UA STAR Pipefitter Certification Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a pipefitter in industrial settings?
To install, maintain, and repair piping systems
Pipefitters are responsible for assembling and maintaining piping
systems in factories, power plants, and other industrial facilities.
2. Which type of drawing shows the physical layout of piping and
equipment?
Isometric drawing
Isometric drawings represent three-dimensional layouts, helping
pipefitters visualize installations.
3. What is the standard angle for a common pipe elbow?
90 degrees
Elbows are typically manufactured in 90° and 45° to change pipe
direction.
4. Which schedule of steel pipe is commonly used for high-pressure
applications?
Schedule 80
Schedule 80 pipes have thicker walls than Schedule 40, making
them suitable for higher pressure systems.
,5. When threading a pipe, what is essential to apply to the threads?
Threading compound or pipe dope
Threading compound lubricates threads and prevents leaks in
threaded connections.
6. What is the purpose of a pipe support?
To hold the pipe in place and reduce stress
Supports prevent sagging, vibration, and excessive stress on the
piping system.
7. Which welding process is commonly used for stainless steel
piping?
TIG welding (GTAW)
TIG welding provides precise, high-quality welds ideal for stainless
steel applications.
8. What is the function of a pressure relief valve?
To protect the system from overpressure
Pressure relief valves open automatically to release excess
pressure and prevent equipment failure.
9. What is the standard pitch for tapered pipe threads (NPT)?
1/16 inch per inch of pipe diameter
NPT threads are tapered to ensure a tight seal as the threads are
engaged.
10. Which type of flange is designed to slip over the pipe before
welding?
Slip-on flange
Slip-on flanges slide over the pipe and are then fillet welded for
connection.
, 11. What is the proper method to measure pipe length for
cutting?
Measure from the centerline of fittings
Measuring from the centerline ensures correct alignment when
installed with elbows and tees.
12. Which material is commonly used for high-temperature
steam piping?
Carbon steel
Carbon steel can withstand high temperatures and pressures
common in steam systems.
13. What is the first step in reading a P&ID (Piping and
Instrumentation Diagram)?
Identify all equipment symbols
Understanding equipment symbols helps interpret the system and
process flow.
14. Which type of valve is commonly used for throttling service?
Globe valve
Globe valves allow precise flow control due to their adjustable disc
and seat design.
15. When performing a hydrostatic test, what is the medium
typically used?
Water
Water is incompressible, reducing the risk of explosive failure
compared to gases.
16. What is the purpose of a union in a piping system?
To allow easy disassembly and maintenance
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a pipefitter in industrial settings?
To install, maintain, and repair piping systems
Pipefitters are responsible for assembling and maintaining piping
systems in factories, power plants, and other industrial facilities.
2. Which type of drawing shows the physical layout of piping and
equipment?
Isometric drawing
Isometric drawings represent three-dimensional layouts, helping
pipefitters visualize installations.
3. What is the standard angle for a common pipe elbow?
90 degrees
Elbows are typically manufactured in 90° and 45° to change pipe
direction.
4. Which schedule of steel pipe is commonly used for high-pressure
applications?
Schedule 80
Schedule 80 pipes have thicker walls than Schedule 40, making
them suitable for higher pressure systems.
,5. When threading a pipe, what is essential to apply to the threads?
Threading compound or pipe dope
Threading compound lubricates threads and prevents leaks in
threaded connections.
6. What is the purpose of a pipe support?
To hold the pipe in place and reduce stress
Supports prevent sagging, vibration, and excessive stress on the
piping system.
7. Which welding process is commonly used for stainless steel
piping?
TIG welding (GTAW)
TIG welding provides precise, high-quality welds ideal for stainless
steel applications.
8. What is the function of a pressure relief valve?
To protect the system from overpressure
Pressure relief valves open automatically to release excess
pressure and prevent equipment failure.
9. What is the standard pitch for tapered pipe threads (NPT)?
1/16 inch per inch of pipe diameter
NPT threads are tapered to ensure a tight seal as the threads are
engaged.
10. Which type of flange is designed to slip over the pipe before
welding?
Slip-on flange
Slip-on flanges slide over the pipe and are then fillet welded for
connection.
, 11. What is the proper method to measure pipe length for
cutting?
Measure from the centerline of fittings
Measuring from the centerline ensures correct alignment when
installed with elbows and tees.
12. Which material is commonly used for high-temperature
steam piping?
Carbon steel
Carbon steel can withstand high temperatures and pressures
common in steam systems.
13. What is the first step in reading a P&ID (Piping and
Instrumentation Diagram)?
Identify all equipment symbols
Understanding equipment symbols helps interpret the system and
process flow.
14. Which type of valve is commonly used for throttling service?
Globe valve
Globe valves allow precise flow control due to their adjustable disc
and seat design.
15. When performing a hydrostatic test, what is the medium
typically used?
Water
Water is incompressible, reducing the risk of explosive failure
compared to gases.
16. What is the purpose of a union in a piping system?
To allow easy disassembly and maintenance
