Construction Safety, Health and Environment
This domain tests how well you spot hazards on a construction site and match each one to the right control, covering PPE, work at height, scaffolding, excavation, electrical safety, housekeeping, health hazards and waste disposal.
The hierarchy of control
Eliminate the hazard first, then substitute, then engineer the risk out (guardrails, shoring, fume extraction), then administer (permits, signage, training), and only then rely on PPE. PPE is the last line of defence, never the first.
- Minimum PPE: helmet, eye protection, gloves, safety footwear, and respiratory protection where dust is present. A helmet is not a fall-arrest system.
- Working platforms need a guardrail at about 1 m, a mid-rail and a 150 mm toe board.
- Ladders at 75 degrees: base 1 unit out for every 4 units of height, tied at the top, extending about 1 m above the landing.
- Trenches deeper than about 1.5 m need shoring or battering; never stack spoil at the edge.
- Site power needs 30 mA RCCB protection; treat all overhead lines as live.
Health and environment
Silica dust from cutting concrete causes silicosis, so wet cut or use extraction. Noise above 85 dB(A) needs hearing protection. Wet cement is alkaline and burns skin. Segregate debris, metal, plastic and e-waste, and never burn waste on site. Know the first-aid point and emergency number.
Worked example
A ladder must reach a 4 m parapet and extend 1 m above it, giving a working length of 5 m. At the 1:4 rule the base sits 5 divided by 4 = 1.25 m from the wall. Steeper than 75 degrees risks tipping backwards; shallower risks slipping.
Traps
Do not answer wear PPE when the question asks for the control that removes the risk. Helmet versus harness, toe board versus guardrail, and the 1.5 m trench depth are favourite swaps.