Occupational Safety, Health and Working Environment
Occupational Safety, Health and Working Environment covers the legal and practical controls that keep a plumber safe on site: hazard identification, PPE, excavation and confined-space work, electrical safety, fire response and welfare. The exam tests whether you can apply a control before starting work, not merely name it.
Site controls
- Before digging, locate buried water, sewer, gas and electrical lines; keep spoil and materials at least 1 m from the trench edge.
- Trenches deeper than 1.5 m need shoring or battering and safe ladder access; never stand under suspended loads.
- Confined spaces such as manholes and septic tanks need a permit, isolation, forced ventilation and gas testing before entry, plus a standby attendant and retrieval harness.
- Use 230 V tools through an RCCB/ELCB; keep leads off wet ground and never make makeshift connections.
Health and fire
Cement dust and silica can cause lung disease; sewer gas contains hydrogen sulphide, which deadens smell at higher concentrations. Wash hands before eating, change out of contaminated clothing, and know fire classes: A solids, B liquids, C gases, D metals; electrical fires need CO2 or dry powder, never water.
Worked example
A manhole meter reads 17.5% oxygen and 12 ppm H2S. The correct action is to stop entry: oxygen is below the 19.5–23.5% safe range and H2S exceeds the 10 ppm limit. Purge with forced air, retest, and enter only under permit with breathing apparatus and a standby person.
Traps
Entering a manhole to retrieve a tool; treating sewer smell as harmless; using water on an electrical fire; leaving a trench unshored because it is “only 1.5 m”; and wearing loose clothing near a pipe threading machine.