Gas Handling Flashcards
Chamber Exhaust piping should be equipped with what?
Tee piece/Diffuser/Silencer
Gas cylinders should be labeled with the following;
Gas Type
%
Chemical Symbol
Name of gas
O2% will be listed first in the gas content
O2 can be stored in a confined space- T or F
False.
Never store O2 in a confined space.
If storing gas below deck the room must have an O2 Hi/Low alarm-
True or False
True
Identify the following gases by color code;
Brown
White
Black
Black/White
Brown/White
Grey
Pink
Brown - Helium
White - Oxygen
Black - Nitrogen
Black/White - Air
Brown/White - Heliox
Grey - Carbon Dioxide
Pink - Cal Gas
O2 % above which should be treated as 100%
25% O2 content shall be treated same as 100%
Are whip checks required on LP gas hoses?
Yes, check whips are required on all hoses under pressure
When putting a new gas online it is required to a analyze at both the quad and the panel-
True or False
True,
when a new gas is put online it must be analyzed at the quad and the panel.
State the max level of contaminants for BSEN12021
Oil
CO
CO2
Water
Oil - 0.5mg/m3
CO - 5ppm
CO2 - 500ppm
Water - 25mg/m3
State the mechanism of action for the following analyzers;
O2 analyzers
CO2 analyzers
Draager Tubes
O2 analyzers;
Battery Fuel Cell
CO2 analyzers;
Radiation and Infrared Beams
Draager Tubes;
Colorimetric Tubes
O2 should be reduced to X bar at the quad
As low as possible with
40bar max at quad
All chambers require a ppO2 meter?
True or False?
True
Considerations for O2 plumbing and valves;
Hard plumbing is preferred
Soft hose as short as possible
Use needle valves
Use O2 safe thread sealants no ptfe tape (phosgene gas)
O2 clean hoses and fittings
Do compressors and pressure vessels require an PRV?
Yes
Considerations for O2 storage location
Stored on upper deck
Clearly marked gas quads
Equipped with a fire or deluge system
100% O2 can be pumped to Kelly’s;
True or False
False.
O2 cannot be pumped
Give the approximate weight of a 50L cylinder and 16 bottle quad.
50L cylinder = 100kg
Therefore 16 bottle quad weighs at least 1.6T.
What is the minimum allowable O2 content in an inert gas offshore?
2%
Lower percentage maybe allowed but with strict procedures in place.
Who is responsible for analyzing divers gas before and during a dive?
The diving supervisor
Can air be used as a scale gas on O2 analyzers?
Yes, but the sample must be taken outdoors not from inside a room and set to 20.9%
How long must new gas mixes sit to ensure complete homogenization?
24hrs
Gases can be mixed by these 2 methods;
Using a blender/mixer
Or
Decanting
Which gas shall be added to the mix first;
2% or 20%
Start by mixing the rich mix first.
This lets the lean mix be pumped at a higher pressure.
Which document states minimum gas requirements offshore?
IMCA D050
Normal maximum working pressure for O2 at source to minimize fire risk?
40bar
What is the purity standard for divers breathing gas?
BSEN 12021
O2 content % should be marked before after other gases on the quad label?
O2 % should be shown first
Gas cylinders used in diving must have marked on them;
Chemical formula of the contents and the color code.
An O2 analyzer works by way of
Paramagnetism or using a fuel cell (battery) which generates electricity in proportion to the ppO2
How often should bail out bottles have an internal and external visual examination for corrosion
Every 6 months
Internal/external
2 years: int/ext plus pressure test to max working pressure
5 years: hydraulic over pressure test 1.5x max working pressure plus the 2 yearly
By which process do gas tubes work?
Colormetric
Gas cylinder sets used underwater must have an hydraulic overpressure test to 1.5x the maximum working pressure every how often?
Every 5 years plus the int/ext examination.
2.5 years is pressure test to max working pressure plus int/ext visual
IMCA D018 states a compressor should have a gas purity check every how often?
6 months
Vs
BSEN 12021
-3 monthly
