EXAM Flashcards
(37 cards)
ISA MSL Pressure
1013.25hPa
At what alt is pressure half that of SL
18,000ft (still 21% oxy)
Above what alt can you expect hypoxia?
10,000ft (physiological atmosphere below)
Atmosphere is made up of?
78% Nitrogen
21% Oxy
1% Mix of other gasses (Argon)
Below which alt is air density highest?
5000ft
Pressure change with altitude
1 hpa/30ft
Explain Daltons law
Partial pressures;
States the total pressure of a mixture of gasses is the sum of the partial pressures of its components
Explain Boyles law
The relationship between pressure & volume.
As pressure increases, volume decreases & vice versa.
Explain Henrys law
(Heinekin)
States that the amount of gas that is dissolved in a liquid is directly proportional to the partial pressure of that gas. When pressure is reduced, the gas will come out of solution.
What is hypoxia
Where the body is receiving insufficient oxygen to maintain normal function.
What is TUC
The time period from the moment hypoxia sets in until you can no longer do anything about it
TUC at F250?
2-5mins
PRICE Check?
Our version?
Pressure, regulator, Indicator, Connections, Emergency.
ON, CONCENTRATION NORM, PRESSURE NORM, FLOW, CONNECTIONS
4 Types of DCS?
Bends, Chokes, Creeps, staggers
Protocol for DCS emergency
Oxy on, 100%
Mask secure
Declare emergency
Stay on Oxy
Restrictions for chamber
Nil blood donations or diving 24hrs prior
Nil vaccines 12hrs prior
4 stages of immersion hypothermia
- cold shock
- swim failure
- hypothermia
- Collapse
Why are our zoomers 3% conductive fibre?
Prevent static charge build up
Why can’t we use bleach or fabric softener?
Parrifins
What is found in the retina
Cones: Colour, sharp vision, daytime.
Rods: Black & white, movement & periherals
Symptoms of hypoxia
dizziness, nausea, air hunger, tingling, drunkenness
How does Boyle’s law apply to trapped gas?
Where would you expect this?
Volume inversely proportional to pressure.
Trapped gas in GI, Teeth, lungs.
Outside pressure decreases, so does pressure inside the body, trapped gasses expand.
How does Henrys law apply to evolved gas & therefore DCS.
Nitrogen is dissolved within the body, during Rapid decompression, bubbles come out of solution & form in peripheral tissues.
When can DCS occur?
exposure to pressures above 18,000ft and rapid decompression.
