API 653 CLOSED BOOK EXAM
QUESTIONS AND ANSWERS
100% PASS
Two methods of quantifying the remaining thickness of tank bottoms are mentioned in
API 653. One method uses the formula involving "MRT". What is the name of the other
method?
a. Deterministic and Analytic
b. Methodological and Non-destructive
c. Quantitative and Destructive
d. Probabilistic and Deterministic - ✔✔Probabilistic and Deterministic
What is the maximum out-of-plumbness allowed from the top of the shell to the bottom
of the shell on a 48' high tank?
a. 5.76"
b. 5.00"
c. 5.48"
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,d. 4.80" - ✔✔5.00"
Due to strength requirements, the minimum thickness of an annular plate ring is
usually greater than:
a. 0.187"
b. 0.125"
c. 0.100"
d. 0.250" - ✔✔0.100"
The joint between the new material of an insert plate and the old material of the existing
tank shell plate shall be:
a. Lap welded
b. Plug welded
c. Butt welded
d. Fillet welded - ✔✔Butt welded
A pressure test at least 1.5 times the __________ shall be performed on a nozzle installed
by hot tapping after the valve has been installed on it and prior to mounting the hot tap
machine.
a. Design head
b. Operating head
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,c. Working head
d. Hydrostatic head - ✔✔Hydrostatic head
Cone roof storage tanks may be as large as ______ feet in diameter.
a. 100'
b. 50'
c. 300'
d. 80' - ✔✔300'
The simplest type of floating roof is the:
a. Pan
b. Pontoon
c. Double deck
d. Cone - ✔✔Pan
An oxygen deficient atmosphere exists when a tank atmosphere has less than what
percent oxygen by volume?
a. 18.5%
c. 15.0%
b. 19.0%
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, d. 19.5% - ✔✔19.5%
Lead-in-Air analyzers must be designed to measure _______ Lead-in-Air
concentrations.
a. Organic
b. Inorganic
c. Radioactive
d. Liquid - ✔✔Organic
Entry into a confined space is considered to have occurred as soon as:
a. Half the entrant's body is inside the confined space.
b. The entrants head enters the confined space.
c. A part of the entrant's body breaks the plane of an opening into the space.
d. The entrant's head and shoulders enters the confined space. - ✔✔A part of the
entrant's body breaks the plane of an opening into the space.
When repairs involve most of the tank bottom, it may be desirable to displace the
flammable liquids beneath the tank by:
a. Purging with CO2
b. Purging with N2
c. Water flooding
EMILY CHARLENE © 2025, ALL RIGHTS RESERVED 4
QUESTIONS AND ANSWERS
100% PASS
Two methods of quantifying the remaining thickness of tank bottoms are mentioned in
API 653. One method uses the formula involving "MRT". What is the name of the other
method?
a. Deterministic and Analytic
b. Methodological and Non-destructive
c. Quantitative and Destructive
d. Probabilistic and Deterministic - ✔✔Probabilistic and Deterministic
What is the maximum out-of-plumbness allowed from the top of the shell to the bottom
of the shell on a 48' high tank?
a. 5.76"
b. 5.00"
c. 5.48"
EMILY CHARLENE © 2025, ALL RIGHTS RESERVED 1
,d. 4.80" - ✔✔5.00"
Due to strength requirements, the minimum thickness of an annular plate ring is
usually greater than:
a. 0.187"
b. 0.125"
c. 0.100"
d. 0.250" - ✔✔0.100"
The joint between the new material of an insert plate and the old material of the existing
tank shell plate shall be:
a. Lap welded
b. Plug welded
c. Butt welded
d. Fillet welded - ✔✔Butt welded
A pressure test at least 1.5 times the __________ shall be performed on a nozzle installed
by hot tapping after the valve has been installed on it and prior to mounting the hot tap
machine.
a. Design head
b. Operating head
EMILY CHARLENE © 2025, ALL RIGHTS RESERVED 2
,c. Working head
d. Hydrostatic head - ✔✔Hydrostatic head
Cone roof storage tanks may be as large as ______ feet in diameter.
a. 100'
b. 50'
c. 300'
d. 80' - ✔✔300'
The simplest type of floating roof is the:
a. Pan
b. Pontoon
c. Double deck
d. Cone - ✔✔Pan
An oxygen deficient atmosphere exists when a tank atmosphere has less than what
percent oxygen by volume?
a. 18.5%
c. 15.0%
b. 19.0%
EMILY CHARLENE © 2025, ALL RIGHTS RESERVED 3
, d. 19.5% - ✔✔19.5%
Lead-in-Air analyzers must be designed to measure _______ Lead-in-Air
concentrations.
a. Organic
b. Inorganic
c. Radioactive
d. Liquid - ✔✔Organic
Entry into a confined space is considered to have occurred as soon as:
a. Half the entrant's body is inside the confined space.
b. The entrants head enters the confined space.
c. A part of the entrant's body breaks the plane of an opening into the space.
d. The entrant's head and shoulders enters the confined space. - ✔✔A part of the
entrant's body breaks the plane of an opening into the space.
When repairs involve most of the tank bottom, it may be desirable to displace the
flammable liquids beneath the tank by:
a. Purging with CO2
b. Purging with N2
c. Water flooding
EMILY CHARLENE © 2025, ALL RIGHTS RESERVED 4
