Pipefitter Blueprint Reading and Symbols 4 — Questions and Answers
Question 1: On an isometric piping drawing, what does a dashed circle with an 'X' through it typically represent?
- A blind flange
- A spectacle blind in the closed position (Correct answer)
- A check valve
- A pressure gauge connection
Correct answer: A spectacle blind in the closed position
A dashed circle with an X indicates a spectacle blind (figure-8 blank) oriented in the closed/blinded position.
Question 2: Which line type on a piping drawing indicates a pipeline that is hidden behind another object or structure?
- Centerline (long dash, short dash)
- Phantom line (long dash, two short dashes)
- Hidden line (evenly spaced dashes) (Correct answer)
- Break line (freehand zigzag)
Correct answer: Hidden line (evenly spaced dashes)
Hidden lines are drawn as evenly spaced dashes to show features or pipes that exist but are concealed from the current view.
Question 3: On a P&ID, a triangle pointing downward connected to a pipe typically symbolizes what?
- A strainer or Y-type filter
- A steam trap
- A pressure reducing valve
- A drain point or funnel (Correct answer)
Correct answer: A drain point or funnel
A downward-pointing triangle or funnel symbol on a P&ID represents a drain point or open funnel drain.
Question 4: A pipefitter reads a drawing dimension noted as '6"-150# RF FLG'. What does '150#' indicate?
- The pipe schedule number
- The ANSI/ASME pressure class rating of the flange (Correct answer)
- The pipe wall thickness in mils
- The maximum flow rate in GPM
Correct answer: The ANSI/ASME pressure class rating of the flange
'150#' refers to the ANSI/ASME Class 150 pressure rating of the flange, defining its allowable pressure-temperature limits.
Question 5: In a plan view drawing, what do elevation markers (e.g., EL. 15'-6") on a piping drawing typically reference?
- The height of the pipe's centerline above the finished floor or datum (Correct answer)
- The depth of the pipe below grade
- The slope of the pipe in inches per foot
- The elevation of the support hanger above the pipe
Correct answer: The height of the pipe's centerline above the finished floor or datum
Elevation markers on plan view piping drawings indicate the height of the pipe centerline above an established datum, usually finished floor (EL. 0'-0").
Question 6: What does the abbreviation 'BW' mean when noted next to a fitting symbol on a piping drawing?
- Back weld
- Butt weld (Correct answer)
- Branch weld
- Bell and whistle (custom fitting)
Correct answer: Butt weld
'BW' stands for Butt Weld, indicating that the fitting end connection is a butt-welded joint rather than socket weld or threaded.
Question 7: On a piping isometric drawing, the notation 'SLOPED 1:100' along a pipe run means:
- The pipe rises 1 inch for every 100 feet of run
- The pipe drops 1 unit vertically for every 100 units of horizontal distance
- The pipe is installed at a 1% grade downward toward flow
- Both B and C are correct descriptions of the same slope (Correct answer)
Correct answer: Both B and C are correct descriptions of the same slope
A slope of 1:100 means 1 unit of vertical drop per 100 units of horizontal run, which is equivalent to a 1% downward grade — both B and C describe this correctly.
Pipefitter Blueprint Reading and Symbols 4
On an isometric piping drawing, what does a dashed circle with an 'X' through it typically represent?