DPLI Screening common mistakes
DPLI Screening · Understand the traps and how to avoid them.
Quoting a regulation clause, permit limit, or inspection interval from memory without confirming the current edition or site-specific permit condition, then building the whole answer on that recalled number.
Candidates study a summary table once and treat it as permanent; regulations get amended, and site permits can be stricter than the general rule, so the recalled figure is often outdated or inapplicable.
What to do instead
For every numeric answer, state the source you would verify (regulation section, permit condition, manufacturer data sheet) and note that the site-specific limit governs when stricter. Practise writing answers as 'value + where confirmed', not bare numbers.
Treating a hazard as isolated to the task at hand, ignoring simultaneous operations, adjacent crews, or energy sources that another worker controls.
Scenario questions are read linearly; candidates focus on the described task and miss the second sentence that mentions a parallel operation or a shared isolation point.
What to do instead
Before answering any safety scenario, list every energy source and every person affected, including those outside the immediate task. If the scenario mentions another crew or a shared system, address the interface explicitly in the answer.
Describing what inspection or test would be done but omitting the acceptance criterion, the instrument used, and the record produced.
Candidates know the procedure name and stop there, assuming the examiner will infer the rest; in practice the marks sit in the criterion and the evidence.
What to do instead
Structure every procedure answer as four parts: method, instrument/calibration status, acceptance criterion, and record. If any part is unknown, say what document it would be taken from.
Performing or accepting a test with out-of-calibration, out-of-range, or unsuitable equipment, or failing to check environmental conditions before a measurement.
Equipment checks feel like paperwork and are skipped under time pressure; candidates also forget that temperature, humidity, or background noise can invalidate a result.
What to do instead
Make a pre-test checklist habit: calibration certificate in date, range covers the expected value, environment within the method's limits. In answers, state the check and what you would do if it failed (recalibrate, substitute, or void the result).
Confusing the function of protective devices, interlocks, and control systems, or assuming a control setting equals a safety limit.
Terminology overlaps across systems and candidates learn labels without the underlying principle, so they misattribute what trips, what alarms, and what merely indicates.
What to do instead
For each device, be able to state what it senses, what it does when triggered, and whether it is fail-safe. Draw a one-line cause-and-effect chain for each and test yourself by predicting the system response to a single fault.
Ignoring redundancy, common-cause failure, or the difference between a fail-safe and fail-dangerous condition when reasoning about a system.
Candidates reason about single components rather than the system, so two redundant channels are assumed to give independent protection even when they share a power supply or sensor.
What to do instead
When analysing any protective arrangement, ask what the channels share and what happens on loss of power or signal. State the failure mode (fail-safe or fail-dangerous) explicitly in the answer.
Recording results without traceability: missing instrument ID, calibration reference, date, time, conditions, or the identity of the person who took the reading.
Candidates treat records as a summary of the outcome rather than evidence that the test was valid and repeatable, so supporting detail is dropped.
What to do instead
Use the rule that a stranger must be able to repeat the test from the record alone. Check every entry against: who, when, with what, under what conditions, and what result. If a field is missing, say it must be completed before sign-off.
Making corrections to a record by overwriting, erasing, or backdating, or signing off on work not personally witnessed.
Candidates want the record to look clean and complete, and they underestimate how a correction trail is treated as evidence of integrity rather than sloppiness.
What to do instead
Apply the correction convention: single line through, initial and date, reason if required, original still legible. Never sign for work you did not observe; state in the answer that the record is returned to the person who performed the task.
Answering an ethical dilemma with the technically correct action but omitting the reporting route, the timeframe, and the interim safety measure.
Candidates treat ethics questions as a judgement about right and wrong, so they say 'stop the job' without saying who is told, how soon, and what happens to the equipment in the meantime.
What to do instead
Use a fixed response frame: make the situation safe, do not falsify or conceal, escalate to the named role within the required timeframe, and record what was done. Name the role and the channel rather than saying 'notify management'.
Deferring to seniority or production pressure when the candidate's own knowledge indicates a non-compliance, or assuming a supervisor's approval transfers responsibility.
Candidates imagine the awkward conversation and look for a way to comply with the instruction while noting the concern, which in practice means the unsafe condition persists.
What to do instead
Practise stating the refusal in one sentence with the reason and the alternative: what you will not do, which requirement it breaches, and what you propose instead. Treat responsibility as personal and non-delegable, and say so in the answer.