Blueprint Reading & Interpretation Flashcards

On a plumbing blueprint, a dashed line adjacent to a backflow preventer symbol typically indicates:

Answer: A hidden or concealed pipe run

Dashed lines in blueprint conventions represent hidden features, such as pipes concealed within walls or underground.

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?

Answer: The centerline height of the assembly

Elevation dimensions on riser diagrams typically reference the centerline of the pipe or assembly unless otherwise noted.

Which symbol on a mechanical drawing most commonly represents a gate valve?

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.

When a blueprint legend lists 'BFP' next to a specific symbol, the tester should expect to find:

Answer: A backflow preventer at that location

BFP is a standard abbreviation for Backflow Preventer used in legends on plumbing and mechanical drawings.

A plan view drawing shows a double check valve assembly (DCVA) with a 'N.T.S.' notation. This means:

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.

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?

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).

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?

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.