8. Fire, CO and explosions Flashcards
What is The Fire Triangle made of
- fuel
- oxygen
- ignition
Give examples of fuel
solid: wood, paper
liquid: petrol
3. gases: methane
Give example of ignition:
to start the fire off: flame, spark, hot sruface, radiant heat, chemical
How do people die in fire (or are injured in them)? (3)
- most common: smoke inhalation
- burn
- other injuries
what toxic gases are found within smoke (3)
a bruning fire produces a great deal of smoke. anyone alive inside will be forced to breathe it in.
the smoke contains various toxic gases:
1. CO (most people die from this)
2. cyanide
3. nitrites
Mechanism of action of carbon monoxide
- produced in all fires and a product of incomplete combustion
- toxic levels can build up very quickly
- breathed into the lungs and gets into blood stream where it combines with Hb to form carboxy-haemoglobin
- haemoglobin has a much greater affinity for CO than O2
- carboxy-haemoglobin is of no use to the body i.e. the cells cant use it, so decreasing levels of oxygen have serious effect
normal level of CO in blood and abnormal
- normal level is up to 5% particularly in cigarette smokers
- when levels build up to 50% or above, as in a fire, they are likely to be fatal
- even lower levels if person has a significant natural disease
evidence of smoke inhalation
1.soot in the airway- a lining of black soot all the way down the trachea
2. raised level of CO in the blood (makes the blood and tisses red and makes external lividity pink)
people tend to die from burning in one of two circumstances (time)
in the fire: from physiological shock (a car fire or other flashover)
later in the hospital: from fluid loss, biochemical distrubance or infection
list factors that determine survival of those reaching hospital (3)
- severity and extent of burning
- co-existing illness
- age
how do we classify burns
by depth and extent of burning
describe classification of burns by depth:
superficial, part thickness, deep
appereances range from: reddening of the skin -> blistering -> epidermal loss -> subcutaneous tissue loss
how do we evaluate extent of burning?
we use the rule of 9s
rough general rule:
if the age of the person + percentage burning is >100, they are less likely to survive
what are the possibilities of people not escaping fire?
- overcome by fumes at an early stage e.g. asleep
- intoxicated and unaware of the fire
- physically disabled, bedridden or injured
- did not want to, i.e. suicide
What are the reason a person is dead before the fire (2)
- from natural causes (and their death triggered a fire e.g. cooker or a heater left on)
- homicide (the person has been murdered and the house set on fire to conceal the crime)