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GAS Flashcards

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1
Q

As per IMCA D043 what colour should the collar of an Oxygen cylinder be?

A

White

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2
Q

As per IMCA D043 what colour should the collar of an Nitrogen cylinder be?

A

Black

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3
Q

As per IMCA D043 what colour should the collar of a Helium cylinder be?

A

Brown

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4
Q

As per IMCA D043 what colour should the collar of an Air or Nitrox cylinder be?

A

Black & White

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5
Q

As per IMCA D043 what colour should the collar of a Heliox cylinder be?

A

Brown & White

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6
Q

As per IMCA D043 what colour should the collar of a Carbon Dioxide cylinder be?

A

Grey

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7
Q

As per IMCA D043 what colour should the collar of a Calibration cylinder be?

A

Pink

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8
Q

Which IMCA document covers the colouring and markings of gas cylinders?

A

IMCA D043

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9
Q

What IMCA document covers the minimum amounts of gas required for offshore diving?

A

IMCA D050

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10
Q

What are the three main areas of concern about water in bail-out bottles?

A
  1. The reduced capacity of the bottle to contain gas
  2. The possibility of water being supplied to diver instead of gas
  3. Potential for serious injury if the bottle explodes during charging due to accelerated corrosion
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11
Q

As per IMCA D018 how often should bail out bottles be checked?

A

Every 6 months by removing the pillar valve and checking for moisture or rust or other corrosion particles

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12
Q

Which IMCA document is ‘Code of Practice for The Initial and Periodic Examination, Testing and Certification of Diving Plant and Equipment’?

A

IMCA D018

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13
Q

As per IMCA D018 how often is testing and certification required for a cylinder that goes underwater?

A

Every 2 years

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14
Q

As per IMCA D018 how often is testing and certification required for a cylinder that remain on surface?

A

Every 5 years

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15
Q

Over what Oxygen percentage should a gas be handled as pure Oxygen?

A

25%

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16
Q

What IMCA document covers ‘Guidance on Stainless Steel in Oxygen Systems’?

A

IMCA D012

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17
Q

As per IMCA D012 what metal should not be used for Oxygen pipework and fittings?

A

Stainless Steel

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18
Q

What valves should not be used in an Oxygen line?

A

Quarter-turn valves
(Unless as an emergency shutoff valve)

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19
Q

Can Teflon PTFE tape be used for a fitting in an Oxygen line?

A

No.
Only oxygen compatible PTFE tape can be used as Teflon tape inside a pipe can ignite easily and will burn

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20
Q

What pressure should an Oxygen quad be reduced to?

A

Maximum 40Bar

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21
Q

Oxygen or any gas containing more than 25% should not be stored where?

A

In a confined space

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22
Q

Helium used within the scope of the IMCA D014 international code of practise for offshore diving must contain a minimum of what?

A

2% Oxygen
Pure inert gas should not be carried on a worksite

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23
Q

How is Oxygen analysis carried out?

A

Analyser using:
1. Fuel Cell or
2. Magneto-dynamic Cell (paramagnetic)

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24
Q

How does a Fuel cell work?

A

A fuel cell is a battery which generates electricity in proportion to the PPO2, Polarography

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25
How does a Magneto-dynamic cell work?
Oxygen is one of the few paramagnetic gasses and the molecules are therefore attracted by a magnetic field. A small quartz dumbbell is suspended in a strong non-uniform field, when gas enter the cell the attraction causes the dumbbell to rotate, the rotations are measured by a beam of light and converted into an electric current
26
How is Carbon Dioxide analysis carried out?
Infra-red
27
How does Infra-red analysis work?
Each gas absorbs specific wavelengths of radiation, equal infra-red beams of the appropriate wavelength are shone onto two cells, one containing a reference gas and one the sample gas. The sample gas absorbs radiation in proportion to its carbon dioxide content and heats up, by comparing the temperature rise with the temperature of the reference cell the proportion of CO2 can be measured
28
How does a chemical sampling tube work?
Colorimetric The glass tube contains a chemical which changes colour in proportion to the amount of sample gas drawn through the tube
29
What document specifies the maximum level for contaminants in compressed air for breathing apparatus?
BS EN 12021
30
As per BS EN 12021, what is the maximum level of Carbon Monoxide allowed in compressed air?
5 ppm
31
As per BS EN 12021, what is the maximum level of Carbon Dioxide allowed in compressed air?
500 ppm
32
As per BS EN 12021, what is the maximum level of Oil allowed in compressed air?
0.5 mg/m3
33
As per BS EN 12021, what is the maximum level of Water allowed in compressed air?
25 mg/m3 (at compressor outlet) 50 mg/m3 (at cylinder outlet, pressure 40-200bar) 35 mg/m3 (at cylinder outlet, pressure over 200bar)
34
Air samples from compressors should be analysed every?
Normally every 3 to 6 months, after any repair or modification to the compressor and following any incident or accident. As per company procedure
35
IMCA D024 states that testing on gas recovery system compressors takes place every?
6 months
36
What fitting is this?
JIC (Joint International Council) 1. a conical seating and no additional sealant is required 2. Designed for use with HP hoses 3. Sizing in 16ths, i.e. JIC 8 = 8x16ths = 1/2 inch
37
What fitting is this?
NPT (National Pipe Tapered) 1. A tapered thread which requires sealant (PTFE tape) 2. Flat crests and troughs
38
PTFE tape should never be used with what fittings?
JIC or Swagelock
39
What valve is this schematic for?
Needle Valve
40
What valve is this schematic for?
Quarter-turn Valve
41
What valve is this schematic for?
Non Return Valve
42
What valve is this schematic for?
Pressure Relief Valve (PRV)
43
All Oxygen over 25% Must:
1. Remain in suppliers quads 2. Be stored in an open, well ventilated area 3. Be apart from the diving system and other stored gasses 4. The stowage area must be marked OXYGEN STOWAGE - NO SMOKING 5. Have a fire deluge system & fire hydrant must be within 10m of stowage area 6. If Transferring then it needs to be signposted to say OXYGEN TRANSFER
44
AODC 037 covers what?
Periodic examination of bail-out bottles
45
AODC 010 covers what?
Gas cylinders used in diving operations in areas governed by UK regulations
46
IMCA D031 document covers what?
Cleaning of oxygen service: Setting up facilities and procedures
47
IMCA D009 document covers what?
Protective guarding of gas cylinder transport containers (quads)
48
IMCA D012 document covers what?
Stainless steel in oxygen systems
49
AODC 038 covers what?
Guidance note on the use of inert gases
50
DMAC 05 covers what?
Recommendation of minimum level of O2 in helium supplied offshore
51
IMCA D050 document covers what?
Minimum quantities of gas required offshore
52
53
What is 1m2 in ft2?
10.765
54
What is 1m3 in ft3?
35.310
55
What is 1m in ft?
3.281
56
What is 1kg in pounds?
2.204
57
Gas suppliers usually blend mixed gasses to what tolerance?
+\- 2.5%
58
Allowable limit of CO2 allowed in the bell?
10mb (1000ppm)
59
How often must hyperbaric lifeboat internal gas cylinders be tested?
Every 5 years
60
Compressed air for diving must comply with what what British standard?
BS 4001
61
What does BS 4001 deal with?
Air Purity
62
The maximum allowable CO in an air supply is?
10PPM
63
IMCA state the maximum recommended PPO2 in Nitrox diving is?
1.5Bar

LST Exam (3 decks)

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