Review of API-653 Exam Questions and 100% Correct Answers
Replacement shell plate may be circular,oblong,square with rounded corners or rectangular with
rounded corners except when: - Answer-an entire shell plate is replaced
Shell replacement patch plates shall be welded with butt joints with complete penetration and complete
fusion, except as: - Answer-permitted for lapped patch shell repairs
Joints in lap-welded shell tanks: - Answer-may be repaired according to the as-built standard of
construction
A 7/8 thick inch circular butt welded repair plate is installed in the 0.875" thick lower course of a tank.
What is the minimum weld spacing required from the vertical and horizontal plate welds of the lower
course? - Answer-10"&10"
Lapped patch shell repairs are: - Answer-an acceptable form or repairs for butt-welded,lap-welded, and
riveted tank shells only when specified by the owner.
Lapped patch shell repairs shall not be used on any shell course thickness (original construction) that
exceeds____ inch. - Answer-0.500
Lapped patch shell repairs shall not be used to replace : - Answer-door sheets or shell plates
Lapped patch plates shall not have a thickness less than: - Answer-0.1875 inches
If a lapped patch plate is installed on a tank,what corner(s) may be exempt from being rounded to a
minimum radius? - Answer-The joint at the shell to bottom intersection
, A lapped repair plate is installed across a butt-welded vertical seam.The seam is ground flush and
checked by ultrasonics.The inspector must specify the minimum overlap of the patch plate.What
minimum distance is selected? - Answer-6 inches beyond the shell seam .
Lapped repair plates positioned on the tank shell interior shall be located such that the toe-to-toe weld
clearances are a minimum of _____ to the shell-to-bottom weld. - Answer-6 inches
The maximum vertical and horizontal dimension of a lapped patch repair plate is: - Answer-48 inches
and 72 inches respectively
The minimum lapped patch shell repair plate dimension is: - Answer-4inches
An owner-user wants to put a NPS 8 shell opening (nozzle) in an AST shell. Which of the below would
not be acceptable to API 653? - Answer-within a lapped patch shell repair.
Prior to application of a lapped patch shell repair, the areas to be welded shall be _____ for plate
defects and remaining thicknesses. - Answer-UT'd
An inspector finds a 36inch by 48 inch lapped repair patch that had been installed on a shell that has a
thin area near the patch center. The owner- user asks that a lapped repair plate be installed on the old
lap patch.This installation: - Answer-is not permitted according to API 653.
What is the minimum hole diameter caused by the removal of an existing shell opening that may be
repaired by a lapped repair plate? - Answer-2 inches.
What joint efficiency is used to calculate the required thickness of a lapped repair plate installed over a
shell opening caused by the removal of an existing nozzle? - Answer-0.7
A NPS 3 nozzle is removed from the 0.325" thick third course of an AST. The reinforcing pad is removed
from around the nozzle and welds are ground smooth. The hole left by removing the NPS 3 nozzle is
Replacement shell plate may be circular,oblong,square with rounded corners or rectangular with
rounded corners except when: - Answer-an entire shell plate is replaced
Shell replacement patch plates shall be welded with butt joints with complete penetration and complete
fusion, except as: - Answer-permitted for lapped patch shell repairs
Joints in lap-welded shell tanks: - Answer-may be repaired according to the as-built standard of
construction
A 7/8 thick inch circular butt welded repair plate is installed in the 0.875" thick lower course of a tank.
What is the minimum weld spacing required from the vertical and horizontal plate welds of the lower
course? - Answer-10"&10"
Lapped patch shell repairs are: - Answer-an acceptable form or repairs for butt-welded,lap-welded, and
riveted tank shells only when specified by the owner.
Lapped patch shell repairs shall not be used on any shell course thickness (original construction) that
exceeds____ inch. - Answer-0.500
Lapped patch shell repairs shall not be used to replace : - Answer-door sheets or shell plates
Lapped patch plates shall not have a thickness less than: - Answer-0.1875 inches
If a lapped patch plate is installed on a tank,what corner(s) may be exempt from being rounded to a
minimum radius? - Answer-The joint at the shell to bottom intersection
, A lapped repair plate is installed across a butt-welded vertical seam.The seam is ground flush and
checked by ultrasonics.The inspector must specify the minimum overlap of the patch plate.What
minimum distance is selected? - Answer-6 inches beyond the shell seam .
Lapped repair plates positioned on the tank shell interior shall be located such that the toe-to-toe weld
clearances are a minimum of _____ to the shell-to-bottom weld. - Answer-6 inches
The maximum vertical and horizontal dimension of a lapped patch repair plate is: - Answer-48 inches
and 72 inches respectively
The minimum lapped patch shell repair plate dimension is: - Answer-4inches
An owner-user wants to put a NPS 8 shell opening (nozzle) in an AST shell. Which of the below would
not be acceptable to API 653? - Answer-within a lapped patch shell repair.
Prior to application of a lapped patch shell repair, the areas to be welded shall be _____ for plate
defects and remaining thicknesses. - Answer-UT'd
An inspector finds a 36inch by 48 inch lapped repair patch that had been installed on a shell that has a
thin area near the patch center. The owner- user asks that a lapped repair plate be installed on the old
lap patch.This installation: - Answer-is not permitted according to API 653.
What is the minimum hole diameter caused by the removal of an existing shell opening that may be
repaired by a lapped repair plate? - Answer-2 inches.
What joint efficiency is used to calculate the required thickness of a lapped repair plate installed over a
shell opening caused by the removal of an existing nozzle? - Answer-0.7
A NPS 3 nozzle is removed from the 0.325" thick third course of an AST. The reinforcing pad is removed
from around the nozzle and welds are ground smooth. The hole left by removing the NPS 3 nozzle is
