Unit of competency Outline

Date retreived
23/07/2026 11:34 AM AWST

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Dive using closed-circuit breathing apparatus (N2O2) in open water to a maximum depth of 40 metres

Dive using closed-circuit breathing apparatus (N2O2) in open water to a maximum depth of 40 metres

Unit of competency
National Code
DEFDV005B
State Code
AVV06
TGA Status
Replaced
DTWD Status
Replaced
Current Release Number
2.00
Current Release Date
24/01/2013
View on TGA
State Implementation and Classification
Approved Date
Field of Education
092101 - Sport And Recreation Activities
Original Release Date
Nominal Hours
0
Description
This unit covers the competency required to dive using closedcircuit breathing apparatus (CCBA) (N2O2) in an open water environment to a maximum depth of 40 metres.This unit specifically covers those aspects of performance unique to CCBA (N2O2), such as operating the N2O2 compressor/handbooster pump, inspecting and operating CCBA (N2O2) equipment, and conducting CCBA (N2O2) specific contingency drills.
Notes
Elements and Performance Criteria
1. Operate an N2O2 compressor/ hand-booster pump
  • 1.1 Compressor and associated equipment are inspected for serviceability.
  • 1.2 Protective equipment is fitted.
  • 1.3 Leads and hoses are connected to the compressor.
  • 1.4 Gas cylinders are charged to maximum working pressure and details are recorded in relevant logs.
  • 1.5 Operator level maintenance is performed on the compressor.
  • 1.6 Compressor is deserviced after use.
2. Conduct dive operations
  • 2.1 CCBA (N2O2) is selected, inspected for serviceability, and fitted and tested (both out of water and inwater).
  • 2.2 Dives are conducted using CCBA (N2O2) and dive contingencies are demonstrated.
  • 2.3 CCBA (N2O2) is deserviced and defects are reported in accordance with organisational procedures.
The Range Statement relates to the Unit of Competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording in the Performance Criteria is detailed below.
Open water environment may include:
day or night
oceans, seas, lakes and rivers
subsurface conditions:
current (0-2 knots)
visibility (0 metre +)
temperature (0 degrees +)
surface and subsurface hazards such as:
anchor drop zones
cathodic protection devices
electrical cabling
inlets and sonar/radio frequency hazards
marine animals
piers and jetties
pipelines
pollutants
propellers/thrusters
trapping hazards:
beams
culverts
gates
grottoes and caves
intakes and outfalls
nets
safety, anchor and communications lines
sewers
submerged ships, vehicles and structures
sluices
vessel rocking and associated movement
Associated equipment includes:
hoses
pumps
Protective equipment may include:
boots
gloves
goggles
CCBA (N2O2) includes:
N2O2 cylinder
counter-lung
emergency cylinder
facemask/mouthpiece
scrubber material
Operator level maintenance may include:
checking existing pressure in cylinders with pressure gauge
conducting charging in (N2O2) clean environment
following correct charging procedure and charging rate
operating high pressure charging panels
Dive contingencies may include:
buddy breathing
companion diver
flooded mask
fouled supply
hose blockage/choking
hose rupture
partial pressure anomalies
set to 40 bar
trouble drill
Critical aspects for assessment and evidence required to demonstrate competency in this unit
Assessment must confirm the ability to:
arrange for others to check equipment
conduct inwater checks
handle nonfunctional equipment items
implement contingency and emergency drills such as:
buddy breathing
ditching drills
unconscious companion diver drills
maintain equipment during the dive
prepare equipment for the dive including charging of cylinders
recover and clear mask and mouthpiece
refurbish equipment postdive
safely enter and exit the water appropriate to the launch platform, equipment and conditions
switch from primary to the reserve air system.

Consistency in performance
Competency will be demonstrated over a minimum of 15 dives with the diver diving to a depth not greater than 40 m using CCBA (N2O2) in open water that includes the following requirements:
day and night
oceans
seas, lakes and rivers
subsurface conditions:
a range of surface and subsurface hazards
current (0-2 knots)
temperature (0 degrees +)
visibility (0 metre +).
Table 1 (below) outlines the minimum dives required by this Unit of Competency.

Table 1
Condition
No of Dives
Inwater time
Remarks
Between 040m
15
600 min
Total accrued subsurface time (010m)
Special Qualifiers (included within above)

Context of and specific resources for assessment
Context of assessment
Competency will be assessed in the ocean over a range of oceanic, diurnal and nocturnal environments, supported by questioning on shore or aboard vessels.
When practicable, assessment should relate to the diver’s vocational focus.
Specific resources for assessment
Access to a complete range of CCBA (N2O2) diving, safety and accessory equipment.
No information