Systems, Equipment, and Technology
Systems, Equipment, and Technology tests how engineered safeguards actually work and where they fail: machine guarding, lockout/tagout, confined spaces, fall protection, electrical safety, gas detection, fire systems, and functional safety. Items often show an equipment scenario and ask for the control that addresses the failure mode, not just the regulation number.
Core rules
- LOTO (29 CFR 1910.147): identify all energy sources, notify affected employees, shut down, isolate, apply locks and tags, dissipate stored energy, and verify zero energy. Group lockout requires a primary lock and personal locks.
- Machine guarding (1910.212): guard points of operation, ingoing nip points, rotating parts; interlocks must prevent operation while the guard is open.
- Confined space (1910.146): test before entry, ventilate, attendant, retrieval, and rescue capability before entry-not after.
- Electrical: de-energize and verify; NFPA 70E guides arc-flash risk assessment and PPE.
- Gas detection: match sensor technology to the gas; calibrate with the correct span gas and check response time.
Worked example
A conveyor jams and a worker wants to clear it with the drive still energized because the stop button is nearby. Reasoning: a stop button is not energy isolation, and gravity or stored hydraulic pressure can still move the belt. The correct sequence is full LOTO: stop, isolate electrical and hydraulic energy, lock, bleed pressure, block the belt against gravity, and verify zero energy before reaching in. Add a jam-clearing procedure and a tool so hands stay out.
Traps
- Treating an emergency stop or interlock as adequate for maintenance.
- Missing stored energy: gravity, springs, capacitors, pneumatics.
- Buying a gas detector without matching it to the hazard.
- Assuming a guard is safe because it exists; check openings and reach distances.