History of NB Registration

Prior to 1921, a boiler manufactured in one state would not necessarily be accepted for operation in a neighboring state even if it had been constructed in accordance with the ASME code. States and several large cities had their own qualification requirements for inspectors, which, in most cases, meant little or no reciprocity. For a boiler to be installed in a state other than in which it was manufactured required inspections to be performed – during fabrication – by an inspector from the state where the boiler would be installed. This was costly and discouraged boiler sales across state borders.

After its founding in 1919, The National Board of Boiler and Pressure Vessel Inspectors knew it had to find an answer to the problem. The solution came in two parts:

• qualifying all inspectors to a common set of requirements and issuing a National Board commission to successful candidates; and
• authorizing manufacturers to stamp a National Board number on boilers inspected by a National Board Commissioned Inspector.

Registration of a boiler with a National Board number could now be completed with the manufacturer submitting an original manufacturer’s data report to the National Board for permanent retention. This document, certified by both the manufacturer and the National Board Commissioned Inspector, gave the chief boiler inspectors of all participating states and cities the assurance they needed to allow a boiler to be installed for operation within their respective jurisdictions.

In 1924, at the National Board convention held in Cleveland, Secretary C.O. Myers (later named the National Board’s first executive director) stated the National Board had developed a system of “registering and recording ASME boilers,” which had become effective July 1, 1921. The system was developed to ensure “that no state need fear of a counterfeit Code boiler, if it bears the National Board stamp.”

The foresight of the National Board’s founders encouraged boiler sales between multiple states and provided the only central repository for manufacturers’ data reports.

Some changes have occurred over the years, including:

• the inspectors authorized to engage in new fabrication inspections are commissioned as “Authorized Inspectors”;
• National Board registration was allowed for pressure vessels, piping, and nuclear components as the ASME code grew to include those items; and
• an NB symbol stamp has been implemented for manufacturers to stamp adjacent to the National Board number.

These changes have enhanced the basic principles of National Board registration, but the goal is still the same as it was in 1921: provide assurance that a pressure-retaining item was constructed in accordance with the ASME Boiler and Pressure Vessel Code and that it was inspected by a qualified National Board Commissioned Inspector.

Questions concerning the NB mark and Authorization to Register? Please Contact Us.