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GAS Flashcards

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
Q

How does a Magneto-dynamic cell work?

A

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

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26
Q

How is Carbon Dioxide analysis carried out?

27
Q

How does Infra-red analysis work?

A

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
Q

How does a chemical sampling tube work?

A

Colorimetric
The glass tube contains a chemical which changes colour in proportion to the amount of sample gas drawn through the tube

29
Q

What document specifies the maximum level for contaminants in compressed air for breathing apparatus?

A

BS EN 12021

30
Q

As per BS EN 12021, what is the maximum level of Carbon Monoxide allowed in compressed air?

31
Q

As per BS EN 12021, what is the maximum level of Carbon Dioxide allowed in compressed air?

32
Q

As per BS EN 12021, what is the maximum level of Oil allowed in compressed air?

33
Q

As per BS EN 12021, what is the maximum level of Water allowed in compressed air?

A

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
Q

Air samples from compressors should be analysed every?

A

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
Q

IMCA D024 states that testing on gas recovery system compressors takes place every?

36
Q

What fitting is this?

A

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
Q

What fitting is this?

A

NPT (National Pipe Tapered)
1. A tapered thread which requires sealant (PTFE tape)
2. Flat crests and troughs

38
Q

PTFE tape should never be used with what fittings?

A

JIC or Swagelock

39
Q

What valve is this schematic for?

A

Needle Valve

40
Q

What valve is this schematic for?

A

Quarter-turn Valve

41
Q

What valve is this schematic for?

A

Non Return Valve

42
Q

What valve is this schematic for?

A

Pressure Relief Valve (PRV)

43
Q

All Oxygen over 25% Must:

A
  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
Q

AODC 037 covers what?

A

Periodic examination of bail-out bottles

45
Q

AODC 010 covers what?

A

Gas cylinders used in diving operations in areas governed by UK regulations

46
Q

IMCA D031 document covers what?

A

Cleaning of oxygen service: Setting up facilities and procedures

47
Q

IMCA D009 document covers what?

A

Protective guarding of gas cylinder transport containers (quads)

48
Q

IMCA D012 document covers what?

A

Stainless steel in oxygen systems

49
Q

AODC 038 covers what?

A

Guidance note on the use of inert gases

50
Q

DMAC 05 covers what?

A

Recommendation of minimum level of O2 in helium supplied offshore

51
Q

IMCA D050 document covers what?

A

Minimum quantities of gas required offshore

53
Q

What is 1m2 in ft2?

54
Q

What is 1m3 in ft3?

55
Q

What is 1m in ft?

56
Q

What is 1kg in pounds?

57
Q

Gas suppliers usually blend mixed gasses to what tolerance?

58
Q

Allowable limit of CO2 allowed in the bell?

A

10mb (1000ppm)

59
Q

How often must hyperbaric lifeboat internal gas cylinders be tested?

A

Every 5 years

60
Q

Compressed air for diving must comply with what what British standard?

61
Q

What does BS 4001 deal with?

A

Air Purity

62
Q

The maximum allowable CO in an air supply is?

63
Q

IMCA state the maximum recommended PPO2 in Nitrox diving is?

LST Exam (3 decks)

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