, Question 1
A high-pressure steam header (ASME B31.1) operates at 600 psig and 750°F.
The pipe material is ASTM A335 P22. Which of the following best explains
why the allowable stress value used in wall thickness calculation must be
adjusted for temperature?
A. Allowable stress decreases with temperature due to reduced yield
strength and creep effects.
B. Allowable stress increases with temperature because thermal
expansion reduces stress.
C. Allowable stress remains constant as long as pressure is constant.
D. Allowable stress is independent of material and depends only on pipe
diameter.
Correct Answer: A - Allowable stress decreases with temperature
due to reduced yield strength and creep effects.
RATIONALE
ASME B31.1 provides allowable stress values that decrease at
elevated temperatures due to material creep and loss of tensile
strength. Options B, C, and D are incorrect because they misrepresent
the temperature dependence of material properties and code
requirements.
Question 2
In a hydronic heating system, a pipe fitting with a Cv of 10 is installed in a
circuit with a flow rate of 20 GPM. What is the pressure drop across the
fitting?
A. 2 psi
B. 4 psi
C. 10 psi
D. 20 psi
Correct Answer: B - 4 psi
Page 2
, RATIONALE
Using the valve sizing equation P = (Q / Cv)^2, where Q is flow in
GPM and Cv is the flow coefficient, P = (20/10)^2 = 4 psi. Options A,
C, and D result from misapplication of the formula or unit errors.
Question 3
Which welding position is most challenging for producing a sound root pass in
a fixed 6-inch schedule 80 carbon steel pipe, and why?
A. 1G (flat) because gravity causes excessive penetration.
B. 5G (vertical) because the welder must manipulate the electrode against
gravity while maintaining consistent travel speed.
C. 6G (45° inclined) because it combines the difficulties of vertical and
overhead positions, requiring precise control to avoid defects.
D. 2G (horizontal) because the molten metal tends to sag, causing lack of
fusion.
Correct Answer: C - 6G (45° inclined) because it combines the
difficulties of vertical and overhead positions, requiring precise
control to avoid defects.
RATIONALE
The 6G position is considered the most difficult because it requires
welding in an inclined plane, simulating combined vertical and
overhead conditions, which challenges bead placement and
penetration. Options A, B, and D describe other positions but do not
capture the full complexity of 6G.
Question 4
A pipe support is required to accommodate 3 inches of vertical thermal
expansion in a 200-foot run of steel pipe. Which type of support is most
appropriate to allow movement while providing structural support?
A. Rigid rod hanger
Page 3
, B. Variable spring hanger
C. Constant spring hanger
D. Roller support
Correct Answer: C - Constant spring hanger
RATIONALE
Constant spring hangers maintain a nearly constant supporting force
throughout the travel range, ideal for large vertical movements where
load variation must be minimized. Variable spring hangers allow
movement but with load variation; rigid hangers and rollers do not
accommodate vertical expansion.
Question 5
When performing a hydrostatic test on a newly installed process piping system
per ASME B31.3, which condition must be met regarding test pressure and
temperature?
A. Test pressure must be at least 1.5 times the design pressure, and test
temperature must be at least 10°F above the minimum design metal
temperature to avoid brittle fracture.
B. Test pressure must be exactly equal to the design pressure, and test
temperature must be ambient.
C. Test pressure must be 1.25 times the design pressure, and test
temperature must be below 32°F to detect leaks.
D. Test pressure must be 2 times the design pressure, and test temperature
must be above 100°F.
Correct Answer: A - Test pressure must be at least 1.5 times the
design pressure, and test temperature must be at least 10°F above
the minimum design metal temperature to avoid brittle fracture.
Page 4
A high-pressure steam header (ASME B31.1) operates at 600 psig and 750°F.
The pipe material is ASTM A335 P22. Which of the following best explains
why the allowable stress value used in wall thickness calculation must be
adjusted for temperature?
A. Allowable stress decreases with temperature due to reduced yield
strength and creep effects.
B. Allowable stress increases with temperature because thermal
expansion reduces stress.
C. Allowable stress remains constant as long as pressure is constant.
D. Allowable stress is independent of material and depends only on pipe
diameter.
Correct Answer: A - Allowable stress decreases with temperature
due to reduced yield strength and creep effects.
RATIONALE
ASME B31.1 provides allowable stress values that decrease at
elevated temperatures due to material creep and loss of tensile
strength. Options B, C, and D are incorrect because they misrepresent
the temperature dependence of material properties and code
requirements.
Question 2
In a hydronic heating system, a pipe fitting with a Cv of 10 is installed in a
circuit with a flow rate of 20 GPM. What is the pressure drop across the
fitting?
A. 2 psi
B. 4 psi
C. 10 psi
D. 20 psi
Correct Answer: B - 4 psi
Page 2
, RATIONALE
Using the valve sizing equation P = (Q / Cv)^2, where Q is flow in
GPM and Cv is the flow coefficient, P = (20/10)^2 = 4 psi. Options A,
C, and D result from misapplication of the formula or unit errors.
Question 3
Which welding position is most challenging for producing a sound root pass in
a fixed 6-inch schedule 80 carbon steel pipe, and why?
A. 1G (flat) because gravity causes excessive penetration.
B. 5G (vertical) because the welder must manipulate the electrode against
gravity while maintaining consistent travel speed.
C. 6G (45° inclined) because it combines the difficulties of vertical and
overhead positions, requiring precise control to avoid defects.
D. 2G (horizontal) because the molten metal tends to sag, causing lack of
fusion.
Correct Answer: C - 6G (45° inclined) because it combines the
difficulties of vertical and overhead positions, requiring precise
control to avoid defects.
RATIONALE
The 6G position is considered the most difficult because it requires
welding in an inclined plane, simulating combined vertical and
overhead conditions, which challenges bead placement and
penetration. Options A, B, and D describe other positions but do not
capture the full complexity of 6G.
Question 4
A pipe support is required to accommodate 3 inches of vertical thermal
expansion in a 200-foot run of steel pipe. Which type of support is most
appropriate to allow movement while providing structural support?
A. Rigid rod hanger
Page 3
, B. Variable spring hanger
C. Constant spring hanger
D. Roller support
Correct Answer: C - Constant spring hanger
RATIONALE
Constant spring hangers maintain a nearly constant supporting force
throughout the travel range, ideal for large vertical movements where
load variation must be minimized. Variable spring hangers allow
movement but with load variation; rigid hangers and rollers do not
accommodate vertical expansion.
Question 5
When performing a hydrostatic test on a newly installed process piping system
per ASME B31.3, which condition must be met regarding test pressure and
temperature?
A. Test pressure must be at least 1.5 times the design pressure, and test
temperature must be at least 10°F above the minimum design metal
temperature to avoid brittle fracture.
B. Test pressure must be exactly equal to the design pressure, and test
temperature must be ambient.
C. Test pressure must be 1.25 times the design pressure, and test
temperature must be below 32°F to detect leaks.
D. Test pressure must be 2 times the design pressure, and test temperature
must be above 100°F.
Correct Answer: A - Test pressure must be at least 1.5 times the
design pressure, and test temperature must be at least 10°F above
the minimum design metal temperature to avoid brittle fracture.
Page 4
