Arkansas AR-IM Industrial
Mechanical Contractor Practice
Exam | Questions, Verified
Answers & Detailed Rationales |
Complete Contractor License
Exam Prep Study Guide |
Updated 2026
1. What is the primary purpose of a pressure relief valve
on a pressurized mechanical system?
A. To increase system pressure
B. To regulate temperature
C. To protect the system from excessive pressure
D. To eliminate all system vibration
Answer: To protect the system from excessive pressure
Rationale: A pressure relief valve opens when pressure
reaches its set point, preventing the pressure vessel or
piping system from exceeding its allowable pressure.
2. Which material is commonly used for industrial
process piping because of its corrosion resistance?
A. Unprotected carbon steel
B. Stainless steel
C. Untreated wood
D. Gypsum board
Answer: Stainless steel
Rationale: Stainless steel provides good corrosion
resistance and is widely used in chemical, food-
,processing, pharmaceutical, and other industrial
applications.
3. What does NPS stand for in piping terminology?
A. Nominal Pressure Standard
B. National Pipe Schedule
C. Nominal Pipe Size
D. Normal Pressure System
Answer: Nominal Pipe Size
Rationale: NPS is the standardized designation used to
identify pipe size. It does not necessarily equal the
actual measured inside or outside diameter.
4. What is the purpose of a pipe support system?
A. Increase fluid temperature
B. Increase pipe roughness
C. Support piping and control movement and loads
D. Reduce pipe diameter
Answer: Support piping and control movement and
loads
Rationale: Proper supports carry the weight of piping,
valves, insulation, and contents while controlling
movement caused by thermal expansion and operating
forces.
5. Which valve is generally designed primarily for on/off
service rather than throttling?
A. Globe valve
B. Needle valve
C. Gate valve
D. Balancing valve
,Answer: Gate valve
Rationale: Gate valves are normally used as isolation
valves. Keeping them fully open or fully closed helps
minimize damage and pressure loss.
6. What is the main function of a check valve?
A. Control temperature
B. Reduce pipe size
C. Prevent reverse flow
D. Increase pump speed
Answer: Prevent reverse flow
Rationale: A check valve permits flow in the intended
direction and closes automatically when flow attempts
to reverse.
7. Which fitting is used to change the direction of a pipe
run?
A. Coupling
B. Union
C. Elbow
D. Reducer
Answer: Elbow
Rationale: Elbows are manufactured in different angles,
with 90-degree and 45-degree elbows among the most
common.
8. What is the primary purpose of a pipe reducer?
A. Increase pressure automatically
B. Connect different pipe sizes
C. Remove air from piping
D. Measure flow
, Answer: Connect different pipe sizes
Rationale: A reducer transitions piping from one
nominal diameter to another.
9. What does a pump primarily do in a mechanical piping
system?
A. Generate electricity
B. Add energy to a fluid to produce flow
C. Remove all dissolved gases
D. Measure pipe thickness
Answer: Add energy to a fluid to produce flow
Rationale: Pumps transfer mechanical energy to liquids,
creating the pressure difference needed to move fluid
through piping and equipment.
10. What is pump cavitation?
A. Excessive pipe insulation
B. Formation and collapse of vapor bubbles in the liquid
C. Electrical grounding
D. Pipe expansion caused by heat
Answer: Formation and collapse of vapor bubbles in the
liquid
Rationale: Cavitation occurs when local pressure falls
below the liquid's vapor pressure. It can cause noise,
vibration, reduced performance, and damage to the
pump.
11. What does NPSH refer to in pump applications?
A. Nominal Pipe System Height
B. National Pump Safety Handbook
Mechanical Contractor Practice
Exam | Questions, Verified
Answers & Detailed Rationales |
Complete Contractor License
Exam Prep Study Guide |
Updated 2026
1. What is the primary purpose of a pressure relief valve
on a pressurized mechanical system?
A. To increase system pressure
B. To regulate temperature
C. To protect the system from excessive pressure
D. To eliminate all system vibration
Answer: To protect the system from excessive pressure
Rationale: A pressure relief valve opens when pressure
reaches its set point, preventing the pressure vessel or
piping system from exceeding its allowable pressure.
2. Which material is commonly used for industrial
process piping because of its corrosion resistance?
A. Unprotected carbon steel
B. Stainless steel
C. Untreated wood
D. Gypsum board
Answer: Stainless steel
Rationale: Stainless steel provides good corrosion
resistance and is widely used in chemical, food-
,processing, pharmaceutical, and other industrial
applications.
3. What does NPS stand for in piping terminology?
A. Nominal Pressure Standard
B. National Pipe Schedule
C. Nominal Pipe Size
D. Normal Pressure System
Answer: Nominal Pipe Size
Rationale: NPS is the standardized designation used to
identify pipe size. It does not necessarily equal the
actual measured inside or outside diameter.
4. What is the purpose of a pipe support system?
A. Increase fluid temperature
B. Increase pipe roughness
C. Support piping and control movement and loads
D. Reduce pipe diameter
Answer: Support piping and control movement and
loads
Rationale: Proper supports carry the weight of piping,
valves, insulation, and contents while controlling
movement caused by thermal expansion and operating
forces.
5. Which valve is generally designed primarily for on/off
service rather than throttling?
A. Globe valve
B. Needle valve
C. Gate valve
D. Balancing valve
,Answer: Gate valve
Rationale: Gate valves are normally used as isolation
valves. Keeping them fully open or fully closed helps
minimize damage and pressure loss.
6. What is the main function of a check valve?
A. Control temperature
B. Reduce pipe size
C. Prevent reverse flow
D. Increase pump speed
Answer: Prevent reverse flow
Rationale: A check valve permits flow in the intended
direction and closes automatically when flow attempts
to reverse.
7. Which fitting is used to change the direction of a pipe
run?
A. Coupling
B. Union
C. Elbow
D. Reducer
Answer: Elbow
Rationale: Elbows are manufactured in different angles,
with 90-degree and 45-degree elbows among the most
common.
8. What is the primary purpose of a pipe reducer?
A. Increase pressure automatically
B. Connect different pipe sizes
C. Remove air from piping
D. Measure flow
, Answer: Connect different pipe sizes
Rationale: A reducer transitions piping from one
nominal diameter to another.
9. What does a pump primarily do in a mechanical piping
system?
A. Generate electricity
B. Add energy to a fluid to produce flow
C. Remove all dissolved gases
D. Measure pipe thickness
Answer: Add energy to a fluid to produce flow
Rationale: Pumps transfer mechanical energy to liquids,
creating the pressure difference needed to move fluid
through piping and equipment.
10. What is pump cavitation?
A. Excessive pipe insulation
B. Formation and collapse of vapor bubbles in the liquid
C. Electrical grounding
D. Pipe expansion caused by heat
Answer: Formation and collapse of vapor bubbles in the
liquid
Rationale: Cavitation occurs when local pressure falls
below the liquid's vapor pressure. It can cause noise,
vibration, reduced performance, and damage to the
pump.
11. What does NPSH refer to in pump applications?
A. Nominal Pipe System Height
B. National Pump Safety Handbook
