PEP common mistakes
PEP · Understand the traps and how to avoid them.
Applying a formula from memory without checking the units of every input first, then reporting a numeric answer in mixed units (e.g., mixing psi and MPa, inches and mm, or lbm and lbf in the same equation).
The exam intentionally mixes US customary and SI data across problems, and candidates under time pressure pattern-match a familiar formula and plug in the numbers as printed rather than converting to a consistent base.
What to do instead
Before substituting, write every given quantity with its unit, convert to a single consistent system (and to absolute pressure/temperature where required), and carry units through the algebra so the final unit is checked dimensionally. Practice a set of 20 mixed-unit drill problems where the only required work is conversion and dimensional check.
Treating a thermodynamics or fluid problem as an ideal, reversible process when the problem statement implies irreversibility or a real device (friction, throttling, finite temperature difference), then using the isentropic relation to find the exit state.
Coursework problems are usually idealized, so candidates reflexively apply isentropic or Bernoulli relations without checking whether the problem gives an efficiency, a pressure drop, or a stated irreversibility.
What to do instead
Read the problem statement and list every stated loss or efficiency before choosing a model. If an isentropic efficiency or a throttling process is stated, use the real relation (h2 = h1 - eta*(h1 - h2s) for a turbine, h constant for a throttle). Build a one-page decision tree mapping problem cues to the correct model.
Jumping to a final answer without a free-body diagram or a clearly drawn control volume, then missing a reaction, a moment, or a pressure force that was not in the obvious direction.
Candidates who are strong in the math skip the sketch to save time, but statics and mechanics problems frequently hinge on a support reaction or a distributed load resultant that is only visible once the system is drawn.
What to do instead
Make the free-body diagram or control volume a mandatory, non-negotiable first step for every mechanics or fluids problem. Mark every unknown reaction, resolve distributed loads to a resultant with a location, and only then write equilibrium equations. Time yourself doing this so it costs under 60 seconds.
Reciting a code clause or a standard's requirement from memory (e.g., a specific allowable stress, a required safety factor, or a clearance) without confirming which edition or which section the exam references.
The codes, standards, and regulations domain rewards precise citation, but candidates study summary tables and forget that values change between editions and that the exam may reference a specific edition in the problem statement.
What to do instead
For every code-related fact you memorize, attach the standard designation, section number, and edition. When a problem cites an edition, use only that edition's values. Practice problems that deliberately give an older edition to train you to read the citation line first.
Answering an ethics or professional-practice question by choosing the option that protects the client or employer's interest, rather than the option that protects public safety and complies with the licensure obligation.
Candidates transfer a workplace loyalty instinct into the exam, and the exam's ethics items are written so that the 'loyal' answer is a distractor when it conflicts with public welfare or a legal duty to report.
What to do instead
Adopt a fixed priority order for every ethics item: public safety and welfare first, then legal/regulatory duty, then contractual obligation, then employer or client preference. Run each answer choice through that order explicitly and reject any choice that subordinates safety to loyalty.
Skipping the professional-practice items or treating them as free points, spending all study time on calculation-heavy topics, and then losing easy marks on licensure, records, and safety-program questions.
Candidates assume the non-quantitative domain is common sense and allocate study time proportional to perceived difficulty, not to the number of items or the pass margin.
What to do instead
Budget a fixed share of study time to professional practice and ethics proportional to its weight in the exam specification, and drill scenario-based items (conflicts of interest, sealing documents, safety reporting) rather than reading rules passively. Track your accuracy by domain so weak non-technical areas are visible.
Forgetting to check the reasonableness of a computed answer (sign, magnitude, order of magnitude) before selecting it, and choosing a distractor that matches an intermediate step rather than the requested quantity.
Distractors are built from common intermediate results and unit errors, and candidates under time pressure match their last computed number to an answer choice instead of confirming it answers the question actually asked.
What to do instead
After computing, restate the question in one line and confirm your number answers that line. Sanity-check magnitude against physical intuition (a pump efficiency above 100 percent or a stress above yield is a red flag). Deliberately practice items where the intermediate value appears as a distractor.
Misreading the question stem's qualifiers ('least', 'except', 'most nearly', 'not required') and answering the inverse of what was asked.
These items are designed to test careful reading, and candidates scan for a familiar technical term and answer the associated concept rather than the logical form of the question.
What to do instead
Underline or mentally flag every qualifier in the stem before looking at the options, and for negative stems rewrite the question in positive form. Build a personal checklist of qualifier words and apply it to every item in timed practice.
Using a single reference value (e.g., a material property, a standard atmosphere value, or a conversion factor) without noting its conditions, then applying it outside those conditions (temperature, pressure, alloy, or grade).
Reference tables are memorized as single numbers, but properties such as yield strength, viscosity, and density vary with temperature and grade, and the exam supplies conditions that change the correct value.
What to do instead
For each memorized property, store the condition it applies to alongside the number. When a problem states a temperature, grade, or pressure, check whether the property must be adjusted or looked up rather than recalled. Practice problems that give two grades of the same material to force the distinction.
Running out of time because calculation items are worked at full precision and full derivation, leaving the final items unanswered even though they may be conceptual and quick.
Candidates treat every item as equally costly and refuse to skip, so a single hard calculation consumes the time budget for several easy items.
What to do instead
Adopt a two-pass strategy: on the first pass answer only items you can complete quickly, flag the rest, and return with remaining time. Cap any single calculation at a set time limit and move on. Practice full-length timed sets to calibrate your per-item pace and rehearse the skip-and-return habit.