Oxygen Flashcards
why is oxygen important
lack of oxygen leads to hypoxia
physiological Effects
above 33,000ft, the effects of hypoxia start to take effect. above 40,000ft the effects are more noticeable
altitude effects with Oxygen at 30,000ft
Will full supply, no ill effects
altitude effects with Oxygen at 35,000ft
With undilute oxygen, judgement and mental reactions, unimpaired
altitude effects with Oxygen at 38,000ft
You can go above this height without pressurisation
altitude effects with Oxygen at 43,000ft
Max alt with appropriate breathing equipment, can provide get down protection
altitude effects with Oxygen at 63,000ft
without suitable pressurisation, bodily fluids boil at this height
Pressure breathing equipment
aircrew personal equipment and the a/c oxygen supple must be capable at providing the same condition as that encounter at 40,000ft when breathing undiluted.
does this with pressure breathing, personal equipment and demand type regulators are used. 3 seconds after the loss of cabin pressure these systems will kick in.
Altitude effects without oxygen at 4000ft
Night vision effected
Altitude effects without oxygen at 10,000ft
Efficiency not seriously effected
Altitude effects without oxygen at 15,000ft
Danger zone; over confidence and judgement affected
Altitude effects without oxygen at 20,000ft
Loss of coordination, double vision and danger of collapse
Altitude effects at without oxygen at 25000ft,
loss of consciousness after 25000ft, followed by death
Pressure suit
must be worn to simulate pressurised cabin. all military a/c capable of 40,000ft are fitted with cabin pressurisation and the pressure equiptment is only used in emergency
Effects on breaking cabin pressure (combat damage)
Since the pressure difference is so big suitable equipment must be worn to protect in the event that the cabin pressure is broken.
Oxygen sources.
O2 is stored either in a gas form or liquid form, depending on the system. its highly volatile when it contacts oil, grease or any petroleum.
Must be 99.5% oxygen whatever the supply is and not contain more that 0.005mg of water per 1L of O2.
cant use other types of oxygen in a/c as they contains impurities which isnt suitable for breathing.
Gaseous oxygen
Most commong form because its easy to work it and transport plus its available at most airports., disadvantage as you dealing with compressed gasses and the weight of the cylinders.
Liquid oxygen (LOX)
Most military a/c carry LOX, expansion ration is 7 times greater than gas oxygen. need less space that gas systems but has its own problems when handling low temp liquids. needs to be refilled often because it losses from venting systems.
Chemical or solid O2
Convenient method of carrying O2. many large a/c use solid oxygen generators as a supplemental source of O2. consist of a shapes block of chemical like sodium chlorate encased in protective steel case.
How Chemical or solid O2 systems work
chemical is ignited and O2 is a by product of this. ignited by electrically or mechanically. safe to use and store because no high pressure is involved, downside being that the heat generate is enough to cause damage if its not dissapated correctly.
Mechanically seperated O2
new process thats extracting O2 from the air by a mechanical process. air pull into molecular sleeve, nitrogen is caught oxygen rich gas passes through.
appears to replace all other types because economy of weight and space and A/c isnt dependant on ground facilities.
O2 Warnings and safety.
Dont mix Aviation O2 with other types as they have a higher water precentage which would freeze
dont smoke near 02 station
dont use oil, grease etc near compresed 02 as it will combust
clean thoroughly and in accordance with regs
use approved adhesives and compounds only
use protective caps , sealed in polythene bad to stop damage from FoD
use only certified materials to stop contamination, dont be lax
only use specified lubes
only refill to set pressures to avoid damage to containers
read health and safety
02 storage
only fill between 1800 and 2400 psi and there are safety systems in place to stop failure. pressure reducing valves etc. often repeat pipework to stop 1 leak causing failure
Standard O2 system layout order
Charging vavle filter NRV to O2 tanks. (O2 tanks have cylinder valve) Filters content valve reducing valve delivery
Continous flow
provides the earliest method of supplying oxygen. however its wasteful because it continuous. sometime used as emergency supplies
Demand oxygen
fixes the downside of the continuous flow system., pressure demand system which varies the flow by the inspiratory rate of the user
most are demand systems, design and principles are all the same. can be panel mounted, man mounted and seat mounted
02 regulators continuous flow
Low demand systems, Allows 02 from storage cylinders regardless of how much you breathing, simple and low cost. used when mask drop from ceiling in airlines.
02 regulators Pressure demand
02 is fed from storage systems to demand regulators. amount depends on how much the user is breathing, the amount of oxygen is increased the higher the alt.
3 switches on pressure demand regulator
-on/off lever, normally wire locked in ON position
-Normal/100% lever, allow 100% 02 regardless of alt
because of blanking off of air mix valve
-emergency /press to test mask toggle, allows delivery of additional pressure at all alts
Distribution (panel mounted)
For seat mounted, delivery pipe work routed from 02 source via regulator which is panel mounted. hoses ether mount directly into seat or straight in PEC. inlet then goes into mask hose
Distribution (seat mounted)
02 hoses passes mask and goes into man portion
02 distribution order (non ejector seat)
Source
Reg p-m (panel mount)
mask
02 distribution order ( ejector seat)
Source
reg p-m
pec
mask
or source PEC reg s-m PEc Mask
or
Source
PEC
reg-m-m
mask
Wide bore 02 hoses
only used after pressure is stepped down. made of natural or vulcanise rubber, reinforces by galvanised steel wire and covered in rubber gauze. anti kink and multiple connector available
Flow indicator
tappings allow the variations in pressure to operate flow indicator
contents indicator
remote connector attached to liquid 02 systems to see the pressure. Gauge operated in pressure but calibrated in quantities of FULL
charging
only use certified equipment and charge to full pressure. high pressure 02 canisters are dangerous to everyone
dont let
Why cant canisters be completely emptied
Air can get in and create moisture, leading to corrosing in canister. this can free inside the mask and can fail with catastrophic results.
