BAT Blueprint Reading & Interpretation 2 — Questions and Answers
Question 1: On a plumbing blueprint, a dashed line adjacent to a backflow preventer symbol typically indicates:
- A future or proposed installation
- A hidden or concealed pipe run (Correct answer)
- A drain line below grade
- A non-potable water line
Correct answer: A hidden or concealed pipe run
Dashed lines in blueprint conventions represent hidden features, such as pipes concealed within walls or underground.
Question 2: A reduced pressure zone (RPZ) assembly is shown on a riser diagram at 18 inches above finished floor. What does this elevation indicate to the tester?
- The test cock height for gauge attachment
- The centerline height of the assembly (Correct answer)
- The height of the relief valve discharge port
- The minimum clearance above the floor drain
Correct answer: The centerline height of the assembly
Elevation dimensions on riser diagrams typically reference the centerline of the pipe or assembly unless otherwise noted.
Question 3: Which symbol on a mechanical drawing most commonly represents a gate valve?
- Two triangles pointing toward each other at their tips (Correct answer)
- A circle with an X inside
- A rectangle with a line through the center
- Two parallel lines with a diagonal cross
Correct answer: Two triangles pointing toward each other at their tips
Gate valves are conventionally shown as two triangles meeting at their tips (bow-tie shape) on mechanical and plumbing drawings.
Question 4: When a blueprint legend lists 'BFP' next to a specific symbol, the tester should expect to find:
- A backflow preventer at that location (Correct answer)
- A backflow prevention plan note
- A building floor plan reference
- A branch flow point in the piping
Correct answer: A backflow preventer at that location
BFP is a standard abbreviation for Backflow Preventer used in legends on plumbing and mechanical drawings.
Question 5: A plan view drawing shows a double check valve assembly (DCVA) with a 'N.T.S.' notation. This means:
- The drawing is not to a consistent scale (Correct answer)
- The assembly is not tested at startup
- The notes to specifications apply
- The device is a non-testable section
Correct answer: The drawing is not to a consistent scale
N.T.S. stands for 'Not To Scale,' indicating that the drawn dimensions should not be measured directly from the print.
Question 6: On a site utility plan, the water service line entering a building is shown with a bold solid line, while the sewer line is shown with a dashed bold line. What is the purpose of this distinction?
- Bold solid = pressurized supply; dashed bold = gravity drain (Correct answer)
- Bold solid = new work; dashed bold = existing work
- Bold solid = hot water; dashed bold = cold water
- Bold solid = potable; dashed bold = reclaimed water
Correct answer: Bold solid = pressurized supply; dashed bold = gravity drain
On utility plans, line weight and type differentiate pressurized supply lines (solid) from gravity-flow drain or sewer lines (dashed).
Question 7: A blueprint detail sheet shows a section cut through a backflow preventer vault. The cutting plane line is labeled 'A-A'. Where would you find the corresponding sectional view?
- On the same sheet or a referenced sheet labeled Section A-A (Correct answer)
- On the cover sheet of the drawing set
- In the project specifications book
- On the riser diagram sheet only
Correct answer: On the same sheet or a referenced sheet labeled Section A-A
Section cut labels like 'A-A' are matched to a corresponding sectional view drawing that is labeled with the same designation, either on the same sheet or a cross-referenced sheet.
BAT Blueprint Reading & Interpretation 2
On a plumbing blueprint, a dashed line adjacent to a backflow preventer symbol typically indicates: