How does 1211-1301 Halon work?

Fire needs three elements to prosper; fuel, oxygen and heat. The most common extinguishing agents like water, carbon dioxide, dry chemical and foams attack the fire physically, deprive the fire of one or more of the three critical elements needed for propagation. Halon differs from all other extinguishing agents in the way it puts out the fire. It offers some of water's cooling effect and some of carbon dioxide's smothering action, but its essential extinguishing technique lies in its capacity to chemically react with the fire's components. It actually interrupts the chain reaction of fire -- a process known as "chain breaking".

1211-1301 Halon Certificates of Conformance.

NFPA provides a Certificate of Conformance with every aviation distributor's order. Below is a sample Certificate of Conformance:

This is to certify that the following 1211-1301 Halon Fire Extinguishers are rated and listed by Underwriter's Laboratory. These units meet A.N.S.I./UL Standards 711 and 1093 as tested and are listed by Underwriter's Laboratory.
   

Model #	RT A400	RT A600	RT A1200
U/L Rating	2B:C	2B:C	5B:C
Agent Weight	14 oz	1 lb 3oz	2 lb. 8 oz.

What are the advantages of Halon blend over 1211?

1. Studies conducted by Factory Mutual (in 1975) demonstrated that the blend of Halon 1211 and 1301 is much more effective than either 1211 or 1301 alone. The optimum blend of 1211 and 1301 possesses up to 50% more fire kill capability, than 1211 alone.

2. Less leakage. 1211-1301 Blended fire extinguishers maintain their pressure when used. Since the Halon molecule is larger than the nitrogen molecule, the blended units experiences less leakage around the valve and "O" rings.

3. The Halon 1211-1301 fire extinguisher does not require a gauge, whereas the Halon 1211 fire extinguisher requires a gauge and ongoing maintenance and recharging.

How safe is 1211-1301 Halon?

Extensive toxicity evaluations have been compiled by nationally recognized US Medical laboratories & institutions on Halon 1301 and 1211. These evaluations have shown that Halon 1301 is the safest extinguishing agent available, and that Halon 1211 is the second safest. Dual Halon concentrations of about 5% by volume in air are adequate to extinguish fires of most combustible materials. This concentration is equivalent to emptying twelve (12) 2.5 lb units in a closed room of 1000 cubic feet, which would be highly unlikely.

Is a "Gauged Unit" required by the FAA?

How should the Halon blend be inspected and maintained?

• In FAA Advisory Circular 20-42C dated 3/7/84 titled "Hand Held Extinguishers for Use in Aircraft", it states:
  "Disposable type fire extinguishers should be maintained and inspected in accordance with the nameplate instructions".

• The nameplate instructions for the RT A1200 are:
  "Inspect monthly or more frequently. Ensure nozzle is not obstructed and safety seal is intact. To be installed, inspected and maintained in accordance with NFPA no. 10. Return to manufacturer... if gross weight is below 1420 grams" (2½ lb. f/e gross weight).

• NFPA no.10 states in Chapter 4 "Inspection, Maintenance, and Recharging" the following:
  "Inspection is a "quick check" that an extinguisher is available and will operate. It is intended to give reasonable assurance that the extinguisher is fully charged and operable. This is done by seeing that it is in its designated place, that it has not been actuated (discharged) or tampered with, and that there is no obvious physical damage or condition to prevent operation... Determine fullness by weighing or "hefting."
  "Extinguishers shall be subjected to maintenance not more than one year apart ... During annual maintenance..., such extinguisher shall be thoroughly examined externally in accordance with the applicable items of 4-4.2(a) mechanical parts."

• Regarding RECHARGING, the 1211-1301 HALON requires no recharging.

Advisory Circular 20-42C "Hand Fire Exting. for Use in aircraft"

• These excerpts relating to 1211-1301 Halon are taken from the above mentioned AC which "provides methods acceptable to the Administrator for showing compliance with the hand fire extinguisher provisions in Parts 25, 29, 91, 121, 125, 127, and 135 of the FAR."
  
  "For occupied spaces on aircraft, Halon 1211 extinguishers should not be less than 2½ pounds capacity. These extinguishers should have a minimum 5 B:C rating; not less than 8 seconds effective discharge time; not less than a 10 foot range..."
  
  "For occupied spaces on aircraft, Halon 1301 extinguishers should have a minimum 2B:C rating, and should have an effective discharge time of not less than 8 seconds."
  
  "Halon fire extinguishing agents approved for use include ... a combination of the two (Halon 1211-1301)."
  
  "Halon 1211 is a multipurpose, Class A, B, C rated agent effective against flammable liquid fires. Halon 1301 offers limited Class A capability when used in portable fire extinguishers."
  
  "In accordance with Section 21.305(d) of the FAR, the FAA accepts hand held extinguishers approved by Underwriters Laboratories...". Also, in accordance with Section 25.851 (601(b1) "An approved type fire extinguisher includes those approved by the Underwriter's Laboratories, Inc., Factory Mutual, Underwriter's Laboratories of Canada..."
  
  "Non-refillable disposable fire extinguishers (1211-1301) are exempt from the periodic hydrostatic test requirements."
  
  

• Advantages of Using Halogenated Agent Extinguishers
  
  " ...1211-1301 is similar to CO2 in that it is suitable for use in cold weather and leaves no residue."
  " ...1211-1301 is three times as effective as a CO2 extinguisher having equal weight of agent."
  " ...Halon 1211 and Halon 1301 leaves no chemical residue behind to contaminate or corrode aircraft parts or surfaces."
  "Other advantages of ...1211-1301 are lower cold shock characteristics on electronic equipment, no degradation of visual acuity, and lower pressure."
  
  Related FAR Sections and CFR.

A complete copy of the above can be obtained from your aviation distributor or
call NFPA at or email info@nfpa.it