Exam Practice Questions And Correct Answers

Association of Diving Contractors International (ADCI) Surface Supplied Air Diver Certification Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary function of a surface-supplied air system?
• To provide heating to the diver
• To supply breathing gas to the diver
• To communicate underwater
• To regulate water temperature

Rationale: The surface-supplied air system is designed primarily to

deliver breathing gas to the diver from the surface.

• What is the purpose of the diver's harness?
• To assist in swimming faster
• To secure the diver to the umbilical and facilitate safe retrieval
• To store tools 1 / 4

• To measure depth

Rationale: The harness is used to secure the diver and provide

attachment points for the umbilical and safety lines.

• Which gas is normally supplied to surface-supplied divers?
• Oxygen
• Carbon dioxide
• Air
• Nitrogen

Rationale: Standard surface-supplied divers use air, which is a

mixture of oxygen and nitrogen.

• What is the maximum depth generally recommended for a surface-

supplied air diver on air?

• 50 meters
• 50 meters (164 feet)
• 100 meters
• 30 meters

Rationale: ADCI standards recommend a maximum working depth of

50 meters for air diving due to nitrogen narcosis and oxygen toxicity risks.

• Which piece of equipment provides communication between the diver

and the surface?

• Buoyancy compensator
• Diving helmet 2 / 4

• Diver communications system
• Depth gauge

Rationale: The diver communication system allows real-time verbal

contact with surface personnel.

• What is the function of the non-return valve in a surface-supplied air

system?

• To allow reverse airflow
• To measure gas consumption
• To prevent water or air from flowing back into the supply line
• To regulate depth

Rationale: The non-return valve ensures that water does not enter

the air supply hose.

• How often should a diver perform pre-dive equipment checks?
• Once per month
• Before every dive
• Once per week
• Only when equipment is new

Rationale: Equipment must be checked before every dive to ensure

safety and functionality.

• What does the term “umbilical” refer to in diving?
• Safety line only
• Hose assembly providing air, communications, and sometimes hot

water to the diver 3 / 4

• Harness component
• Surface support vessel

Rationale: The umbilical connects the diver to surface-supplied air

and other essential services.

• Why is it important to purge a helmet before a dive?
• To warm the diver
• To remove water and ensure the helmet is filled with air
• To check the diver's weight
• To check buoyancy

Rationale: Purging removes water from the helmet and ensures a

safe supply of breathing air.

• What is the main hazard associated with contaminated air in

diving?

• Increased buoyancy
• Breathing difficulties, unconsciousness, or poisoning
• Slower swimming
• Cold stress

Rationale: Contaminated air can contain carbon monoxide or other

harmful substances, posing serious risks.

• How should a diver respond if the air supply is lost underwater?
• Swim to the surface immediately without signaling
• Panic and remove the helmet
• Use emergency air supply and signal the tender for assistance
• / 4