The following items will test your knowledge of the material covered in this lesson. There is only one correct
answer for each item. When you complete the exercise, check your answers with the appropriate answer key at
the end of this subcourse. If you answer any items incorrectly, go back to the part of the lesson that contains the
information involved and study again.
1. What type of tank has a bolted steel cone roof tank?
A. Floating roof tank.
B. Fixed roof tank.
C. Cone roof with floating pan.
D. Cut and cover tank.
2. What is installed on the roofs of floating roof tanks to facilitate gaging?
A. Flame arrester.
B. Gage hatch.
3. What is the most commonly used method of vapor freeing?
A. Mechanical ventilation.
B. Forced ventilation.
C. Natural ventilation.
D. Steam ventilation.
4. What is used to indicate the concentration of vapors as percent of the lower combustible limit?
C. Oxygen detector.
D. Vacuum truck.
5. What is considered a dangerous concentration of oxygen?
A. Less than 21 percent.
B. Less than 14 percent
C. Less than 9 percent.
D. Less than 7 percent.