Occupational Health, Safety and Workplace Practices
This domain tests how you identify plumbing-site hazards, choose controls in the correct order, and work safely in trenches, on roofs, in occupied buildings and in confined spaces. Expect questions on PPE, electrical isolation, hot-work permits, housekeeping, first aid and legal duties.
Control the risk, not just the person
Apply the hierarchy of control: eliminate the hazard, substitute a safer method, add engineering controls such as guards, ventilation and shoring, then administrative controls such as permits and training, and use PPE last. A safety helmet, impact goggles, cut-resistant gloves, safety shoes and hearing protection are routine. Solvent cements, lead solder and dust need ventilation; a dust mask will not stop solvent vapour.
Height, trenches and confined spaces
Use the 4:1 ladder rule: base one unit out for every four units up, tie the ladder, and extend it about 1 m above the landing. Trenches deeper than about 1.5 m need shoring, battering or a trench box and a safe means of escape. Septic tanks, sumps and sewers are confined spaces: test the atmosphere before entry and monitor continuously; oxygen must remain between 19.5% and 23.5%, with an attendant and rescue plan outside.
Worked example
A ladder must reach a roof edge 4.0 m above ground. Base distance = 4.0 ÷ 4 = 1.0 m. Ladder length ≈ √(4.0² + 1.0²) = 4.12 m, so choose a 4.5 m ladder, tie it at the top and extend it about 1 m above the landing.
Traps that cost marks
Never treat a respirator as protection in an oxygen-deficient tank; never enter a septic tank to clear a choke; do not rely on a verbal switch-off for electricity - use lockout/tagout; and keep hot-work slag away from PVC, solvent cans and other combustibles.