equipment

Question 1

Normal breathing air ratio for nitrogen and oxygen

Answer 1

N: 79 O: 21

Question 2

what is nitrox?

Answer 2

when oxygens percentage is over 21%

Question 3

what does nitrox36 mean?

Answer 3

36% oxygen

Question 4

advantages of nitrox

Answer 4

if using a normal dive computer then greater safety margins so reduced DCI incident
increased bottom time when using a nitrox computer

Question 5

disadvantages of nitrox

Answer 5

in o2 servicing needed
increased risk of oxygen toxicity
only shallow diving

Question 6

buddy check

Answer 6

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)

Question 7

downstream vs upstream valves

Answer 7

downstream: 2nd stage fails YES air to diver
upstream: 2nd stage fails NO air to diver

Question 8

problem with spare air method

Answer 8

fits HSE regs but doesnt supply enough air for safety/ DCI stop as only lasts 2 mins at 10m

Question 9

what is aqualung

Answer 9

Equipment to allow diver to breathe air underwater

Air cylinder, BCD (+ harness), regs

Question 10

what is a cross flow valve?

Answer 10

pressure on both sides of the valve

Question 11

what is a burst disk?

Answer 11

Pressure relief valve

Question 12

anti debris tube on cylinder?

Answer 12

No dust into reg when in a head down position

Question 13

A clamp vs D clamp

Answer 13

A clamp needs an insert into a D clamp
A from both sides
D clamp safer

Question 14

DIN200 vs DIN300

Answer 14

din 300 fits din300 + din 200

din200 only fits din 200

Question 15

what does SMB stand for?

Answer 15

Surface marker buoy

Question 16

what is ‘in o2 servicing?’

Answer 16

all parts are oxygen compatible and clean (nitrox)

Question 17

disadvantages of nitrox with equipment

Answer 17

needs special serving

easily contaminated

Question 18

how often does nitrox equ. need serving?

Answer 18

12 months

Question 19

with commercial diving what percentage of o2 requires in o2 serving

Answer 19

over 25 %

Question 20

Air cylinder standards

Competent diver needs to check their cylinder every … hrs

Answer 20

6 hrs

Question 21

Periodic air cylinder inspection is every … years

Answer 21

2.5 years from manufacturer date

Question 22

Periodic inspection and hydrostatic test is every … years

Answer 22

5 yrs

Question 23

B+W tab on cylinder vs blue tab

Answer 23

B+W normal breathing air

Blue - nitrox

Question 24

On an air cylinder what does MOD stand for?

Answer 24

Max breathing depth

Question 25

Anything over …% of o2 must be o2 cleaned and serviced

Answer 25

25 %

Question 26

IDEST stands for

Answer 26

Inspectorate of diving equipment serving and testing

Question 27

PIAT stands for

Answer 27

Periodic inspection and test

Question 28

Air cylinder normal bar pressure

Answer 28

232 bar

Question 29

Aluminium vs steel cylinder

Answer 29

Aluminium is resistant to corrosion but bigger

Steel is smaller (less buoyant) but stronger

Question 30

What does WC stand for

average WC sizes

Answer 30

Water capacity

10, 12, 15 litres

Question 31

What does WP stand for?

Average WP

Answer 31

working pressure

207, 232, 300 Bar

Question 32

what does cp stand for

standard size

Answer 32

capacity pressure

207, 232, 300 Bar

Question 33

What does PS stand for

Answer 33

Pressure in service

Question 34

What does PT stand for

Answer 34

Pressure cylinder is tested too