Health, Safety, Environment and Engineering Ethics
Safety and ethics are integral to professional practice. Key concepts: hazard identification (HAZOP, what-if, FMEA); risk = likelihood × consequence; inherently safer design (minimize, substitute, moderate, simplify); fire and explosion fundamentals (flammability limits, flash point, autoignition); relief systems (PSV, rupture disc); toxicology and exposure limits (TLV, PEL); environmental regulations (emissions, effluent, waste); and professional ethics (public safety paramount, honesty, confidentiality, conflict of interest, competence).
Traps: confusing flash point (lowest temperature for ignitable vapor) with autoignition temperature (spontaneous ignition without an ignition source); and misidentifying LEL/UEL (flammable range). Ethics questions often present a scenario where a supervisor pressures an engineer to sign off on unsafe work - the correct answer is to refuse and escalate through proper channels, prioritizing public safety.
Worked example (rule of thumb): inherently safer design should be considered before adding engineering controls or PPE. For a flammable solvent, keeping the process temperature well below its flash point and operating outside the flammability envelope (below LEL or above UEL) are the primary safeguards.