NFPA 99 Exam with Accurate Questions & Correct
Answers (Verified Answers) and Full Deep Expert
Rationales | Latest (2026/2027) Updated Version
{JUST RELEASED}
1. Under which of these conditions shall the instrument Air Reserve
header cylinders be permitted to be stored with the instrument air
compressor?
A) The mechanical equipment room does not contain a boiler
B) The medical air compressors are in the same room
C) The only motor-driven machinery in the room is for instrument air equipment
D) The room is secured with lockable doors
Correct Answer: C
Expert Rationale: Instrument Air Reserve header cylinders are permitted to be
stored with the instrument air compressor when the only motor-driven
machinery in the room is for instrument air equipment. This ensures that no
other equipment could contaminate the instrument air supply or create a hazard.
Test-Taking Tip: The key phrase is "only motor-driven machinery" – the room
must be dedicated to instrument air equipment.
2. Riser valves are those valves located where?
A) Adjacent to the main riser downstream of any zone valve
B) Anywhere in the lateral branches of the piping system
C) In the mainline adjacent to the base of the riser
D) In the riser adjacent to the mainline
Correct Answer: C
,Expert Rationale: Riser valves are located in the mainline adjacent to the base
of the riser. These valves control the flow of gas or vacuum to the riser, which is
the vertical pipe connecting main lines to branch lines on various floors.
Test-Taking Tip: Riser valve = mainline at the base of the riser. Think of it as
the "gatekeeper" to the vertical pipe.
3. When is the initial pressure test conducted by the installer?
A) After blowdown of the distribution piping
B) After installation of alarm sensors
C) Before blowdown of distribution piping
D) Before installation of station rough in assembly
Correct Answer: C
Expert Rationale: The initial pressure test is conducted by the installer before
blowdown of distribution piping. This test verifies the integrity of the piping
system before any cleaning or purging operations begin.
Test-Taking Tip: Initial pressure test = before blowdown. Test first, then clean.
4. In those portions of systems intended to handle oxygen at pressure
greater than 350 psi the interconnecting hose shall not contain what
materials?
A) Brass
B) Copper
C) Polymeric
D) Stainless steel
Correct Answer: C
Expert Rationale: In portions of systems intended to handle oxygen at
,pressure greater than 350 psi, the interconnecting hose shall not contain
polymeric materials. Polymeric materials can be combustible and pose a fire
hazard in high-pressure oxygen environments.
Test-Taking Tip: High-pressure oxygen = no polymeric materials. Polymers
can burn in oxygen-enriched atmospheres.
5. The tool shown here allows the installer to mechanically limit the
makeup depth of the fitting to be brazed. Under what condition is this
method permitted for the installation of medical gas piping?
A) Only on final line connectors
B) Only on vacuum systems
C) Where only B cup 5 brazing rod is used
D) Where the limited makeup depth is not less than minimum cup depth per
ANSI/ASME recommendations
Correct Answer: D
Expert Rationale: The method of mechanically limiting the makeup depth of
the fitting to be brazed is permitted where the limited makeup depth is not less
than the minimum cup depth per ANSI/ASME recommendations. This ensures
the brazed joint has sufficient engagement for a proper seal.
Test-Taking Tip: Limited makeup depth = must be at least minimum cup
depth. Don't shortchange the joint.
6. What is the standard gauge pressure for nitrogen gas service?
A) 15 - 30 psi
B) 50 - 55 psi
C) 162 - 185 psi
, D) It varies with system type
Correct Answer: C
Expert Rationale: The standard gauge pressure for nitrogen gas service is 162 -
185 psi. This is the standard pressure for nitrogen used in medical gas piping
systems for purging and testing.
Test-Taking Tip: Nitrogen service = 162-185 psi. Remember this specific range.
7. What is a NFPA 99 requirement for labeling of pipes in a medical
gas system?
A) Color coding
B) Fixed label with
C) Label shall wrap completely around pipe
D) Reflective label
Correct Answer: C
Expert Rationale: NFPA 99 requires that the label shall wrap completely
around the pipe. This ensures that the label is visible from all directions and
cannot be missed, which is critical for safety.
Test-Taking Tip: Medical gas pipe labels = wrap completely around the pipe.
8. A wireless communication device is employed in a medical gas or
vacuum warning system. What type of supervision is required for this
device?
A) A visual indicator shall be located in maintenance officer or engineering
department
B) This device shall be installed at the medical gas or vacuum source
C) This device will be supervised such that failure of communication shall initiate
Answers (Verified Answers) and Full Deep Expert
Rationales | Latest (2026/2027) Updated Version
{JUST RELEASED}
1. Under which of these conditions shall the instrument Air Reserve
header cylinders be permitted to be stored with the instrument air
compressor?
A) The mechanical equipment room does not contain a boiler
B) The medical air compressors are in the same room
C) The only motor-driven machinery in the room is for instrument air equipment
D) The room is secured with lockable doors
Correct Answer: C
Expert Rationale: Instrument Air Reserve header cylinders are permitted to be
stored with the instrument air compressor when the only motor-driven
machinery in the room is for instrument air equipment. This ensures that no
other equipment could contaminate the instrument air supply or create a hazard.
Test-Taking Tip: The key phrase is "only motor-driven machinery" – the room
must be dedicated to instrument air equipment.
2. Riser valves are those valves located where?
A) Adjacent to the main riser downstream of any zone valve
B) Anywhere in the lateral branches of the piping system
C) In the mainline adjacent to the base of the riser
D) In the riser adjacent to the mainline
Correct Answer: C
,Expert Rationale: Riser valves are located in the mainline adjacent to the base
of the riser. These valves control the flow of gas or vacuum to the riser, which is
the vertical pipe connecting main lines to branch lines on various floors.
Test-Taking Tip: Riser valve = mainline at the base of the riser. Think of it as
the "gatekeeper" to the vertical pipe.
3. When is the initial pressure test conducted by the installer?
A) After blowdown of the distribution piping
B) After installation of alarm sensors
C) Before blowdown of distribution piping
D) Before installation of station rough in assembly
Correct Answer: C
Expert Rationale: The initial pressure test is conducted by the installer before
blowdown of distribution piping. This test verifies the integrity of the piping
system before any cleaning or purging operations begin.
Test-Taking Tip: Initial pressure test = before blowdown. Test first, then clean.
4. In those portions of systems intended to handle oxygen at pressure
greater than 350 psi the interconnecting hose shall not contain what
materials?
A) Brass
B) Copper
C) Polymeric
D) Stainless steel
Correct Answer: C
Expert Rationale: In portions of systems intended to handle oxygen at
,pressure greater than 350 psi, the interconnecting hose shall not contain
polymeric materials. Polymeric materials can be combustible and pose a fire
hazard in high-pressure oxygen environments.
Test-Taking Tip: High-pressure oxygen = no polymeric materials. Polymers
can burn in oxygen-enriched atmospheres.
5. The tool shown here allows the installer to mechanically limit the
makeup depth of the fitting to be brazed. Under what condition is this
method permitted for the installation of medical gas piping?
A) Only on final line connectors
B) Only on vacuum systems
C) Where only B cup 5 brazing rod is used
D) Where the limited makeup depth is not less than minimum cup depth per
ANSI/ASME recommendations
Correct Answer: D
Expert Rationale: The method of mechanically limiting the makeup depth of
the fitting to be brazed is permitted where the limited makeup depth is not less
than the minimum cup depth per ANSI/ASME recommendations. This ensures
the brazed joint has sufficient engagement for a proper seal.
Test-Taking Tip: Limited makeup depth = must be at least minimum cup
depth. Don't shortchange the joint.
6. What is the standard gauge pressure for nitrogen gas service?
A) 15 - 30 psi
B) 50 - 55 psi
C) 162 - 185 psi
, D) It varies with system type
Correct Answer: C
Expert Rationale: The standard gauge pressure for nitrogen gas service is 162 -
185 psi. This is the standard pressure for nitrogen used in medical gas piping
systems for purging and testing.
Test-Taking Tip: Nitrogen service = 162-185 psi. Remember this specific range.
7. What is a NFPA 99 requirement for labeling of pipes in a medical
gas system?
A) Color coding
B) Fixed label with
C) Label shall wrap completely around pipe
D) Reflective label
Correct Answer: C
Expert Rationale: NFPA 99 requires that the label shall wrap completely
around the pipe. This ensures that the label is visible from all directions and
cannot be missed, which is critical for safety.
Test-Taking Tip: Medical gas pipe labels = wrap completely around the pipe.
8. A wireless communication device is employed in a medical gas or
vacuum warning system. What type of supervision is required for this
device?
A) A visual indicator shall be located in maintenance officer or engineering
department
B) This device shall be installed at the medical gas or vacuum source
C) This device will be supervised such that failure of communication shall initiate
