Basic Water Survival

1
Basic Water Survival
2
Aim

• To give firefighters an overview of survival
  physiology and in-water survival techniques.

3
Learning OutcomesAt 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.

4
What is survival

• Survival is the ability to stay alive when
  life is threatened by voluntary or involuntary
  immersion in water.

5
Survival factors
Survival difficulties can be minimised by

• The equipment available
• The action taken by the survivors or any
  bystanders.

6
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.

7
Approximate survival times

• Survival times for a clothed person

8
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.

9
Marine lifejackets

• Duncan III Lifejacket
• Used for offshore firefighting tug response
• Bulky garments with inherent buoyancy
• Do not require inflation to achieve full buoyancy.

10
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.

11
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.

12
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.

13
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.

14
Water entry
15
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.

16
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.

17
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 50F (10C) water on a calm day
• People who tread water lose heat about 30 faster
  than people holding still while wearing a life
  jacket.

18
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.

19
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

20
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.

21
Immersion hypothermia

• Knowledge of how immersion hypothermia works and
  being prepared will definitely help you to extend
  your survival time.

22
At risk situations

• Unprotected immersion in water cooler than
  60-70F (16-21C) 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.

23
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 waters ability to penetrate
  clothing, make immersion hypothermia a potential
  hazard.

24
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.

25
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

26
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.

27
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.

28
Visual distress signals

• 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).

29
Visual distress signals

• Slowly raising and lowering arms
• SOS in morse by radio
• Spoken word Mayday
• Radio-telegraph or radio alarm signal
• EPIRB

30
Means of location

• 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.

31
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.

32
THE END