Transcript No Slide Title

Basic Water Survival
Aim
To give firefighters an overview of
survival physiology and in-water survival
techniques.
Learning Outcomes
At the end of the session students will be able to:
• State the physiological effects of cold water
immersion
• Demonstrate the treatment for hypothermia
• Demonstrate in-water survival techniques
as a single survivor and in group conditions.
What is survival
Survival is the ability to stay alive when life
is threatened by voluntary or involuntary
immersion in water.
Survival factors
Survival difficulties can be minimised by;
• The equipment available
• The action taken by the survivors or any
bystanders.
Survival difficulties
• Heat lost when immersed in water is 26
times greater than the normal loss of
heat when dry
• Survival time will depend on the
protection provided, movement of the
body and build
• Alcohol and swimming increase the rate
of heat loss.
Approximate survival times
Survival times for a clothed person
32°F
15 minutes
36°F
30 minutes
41°F
60 minutes
50°F
3 hours
68°F
16 hours
Lifejackets
Well-constructed life jackets can decrease
heat loss rates by 40%-50%
Must be able to:
• Hold the mouth and nose of an unconscious
person clear of the water
• Right them from face down in no more than 5
seconds.
Marine lifejackets
Duncan III Lifejacket:
• Used for offshore firefighting tug response
• Bulky garments with inherent buoyancy
• Do not require inflation to achieve full
buoyancy.
Marine lifejackets
Crewsaver BSI 150N Lifejacket:
• Carried on selected appliances with an
identified water risk in the station area
• Contain synthetic material within the
garment but full buoyancy is not
achieved until inflated using the oral
tube.
Aviation lifejackets
• Carried by airborne response stations
• Only type of lifejacket acceptable for
helicopter travel
• Have no buoyancy until inflated
• Must not be inflated until clear of the
aircraft.
Immersion hypothermia
• No matter how warm it is above the
water, keep on wearing that life jacket!
• If you do end up in the water, it keeps
you afloat, and helps slow heat loss
from the trunk.
Water entry
• Remove any false teeth, spectacles and
sharp objects
• Get down to less than 10 m if possible
• Block off nose and mouth with one hand
brace with the other hand
• Look down and check clear below
• Stand up, look straight ahead, step off.
Water entry
Actions in the water
• Immersion hyperventilation is the first risk...
• The first few seconds of immersion in cold
water bring a breathing pattern of deep,
involuntary gasps (Gasp Reflex)
• This is followed by a minute or more of deep,
rapid breaths, with tidal (breathing) volumes
about five times normal
• Drowning can easily happen in this early
stage, especially if you are plunged deep
below the surface, or fall into rough water.
Actions in the water
• However, most people immersed in cold
water survive this initial stage
• If you have the time to exercise the choice,
enter cold water as gradually as possible
• Consciously control your breathing, if at all
possible, during entry and for the first few
minutes afterward, until the feeling of not
being able to catch your breath is gone.
Actions in the water
• Once immersed, swimming is a dangerous
choice to make
• An average person who can ordinarily swim
well probably will not be able to swim more
than 1 km (.062 mi) in 50°F (10°C) water on a
calm day
• People who tread water lose heat about 30%
faster than people holding still while wearing
a life jacket.
Actions in the water
• Any motion you make while you are in cold
water takes heat away from you much more
quickly than holding still
• Do not swim unless you need to avoid a
hazard or self rescue is easily achieved
• Get into the single survivor position to
conserve body heat
• If in a group form a huddle, any injured
persons should be in the centre.
Actions in the water
• Huddling with one or more other people will
reduce heat loss rates by about a third,
especially if chest to chest contact is
maintained
Actions in the water
• Single Survivor
• Placing your hands
under the life jacket
and raising your
knees towards your
chest will reduce
your heat loss rate.
Immersion hypothermia
• Knowledge of how immersion hypothermia
works and being prepared will definitely help
you to extend your survival time.
At risk situations
• Unprotected immersion in water cooler than
60°-70°F (16°-21°C) places you at risk of
developing hypothermia
• Injured people are more likely to develop
hypothermia than healthy people due to
shock or other complications caused by their
injuries
• Hypothermia can develop rapidly if you are
immobilized involuntarily or voluntarily.
Hypothermia
In relation to hypothermia, cold water has two
specific threat characteristics:
• Extreme thermal conductivity (the rate at
which it can conduct heat away from you)
• The specific heat of water (the large amount
of heat needed to raise water temperature)
• These, plus water’s ability to penetrate
clothing, make immersion hypothermia a
potential hazard.
Hypothermia
Diagnosis
• Subject cold to touch
• Subject looks cold (blue)
• Subject may be shivering
• Subject shows signs of abnormal
behaviour
• Subject is aggressive, speech slurred.
Treatment
• The coldest part of the body is always
the surface
• Blood that has passed under the
surface during a slow re-heating will be
cooled
• This will further lower the core
temperature, with possible fatal results
Treatment
• Rapid re-warming should not be undertaken
except under medical supervision
• This may cause circulatory collapse with
fatal results
• Spontaneous re-warming allows the victim to
re-warm using their own body heat
• Wrap victim in blankets and allow them to
slowly re-heat using their own body heat.
Treatment
• Do not under any circumstances use foil
emergency blankets
• This is similar to wrapping a frozen
chicken in tinfoil and expecting it to
defrost.
Visual distress signals
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Gun or other explosive signal (1min intervals)
Continuous sounding of any fog apparatus
Rockets or Flares throwing red stars
International code N.C
Square flag with ball above or below
Flames on a vessel
Parachute or hand flare
Smoke signal (orange smoke).
Visual distress signals
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Slowly raising and lowering arms
SOS in morse by radio
Spoken word ‘Mayday’
Radio-telegraph or radio alarm signal
EPIRB
Means of location
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Nimrod Aircraft (1 hour readiness)
Rescue Helicopters (15 min to 1 hour)
Ships in the vicinity
RNLI rescue craft.
At night or poor visibility, nimrod will
show green flares
Survivors answer with red flares.
Confirmation
Assessments will be based on this lesson and
the corresponding study note:
• State the physiological effects of cold
water immersion
• Demonstrate the treatment for
hypothermia
• Demonstrate in-water survival
techniques as a single survivor and in
group conditions.
THE END