Page 1 of 142
ADCI Surface-Supplied Mixed Gas Diver
Certification Exam QUESTIONS AND VERIFIED
ANSWERS WITH RATIONALES JUST RELEASED
ADCI Surface-Supplied Mixed Gas Diver Certification Exam
10 MOST-TESTED EXAM COVERAGE AREAS
1. Mixed-Gas Diving Fundamentals — helium-oxygen breathing mixtures, gas properties, partial
pressures, gas selection, depth effects, narcosis, oxygen exposure, and gas density.
2. ADCI Standards and Commercial Diving Operations — certification requirements, diver
qualifications, operational planning, minimum team requirements, documentation, and
responsibilities.
3. Surface-Supplied Mixed-Gas Equipment — helmets, masks, umbilicals, gas panels, regulators,
manifolds, compressors, storage banks, bailout systems, communications, and monitoring
equipment.
4. Gas Mixing, Analysis, and Management — oxygen and helium handling, mixture verification,
analyzer use, labeling, pressure management, contamination control, and emergency gas
supplies.
5. Decompression and Dive Tables — decompression planning, schedules, stops, surface
decompression, chamber operations, repetitive diving, and decompression emergencies.
6. Diver Emergency Procedures — loss of breathing gas, umbilical problems, communication
failure, free-flow, helmet problems, bailout use, lost diver procedures, and standby diver
response.
7. Diving Physics and Physiology — pressure changes, buoyancy, Boyle's law, Dalton's law,
decompression sickness, oxygen toxicity, nitrogen narcosis, hypothermia, and barotrauma.
8. Dive Planning and Risk Management — job hazard analysis, weather, currents, water
conditions, tools, worksite hazards, personnel assignments, communications, and contingency
planning.
9. Chamber, Decompression, and Life-Support Systems — chamber readiness, chamber
atmosphere, oxygen control, gas supplies, environmental controls, treatment capability, and
monitoring.
10. Safety, Maintenance, Records, and Regulatory Practice — pre-dive inspections, equipment
maintenance, logs, incident reporting, OSHA/USCG considerations, safe work practices, and
post-dive procedures. (ADC International)
1.
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Before a surface-supplied mixed-gas dive begins, which action best confirms that the breathing mixture
is suitable for the planned maximum depth?
A. Check only the cylinder color
B. Analyze the breathing mixture
C. Ask the diver to identify it
D. Estimate the mixture from pressure
Answer: B
Rationale: Mixed-gas breathing mixtures must be analyzed to verify that the mixture is appropriate for
the planned dive depth. (ADC International)
2.
During a commercial mixed-gas dive, why is helium commonly added to oxygen for deeper operations?
A. It increases nitrogen narcosis
B. It eliminates decompression requirements
C. It reduces nitrogen exposure and can reduce breathing-gas density
D. It makes the diver completely immune to pressure effects
Answer: C
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Rationale: Helium can reduce nitrogen exposure and is useful because it is less dense than nitrogen at
depth.
3.
A diver loses the normal surface-supplied breathing gas while working underwater, so what should the
diver use immediately?
A. The diver's emergency gas supply
B. The hydraulic tool supply
C. The communications line
D. The exhaust valve
Answer: A
Rationale: A diver-worn emergency breathing-gas supply provides an independent breathing source
during a primary-gas failure.
4.
Why should the mixed-gas diving supervisor remain available throughout the planned diving operation?
, Page 4 of 142
A. To operate every underwater tool personally
B. To control and coordinate the diving operation
C. To replace the standby diver
D. To perform all equipment maintenance
Answer: B
Rationale: The supervisor coordinates the operation, monitors conditions, directs personnel, and
manages emergency actions.
5.
A mixed-gas diver is scheduled for a deeper dive than planned, so which planning action should occur
before starting the dive?
A. Ignore the change if the diver feels ready
B. Reassess gas mixture, decompression, equipment, and operational risks
C. Remove the standby diver
D. Reduce communications checks
Answer: B
ADCI Surface-Supplied Mixed Gas Diver
Certification Exam QUESTIONS AND VERIFIED
ANSWERS WITH RATIONALES JUST RELEASED
ADCI Surface-Supplied Mixed Gas Diver Certification Exam
10 MOST-TESTED EXAM COVERAGE AREAS
1. Mixed-Gas Diving Fundamentals — helium-oxygen breathing mixtures, gas properties, partial
pressures, gas selection, depth effects, narcosis, oxygen exposure, and gas density.
2. ADCI Standards and Commercial Diving Operations — certification requirements, diver
qualifications, operational planning, minimum team requirements, documentation, and
responsibilities.
3. Surface-Supplied Mixed-Gas Equipment — helmets, masks, umbilicals, gas panels, regulators,
manifolds, compressors, storage banks, bailout systems, communications, and monitoring
equipment.
4. Gas Mixing, Analysis, and Management — oxygen and helium handling, mixture verification,
analyzer use, labeling, pressure management, contamination control, and emergency gas
supplies.
5. Decompression and Dive Tables — decompression planning, schedules, stops, surface
decompression, chamber operations, repetitive diving, and decompression emergencies.
6. Diver Emergency Procedures — loss of breathing gas, umbilical problems, communication
failure, free-flow, helmet problems, bailout use, lost diver procedures, and standby diver
response.
7. Diving Physics and Physiology — pressure changes, buoyancy, Boyle's law, Dalton's law,
decompression sickness, oxygen toxicity, nitrogen narcosis, hypothermia, and barotrauma.
8. Dive Planning and Risk Management — job hazard analysis, weather, currents, water
conditions, tools, worksite hazards, personnel assignments, communications, and contingency
planning.
9. Chamber, Decompression, and Life-Support Systems — chamber readiness, chamber
atmosphere, oxygen control, gas supplies, environmental controls, treatment capability, and
monitoring.
10. Safety, Maintenance, Records, and Regulatory Practice — pre-dive inspections, equipment
maintenance, logs, incident reporting, OSHA/USCG considerations, safe work practices, and
post-dive procedures. (ADC International)
1.
, Page 2 of 142
Before a surface-supplied mixed-gas dive begins, which action best confirms that the breathing mixture
is suitable for the planned maximum depth?
A. Check only the cylinder color
B. Analyze the breathing mixture
C. Ask the diver to identify it
D. Estimate the mixture from pressure
Answer: B
Rationale: Mixed-gas breathing mixtures must be analyzed to verify that the mixture is appropriate for
the planned dive depth. (ADC International)
2.
During a commercial mixed-gas dive, why is helium commonly added to oxygen for deeper operations?
A. It increases nitrogen narcosis
B. It eliminates decompression requirements
C. It reduces nitrogen exposure and can reduce breathing-gas density
D. It makes the diver completely immune to pressure effects
Answer: C
, Page 3 of 142
Rationale: Helium can reduce nitrogen exposure and is useful because it is less dense than nitrogen at
depth.
3.
A diver loses the normal surface-supplied breathing gas while working underwater, so what should the
diver use immediately?
A. The diver's emergency gas supply
B. The hydraulic tool supply
C. The communications line
D. The exhaust valve
Answer: A
Rationale: A diver-worn emergency breathing-gas supply provides an independent breathing source
during a primary-gas failure.
4.
Why should the mixed-gas diving supervisor remain available throughout the planned diving operation?
, Page 4 of 142
A. To operate every underwater tool personally
B. To control and coordinate the diving operation
C. To replace the standby diver
D. To perform all equipment maintenance
Answer: B
Rationale: The supervisor coordinates the operation, monitors conditions, directs personnel, and
manages emergency actions.
5.
A mixed-gas diver is scheduled for a deeper dive than planned, so which planning action should occur
before starting the dive?
A. Ignore the change if the diver feels ready
B. Reassess gas mixture, decompression, equipment, and operational risks
C. Remove the standby diver
D. Reduce communications checks
Answer: B
