Electrical, confined space and hot work hazards
This domain tests three permit-controlled hazards: electricity, confined spaces and hot work. The exam expects isolation, testing and fire precautions before work starts.
Core rules
- Electrical work: isolate and lock off, test for dead, use RCD protection, inspect leads and use competent persons. Treat water and damp conditions as increased risk. Do not work live unless justified and controlled.
- Confined spaces: a permit, gas test, ventilation, attendant and rescue plan are needed. Do not enter to rescue without breathing apparatus and training; many fatalities are would-be rescuers.
- Hot work: remove combustibles, use a permit, provide a fire extinguisher and a fire watch during and after work. Seal gaps and protect surrounding areas from sparks.
Worked example
Welding inside a steel tank is both confined space and hot work. The correct sequence is to isolate and clean the tank, test the atmosphere, ventilate, issue both permits, provide a fire watch and extinguisher, and station a trained attendant outside. The reasoning is that the tank can trap fumes and sparks can ignite residue; one permit does not cover the other hazard.
Traps
Do not use water on live electrical equipment. Do not enter a confined space because 'it smells normal'. Do not leave hot work unattended after the flame stops. Do not assume a gas test is valid all day.