Medical Gas Installer License Exam
Questions And Verified Answers With
Rationales| 2026 Updated
1. What is the standard that governs the installation of medical gas and
vacuum systems?
A. NFPA 58
B. NFPA 99
C. NFPA 70
D. ASME B31.1
B. NFPA 99
NFPA 99 is the Health Care Facilities Code and sets the standards for
medical gas and vacuum systems.
2. Which type of brazing alloy is required for medical gas piping?
A. Lead-based alloy
B. Aluminum-based alloy
C. Copper-phosphorus alloy without flux
D. Tin-silver alloy with flux
C. Copper-phosphorus alloy without flux
Flux is not allowed in medical gas systems to prevent contamination.
Copper-phosphorus alloy is acceptable for joining copper pipes.
, 3. Before brazing, what must be done to purge the pipe?
A. Fill with compressed air
B. Fill with oxygen
C. Purge with nitrogen
D. Fill with helium
C. Purge with nitrogen
Nitrogen purging is required during brazing to prevent internal oxidation
and contamination of the pipe.
4. What is the minimum pressure test required for medical gas piping
after installation?
A. 50 psig
B. 100 psig
C. 150 psig
D. 150% of the system pressure
D. 150% of the system pressure
NFPA 99 requires pressure testing at 1.5 times the operating pressure to
ensure the system’s integrity.
5. What type of piping material is approved for medical gas installations?
A. PVC
B. Black steel
C. Copper Type K cleaned for oxygen service
D. Galvanized steel
C. Copper Type K cleaned for oxygen service
Only Type K copper that has been cleaned and capped is suitable for
medical gas systems to ensure purity and strength.
6. How should copper medical gas pipe be identified?
,A. By size only
B. With red color coding
C. With manufacturer’s logo
D. By a label stating “OXY” and a green color band
D. By a label stating “OXY” and a green color band
Medical gas piping must be clearly labeled with the gas name and color
code to prevent cross-connection and ensure safety.
7. What color is used to identify oxygen piping?
A. Yellow
B. Black
C. Green
D. Blue
C. Green
Green is the designated color for oxygen systems in medical gas piping, as
per NFPA 99.
8. Who must verify the medical gas system before it is placed into
service?
A. Installing contractor
B. Hospital staff
C. Certified third-party verifier
D. Project manager
C. Certified third-party verifier
NFPA 99 requires verification by a certified verifier to ensure the system
meets all safety and performance standards.
9. What is the function of a zone valve box?
A. Increase gas pressure
B. Store excess gas
C. Isolate specific areas during maintenance or emergencies
, D. Regulate temperature
C. Isolate specific areas during maintenance or emergencies
Zone valves allow specific sections of the system to be shut off for repairs
or in case of emergency.
10. At what location must zone valves be installed?
A. At every outlet
B. Outside the building
C. Immediately outside each operating room or critical care area
D. At the central supply system
C. Immediately outside each operating room or critical care area
This allows for quick isolation of gas supply in emergency situations.
11. What is the acceptable method to clean medical gas copper
tubing before installation?
A. Using sandpaper and water
B. Mechanical brushing with solvent
C. Use of oily cloth
D. Abrasive blasting
B. Mechanical brushing with solvent
Cleaning with a solvent and mechanical means ensures removal of
contaminants without introducing oils or residue.
12. What is the minimum distance between a medical gas pipeline
and an electrical conduit?
A. 1 inch
B. 2 inches
C. 6 inches
D. 12 inches
Questions And Verified Answers With
Rationales| 2026 Updated
1. What is the standard that governs the installation of medical gas and
vacuum systems?
A. NFPA 58
B. NFPA 99
C. NFPA 70
D. ASME B31.1
B. NFPA 99
NFPA 99 is the Health Care Facilities Code and sets the standards for
medical gas and vacuum systems.
2. Which type of brazing alloy is required for medical gas piping?
A. Lead-based alloy
B. Aluminum-based alloy
C. Copper-phosphorus alloy without flux
D. Tin-silver alloy with flux
C. Copper-phosphorus alloy without flux
Flux is not allowed in medical gas systems to prevent contamination.
Copper-phosphorus alloy is acceptable for joining copper pipes.
, 3. Before brazing, what must be done to purge the pipe?
A. Fill with compressed air
B. Fill with oxygen
C. Purge with nitrogen
D. Fill with helium
C. Purge with nitrogen
Nitrogen purging is required during brazing to prevent internal oxidation
and contamination of the pipe.
4. What is the minimum pressure test required for medical gas piping
after installation?
A. 50 psig
B. 100 psig
C. 150 psig
D. 150% of the system pressure
D. 150% of the system pressure
NFPA 99 requires pressure testing at 1.5 times the operating pressure to
ensure the system’s integrity.
5. What type of piping material is approved for medical gas installations?
A. PVC
B. Black steel
C. Copper Type K cleaned for oxygen service
D. Galvanized steel
C. Copper Type K cleaned for oxygen service
Only Type K copper that has been cleaned and capped is suitable for
medical gas systems to ensure purity and strength.
6. How should copper medical gas pipe be identified?
,A. By size only
B. With red color coding
C. With manufacturer’s logo
D. By a label stating “OXY” and a green color band
D. By a label stating “OXY” and a green color band
Medical gas piping must be clearly labeled with the gas name and color
code to prevent cross-connection and ensure safety.
7. What color is used to identify oxygen piping?
A. Yellow
B. Black
C. Green
D. Blue
C. Green
Green is the designated color for oxygen systems in medical gas piping, as
per NFPA 99.
8. Who must verify the medical gas system before it is placed into
service?
A. Installing contractor
B. Hospital staff
C. Certified third-party verifier
D. Project manager
C. Certified third-party verifier
NFPA 99 requires verification by a certified verifier to ensure the system
meets all safety and performance standards.
9. What is the function of a zone valve box?
A. Increase gas pressure
B. Store excess gas
C. Isolate specific areas during maintenance or emergencies
, D. Regulate temperature
C. Isolate specific areas during maintenance or emergencies
Zone valves allow specific sections of the system to be shut off for repairs
or in case of emergency.
10. At what location must zone valves be installed?
A. At every outlet
B. Outside the building
C. Immediately outside each operating room or critical care area
D. At the central supply system
C. Immediately outside each operating room or critical care area
This allows for quick isolation of gas supply in emergency situations.
11. What is the acceptable method to clean medical gas copper
tubing before installation?
A. Using sandpaper and water
B. Mechanical brushing with solvent
C. Use of oily cloth
D. Abrasive blasting
B. Mechanical brushing with solvent
Cleaning with a solvent and mechanical means ensures removal of
contaminants without introducing oils or residue.
12. What is the minimum distance between a medical gas pipeline
and an electrical conduit?
A. 1 inch
B. 2 inches
C. 6 inches
D. 12 inches
