Question 1: What color is the standard pipeline and cylinder coding for medical oxygen in the United States?

• Yellow
• Green (Correct answer)
• Blue
• White

Correct answer: Green

In the US, medical oxygen is color-coded green per CGA standards.

US CGA color coding: Oxygen=Green, Air=Yellow, Nitrogen=Black, Nitrous Oxide=Blue. ISO uses White for oxygen. DISS and PISS provide mechanical keying against cross-connection.

Question 2: What is the purpose of a zone valve in a medical gas pipeline system?

• To regulate gas pressure at each outlet
• To allow isolation of gas supply to a specific area for maintenance or emergencies without affecting the entire facility (Correct answer)
• To mix gases to the correct concentration
• To filter contaminants from the gas supply

Correct answer: To allow isolation of gas supply to a specific area for maintenance or emergencies without affecting the entire facility

Zone valves allow specific sections to be shut off without interrupting supply to the rest of the facility.

NFPA 99 requires zone valves for each gas serving each area. Biomedical technicians must verify they operate freely, labeling is accurate, and alarm activation occurs when closed.

Question 3: What safety system prevents connecting a medical gas cylinder to the wrong yoke or regulator?

• Color coding only
• Pin Index Safety System (PISS) (Correct answer)
• The cylinder label
• The pressure gauge

Correct answer: Pin Index Safety System (PISS)

PISS uses specific pin positions on the cylinder valve that correspond to holes on the yoke, mechanically preventing wrong gas connection.

PISS can be defeated by missing pins, multiple washers, or forcing connections. Biomedical technicians must inspect pin condition and educate staff never to force connections.

Question 4: What does a medical gas alarm panel monitor and how should alarms be responded to?

• Room temperature requiring HVAC adjustment
• Pipeline pressure, reserve supply status, and system conditions, requiring immediate investigation (Correct answer)
• Individual cylinder levels for automatic reordering
• Gas purity requiring filter replacement

Correct answer: Pipeline pressure, reserve supply status, and system conditions, requiring immediate investigation

Medical gas alarm panels monitor pipeline pressures, reserve supply status, and operating conditions.

Alarm conditions include: main supply low, reserve in use, reserve low, pipeline pressure abnormal. Biomedical technicians must test alarm systems during PM by simulating alarm conditions.

Question 5: What is the standard operating pressure for medical gas pipeline systems (oxygen, air, nitrous oxide) in a US hospital?

• 15 psi
• 50 psi (Correct answer)
• 100 psi
• 200 psi

Correct answer: 50 psi

Standard medical gas pipeline operating pressure is 50 psi per NFPA 99.

Exception: Nitrogen operates at 160-200 psi for pneumatic surgical instruments. Low pressure can cause equipment malfunction; high pressure can damage equipment.

Question 6: Why must oil and grease be kept away from oxygen equipment and fittings?

• They can clog the gas outlets
• Oxygen is a powerful oxidizer and can cause spontaneous ignition of hydrocarbons under pressure (Correct answer)
• They reduce the purity of the oxygen
• They can corrode the metal fittings

Correct answer: Oxygen is a powerful oxidizer and can cause spontaneous ignition of hydrocarbons under pressure

Oxygen drastically lowers the ignition temperature of hydrocarbons, which can spontaneously ignite under high-pressure oxygen.

Never use petroleum-based lubricants or Teflon tape on oxygen equipment. Use only oxygen-compatible lubricants. Open cylinder valves slowly to prevent adiabatic heating.

Question 7: What type of compressor is typically used in a medical air supply system, and what quality standards must the air meet?

• A standard industrial compressor
• An oil-free compressor producing air meeting USP grade purity standards (Correct answer)
• A turbine compressor with no filtration requirements
• A reciprocating compressor with automotive oil

Correct answer: An oil-free compressor producing air meeting USP grade purity standards

Medical air systems use oil-free compressors producing air meeting USP standards for purity.

USP requirements: O2 19.5-23.5%, CO < 10 ppm, CO2 < 500 ppm. NFPA 99 requires continuous CO monitoring with automatic shutdown if CO exceeds 10 ppm.

Question 8: What is the function of a medical vacuum system in a hospital, and what minimum vacuum level must it maintain?

• Removes dust at 5 inches Hg
• Provides suction for clinical procedures maintaining at least 12 inches Hg at the most remote outlet (Correct answer)
• Creates negative pressure rooms at 1 inch Hg
• Removes smoke during surgery at 20 inches Hg

Correct answer: Provides suction for clinical procedures maintaining at least 12 inches Hg at the most remote outlet

Medical vacuum provides suction for clinical procedures and must maintain a minimum of 12 inches Hg per NFPA 99.

Applications include suctioning, surgical aspiration, wound drainage, chest tube suction, and waste anesthetic gas scavenging. The vacuum pump exhaust must be piped outdoors.

Question 9: What is a medical gas manifold system and how does it ensure continuous gas supply?

• A single large cylinder connected directly to the pipeline
• A dual-bank arrangement of cylinders with automatic switchover between primary and reserve banks (Correct answer)
• A mixing chamber that combines multiple gases
• A pressure boosting system

Correct answer: A dual-bank arrangement of cylinders with automatic switchover between primary and reserve banks

A manifold uses two banks with automatic switchover to ensure uninterrupted supply.

Biomedical technicians must verify automatic changeover function during PM, check changeover pressure settings, and verify alarm activation during changeover.

Question 10: What special precautions must be taken when working on medical gas pipelines during construction in an occupied hospital?

• Standard construction practices are sufficient
• Pipeline isolation, gas verification at every affected outlet, infection control measures, and NFPA 99 compliance (Correct answer)
• Only color verification is needed
• Just closing zone valves is sufficient

Correct answer: Pipeline isolation, gas verification at every affected outlet, infection control measures, and NFPA 99 compliance

Construction near gas pipelines requires comprehensive safety measures including ICRA, clinical notification, and verification at every outlet.

Cross-connection testing is especially critical because medical gas cross-connection during construction has caused patient deaths. ALL outlets in the affected zone must be tested.

Question 11: What is the purpose of a waste anesthetic gas disposal (WAGD) system?

• To recycle expired anesthetic gases
• To safely remove exhaled and waste anesthetic gases from the operating room to protect healthcare workers (Correct answer)
• To measure anesthetic gas concentration in blood
• To store anesthetic gases after surgery

Correct answer: To safely remove exhaled and waste anesthetic gases from the operating room to protect healthcare workers

WAGD collects and removes waste anesthetic gases to protect healthcare workers from chronic exposure.

NIOSH recommends 25 ppm for N2O and 2 ppm for halogenated agents. WAGD must NOT be connected to the medical-surgical vacuum system.

Question 12: How should a biomedical technician verify that a repaired medical gas outlet is delivering the correct gas before returning it to service?

• Check the color coding only
• Use a gas-specific analyzer to verify gas identity, then test flow rate and pressure (Correct answer)
• Ask a nurse to smell the gas
• Connect a flowmeter and check the reading

Correct answer: Use a gas-specific analyzer to verify gas identity, then test flow rate and pressure

A gas-specific analyzer must be used to positively verify the gas identity at the outlet.

NFPA 99 requires verification testing at ALL outlets in the affected zone, not just the repaired outlet. Documentation of test results must be maintained.

Question 13: 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 14: 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 15: 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 16: 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 17: 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 18: 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 19: 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.