4th Class Power Engineering plant drawings and communication practice questions (4A).

Five free practice questions on plant drawings and communication: unit J of paper A (4A) of the 4th Class Power Engineer certificate exam, written to the SOPEEC syllabus. They are in the exam's format: four options, one correct answer. Answer each one before opening the explanation. No account, no email.

01The questions

1. Procedural · Recognize standard views of an object

   A horizontal cylindrical tank is drawn in front, top and right-side orthographic views, with its full length showing in the front view. In which other view does the tank's length also appear?

   1. In the right-side view
   2. In the top (plan) view
   3. In an auxiliary view only
   4. In neither of the other views
   Show the answer

   B. Correct. The front and top views share the width direction, so a length that runs left to right in the front view also shows at full length in the top view, as a rectangle as deep as the tank's diameter. The right-side view looks along the axis and shows the circular end.

   Why not the others

   A. The right-side view looks along the tank's axis, so it shows the circular end and the tank's diameter, not its length. The length appears in the front and top views, which share the width direction.

   C. Auxiliary views are needed for surfaces inclined to the principal planes. A horizontal tank lies parallel to them, so its length shows at full size in the top view as well as the front view.

   D. Each principal dimension appears in two of the three views. Width (here the tank's length) shows in both the front and the top views; height in front and side; depth in top and side.

2. Recall · Explain the use of process flow diagrams (PFDs)

   A new operator wants one drawing that shows the plant's major equipment and main process streams with their design flows, temperatures and pressures, without every valve and instrument. Which drawing is that?

   1. The general arrangement drawing
   2. The piping and instrumentation diagram (P&ID)
   3. The process flow diagram (PFD)
   4. The block diagram
   Show the answer

   C. Correct. A process flow diagram shows the major equipment and the main streams between them, usually with the design flows, temperatures and pressures, and leaves out the minor piping, valves and instruments. It is the best drawing for learning how a process works before studying the detail.

   Why not the others

   A. A general arrangement drawing shows where equipment physically sits, to scale, in plan and elevation. It does not show the process streams or their flows, temperatures and pressures; the PFD does.

   B. A P&ID adds every line, valve, instrument and control loop to the equipment, which makes it the detailed working drawing, not the simplified overview asked for. The overview with design conditions is the PFD.

   D. A block diagram shows whole plant sections as boxes joined by lines. It is simpler still and does not show the individual major equipment or design conditions of each stream, which the PFD does.

3. Recall · Discuss the elements of Maintenance Management Systems, including work requests and work orders

   In a maintenance management system, what does a work order do that a work request does not?

   1. It logs the plant's operating readings for the shift
   2. It reports that a defect exists and needs to be looked at
   3. It isolates and locks out the equipment for the crew
   4. It authorizes the job and plans its labour and materials
   Show the answer

   D. Correct. A work request only reports a problem. Once it is reviewed and approved it becomes a work order: the document that authorizes the job and plans it, with the trades, parts, priority and safety requirements, and that is closed out when the work is done.

   Why not the others

   A. Operating readings go on log sheets and in the log book. A work order is a maintenance document that authorizes and plans a job.

   B. Reporting a defect is the job of the work request, usually raised by whoever finds the problem. The work order comes after review and approval and authorizes and plans the job.

   C. Isolation is done under the plant's lockout procedure and work permits, not by a maintenance document. The work order authorizes and plans the job, and may list the isolation needed, but does not isolate anything.

4. Recall · Recognize cross hatching methods in sectional drawings

   A sectional drawing of a gate valve cuts through the body and the bonnet where they bolt together. How does the drawing show that these are two separate parts?

   1. A hidden line is drawn along the joint between them
   2. Only the body is hatched, and the bonnet is left clear
   3. Each part's hatching runs in a different direction
   4. Both are hatched alike and labelled with leaders
   Show the answer

   C. Correct. Every part cut by the cutting plane is hatched, and adjoining parts are hatched at different angles or in opposite directions so the boundary between them shows. All cut areas of one part keep the same hatching, so a part can be followed across the view.

   Why not the others

   A. Hidden (dashed) lines show edges behind a surface and are normally left out of section views. The boundary between two cut parts is shown by hatching them in different directions.

   B. Leaving a cut part unhatched would make it look as if the plane did not pass through it. Both cut parts are hatched, at different angles, so the joint between them shows.

   D. Identical hatching makes two adjoining parts read as one piece; labels name parts but do not show where one ends. Adjoining parts are hatched in different directions.

5. Procedural · Explain the layout of plant diagrams

   Tracing the condensate return on a P&ID, you reach a line that ends at an arrow-shaped flag marked with another drawing number. What does the flag tell you?

   1. The line is capped at that point and goes no further
   2. The line continues on the drawing with that number
   3. The line was removed in the revision with that number
   4. The line's piping specification is shown on that drawing
   Show the answer

   B. Correct. An off-page (continuation) connector shows that the line leaves this sheet and carries on, on the drawing named in the flag, where a matching connector points back. Following the connectors from sheet to sheet is how a whole system is traced.

   Why not the others

   A. A capped or blanked line has its own symbol, a cap or blind, at the line end. A flag carrying another drawing number is a continuation connector: the line carries on, on that drawing.

   C. Removed items are recorded in the revision block and taken off the drawing, not flagged with a drawing number. The flag means the line continues on the drawing it names.

   D. A line's specification is carried in its line number and the piping class it refers to, not in an arrow flag. The flag is an off-page connector: the line continues on that drawing.

02Answer key

03What unit J covers

Reading and making plant drawings and keeping plant records: freehand sketches, centre lines and dimensions, orthographic views and sectional hatching, piping symbols and line tracing, PFDs, P&IDs and general arrangement drawings, instrument tags, two-way radio use, log books, work requests and work orders, control of operating procedures, and updating P&IDs after a change.

The SOPEEC 4th Class syllabus names this unit “Plant Communication” (ABSA numbers it A10) and lists three objectives under it. SOPEEC does not publish how many exam questions come from each unit, and neither do the ABSA, Technical Safety BC, TSASK or TSSA pages we checked. The right-hand column is how many questions our bank holds on each objective, Standard and Advanced together, not a count from the exam.

04What the questions turn on

Pick the drawing for the job

A process flow diagram shows the major equipment and main streams with their design conditions. A P&ID shows the valves and instrument loops. A general arrangement drawing shows true positions and sizes, so clearances can be checked.

Read instrument tags letter by letter

The first letter of an instrument tag is the measured variable and the letters after it are functions. PT is a pressure transmitter, PIC a pressure indicating controller and TI a temperature indicator with no output to anything.

Log books are legal records

Log entries are made in ink as events happen, and nothing is erased, covered or removed. A wrong entry gets a single line through it, with the correct value and the writer's initials beside it.

Work from the approved revision

The controlled-document list, not the date on a printout, says which procedure revision is current. After a plant change the P&ID is red-lined, then the master is revised, given the next revision number and reissued.

05The other units

Paper 4A has twelve units, A to L. Each has its own page of free questions:

The 4th Class Power Engineering practice exam (4A) page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.