CBET Medical Gas Systems 4 — Questions and Answers
Question 1: What is the maximum allowable pressure drop across a zone valve in a medical gas piping system under full flow conditions per NFPA 99?
- 5 psi (Correct answer)
- 10 psi
- 15 psi
- 25 psi
Correct answer: 5 psi
NFPA 99 requires that zone valve pressure drop not exceed 5 psi under full-flow conditions to maintain adequate downstream pressure.
Question 2: Which color-coded label is assigned to nitrous oxide piping in a US hospital per NFPA 99 and CGA standards?
- Blue
- Gray
- Light blue (Correct answer)
- Green
Correct answer: Light blue
Nitrous oxide piping is identified with a light blue label per CGA C-9 and NFPA 99 to distinguish it from oxygen (green) and medical air (yellow).
Question 3: A biomedical technician is verifying a medical air compressor system. Which parameter must be continuously monitored and alarmed per NFPA 99?
- Compressor oil level
- Dew point of the air supply (Correct answer)
- Ambient temperature of the compressor room
- Filter replacement interval
Correct answer: Dew point of the air supply
NFPA 99 requires continuous monitoring and alarming of the dew point of medical air to ensure adequate moisture removal and prevent contamination.
Question 4: In a bulk liquid oxygen system, what safety device prevents overpressure in the storage vessel?
- Check valve
- Pressure relief valve (Correct answer)
- Zone valve
- Backflow preventer
Correct answer: Pressure relief valve
Pressure relief valves are required on bulk liquid oxygen storage vessels to vent excess pressure and prevent catastrophic failure.
Question 5: When performing a cross-connection test on a newly installed medical gas system, which method is used to verify outlet identity?
- Apply vacuum to one outlet and check for flow at all others
- Pressurize one gas at a time and verify only labeled outlets flow that gas (Correct answer)
- Use a flow meter on each outlet simultaneously
- Check gas purity with a gas analyzer at the source
Correct answer: Pressurize one gas at a time and verify only labeled outlets flow that gas
Cross-connection testing pressurizes one gas source at a time while verifying that only the correctly labeled outlets supply that gas and no cross-flow occurs.
Question 6: Which NFPA 99 health care facility category requires the highest level of medical gas system redundancy and emergency backup?
- Category 1 (Correct answer)
- Category 2
- Category 3
- Category 4
Correct answer: Category 1
Category 1 facilities (e.g., operating rooms, ICUs) require the highest redundancy because failure of equipment could cause major injury or death.
Question 7: What is the primary hazard of using a cylinder of compressed oxygen in an area with oil-contaminated fittings?
- Rapid depletion of oxygen supply
- Risk of fire or explosion due to oxygen-enriched ignition of oil (Correct answer)
- Increase in pipeline dew point
- Back-pressure damage to the regulator
Correct answer: Risk of fire or explosion due to oxygen-enriched ignition of oil
Oil in contact with high-pressure oxygen can ignite spontaneously, creating a severe fire or explosion hazard; all oxygen equipment must be oil-free.
CBET Medical Gas Systems 4
What is the maximum allowable pressure drop across a zone valve in a medical gas piping system under full flow conditions per NFPA 99?