211 for 

airport fire fighting use. Halotron ® I has additionally been deemed to be an environmentally acceptable

replacement for Halon 1211 by the Environmental Protection Agency. Due to the slight differences in 

specific gravity of these two chemicals in a 1:1 by-volume basis, approximately 468 pounds of Halotron® 

I can be placed in the existing vessel (tank) that holds approximately 500 pounds of Halon 1211. Fire 

performance tests have shown that Halotron® I will generally suppress or extinguish fires in the same 

manner as Halon 1211. In considering the substitution of Halotron® I for Halon 1211, the ratio for 

equivalency in performance might be as great as 1.5 to 1 pound by weight. 

1.2.2.3 Carbon Dioxide. 

Tests show that low-pressure carbon dioxide (CO2) is more effective in aircraft rescue and fire fighting 

operations than high pressure CO2. The tests further indicate that CO2 can be given parity with dry 

chemical powder on the basis of 4.4 pounds of CO2 gas per 2.2 pounds of dry chemical. 

1.2.3 Other Agents. 

In general there are other special-use fire extinguishing agents available to airport firefighting services. In

particular, those agents used to combat Class D fires, such as magnesium fires, are referred to as

combustible metal agents. These agents can be either in the form of liquid or powder. For information on 

powder agents, refer to NFPA 403 Annex A, §A.5.5. 

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AC 150/5210-6D 7/08/04 

Under certain fire situations “wetting agents” may be appropriate. A wetting agent is defined as a 

chemical compound that, when added to water in proper quantities, materially reduces its surface tension, 

increases its penetrating and spreading abilities, and might also provide emulsification and foaming 

characteristics. These agents should be discharged through an in-line proportioning system to a handline 

so as not to contaminate the vehicles primary foam distribution system. These agents should not be 

mixed in any primary agent tanks. For further information on wetting agents, refer to NFPA 18, Standard 

on Wetting Agents. 

1.2.4 Theoretical Critical Fire Area (TCA).

The TCA serves as a means of categorizing aircraft in terms of the magnitude of the potential fire hazard

in which they may become involved. It is not intended to represent the average, maximum, or minimum 

spill fire size associated with a particular aircraft. For information on TCA, refer to NFPA 403, Annex B, 

§B.1.1. 

1.2.5 Practical Critical Fire Area (PCA). 

The PCA and the related quantities of extinguishing agents are based on criteria formulated during the 

Second Meeting of the International Civil Aviation Organization (ICAO) Rescue and Fire Fighting Panel

(RFFP II) in June 1972. RFFP II developed material indicating the practical area is two-thirds of the 

theoretical area based on the Panel’s work, which included a study of extinguishing agents used on actual 

aircraft fires. In 99 out of 106 studied fires, the quantities of agents used were less than those previously

recommended by ICAO. For information on PCA, refer to NFPA 403, Annex B, §B.1.1. 

1.2.6 Control Time. 

The control time is the time required from the arrival of the first fire fighting vehicle and the beginning of

agent discharge to reduce the initial intensity of the fire by 90 percent. The equipment and techniques to 

be used should be capable of controlling the fire in the PCA in 1 minute. For information on control time, 

refer to NFPA 403, Annex B, §B.2. 

1.2.7 Extinguishment Time. 

Extinguishment time is the time required from the application of the agent of the first fire fighting vehicle 

to the time the fire is extinguished. For information on extinguishment time, refer to NFPA 403, Annex

B, §B.2. 

CHAPTER 2. QUANTITIES FOR AIRPORTS SERVING DOT-CERTIFICATED AIR 

CARRIERS/COMMERCIAL SERVICE. 

part 139, §139.315 is to be used to determine the aircraft rescue and firefighting Index (A through E) for 

airports serving Department of Transportation (DOT) certificated air carriers/commercial service. These

numbers can then be converted to NFPA categories using NFPA 403, Chapter 4, Table 4.3.1. The 

extinguishing agents, quantities, and discharge and response capability for each Index is referenced in

NFPA 403, Chapter 5, Table 5.3.1 (b), in U.S. customary units and could be used to comply with

§139.315. NFPA 403, Annex B, additionally describes the methodology used to arrive at the designated 

control times (§B.2), discharge rates (§B.3), and quantities of agents to be provided (§B.4 and §B.5). It

should be noted that part 139 takes precedence and that NFPA 403 may, in some cases, exceed part 139 

requirements. 

Each truck, when purchased, should be equipped with its design capacity of extinguishing agents. For 

operating and training purposes, airports should also provide: (1) Twice the quantity of agents carried on 

each truck available in the fire station and (2) A supply of agents to be used for training. Note also that 

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7/08/04 AC 150/5210-6D 

§139.317(i) requires each vehicle that is required to carry AFFF to carry AFFF in an appropriate amount

to mix with twice the water required to be carried by the vehicle. 

CHAPTER 3. QUANTITIES FOR GENERAL AVIATION AIRPORTS.

The Indexes for general aviation airports are identified in NFPA 403, Chapter 4, Table 4.3.1 and cover the 

areas not governed by the FAA. The extinguishing agents, quantities, and discharge and response 

capability for each Index are referenced in NFPA 403, Chapter 5, Table 5.3.1 (b), in U.S. customary units. 

NFPA 403, Annex B, additionally describes the methodology used to arrive at the designated control

times (§B.2), discharge rates (§B.3), and quantities of agents to be provided (§B.4 and §B.5). 

CHAPTER 4. COMPATIBILITY OF AGENTS. 

The compatibility of agents is discussed in NFPA 403, Chapter 5, §5.4. 

CHAPTER 5. EXTINGUISHING AGENT SUBSTITUTES.

Extinguishing agent substitutes are discussed in part 139, §139.317 (i). 

CHAPTER 6. PERFORMANCE REQUIREMENTS. 

AFFF agents must meet the requirements of Mil-F-24385F. It is important to note that if one vendor’s 

foam is mixed with another vendor’s foam in the re-servicing process, there must be compatibility

between foams to prevent gelling of the concentrate. 

When used, FFFP, FP, and protein foam must meet the applicable performance requirements discussed in 

UL 162 (Type 3 application), Standard for Safety for Foam Equipment and Liquid Concentrates. 

CHAPTER 7. TESTING AND QUALITY ASSURANCE. 

7.1 QUALITY CONTROL.

While it is recognized that acceptance testing of extinguishing agents is necessary, the technical

characteristics, quality, stability compatibility, etc. cannot be determined during other system tests or 

demonstrations (e.g., for trucks). Therefore, airport management should request that prospective bidders 

or suppliers of fire extinguishing agents furnish proof of tests on performance and quality by a recognized 

testing laboratory. Technical data on the evaluation of agents and information on the characteristics of 

foam extinguishing agents are contained in NFPA 412, Chapter 5.

7.2 RESPONSIBILITY FOR INSPECTION. 

Unless specified by the airport owner, the manufacturer is responsible for the performance of all

inspection requirements as stated in §7.1 above. Unless specified in the contract, the manufacturer may

use his/her own or any other facilities suitable for the performance for the inspection requirements. 

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AC 150/5210-6D 7/08/04 

CHAPTER 8. ENVIRONMENTAL

8.1 ENVIRONMENTAL ISSUES 

For Federal environmental and health concerns, and issues in the use of aircraft fire fighting agents, 

contact the following organizations concerning information: 

Environmental Protection Agency (EPA) 

Ariel Rios Building 

1200 Pennsylvania Ave., N.W. 

Washington, DC 20460 

(202) 272-0167 

www.epa.gov

Occupational Safety and Health Administration (OSHA) 

200 Constitution Ave., N.W. 

Washington, DC 20210 

1-800-321-OSHA 

www.osha.gov

For information on material safety, contact: 

Material Safety Data Sheets 

121 Shivel Drive 

Hendersonville, TN 37075 

(877)673-7123

www.msdssearch.com

For information on state and local agencies pertaining to specific airports, refer to the appropriate 

organization in your state and/or local area. 

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AC 150/5210-6D 7/08/04 

APPENDIX A. RELATED FAA ADVISORY CIRCULARS.

AC 150/5210-7, Aircraft Rescue and Firefighting Communications

AC 150/5210-14, Airport Fire and Rescue Personnel Protective Clothing 

AC 150/5210-17, Programs for Training of Aircraft Rescue and Firefighting Personnel

AC 150/5220-10, Guide Specification for Water/Foam Aircraft Rescue and Firefighting Vehicles 

AC 150/5220-19, Guide Specification for Small Agent Aircraft Rescue and Fire Fighting Vehicles 

AC 150/5300-13, Airport Design, Appendices 12 and 13 

7