Safety, Codes, and Regulatory Compliance
Core concepts
This domain covers the legal and safety framework around mechanical systems. Know the roles of codes and standards, employer and worker responsibilities, hazard assessment, lockout/tagout, confined-space entry, hot work, and personal protective equipment. Understand pressure-equipment regulations, boiler and refrigeration registration, inspection intervals, and incident reporting. Study permit systems, energy isolation, and the hierarchy of controls, which places elimination and engineering controls ahead of administrative measures and PPE.
Traps to watch
A frequent trap is treating PPE as the first line of defense when it is the last. Questions may blur lockout with tagout, or assume a tag alone isolates energy. Confined-space items often hide the need for atmospheric testing before and during entry. Watch for confusion between a code requirement and a recommended practice, and for items where a worker may override an interlock, which is generally prohibited. Another trap is assuming verbal communication substitutes for a written permit.
Worked example
Before entering a confined space, test the atmosphere for oxygen, flammables, and toxics. Acceptable oxygen is typically around 19.5–23.5 percent by volume. If oxygen reads 18 percent, entry is prohibited regardless of the task, because the atmosphere is oxygen-deficient. Rule of thumb: no entry without a permit, atmospheric testing, an attendant, and a rescue plan.