Laboratory Safety, Data Quality, and Reporting
Safety in the aggregate lab
Aggregate laboratories present hazards from dust (silica), noise, heavy lifting, hot ovens, and rotating equipment (abrasion machines, splitters). Candidates should know basic controls: dust suppression or respiratory protection, hearing protection, proper lifting technique, heat-resistant gloves, and guarding around rotating parts. Traps include: assuming a small lab has no silica hazard, ignoring noise from sieving and abrasion equipment, and failing to secure loose clothing near rotating machinery.
Data quality
Data quality rests on representative sampling, proper calibration, documented procedures, and checks such as duplicate tests, reference samples, and arithmetic verification (e.g., percent retained plus percent passing equals 100%). Traps include: recording data after the fact, failing to note deviations, and reporting a result without the test method or conditions.
Reporting
A valid report identifies the sample, the test method, the result with units, the specification limit where applicable, and any deviations. Traps include: omitting units, reporting more significant figures than the equipment supports, and failing to state which method variant was used.
Worked example
A technician reports "gradation passed" with no numbers. A proper report states: sample ID, method, percent passing each sieve, the applicable band, and the pass/fail decision for each sieve. If a sieve result is outside the band, the report must say so explicitly rather than summarizing as "passed."
Rule of thumb
If a result cannot be traced back to a sample, a method, and a calibration record, it is not a defensible result - treat missing traceability as a data-quality failure.