Hand fire extinguisher agents

Fire classes (TC AIM AIR 1.4.2): each agent suits only some classes.

Agents and class coverage (TC AIM AIR 1.4.3):

Agent notes:

• CO2: 5 lb cap: portable, limits CO2 buildup in crew compartment.
• Water: good on fire that might smolder.
• Monoammonium phosphate:
  • Only dry chemical rated for A.
  • Nozzle must allow intermittent or continuous discharge.
  • Powder can abrade or corrode electrical insulation.
  • In crew compartment, impairs visibility, can deposit powder on live contacts not in the fire.
  • Inspect affected equipment right after use.
• Halon 1211:
  • Equally effective on A, B, and C.
  • Best agent on gasoline-upholstery fires.
  • Colourless, evaporates fast; won't freeze, cold-burn, stain, or corrode.
  • At least twice as effective as CO2.
  • Heavier than air.
  • Breakdown product stinks: hard to inhale unnoticed.
• Halon 1301:
  • Less toxic than 1211, also less effective.
  • Discharges as invisible gas, no visible stream.

Toxicity (TC AIM AIR 1.4.1):

• Groups 2 to 4 inclusive should not be installed in aircraft.
• Older aircraft: use Group 5 or above when renewing units.

Fire in flight:

• Extinguisher in closed cabin can deplete oxygen. Ventilate right after use.
• Fire can't be put out: land immediately.

Trap: Class A: water, monoammonium-phosphate dry chemical, Halon 1211 only; plain CO2, bicarbonate dry chemical, Halon 1301 are B/C only.

Practice