equipment Flashcards
Normal breathing air ratio for nitrogen and oxygen
N: 79 O: 21
what is nitrox?
when oxygens percentage is over 21%
what does nitrox36 mean?
36% oxygen
advantages of nitrox
if using a normal dive computer then greater safety margins so reduced DCI incident
increased bottom time when using a nitrox computer
disadvantages of nitrox
in o2 servicing needed
increased risk of oxygen toxicity
only shallow diving
buddy check
Air: air fully on then 1/4 turn back. octupus and normal reg both taste fine, gauge pressure doesn’t drop when you breathe in and out
BCD: jacket holds pressure, dump valves, inflate + deflate button, Inflate and deflate on drysuit
W: weights right hand release
final check: rest of kit (hood, gloves, fins, mask, buddyline, SMB, knife)
downstream vs upstream valves
downstream: 2nd stage fails YES air to diver
upstream: 2nd stage fails NO air to diver
problem with spare air method
fits HSE regs but doesnt supply enough air for safety/ DCI stop as only lasts 2 mins at 10m
what is aqualung
Equipment to allow diver to breathe air underwater
Air cylinder, BCD (+ harness), regs
what is a cross flow valve?
pressure on both sides of the valve
what is a burst disk?
Pressure relief valve
anti debris tube on cylinder?
No dust into reg when in a head down position
A clamp vs D clamp
A clamp needs an insert into a D clamp
A from both sides
D clamp safer
DIN200 vs DIN300
din 300 fits din300 + din 200
din200 only fits din 200
what does SMB stand for?
Surface marker buoy
what is ‘in o2 servicing?’
all parts are oxygen compatible and clean (nitrox)
disadvantages of nitrox with equipment
needs special serving
easily contaminated
how often does nitrox equ. need serving?
12 months
with commercial diving what percentage of o2 requires in o2 serving
over 25 %
Air cylinder standards
Competent diver needs to check their cylinder every … hrs
6 hrs
Periodic air cylinder inspection is every … years
2.5 years from manufacturer date
Periodic inspection and hydrostatic test is every … years
5 yrs
B+W tab on cylinder vs blue tab
B+W normal breathing air
Blue - nitrox
On an air cylinder what does MOD stand for?
Max breathing depth
Anything over …% of o2 must be o2 cleaned and serviced
25 %
IDEST stands for
Inspectorate of diving equipment serving and testing
PIAT stands for
Periodic inspection and test
Air cylinder normal bar pressure
232 bar
Aluminium vs steel cylinder
Aluminium is resistant to corrosion but bigger
Steel is smaller (less buoyant) but stronger
What does WC stand for
average WC sizes
Water capacity
10, 12, 15 litres
What does WP stand for?
Average WP
working pressure
207, 232, 300 Bar
what does cp stand for
standard size
capacity pressure
207, 232, 300 Bar
What does PS stand for
Pressure in service
What does PT stand for
Pressure cylinder is tested too
