Safety and Health
Core concepts
Safety questions test hazard recognition and control. Know the hierarchy of controls (elimination, substitution, engineering controls, administrative controls, PPE), and apply it to plumbing tasks: confined-space entry, trenching and excavation, soldering and brazing fumes, lead and asbestos in older systems, sewer gas (hydrogen sulfide, methane), and biological hazards from sewage.
Traps in questions
- PPE as a first resort: PPE is the last line of defense, not the first. Answers that jump to PPE before engineering controls are usually wrong.
- Confined space: never enter without atmospheric testing, ventilation, and an attendant. "Hold your breath" or "ventilate after entry" options are wrong.
- Trenching: spoils and equipment stay back from the edge; shoring or sloping is required beyond the depth threshold in your jurisdiction.
- Hot work: fire watch and clearance from combustibles before torches.
Worked example
A worker must enter a sump pit to clear a blockage. Correct sequence: treat it as a permit-required confined space, test the atmosphere for oxygen and combustible gas, ventilate, assign an attendant, then enter with retrieval equipment. Any option that skips testing is wrong regardless of how brief the entry seems.
Rule of thumb
If a hazard can be engineered out, do that before reaching for PPE.