b. Additional Rating Guidelines for Halocarbon Extinguishers. For occupied spaces on transport category aircraft, extinguishers employing halocarbon clean agents, replacing required Halon 1211 extinguishers, should have a minimum U.S. - UL 5B:C or an equivalent rating. Halocarbon extinguishers are most effective on Class B and C fires. Extinguishers with greater capacity are also rated for Class A fires. Extinguishers with a 2B:C or 5B:C U.S. - UL rating, although not rated for use on Class A fires, have been shown to be effective in extinguishing surface Class A fires.
3. What Extinguishing Agents are Appropriate for the Different Types of Fires? The following extinguishing agents are appropriate for use on the types of fires specified in paragraph la above:
a. Water. Class A type fires are best controlled with water by cooling the material below its ignition temperature and soaking the material to prevent re-ignition.
b. Carbon Dioxide. Class B or C fires are effectively controlled by carbon dioxide as a blanketing agent.
Note: Carbon dioxide is not recommended for hand-held extinguishers for internal aircraft use.
Dry Chemicals. Class A, B, or C fires are best controlled by dry chemicals. The only "all purpose" (Class A, B, C rating) dry chemical powder extinguishers contain monoammonium phosphate. All other dry chemical powders have a Class B, C U.S - UL fire rating only.
Note 1: In general, dry chemicals are not recommended for hand extinguishers for internal aircraft use, due to the potential for corrosion damage to electronic equipment, the possibility of visual obscuration if the agent were discharged into the flight deck area, and the cleanup problems from their use.
Note 2: When approving a non-gaseous agent for installation on aircraft, evaluate the contamination impact to the structure, wiring and surrounding systems, and consider potential mixing of the agent residue with water. Using such extinguishers may require specific maintenance procedures addressing cleanup.
d. Halons. Class A, B, or C fires are appropriately controlled with halons. However, do not use halons on a class D fire. Halon agents may react vigorously with the burning metal.
Note: While halons are still in service and are appropriate agents for these classes of fires, the production of these ozone depleting agents has been restricted. Although not required, consider replacing halon extinguishers with halon replacement extinguishers when discharged.
Halocarbon Clean Agents. (Halons are a subcategory of halocarbons.) Class A, B, or C fires are appropriately controlled with the use of halocarbon clean agents. Never discharge halocarbon clean agents or water on a Class D (burning metal) fire. Halocarbon agents may react vigorously with the burning metal.
f. Specialized Dry Powder. Class D fires are best controlled by dry powder. Follow the recommendations of the extinguisher manufacturer because of the possible chemical reaction between the burning metal and the extinguishing agent.
Note 1: Specialized dry powder is not recommended for hand extinguishers for internal aircraft use.
Note 2: Fires involving a small number of Lithium primary batteries (containing molten Lithium) should not be treated as class D fires and specialized dry powder should not be used. See chapter 4, paragraph 1f of this AC for a discussion of appropriate extinguishing agents for Lithium battery fires.
4. What Extinguishing Agents are Compatible with Aircraft Materials?
Corrosion by Extinguishing Agents. Halocarbon clean agents are not corrosive, but review the material compatibility properties for acceptability to aircraft materials. Water itself is not corrosive, but may be rendered corrosive by the addition of antifreeze solutions. Specialized dry powder and monammonium phosphate dry chemical are corrosive to most sensitive electronic components and instruments.
b. Material Compatibility. Halocarbon clean agents can be used in numerous aircraft applications and it is important to review the materials of construction for compatibility when designing new equipment, retrofitting existing equipment, or preparing storage and handling equipment to incorporate halocarbon clean agents. Materials that should be considered include metals, elastomers, and plastics. Halocarbon clean agents or water should never be discharged on Class D (burning metal) fires. These agents may react vigorously with the burning metal.
See paragraph Ib above for the exception: Lithium battery fires involving carry-on appliances.
c. Corrosivity of Decomposition Products. The thermal decomposition products of halocarbon extinguishing agents are corrosive, particularly the acid halides: HF, HCI and HBr.
The decomposition products of burning aircraft materials are also corrosive. Yet decomposition products are minimized by quickly extinguishing the fire. Acid halide production is also based on the agent used and the size of the fire.
What are the Operating Temperature Tolerances?
Halocarbon clean agent extinguishers should operate properly after being conditioned at -40°F (-40°C) or -65°F (-54°C) as applicable and 120°F (49°C) for 16 hours as specified in U.S. - UL 2129 or U.S. - UL 1093, as applicable. Water extinguishers should be protected to -40°F (-40°C) by adding antifreeze and stipulated on the extinguisher nameplate.
Cold operation may require additional consideration in the selection of an extinguisher. This is particularly true for general aviation aircraft in extremely cold climates.
The hidden fire extinguishment tests in the MPS were conducted on halocarbon extinguishers equilibrated to 70°F. More agent, a lower boiling point agent, or an extinguisher design change, may be needed to extinguish hidden fires. Testing may be needed to select an appropriate extinguisher. The boiling points of the halocarbons (at 1 atmosphere) listed in this AC are:
(1) HCFC Blend B = 80.6°F (27.0°C),
(2) HFC-227ea 1.9°F (-16.4°C),
(3) HFC-236fa = 29.5°F (-1.4°C),
(4) Halon 1211 = 26.0°F (-3.4°C), and
(5) Halon 1301 = -72.0°F (-57.8°C).
6. General Guidelines for Hand Fire Extinguishers.
a. Consider the effects of agent toxicity, aircraft ventilation, agent stratification and hypoxia when selecting and sizing the necessary fire extinguisher for your specific application.
Chapter 4 of this AC provides more details.
Provide the required minimum number of hand held extinguishers. See chapter 5, paragraph 4 of this AC. All extinguishers must have the proper U.S. - UL rating, even in spaces where the safe use guidelines, as outlined in chapter 4 paragraphs 2, 4, 5, and 6 of this AC, are exceeded. The failure to extinguish a fire has catastrophic consequences for all aircraft occupants. Agent toxicity should be considered secondary to the immediate need to extinguish the fire.
Follow the safe-use guidance recommendations in chapter 4 of this AC for selecting extinguishers for your aircraft compartments to, "...minimize the hazard of toxic gas concentration...", mentioned in 14 CFR §§ 23.851(c)(2), 25.851(a)(8), and 29.851(a)(3).
d. Do not substitute two smaller extinguishers for one extinguisher of the proper UL rating, except as provided for accessible cargo compartments, as noted in chapter 4, paragraph 5c of this AC. The fire can grow quickly prior to the discharge of the second extinguisher.
e. Due to the relatively short discharge time of hand fire extinguishers: a U.S. - UL 5B and a U.S. - UL 1A: 10B:C rated extinguisher at approximately 8 seconds; and 13 seconds for a U.S. - UL 2A:10B:C extinguisher; training on the proper use of the fire extinguishers is very important.
f. For access to under seat, overhead, and other difficult to reach locations, hand extinguishers equipped with a discharge hose or adjustable wand mounted directly to the extinguisher are highly recommended. A discharge hose or adjustable wand is preferred because it is likely to result in the extinguisher being properly held in an upright position during use and provides a means of directing a stream of agent to more inaccessible areas. Adjustable wand or fixed nozzle extinguishers allow for one-handed use. See AC 120-80 for more details and guidance on in-flight fire fighting. A video for flight crew training is available from the FAA.
The title of the video is "Aircraft In-flight Fire Fighting." The tape version of the video is referenced as "MST 730" and the DVD version is referenced as "MST 730.01." It can be obtained from Dale Dingler, FAA William J. Hughes Technical Center, Advanced Imaging Division, AJP-7960, Atlantic City International Airport, NJ 08405, phone: (609) 485-6646, email:dale.dingler@faa.gov. The in-flight training video is also available at the following public website: http://www.fire.tc.faa.gov/2007Conference/session_details.asp?sessionID=26.
g. U.S. - UL 5B:C extinguishers should have no less than an & foot (3 m) throw range (passing the MPS seat tests assures a 8 foot throw range). Longer throw ranges of 10 feet and greater provide a significant advantage in fighting fires in large transport category aircraft. See appendix 4, paragraph 1 of this AC for more information on replacement agent throw ranges.
h. Halocarbons that are gaseous upon discharge have a more limited throw range.
Halocarbons have discharge characteristics dependent on the halocarbon, nozzle design, extinguisher super pressurization, cold soak times, and operational temperatures.
7. Replacement of TSO Water Extinguishers:
a. Halon replacement extinguishers with a minimum rating of 5B:C can be used in place of required technical standard order (TSO) C19 water extinguishers, if you can show that the replacement extinguisher has comparable or better Class A extinguishing performance than the TSO'd water extinguisher. A TSO C19 water extinguisher can fight small Class A fires but are not large enough to have a 1A rating. The halon replacement extinguisher must have a sufficient throw range to extinguish fires likely to occur.
b. For aircraft that are required to carry two or more extinguishers and two water extinguishers are in close proximity, the two water extinguishers may be replaced by one halon replacement extinguisher. This is allowed only if the extinguisher has been shown to have comparable or better Class A fire extinguishing capability as both water extinguishers and a sufficient throw range to extinguish fires likely to occur.
Chapter 4. Safe Use of Hand Fire Extinguisher
1. What Basic Fire Fighting Training Should be Provided?
a. Flight crewmembers should be trained on the urgency of immediate and aggressive extinguishment of an onboard fire. As fires can grow exponentially with time, the risks of exceeding the hazardous concentration levels of extinguishant are considered minimal compared to the risks of an in-flight fire.
(1) Quickly extinguish the fire.
(2) Immediately turn off all air recirculation systems, as permitted by your flight manual.
b. Train flight crewmembers on the proper use of hand extinguishers. See AC120-80, In-Flight Fires, for additional guidance. A training video on the use of hand extinguishers to fight on-board fires is available at the following website:
http://www.fire.tc.faa.gov/2007Conference/session_details.asp?sessionID=26.
c. Operators should ensure that all crew members receive proper training in the appropriate use of hand fire extinguishers onboard their aircraft
d. Attack the base of the fire at the near edge of the fire and then move the fire extinguisher nozzle with a side-to-side sweeping motion, progressing toward the back of the fire.
The optimum firefighting technique differs for each approved extinguisher.
e. Do not direct the initial discharge at the burning surface at close range, if the burning material might splash and/or splatter.
Lithium Battery Fires. Crew members should be trained not to treat a small number of lithium batteries as a Class D fire. Halon, Halon replacement, or water extinguishers can be used to control fires involving a small number of rechargeable lithium batteries as found in PED e.g. laptop computers, cell phones, pagers, audio/video/data recording or playback devices, messaging devices, PDAs, and two-way radios. Water or other water based liquid from any available source should be poured over the cells immediately after fire knockdown or extinguishment, since only water or water based liquids can provide sufficient cooling to prevent re-ignition and/or propagation of the fire to adjacent cells of the battery pack. A water extinguisher, by itself, can be used safely (from a distance) to extinguish a lithium battery fire and will usually cool it sufficiently to end the event. If needed, it can be followed up by water from any available source.
(1) Crew members should be trained not to use fire resistant burn bags to isolate burning Lithium batteries. Transferring a burning appliance into a bur bag may be extremely hazardous.
(2) See SAFO 09013 and the training video referred to in paragraph 1b above for further guidance on how to fight Lithium battery fires.
2. What are Some General Guidelines for the Safe-Use of Halocarbon Extinguishers?
a. Quickly Extinguish the Fire. Although exposure to halocarbon agents and their decomposition products are a concern, it is far less of a concern than the consequences of an unextinguished in-flight fire. It is critically important to quickly extinguish an in-flight fire. The consequences of an unextinguished in-flight fire include the loss of the aircraft and its occupants and immediate toxic hazards from exposure to thermal decomposition products of the burning materials, including carbon monoxide, hydrogen cyanide, smoke, heat, and subsequent oxygen depletion.
b. Control Exposure to Combustion Gases and Halocarbon Vapors. The following guidance is affected by and may be adjusted for agent stratification and localization, as discussed in chapter 4, paragraph 4b(4).
(1) Turn off all air recirculation systems immediately, if allowed by your aircraft flight manual (AFM) or flight crew operations manual (FCOM). Halocarbon agents are much heavier than air and under most conditions they stratify with time at lower levels. Turning off the recirculation allows the agent entering the low level air returns to be directed to the air outflow valves and out of the aircraft. This increases the rate of agent removal from the aircraft.
Some aircraft have up to 50% recirculation, so it is important to turn off the air recirculation quickly.
(2) While it is impossible to accurately predict the hazard level in most situations, try to avoid selecting extinguishers that could result in exposure to halocarbon vapors above the safe-use levels. Exposure may result in dizziness, impaired coordination, reduced mental acuity, and heart arrhythmias.
(3) Halocarbon agents also decompose when they contact open flames or hot surfaces. The decomposition products have a characteristic sharp, acrid odor, and an eye irritating effect, even in concentrations of only a few parts per million. See Annex A, Paragraph
1.5.1.2 and 5.7.1.2 of the standard in appendix 3, paragraph 11d of this AC, or the most current revision, for more detailed information on the effects of neat agent and hydrogen fluoride (HF) respectively, as well as further discussion of factors affecting the formation of thermal decomposition products.
c. Use Portable Protective Breathing Equipment (PBE). In compartments where extinguisher(s) are used that do not meet the sate-use guidance in this AC, flight crewmembers should use portable PBE, if available and/or as directed by FCOM procedures or AFM.
Unprotected personnel should not enter a protected space during or after agent discharge, until ventilated. Crewmembers should follow fire fighting procedures when using portable PBE. See paragraph 5b below for additional information on portable PBE use in cargo compartments.
d. Ventilate the Compartment.
(1) When you are reasonably sure the fire is extinguished, ventilate the compartment overboard at the highest possible rate allowed by established crew procedures for your particular aircraft to rid the cabin and flight deck of hazardous gases and smoke. Stay alert when increasing airflow, if the fire is not completely extinguished or smoldering, increasing airflow could promote fire growth.
(2) Small aircraft lack some of the safety advantages available to large transport category aircraft. Large aircraft with small volume occupied spaces (flight decks) have a forced ventilation system, availability of supplemental oxygen (quick donning oxygen masks), and a copilot available. Therefore, operators of small unpressurized aircraft should open a window, if at all possible.
3. How to Prevent Hypoxia in an Unpressurized Aircraft. You can avoid life-threatening hypoxia (low oxygen) hazards that may result from the discharged halocarbon agent displacing air in unpressurized aircraft, by following the descent, ventilation, and supplemental oxygen guidance below. See the report referenced in appendix 3, paragraph 7m of this AC for information on the development of the guidance below.
a. Extinguish Fire and Ventilate Cabin. As mentioned above, make sure the fire is completely extinguished. To rid the cabin and flight deck of hazardous gases and smoke, ventilate all unpressurized aircraft compartments overboard at the highest possible rate allowed by established crew procedures for your particular aircraft. If the fire is not completely extinguished, or a smoldering fire exists, increasing airflow could promote fire growth
b. Descend to Lower Altitudes. Immediately descend at the maximum safe rate to 8,000 ft. or to an altitude that is as low as practicable. Descending dilutes agent concentration, lowers exposure to agent and combustion gases, and increases oxygen concentration. We recommend descending regardless of the amount of agent used, the aircraft size, or ventilation rate. Aircraft with a maximum flying altitude of 12,500 ft. are protected from hypoxia, without the need for supplemental oxygen, by immediately descending as described above.
c. Use Supplemental Oxygen. Use of supplemental oxygen can prevent hypoxia.
However, if a supplemental diluter demand personal oxygen system at CPAs above 12,500 ft., a nasal cannula up to and including 18,000 ft CPA, or an oral-nasal mask between 18,000 ft. and 25,000 ft. CPA are used, the user will not be fully protected from hypoxia. This lack of protection is because the oxygen flow control for these systems is based on pressure altitude, not oxygen partial pressure.
(1) Occupants flying at altitudes above 12,500 ft. should immediately switch their masks or nasal cannula to the maximum flow of oxygen, if so equipped, to get additional protection during the time it would take to exchange the air in the compartment three times.
(2) Fingertip probe oxygen sensors should be used with oxygen systems on unpressurized aircraft with maximum flying altitudes above 12,500 ft. These devices provide user feedback on the effects of hypoxia after halocarbon agent discharge such that the wearer can increase the oxygen flow to their breathing device to compensate for the hypoxia.
(3) Unpressurized aircraft are allowed to use nasal cannula supplementary oxygen systems up to 18,000 ft. altitude. These systems provide no protection to a wearer when he or she breaths through the mouth, which can occur at times of stress.
4. What are the Guidelines on the Selection of Halocarbon Extinguishers?
Extinguisher Performance. Primary consideration in selecting a fire extinguisher should be performance, size, and weight (see appendix 4, paragraph 3 of this AC), hardware configuration, extinguisher throw range (see appendix 4, paragraph 1 of this AC), ease of use for novices, commercial availability of the agent, and environmental issues (ODP and GWP).
Special consideration needs to be made for cold temperature operation, as noted in chapter 3, paragraph 5b of this AC. Agent physical and chemical properties may also be considered.
Toxicity/Human Exposure. As mentioned previously, human exposure to halocarbon agents is a concern and needs to be addressed as noted in paragraph 2b above.
However, it is far less of a concern than the consequences of an unextinguished in-flight fire.
From a hazardous exposure perspective, you may elect to select a halocarbon hand extinguisher using the safe-use W/V guidance (based on perfect mixing) described below for your specific compartment size. Safe-use W/V guidance provides an objective scientific evaluation of the currently approved agents.
(1) The exposure hazard presented by the decomposition products of the agent may be considered when choosing a fire extinguisher for a particular installation.
(2) Safe-use W/V guidance for various air change times, assuming perfect mixing, is presented in appendix 4, paragraph 2 of this AC. The methodology used to develop the safe-use W/Vs of halocarbon agents and their blends was developed in the report referenced in appendix 3, paragraph 7m of this AC. The safe-use W/V guidance is based on the discharge of the largest extinguisher in a compartment at 70° F at the aircraft certificated CPA.
(3) These safe-use W/Vs may be used as general guidance and are based on perfect mixing gas concentration histories. This safe-use W/V guidance is not rigid, as there are many variables that can affect the agent concentration histories. Actual concentrations encountered by occupants may be significantly lower than would be encountered if there was perfect mixing depending on agent stratification, air distribution, air flow, and geometry of a particular aircraft/aircraft compartment and may be adjusted accordingly.
Agent stratification/localization within a compartment, as mentioned in paragraph 4b(3) above, will be addressed in a report to be published at the FAA Technical Center. This report will provide limited examples and the method to properly adjust the safe-use concentrations for those examples. See appendix 4, paragraph 2a(4) 17
(5) For unpressurized aircraft, you should consider safe-use guidance for the highest altitude for which the aircraft is certified.
(6) The cabin is considered and referred to as a compartment. The total charge weight of the largest extinguisher divided by the compartment volume should not exceed the safe-use W/V.
(7) In a pressurized aircraft (6000 to 8,000 ft CPA), the hypoxic hazard is minimal for the safe-use concentrations for the halocarbon agents in this AC. Immediate descent is not necessary. Pressurized aircraft benefit (increased oxygen and decreased agent concentrations) only from descent to altitudes below the CPA. The worst case oxygen equivalent CPA for pressurized aircraft using the safe-use W/V guidance provided in this AC is 10,000 ft at 2 minutes after discharge when 8,000 ft CPA is maintained. However, landing as quickly as possible is always recommended when an onboard fire is suspected.
c. Relative Agent Toxicity. You may want to consider the relative toxicity of extinguishers in Figure 1 below when selecting an extinguisher. Figure 1 shows the normalized toxicities of approved 5B:C extinguishers relative to the NOAEL-based toxicity of a 5B:C Halon 1211 extinguisher. These normalized toxicities are based on exposure to neat (un-decomposed) agent using 3 different measures: NOAEL, Safe Human Concentration and LOAEL.
Figure 1. Relative Toxicity of 5 B:C Halocarbon Extinguishers
1.3
• NOAEL Basis 1 • Safe Human Concentration Toxicity of 5 B:C Extinguishers .9 Basis Relative to Halon 1211 • LOAEL Basis 2
0.0 Halon 1211 Halon 1301 HCFC Blend B HFC-227 ea HFC-236 Agent
d. Minimum Safe Volume. Alternatively, you may consider minimum safe volumes to make your extinguisher selection. In this case, the minimum safe volume of one extinguisher is obtained by dividing that extinguisher's charge weight by the safe-use agent W/V for the appropriate altitude and ventilation (See appendix 4, paragraph 3 of this AC).
5. How to Safely Use Halocarbon Extinguishers in Accessible Cargo Compartments.
a. Unsafe Concentrations of Extinguishing Agent. 14 CFR § 25.857 and § 29.855(d) require aircratt to be designed to prevent the harmful accumulation of smoke, flame, extinguishing agent and noxious gases from entering occupied areas. Airplane Flight Manual (AFM) fire fighting procedures should state that the crew member should close the Class B cargo compartment door after extinguishing a fire.
When to Use Portable Protective Breathing Equipment (PBE). Portable PBE should be worn before entering the cargo compartment and attempting to extinguish a fire, as outlined in 14 CFR § 25.1439. Note that AFM and/or Crew Operations Manual are required to have the appropriate procedure including calling out the use of portable PBE and other emergency equipment necessary to fight a fire.
Compartments Under 200 Cubic Feet. Halon replacement extinguishers should have a minimum fire rating classification of U.S. - UL 2A:10B:C for accessible Class B cargo compartments, combination passenger/cargo (combi) and cargo airplane/rotorcraft. The fire threat for accessible cargo compartments is primarily from Class A fires. Usually, one extinguisher with a U.S. - UL 2A: 10B:C rating is sufficient to fight most fires likely to occur.
(1) Multiple hand-held fire extinguishers may be shared to comply with the cabin and accessible Class B cargo compartment regulations, if they are located where a person fighting a fire in the compartment could quickly retrieve them and continue fighting the fire with minimal delay between the discharges. It must be demonstrated that the extinguishers, as installed, can extinguish 2A and 10B:C rated fires. The combined rating is to be determined by performing the UL 711 fire tests by discharging the extinguishers with a delay between the end of each extinguisher's discharge and the start of the discharge of the next extinguisher based on the location of each extinguisher and an assessment of factors such as:
(a) The manpower available to fight the fire. If two trained crew members are available to fight the fire, it may be possible to avoid a delay between discharges of the extinguishers.
(b) The time to recognize the completion of the discharge, to walk to the location of the next bottle, remove it from it's mounting bracket, pull the pin, return to the cargo compartment, position the extinguisher to continue to fight the fire and initiate discharge.
(2) The rating is based on UL 711 performance tests, not agent weight, as the agent weight is not sufficient to predict performance. Nozzle design, super pressurization and other factors affect performance. The UL fire tests can be preformed by the applicant or an approved test laboratory such as UL.
Note: The recommended extinguisher rating of 2A: 10B:C is lower than the 2A:40B:C rating in AC 20-42C. This is because the fire threat for accessible cargo compartments is primarily from Class A fires. The prior guidance in AC 20-42C was based on the need for at least a 2A rating for class A fires using a Halon 1211 extinguisher to extinguish a fire. Halon 1211 extinguishers that have a class A rating of 2A also have a 40B:C rating. It has been determined that a 10B:C rating is more then adequate for the type and size of class B and C fires likely to occur in a Class B cargo compartment.
Compartments Over 200 Cubic Feet. Accessible cargo compartments of 200 ft3 and larger, in combination passenger/cargo and cargo aircraft/rotorcraft, should comply with the requirements of the FAA Airworthiness Directive (AD) 93-07-15. This AD specifies acceptable forms of fire protection equipment and operational procedures. The options provided include converting the compartment to meet the requirements of a Class C cargo compartment, use of hand-held fire extinguishers, or the use of fire containment containers or covers, fire extinguishing systems and smoke or fire detectors.
(1) If you elect to use hand fire extinguishers provide the following:
(a) A minimum of three U.S. - UL listed Halon 1211 or its equivalent 2A: 10B:C hand held fire extinguishers (equivalent to the AD's requirement of 48 Ibs. of Halon 1211) readily available for use in the cargo compartment.
(b) At least two U.S. - UL 2A (2-1/2 gallon) listed water portable fire extinguishers, usually TSO C19 or its equivalent, adjacent to the cargo compartment entrance for use in the compartment.
(c) Protective garments stored adjacent to the cargo compartment entrance.
(d) Portable PBE with a minimum of 15 minutes of protective breathing, per 14 CFR § 25.1439(b)(5). This portable PBE should be TSO C116 approved or equivalent, and be stored adjacent to the cargo compartment entrance.
(2) If no extinguisher is available that meets the safe-use criteria for the aircraft/rotorcraft cabin, consider converting that cargo compartment to a class C compartment with a built-in fire suppression system, or any other technology that would provide effective fire protection. Restrict personnel from entering the cargo compartment for the duration of the flight.
How to Inspect and Maintain the Hand Fire Extinguisher for Continued Safe-Use.
Maintain and inspect hand fire extinguishers in accordance with the manufacturer's nameplate instructions. Follow the maintenance procedures, inspections and testing specified in the applicable NFPA and U.S. - UL standards.
a. Non-refillable, disposable fire extinguishers may have plastic discharge heads installed. Locate this type of fire extinguisher in a safe area to assure there will be no damage to the plastic discharge heads.
b. Non-refillable, disposable fire extinguishers are exempt from periodic hydrostatic testing. However, replace these extinguishers with a serviceable unit upon reaching:
(1) The service life where hydrostatic testing would normally be required for a similar extinguisher, or
(2) The service life guidelines established by the manufacturer if sooner.
c. Recommended procedures for the inspection, hydrostatic test and life limits of pressure cylinders are outlined in:
(1) Specification of cylinders is in 49 CFR, part 178, subpart C.
(2) Inspection and maintenance of cylinders is in 49 CFR, part 180, subpart B.
(3) Fire extinguishers are addressed in 49 CFR § 173.309 and in 29 CFR § 1910.157.
d. Manufacturers of fire extinguishers containing halon replacement agents approved for use on FAA certified aircraft should take immediate action through the appropriate channel(s) to have their retest requirements included in the aforementioned regulatory guidelines.