Safety, Emergency Response, and Security
Core concepts
Understand confined space entry: classification (permit-required), atmospheric testing (oxygen, flammables, toxics), ventilation, attendant, and rescue planning. Know excavation/trench safety (shoring, sloping, spoil placement, access/egress). Grasp chemical safety - SDS, PPE, and safe handling of chlorine and other treatment chemicals. Understand lockout/tagout, hazard communication, and electrical safety. Know emergency response concepts: boil-water notices, loss-of-pressure events, main breaks, contamination response, and the emergency response plan. Grasp security basics: securing facilities, access control, vulnerability assessment, and reporting suspicious activity. Understand incident command roles and communication during emergencies.
Traps to watch
Confined-space questions often test the order: test atmosphere → ventilate → enter with attendant and rescue plan. Another trap: forgetting that a loss of pressure below the threshold triggers a boil-water notice and notification. Watch for PPE and chemical-handling specifics (never add water to concentrated chlorine; add chemical to water as directed).
Worked example
A crew must enter a wet well. Correct sequence: classify as permit-required confined space → test atmosphere (O₂, LEL, H₂S/toxics) → ventilate → assign attendant and rescue plan → enter with proper PPE and communication. Entering after only a quick sniff is the classic wrong answer.
Rule of thumb
Confined space: test, ventilate, attendant, rescue plan - in that order. Loss of pressure = consider boil-water notice.