What Is a National Board Commissioned Inspector?

The National Board of Boiler and Pressure Vessel Inspectors (commonly called "the National Board" or "NB") is a nonprofit organization founded in 1919, headquartered in Columbus, Ohio. It was created to promote uniform boiler and pressure vessel safety standards across state lines — before the National Board existed, every state had different inspection standards, different inspector qualifications, and no mechanism for reciprocity.

The National Board has three primary functions:

• Commissioning inspectors: The NB administers the commission examination and maintains a registry of qualified inspectors. A National Board commission is the gold standard credential for boiler inspectors in the US and Canada.
• Registration of pressure vessels: Every ASME-stamped boiler and pressure vessel manufactured in the US is registered with the National Board and assigned an NB number. This number provides a permanent record of the vessel's design, construction, and inspection history.
• Publishing the NBIC: The National Board Inspection Code is the standard used for in-service inspection, repair, and alteration of boilers and pressure vessels. Most state boiler laws reference the NBIC as the governing inspection standard.

The National Board does not employ inspectors or perform inspections. It sets the standards, administers the examination, and maintains the credential system. Actual inspections are performed by insurance company inspectors, state-employed inspectors, and independent inspectors — all of whom hold NB commissions.

A National Board commissioned inspector is an individual who has met the NB's experience requirements and passed the NB commission examination, and whose commission has been endorsed by at least one jurisdiction (state, city, or province).

The process works as follows:

1. Experience requirement: Candidates must have a minimum of one year of experience in the design, construction, operation, maintenance, repair, or inspection of boilers and pressure vessels. Many candidates have significantly more — insurance company inspector trainees typically complete 12-24 months of supervised field training before sitting for the exam.

2. NB commission examination: The exam tests knowledge of ASME Boiler and Pressure Vessel Code (Sections I, IV, and VIII), the National Board Inspection Code (NBIC), basic metallurgy, welding processes, non-destructive examination methods, and practical inspection procedures. The exam is proctored and has a pass rate of approximately 60-70%. It is considered moderately difficult — candidates typically study for 3-6 months.

3. Jurisdictional endorsement: After passing the exam, the candidate must be endorsed by the jurisdiction where they will inspect. Each state or province has its own endorsement process, which may include additional requirements (background check, state-specific training, application fees). The endorsement authorizes the inspector to perform inspections in that jurisdiction.

4. Continuing education: Commissioned inspectors must maintain their credential through periodic renewal (every 3 years in most jurisdictions) and continuing education requirements.

The distinction between NB commissioned and state-licensed inspectors confuses many building owners. Here is how they relate:

National Board commission: A credential issued by the National Board that certifies the inspector has passed a standardized examination and met experience requirements. It is recognized across jurisdictions — an inspector with an NB commission endorsed in Ohio can typically get endorsed in other states without retaking the exam.

State license: Authorization from a specific state to perform inspections within that state's borders. Most states require NB commission as a prerequisite for state licensing, but some states (particularly those with large boiler programs) have their own examination in addition to or instead of the NB exam.

In practice: The vast majority of boiler inspectors in the US hold an NB commission that has been endorsed by one or more states. When a state says it requires a "licensed" or "authorized" inspector, they almost always mean someone who holds an NB commission endorsed by that state.

Notable exceptions: A few states and jurisdictions maintain their own licensing systems that do not require NB commission. These are becoming less common as states adopt the NBIC and NB credentialing standards. New York City is notable for having additional local requirements on top of NB commission and state licensing.

Bottom line for building owners: When hiring an independent inspector or evaluating your insurance company's inspector, ask whether they hold a current NB commission endorsed in your state. This confirms they have met the industry standard for competence and are legally authorized to inspect in your jurisdiction.

You can verify that an inspector holds a current NB commission through the National Board's online registry at nationalboard.org. The verification process is straightforward:

• Visit the National Board website and navigate to the inspector search function
• Search by the inspector's name or NB commission number (which should appear on their identification card and on inspection reports they issue)
• The registry will confirm whether the commission is current, what jurisdictions have endorsed the inspector, and the commission type (Inservice Inspector, Authorized Inspector, or both)

Commission types you may see:

• Inservice Inspector (IS): Authorized to inspect boilers and pressure vessels that are already in service — this is the credential relevant to building owners. Your insurance company inspector and state inspectors hold this credential.
• Authorized Inspector (AI): Authorized to inspect during new construction at the manufacturer's facility. This is relevant to boiler manufacturers, not building owners.
• Authorized Nuclear Inspector (ANI): For nuclear power plant components. Not relevant to commercial building owners.

Red flags: If an inspector cannot provide their NB commission number, refuses to provide verification, or their commission shows as expired or revoked in the NB registry, do not allow them to inspect your boiler. An inspection performed by an unqualified individual may not be accepted by your state boiler division or insurance carrier, wasting your money and leaving you non-compliant.

The majority of commercial boiler inspections in the US are performed by insurance company inspectors — employees of authorized inspection agencies (AIAs) that are typically the inspection departments of boiler and machinery insurance carriers.

Major insurance companies with large inspection departments include Hartford Steam Boiler (HSB, a Munich Re company), FM Global, Zurich, Liberty Mutual, and Travelers. These companies employ hundreds of NB commissioned inspectors nationwide who perform periodic inspections as part of the insurance coverage.

How insurance inspections work:

• When you purchase boiler and machinery (B&M) insurance, periodic inspections are included in your premium — there is no separate inspection fee.
• The insurance company assigns an inspector to your account who is responsible for your geographic area.
• The inspector schedules visits based on the required inspection frequency and the insurance company's internal risk assessment.
• Inspection reports go to both you (the policyholder) and the state boiler division (in states that accept insurance company inspections).
• In most states, the insurance company inspection satisfies the state's legal inspection requirement — you do not need a separate state inspection.

Key advantage: Insurance company inspectors have a vested interest in identifying problems early — their employer is financially liable if a boiler fails. This means they are generally thorough and proactive about recommending maintenance and repairs. They are not trying to sell you services (they do not perform repairs), so their recommendations are objective.

Key limitation: Insurance company inspectors manage large territories and may have limited scheduling flexibility. If you need an inspection on a specific date (for a planned shutdown window, for example), communicate this well in advance — 4-6 weeks of lead time is recommended.