Chapter 4 - Gases under pressure Flashcards
(17 cards)
Combined gas law
PV/T = k (k is constant)
Boyles Law
the pressure of a gas is inversely proportional to its volume when temp remains constant. Helps us mitigate barotrauma
Charles Law states
the volume of a gas is proportional to its absolute temp at constant pressure.
Gay- Lussacs law
Pressure of a gas is proportional to temperature. e.g when quickly filled, cylinders will heat up.
Henrys Law
when a gas and liquid are in contact gas will dissolve into liquid linked to decompression sickness.
Daltons Law
the total pressure exerted is equal to the sum of the partial pressures of the individual gases.
Daltons triangle
partial pressure of gas (bar)/(fraction of gas (e.g 0.2 if 20%) x absolute pressure (bar)
Management of narcosis
Immediate return to shallow depths
Oxygen Toxicity Types (2)
CNS - short term disorder caused by breathing oxygen at a raised partial pressure
Pulmonary - Caused by breathing oxygen with a pressure of 0.6 bar or over for a long period.
What is VENTID?
Way to measure oxygen toxicity
What does VENTID stand for?
Visual disturbance, ears, nausea, twitching of face, irritable, dizziness
First indication of CNS Oxygen toxicity is often…
convulsions
Pulmonary Toxicity symptoms
Coughing, sore chest, pneumomnia-like condition.
What is the disadvantage of nitrox?
Increases partial pressure of oxygen s (up to a max of 1.4) which can cause hyperoxia or oxygen toxicity.
EAD formula
Equivalent air depth = (((1-O2% decimal) x (absolute pressure))/0.79) - 10
When should nitrox equipment be serviced?
12 months
