National Board ” REDBOOK”

Pressure Relief Device Certifications

This publication includes:

  • a complete listing of and information pertaining to the device designs certified by the National Board.
  • certifications issued to pressure relief device manufacturers and assemblers, thereby granting permission to apply the National Board “NB” and construction code symbols.
  • listing of combination capacity factors determined for various rupture disk devices installed in series with pressure relief valves.
  • companies holding “VR” Certificates of Authorization for the repair of pressure relief valves are also listed.

The online Pressure Relief Device Certifications are updated once a month, making it easier to access the most current information available. Because the NB-18 is presented in a portable document format (PDF), it will be necessary to obtain and use Adobe Reader. Once this file is downloaded, the NB-18 may be used in an electronic format or printed as desired.