Operations
Pressure vessel inspection
Periodic internal and external inspection of boilers, pressure vessels, and storage tanks — mandated by ASME code and jurisdictional regulations.
Pressure vessel inspection is the scheduled examination of boilers, pressure vessels, air receivers, heat exchangers, and storage tanks to confirm they remain safe to operate at their design pressure. In the United States, vessel design and construction are governed by the ASME Boiler and Pressure Vessel Code (BPVC) Section VIII, and in-service inspection follows the National Board Inspection Code (NBIC). Vessels covered by OSHA's Process Safety Management standard (29 CFR 1910.119) — those holding a hazardous substance above the threshold quantity — must also meet the PSM mechanical-integrity requirements for inspection, testing, and deficiency correction.
There are five main inspection types. An external inspection is performed annually while the vessel is in service, checking for leaks, corrosion, insulation damage, and relief-valve condition. An internal inspection requires the vessel to be shut down, isolated, and entered (or boroscoped) on a 3-5 year interval to examine the shell, heads, welds, and internal components for cracking, pitting, and wall thinning. Thickness testing (ultrasonic measurement) maps remaining wall at corrosion-prone locations and feeds the remaining-life calculation. Pressure-relief devices are tested and recalibrated on their own schedule. Non-destructive examination (NDE) — ultrasonic, magnetic-particle, dye-penetrant, and radiography — is used for weld inspection and crack detection without removing material.
Inspection intervals are set by the NBIC, the manufacturer's recommendation, and jurisdictional rules, which in many states and provinces require a commissioned inspector and a filed report. Every inspection must be documented: the record identifies the vessel (including its ASME U-stamp serial and National Board number), the inspector, the methods and tests used, thickness readings, any corrosion or crack findings, the remaining-life calculation, and the next due date. In a QEHS platform these records live against the asset, with automated renewal schedules that flag the next inspection before it falls due and trigger a permit-to-work for the shutdown.
Pressure vessel certification is the authority to sign off an inspection or perform a repair. In-service inspection is typically performed by an Authorized Inspector commissioned by the National Board, often working for an Authorized Inspection Agency (AIA) or, in jurisdictions that operate it, the state boiler inspector. Repairs and alterations must be performed by an ASME-certified organization holding an R Stamp (the NBIC repair stamp), and the repair must be documented on an R-1 form filed with the National Board. A vessel that has been repaired outside this process is not certified and should not be returned to service.
Insurance is closely tied to inspection. Boiler and machinery (B&M) insurance carriers require current inspection records as a condition of coverage, and many jurisdictions require a valid certificate of inspection before a vessel may legally operate; uninspected vessels are typically excluded from property and liability policies and can void business-interruption cover. CSB investigations have documented fatalities from uninspected or improperly repaired vessels, which is why insurers and auditors treat a missing or overdue pressure vessel inspection as a finding, not a paperwork issue.
Pressure vessel inspection — frequently asked questions
How often should a pressure vessel be inspected?
Most pressure vessels require an external inspection annually and an internal inspection every 3 to 5 years, with ultrasonic thickness testing at corrosion-prone points on the same interval. The exact schedule is set by the NBIC, the manufacturer, and the jurisdiction; vessels covered by OSHA PSM 1910.119 must also meet the PSM mechanical-integrity interval.
What tests are performed during pressure vessel inspection?
Common tests include ultrasonic thickness measurement, magnetic-particle and dye-penetrant surface examination, radiographic and ultrasonic weld examination, pressure-relief valve set-pressure testing, and visual inspection of the shell, heads, nozzles, and supports. Together these are non-destructive examination (NDE) — they confirm integrity without removing material.
Who can certify a pressure vessel inspection or repair?
In-service inspections are typically signed off by an Authorized Inspector commissioned by the National Board, often via an Authorized Inspection Agency. Repairs and alterations must be done by an organization holding an ASME R Stamp (the NBIC repair stamp), and the repair is filed on an R-1 form. A repair made outside this process is not certified.
What documentation must a pressure vessel inspection record contain?
The record should identify the vessel (ASME serial and National Board number), the inspector and their commission, the methods and tests performed, thickness readings and remaining-life calculation, any corrosion or crack findings, corrective actions, and the next inspection due date. QEHS platforms attach these records to the asset and auto-schedule the next inspection.
What is the difference between a pressure vessel examination and an inspection?
The terms overlap in practice. "Examination" usually refers to a specific non-destructive test — ultrasonic, magnetic-particle, or visual examination of a weld or region — while "inspection" is the broader scheduled event that includes the external and internal review plus the examinations. An inspection comprises several examinations.
Does insurance require pressure vessel inspections?
Yes. Boiler and machinery insurers require a current inspection before binding or renewing coverage, and most jurisdictions require a valid certificate of inspection before a vessel may operate. An uninspected or overdue vessel can be excluded from property and liability policies and can void business-interruption cover.