Workshop Safety
Workshop safety is tested through hazard recognition, correct selection of PPE and fire equipment, and simple quantitative checks such as ventilation or floor loading. Questions often ask why a control is needed, not just its name.
Hierarchy of controls
- Elimination or substitution comes first; engineering controls (guards, interlocks, local exhaust ventilation) next; administrative controls and PPE last.
- Machine guards must prevent access to nip points; interlocks must stop motion before access is possible.
- Lockout/tagout: isolate energy, dissipate stored energy (hydraulic, pneumatic, spring), verify zero energy, tag, then work.
- Housekeeping: keep aisles clear, store gas cylinders upright and chained, keep oily rags in covered metal bins.
Fire and first aid
Class A is solid fuel, B flammable liquid, C electrical or gas, D metal. Use CO2 or dry powder on live electrical equipment because water conducts and damages. PASS means pull, aim, squeeze, sweep.
Worked example: air changes
A shop 12 m × 8 m × 3.5 m has an extractor rated 2,400 m³/h. Volume = 336 m³. Air changes per hour = 2,400 ÷ 336 = 7.14. If the process rule is at least 10 ACH, the fan is undersized; required flow = 10 × 336 = 3,360 m³/h.
Traps
- Quoting PPE as the primary control instead of guarding or extraction.
- Using water or foam on electrical fires.
- Mixing m³/h with m³/min, or using floor area instead of room volume.
- Forgetting stored energy in hydraulic clamps and compressed-air lines.