Boiler and Pressure Vessel Safety Inspection
This domain tests how you plan, perform, and document in-service inspections of boilers and pressure vessels under NBIC Part 2 and the governing jurisdiction. The exam expects you to know what to inspect, how to prepare the item, and how to decide whether a finding is acceptable, a repair, or an alteration.
Inspection types and preparation
- External inspection: accessible surfaces, insulation, supports, foundations, piping, valves, gauges, and safety devices.
- Internal inspection: fireside and waterside surfaces, drums, tubes, headers, shells, heads, and staybolts; use entry permits, lockout/tagout, venting, and cooling before entry.
- Hydrostatic test: only when required or when evidence is insufficient; it is not a substitute for internal examination.
What to look for
Corrosion (general, pitting, under-deposit, CUI), cracking (fatigue, stress-corrosion), erosion, overheating, deformation, leaks, and deteriorated refractory or supports. For boilers, check scale, sludge, caustic attack, tube-end cracks, and low-water fuel cutoff and gauge glass condition. For vessels, check nozzle reinforcement, weld seams, cladding, and support contact points.
Worked example
An insulated horizontal air receiver shows wet insulation and rust staining at a saddle support. You remove insulation locally, find external corrosion, and measure remaining thickness. Compare it with the minimum required thickness from the original design or a rerating calculation. If below minimum, the item is unsafe for continued service: recommend repair by an R stamp holder or rerating before return to service. Document the location, measurements, method, and photos in the inspection report.
Traps
Assuming NBIC sets the inspection interval-the jurisdiction does. Treating an external inspection as equivalent to an internal one. Missing safety devices and supports because the focus is on the shell. Failing to verify relief valve set pressure and capacity.