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NBBI administers three accreditation programs for organizations that perform repairs and alterations on pressure equipment (R, VR, NR) and one program for organizations that test pressure relief valves (T/O). Accreditation involves thorough evaluation of an organization’s quality system manual and requires a demonstration of its ability to implement the system. Authorized repair organizations are issued an NBBI stamp that is applied to the equipment nameplate. The stamp signifies strict repair and/or alteration requirements have been met and verified by an NBBI Commissioned Inspector.

A description of the scope, requirements, and estimated cost of each program is outlined in each section below:

  • R Stamp — for the repair and/or alteration of boilers, pressure vessels, and other pressure-retaining items
  • VR Stamp — for the repair of pressure relief valves
  • NR Stamp — for the repair and replacement of nuclear components
  • T/O Mark — for the inservice testing of pressure relief valves


Use of Marks Policy