CHT Equipment Operation & Maintenance 3 — Questions and Answers
Question 1: Which ASME standard governs the design, fabrication, and inspection of pressure vessels used as hyperbaric chambers in the United States?
- ASME PVHO-1 (Correct answer)
- ASME B31.3
- ASME Section VIII Division 1
- ASME B16.5
Correct answer: ASME PVHO-1
ASME PVHO-1 (Safety Standard for Pressure Vessels for Human Occupancy) specifically addresses hyperbaric and diving chambers.
Question 2: A compressor used to fill a hyperbaric chamber's air banks develops an unusually high discharge temperature. The most likely cause is:
- Fouled or restricted intake filter reducing airflow (Correct answer)
- Excessive chamber pressure demand
- Low ambient humidity
- Incorrect oil viscosity in the crankcase
Correct answer: Fouled or restricted intake filter reducing airflow
A clogged intake filter restricts airflow, causing the compressor to work harder and generate excess heat at the discharge.
Question 3: What is the function of the actuator on an automatic chamber depth control system?
- Modulates the supply or exhaust valve to maintain a set pressure profile (Correct answer)
- Monitors and logs chamber pressure continuously
- Provides emergency pressure relief if depth exceeds limits
- Controls the flow rate of oxygen to the BIBS masks
Correct answer: Modulates the supply or exhaust valve to maintain a set pressure profile
The actuator physically opens or closes the supply/exhaust valves in response to signals from the controller to track the prescribed depth profile.
Question 4: Carbon monoxide contamination in a hyperbaric chamber's compressed-air supply is MOST likely caused by:
- Compressor air intake located near an internal combustion engine exhaust (Correct answer)
- Use of non-oil-free compressor piston rings
- High ambient humidity at the compressor intake
- Excessive compressor discharge pressure
Correct answer: Compressor air intake located near an internal combustion engine exhaust
CO enters the intake when it is sited near engine exhaust, diesel generators, or vehicle emissions; this is a critical placement and monitoring concern.
Question 5: When performing a pre-treatment inspection of a monoplace hyperbaric chamber, the technician should verify the acrylic viewport is free from:
- Crazing, cracks, deep scratches, and chemical solvent contact marks (Correct answer)
- Condensation on the inner surface
- Minor surface oxidation consistent with age
- External dust or fingerprints only
Correct answer: Crazing, cracks, deep scratches, and chemical solvent contact marks
Crazing, cracks, and solvent damage compromise acrylic structural integrity under pressure and must disqualify the viewport from use until assessed.
Question 6: In a multiplace chamber, the purpose of the medical lock (pass-through lock) is to:
- Transfer medications, equipment, and small items to patients at pressure without decompressing the chamber (Correct answer)
- Provide a secondary escape route for chamber occupants
- Allow medical personnel to enter the chamber during treatment
- Equalize pressure between the personnel lock and treatment compartment
Correct answer: Transfer medications, equipment, and small items to patients at pressure without decompressing the chamber
The medical lock is a small pressure vessel that allows items to be pressurized and passed into the chamber without disrupting treatment pressure.
Question 7: A hyperbaric chamber's exhaust (overboard dump) line must be routed to:
- A safe outdoor location away from ignition sources, air intakes, and occupied areas (Correct answer)
- The facility's HVAC return air duct
- A sealed room to prevent oxygen-enriched air from dispersing
- The compressor intake to recycle air
Correct answer: A safe outdoor location away from ignition sources, air intakes, and occupied areas
Overboard dump lines discharge oxygen-enriched gas; routing outdoors away from ignition sources and intakes prevents fire hazard and re-contamination.
CHT Equipment Operation & Maintenance 3
Which ASME standard governs the design, fabrication, and inspection of pressure vessels used as hyperbaric chambers in the United States?