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 TM 55-1905-223-SDC
d. Hydrogen cyanide is highly toxic and is formed when urethane, nylon, or melamine are burned.
Breathing a concentration of 0.3% is fatal. It can also be absorbed through the skin, causing the same
results. The characteristic bitter almond odor sometimes warns of hydrogen cyanide presence.
e. Hydrogen chloride is a fire gas produced during the combustion of chlorine-based plastics such as
PVC electrical cable insulation. It is absorbed in smoke and, when breathed, desorbs as hydrochloric acid
deep in the lungs. It can cause death due to lung edema.
f. Phosgene gas is highly toxic and is produced when polyvinyl-chloride, refrigerant, or other chlorinated
compounds are involved in a fire.
6-9.
FLAME. The burning of materials in the presence of a normal oxygen-rich atmosphere is generally
accompanied by flame. For this reason, flame is considered a distinct product of combustion. Burns can be
caused by direct contact with flames or heat radiated from flames. It is rarely separated from the burning
materials by an appreciable distance. In certain types of smoldering fires without evidence of a flame, heat
and smoke and gas can develop. Air currents can carry these elements far in advance of the fire.
6-10. HEAT. Heat is the combustion product mostly responsible for the spread of fire. It poses dangers
that range from minor injury to death. Exposure to heated air can cause heat exhaustion, dehydration,
blockage of the respiratory tract, and burns. Exposure to temperatures above 1300 F without respiratory
protection is extremely hazardous. One or two breaths of moisture-saturated air at such temperatures can
cause serious respiratory system damage.
6-11. SMOKE. Smoke is matter consisting of very fine solid particles and condensed vapor. These
combustion products are usually evolved from the combustible with sufficient velocity to carry with them
droplets of flammable tars which appear as smoke. Smoke provides the warning of fire and simultaneously
contributes to the fear of those in the smoke by the nature of its blinding and irritating effects. Smoke causes
eyes to water, which impairs vision and also causes irritation to the respiratory tract and uncontrollable
coughing.
6-12. ASH. Ash is the residue of burned materials. It can contain any chemical that results from the
burning of basic fuel such as hydrogen chloride and carbon fibers. It may also contain residue from fire
extinguishing agents (i.e., dry chemicals).
Section V. FIRE HAZARDS OF MATERIALS
FIRE HAZARD MATERIALS.
Several materials than can support a fire are briefly discussed here.
6-13.
a. Cable insulation. Most cable insulation contains a large quantity of polyvinyl chloride (PVC) which will
sustain combustion at 680 F when decomposed in a fire. PVC will liberate hydrogen chloride and hydrogen
cyanide gases when heated to about 390 F. These gases interfere with vision, cause intense respiratory
irritation, and may cause death due to lung edema 12 to 36 hours later. The best way to extinguish this type
of fire is to bring water
Change 1 6-3
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