Ch. 2

Question 1

658. Calculate the minimum required wall thickness of a superheater tube. The tube is 40 mm O.D. and is connected to a header by strength welding. The maximum allowable working pressure is 2000 kPa gauge and the average tube temperature is 212°C. The tube material is alloy steel with specification SA-213-T11.
     a. 1.0 mm
     b. 0.25 mm
     c. 0.5846 mm
     d. 0.7546 mm

Answer 1

c. 0.5846 mm

Question 2

659. Calculate the minimum required wall thickness of a superheater tube. The tube is 100 mm O.D. and is connected to a header by strength welding. The maximum allowable working pressure is 2430 kPa gauge and the average tube temperature is 375°C. The tube material is alloy steel with specification SA-192.
     a. 5.025 mm
     b. 1.58 mm
     c. 3.258 mm
     d. 2.014 mm

Answer 2

d. 2.014 mm

Question 3

660. Calculate the maximum allowable working pressure, in kPa, for a watertube boiler tube, which is 73.5 mm O.D. and has a minimum wall thickness of 4.71 mm. The tube is strength-welded into place in the boiler and is located in the furnace area of the boiler. Tube material is carbon steel, SA-192, with a mean wall temperature of 370°C.
     a. 8.52 Mpa
     b. 9.921 Mpa
     c. 10.59 Mpa
     d. 22 Mpa

Answer 3

c. 10.59 Mpa

Question 4

661. Calculate the minimum required wall thickness of a boiler tube which is strength welded to a header. The maximum allowable working pressure is 4450 kPa, and the mean wall temperature is 370°C. The tube material is SA-192 and the outside diameter is 50 mm.
     a. 3.14 mm
     b. 1.62 cm
     c. 1.62 mm
     d. 3.26 cm

Answer 4

c. 1.62 mm

Question 5

662. Calculate the maximum allowable working pressure, in kPa, for a watertube boiler tube, which is 76 mm O.D. and has a minimum wall thickness of 3.25 mm. The tube is strength-welded into place in the boiler and is located in the furnace area of the boiler. Tube material is carbon steel, SA-192, with a mean wall temperature of 375°C.
     a. 6.2 Mpa
     b. 7.5 Mpa
     c. 5.2 Mpa
     d. 9.0 Mpa

Answer 5

a. 6.2 Mpa

Question 6

663. Calculate the minimum required wall thickness of a superheater tube. The tube is 76 mm O.D. and is connected to a header by strength welding. The maximum allowable working pressure is 4150 kPa gauge and the average tube temperature is 400°C. The tube material is alloy steel with specification SA-213-T11.
     a. 2.125 mm
     b. 1.88 mm
     c. 1.5 mm
     d. 1.0 mm

Answer 6

b. 1.88 mm

Question 7

664. Calculate the minimum required plate thickness of a welded boiler drum having an inside radius of 935 mm and a maximum design working pressure of 9020 kPa. The plate material is SA-516 grade 70 and metal temperature does not exceed 320°C. Weld reinforcement on the longitudinal joints has been removed flush with the surface of the plate.
     a. 72.96 mm
     b. 55 mm
     c. 62.96 mm
     d. 83.55 mm

Answer 7

a. 72.96 mm

Question 8

665. Calculate the minimum thickness required for a welded steel pipe of material SA-209 grade T1b, plain end. The outside diameter of the pipe is 273.05 mm and the operating pressure and temperature are 2000 kPa and 400°C, respectively.
     a. 0.304 mm
     b. 3.04 mm
     c. 2.68 mm
     d. 2.68 cm

Answer 8

b. 3.04 mm

Question 9

666. A steam header between the boiler and first stop valve is to be fabricated of 152.4 mm O.D. pipe. The material specification is SA-369 FPA seamless pipe. The operating pressure will be 8440 kPa at 420°C. The pipe will be joined by full penetration welds and will be fully radiographed. Calculate the minimum thickness of the pipe wall if the manufacturer’s tolerance is 12.5%.
     a. 12.04 mm
     b. 15 mm
     c. 25.36 mm
     d. 10.90 mm

Answer 9

d. 10.90 mm

Question 10

667. A boiler drum is made of SA-515-70 steel and has a ligament efficiency of 0.66. If the steam temperature is 280°C and the inside diameter of the drum is 1.6 m and the thickness of the drum is 68.45 mm. What will the maximum operating pressure be, in kPa?
     a. 2500 kPa
     b. 6500 kPa
     c. 7500 kPa
     d. 5200 kPa

Answer 10

b. 6500 kPa

Question 11

668. Calculate the required minimum thickness (in mm) of steam piping which will carry steam at a pressure of 4300 kPa gauge and a temperature of 370°C. The piping is plain-end, 273.05 mm O.D.; the material is low alloy steel, SA-335 P11. A manufacturer’s tolerance of 12.5% must be added to the pipe.
     a. 5.61 mm + tolerance = 6.31 mm
     b. 6.51 mm + tolerance = 7.21 mm
     c. 8.55 mm + tolerance = 9.55 mm
     d. 5.00 mm + tolerance = 6.00 mm

Answer 11

a. 5.61 mm + tolerance = 6.31 mm

Question 12

669. Calculate the minimum thickness required for a seamless steel feedwater pipe of material SA-209, grade T1. The outside diameter of the pipe is 323.85 mm and the operating pressure and temperature are 5200 kPa and 500°C respectively. The pipe is plain-ended. Assume that the material is an austenitic steel.
     a. 12.66 mm
     b. 15.85 mm
     c. 9.95 mm
     d. 11.85 mm

Answer 12

d. 11.85 mm

Question 13

670. Calculate the required thickness, in mm, of a superheater outlet header, operating at 500°C and having a maximum allowable working pressure of 17 MPa. The header material is SA-335-P7 and the outside diameter is 457.2 mm.
     a. 54.35 mm
     b. 45.23 mm
     c. 22.14 mm
     d. 38.26 mm

Answer 13

a. 54.35 mm

Question 14

671. Calculate the maximum allowable working pressure for a welded drum if the plates are 25 mm thick and of material SA-299. The inside diameter of the drum is 988 mm and the joint efficiency is 100%. Assume the steam temperature will not exceed 400°C.
     a. 6.035 Mpa
     b. 5.305 Mpa
     c. 4.0 Mpa
     d. 7.225 Mpa

Answer 14

b. 5.305 Mpa

Question 15

672. Calculate the thickness of a seamless, unstayed dished head with pressure on the concave side, having a flanged-in manhole 280 mm by 380 mm. The head has a diameter of 1235 mm and is a segment of a sphere with a dish radius of 1016 mm. The maximum allowable working pressure is 1380 kPa, the material is SA-285 C and the metal temperature does not exceed 204°C.
     a. 18.37 mm
     b. 22 mm
     c. 38 mm
     d. 17.63 mm

Answer 15

a. 18.37 mm

Question 16

673. Calculate the thickness of a seamless, blank unstayed dished head having pressure on the concave side. The head has a diameter of 1067 mm and is a segment of a sphere with a dish radius of 915 mm. The maximum allowable working pressure is 2068 kPa and the material is SA-285 A. The metal temperature does not exceed 250°C.
     a. 25.27 mm
     b. 30.55 mm
     c. 19.33 mm
     d. 35.33 mm

Answer 16

a. 25.27 mm

Question 17

674. Calculate the thickness required for a dished seamless head, which is attached to a boiler having a shell diameter of 1200 mm. The head has a flanged-in manhole with one dimension equal to 150 mm. The head is a segment of a sphere with a dished radius of 1120 mm. The head material is SA-285 Grade C, the maximum allowable working pressure is 1930 kPa and the steam temperature does not exceed 260°C.
     a. 25 mm
     b. 35 mm
     c. 20.033 mm
     d. 23.7 mm

Answer 17

d. 23.7 mm

Question 18

675. Calculate the thickness of a seamless blank unstayed dished head having pressure on the concave side. The head has a diameter of 830 mm and is a segment of a sphere with a dish radius of 615 mm. The maximum allowable working pressure is 1650 kPa, the material is SA-299 and the metal temperature does not exceed 200°C.
     a. 8.77 mm
     b. 10.25 mm
     c. 5.22 mm
     d. 15 mm

Answer 18

a. 8.77 mm

Question 19

677. A seamless, welded, full-hemispherical head is welded to a boiler shell that has an inside diameter of 1100 mm. Maximum working pressure is 3500 kPa, the material is SA-226, and operating temperature is 300°C. The head has a flanged in manhole that meets code requirements. Calculate the minimum required thickness for the head.
     a. 45.55 mm
     b. 60.55 mm
     c. 22 mm
     d. 52.87 mm

Answer 19

a. 45.55 mm

Question 20

676. Calculate the minimum required thickness, in mm, for a blank, unstayed, full-hemispherical head, with the pressure on the concave side. The head is fabricated from seamless material and is double butt welded to the shell. All reinforcement is removed and fully radiographed. The radius to which the head is dished is 700 mm, maximum allowable working pressure is 4000 kPa, and the head material (SA-285 C) will not reach a temperature greater than 340°C. Use code 29.11.
     a. 30.79 cm
     b. 14.8 mm
     c. 30.16 mm
     d. 14.8 cm

Answer 20

b. 14.8 mm

Question 21

679. What is the minimum required thickness for a blank, full-hemispherical head if the material of construction is SA-515-65, operating temperature is 425°C, pressure is 1800 kPa, and the head is dished to a radius of 870 mm?
     a. 8.81 mm
     b. 9.81 cm
     c. 6.32 cm
     d. 9.81 mm

Answer 21

d. 9.81 mm

Question 22

678. Calculate the minimum required thickness for an unstayed full-hemispherical head with the pressure on the concave side if the head has the following specifications:
     1) Inside diameter = 1.0 m
     2) Pressure = 1500 kPa
     3) Temperature = 285°C
     4) Plate specification is SA-285 C

The head is fabricated from seamless material and is double butt welded to the shell. All weld reinforcement is removed and has a flanged-in manhole that complies with the code.
a. 22 mm
b. 38.45 mm
c. 16.15 mm
d. 28.59 mm

Answer 22

c. 16.15 mm

Question 23

The head is fabricated from seamless material and is double butt welded to the shell. All weld reinforcement is removed and has a flanged-in manhole that complies with the code.
a. 22 mm
b. 38.45 mm
c. 16.15 mm
d. 28.59 mm

Answer 23

c. 16.15 mm

Question 24

680. With reference to the Code a stoker-fired firetube boiler has 62 m2 of heating surface. How much steam must the safety valve on this boiler be capable of discharging per hour?
     a. 1587 kg/h
     b. 2815 kg/h
     c. 2108 kg/h
     d. 3269 kg/h

Answer 24

c. 2108 kg/h

Question 25

681. Utilizing the Code a watertube boiler is gas-fired and has 65 m2 of boiler heating surface, plus 85 m2 of waterwall surface. What is the minimum required relieving capacity for all the safety valves?
     a. 9815 kg/h
     b. 12000 kg/h
     c. 14500 kg/h
     d. 10000 kg/h

Answer 25

a. 9815 kg/h

Question 26

682. Utilizing the Code a watertube boiler, equipped with a superheater, has two safety valves on the steam drum and one safety valve on the superheater. The boiler is fired on pulverized coal and has 70 m2 of boiler surface, 95 m2 of waterwall surface, and 20 m2 of superheater surface. What is the minimum combined relieving capacity permitted for the steam drum safety valves?
     a. 9000 kg/h
     b. 7500 kg/h
     c. 6900 kg/h
     d. 8130 kg/h

Answer 26

d. 8130 kg/h

Question 27

683. Utilizing the Code a stoker-fired firetube boiler has 100 m2 of heating surface. How much steam must the safety valve on this boiler be capable of discharging per hour?
     a. 3400 kg/h
     b. 2850 kg/h
     c. 2500 kg/h
     d. 5500 kg/h

Answer 27

a. 3400 kg/h

Question 28

684. Utilizing the Code a watertube boiler is gas-fired and has 50 m2 of boiler heating surface, plus 70 m2 of waterwall surface. What is the minimum required relieving capacity for all the safety valves?
     a. 5452 kg/h
     b. 6500 kg/h
     c. 9800 kg/h
     d. 7910 kg/h

Answer 28

d. 7910 kg/h