Nevada Combination Inspector
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
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1. Which of the following is the primary purpose of a combination
inspector?
A. Installing mechanical systems
B. Designing plumbing systems
C. Ensuring compliance with building, plumbing, and mechanical
codes
D. Performing energy efficiency audits
A combination inspector’s main role is to verify that building,
plumbing, and mechanical systems comply with applicable codes and
regulations.
2. According to the International Building Code (IBC), the minimum
headroom for a stairway is:
A. 6 feet 6 inches
B. 6 feet 8 inches
C. 6 feet 8 inches
D. 7 feet 0 inches
IBC requires a minimum stairway headroom of 6 feet 8 inches to
ensure safe passage without obstruction.
3. What is the maximum distance a water service pipe can run
horizontally before a support is required according to IPC?
A. 3 feet
B. 4 feet
, C. 5 feet
D. 6 feet
The IPC mandates that horizontal water service piping be supported
at intervals not exceeding 5 feet to prevent sagging and maintain
proper flow.
4. Which type of vent is used to relieve pressure and prevent siphoning
in a plumbing system?
A. Circuit vent
B. Loop vent
C. Air admittance valve (AAV)
D. Stack vent
An AAV allows air into the drainage system to prevent siphoning
while avoiding odors, maintaining proper venting without
penetrating the roof.
5. When inspecting a mechanical system, what is the recommended
minimum clearance around a furnace for service access?
A. 12 inches
B. 18 inches
C. 30 inches
D. 36 inches
A minimum of 30 inches clearance is required around a furnace to
allow safe maintenance and service access according to mechanical
codes.
6. In fire-rated assemblies, which material is commonly used to maintain
a fire-resistance rating for penetrations?
A. Fiberglass
B. Foam insulation
C. Intumescent sealant
D. Cement plaster
Intumescent sealants expand when exposed to heat, sealing
penetrations and preserving the fire-resistance rating of walls and
floors.
7. For residential gas piping, the maximum allowable pressure for natural
gas systems is:
A. 1 psi
, B. 0.5 psi
C. 2 psi
D. 5 psi
Residential natural gas systems are limited to 0.5 psi to ensure safe
operation and reduce the risk of leaks or explosion.
8. Which device is used to prevent backflow in a potable water system?
A. Check valve
B. Backflow preventer
C. Pressure regulator
D. Gate valve
A backflow preventer stops contaminated water from flowing back
into the potable water supply, maintaining water safety.
9. When inspecting a commercial kitchen hood, the minimum clearance
from combustible materials is:
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
NFPA and mechanical codes require at least 18 inches between a
commercial hood and combustible materials to prevent fire hazards.
10. According to code, what is the minimum slope required for a
horizontal drainage pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A slope of 1/4 inch per foot ensures proper drainage and prevents
stagnant water or blockages in horizontal pipes.
11. Which type of insulation is typically required for mechanical
ductwork to prevent condensation?
A. Fiberglass
B. Foil-faced fiberglass
C. Mineral wool
D. Spray foam
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary purpose of a combination
inspector?
A. Installing mechanical systems
B. Designing plumbing systems
C. Ensuring compliance with building, plumbing, and mechanical
codes
D. Performing energy efficiency audits
A combination inspector’s main role is to verify that building,
plumbing, and mechanical systems comply with applicable codes and
regulations.
2. According to the International Building Code (IBC), the minimum
headroom for a stairway is:
A. 6 feet 6 inches
B. 6 feet 8 inches
C. 6 feet 8 inches
D. 7 feet 0 inches
IBC requires a minimum stairway headroom of 6 feet 8 inches to
ensure safe passage without obstruction.
3. What is the maximum distance a water service pipe can run
horizontally before a support is required according to IPC?
A. 3 feet
B. 4 feet
, C. 5 feet
D. 6 feet
The IPC mandates that horizontal water service piping be supported
at intervals not exceeding 5 feet to prevent sagging and maintain
proper flow.
4. Which type of vent is used to relieve pressure and prevent siphoning
in a plumbing system?
A. Circuit vent
B. Loop vent
C. Air admittance valve (AAV)
D. Stack vent
An AAV allows air into the drainage system to prevent siphoning
while avoiding odors, maintaining proper venting without
penetrating the roof.
5. When inspecting a mechanical system, what is the recommended
minimum clearance around a furnace for service access?
A. 12 inches
B. 18 inches
C. 30 inches
D. 36 inches
A minimum of 30 inches clearance is required around a furnace to
allow safe maintenance and service access according to mechanical
codes.
6. In fire-rated assemblies, which material is commonly used to maintain
a fire-resistance rating for penetrations?
A. Fiberglass
B. Foam insulation
C. Intumescent sealant
D. Cement plaster
Intumescent sealants expand when exposed to heat, sealing
penetrations and preserving the fire-resistance rating of walls and
floors.
7. For residential gas piping, the maximum allowable pressure for natural
gas systems is:
A. 1 psi
, B. 0.5 psi
C. 2 psi
D. 5 psi
Residential natural gas systems are limited to 0.5 psi to ensure safe
operation and reduce the risk of leaks or explosion.
8. Which device is used to prevent backflow in a potable water system?
A. Check valve
B. Backflow preventer
C. Pressure regulator
D. Gate valve
A backflow preventer stops contaminated water from flowing back
into the potable water supply, maintaining water safety.
9. When inspecting a commercial kitchen hood, the minimum clearance
from combustible materials is:
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
NFPA and mechanical codes require at least 18 inches between a
commercial hood and combustible materials to prevent fire hazards.
10. According to code, what is the minimum slope required for a
horizontal drainage pipe?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A slope of 1/4 inch per foot ensures proper drainage and prevents
stagnant water or blockages in horizontal pipes.
11. Which type of insulation is typically required for mechanical
ductwork to prevent condensation?
A. Fiberglass
B. Foil-faced fiberglass
C. Mineral wool
D. Spray foam
