T/O Certificate of Authorization
The National Board offers the Certificate of Authorization and T/O mark for the inservice testing of pressure relief valves. Requirements are described in NB-528, Accreditation of T/O Test Only Organizations.
Organizations seeking a National Board T/O Certificate of Authorization must complete and submit the following:
And:
- have a written quality system that complies with the requirements of the current edition of the National Board Inspection Code (NBIC), NB-528, Accreditation of T/O Test Only Organizations, and includes the expected scope of activities,
- have the current edition of all parts of the NBIC. Organizations have the option of using either a printed version or an electronic version; and,
- have available a copy of the Code of Construction appropriate for the intended scope of work.
Prior to issuance of a National Board T/O Certificate of Authorization, the organization and its facilities are subject to a review of its quality system. An important part of that review will be the witnessing of the testing of several sample pressure relief valves.
An independent test for operation of these sample pressure relief valves will be conducted at a National Board-accepted laboratory. The test is to verify the tested valves meet applicable ASME Code requirements for performance.
- The National Board Testing Laboratory is available to perform this testing, along with several other major valve manufacturers which operate National Board-accepted testing laboratories.
- A National Board representative will witness the valve testing.
All forms should be returned via email to: prd@nbbi.org or by mail to:
National Board Pressure Relief Laboratory
7437 Pingue Drive
Worthington, Ohio 43085
Renewal, extension, revision, and replacement/additional stamp(s) applications for the T/O Certificate of Authorization are now located on the National Board Business Center. Once logged in with the company’s Certificate Administrator credentials, click the Company Certifications tab to view all online applications.
Please contact prd@nbbi.org if you have any issues or questions regarding your company’s Certificate Administrator login to the Business Center.
Pressure Relief Laboratory staff will contact you to schedule a date for the review of the T/O Quality System and its implementation, and to witness the testing of the required sample pressure relief valves once all documents and fees are received, and a date for your review has been established.
Shop Reviews are typically scheduled 2 months in advance.
Certification Fees:
The certificate fee for the T/O Certificate of Authorization is $660 USD ($1150 USD beginning January 1, 2025) for a three-year period.
Review Fees:
The review of an organization’s quality control system for T/O certification, conducted by the National Board, can be performed in conjunction with its ASME review, where applicable, or as a standalone T/O review. The National Board requires an advance deposit to schedule reviews for ASME and T/O certifications or the standalone T/O certification, as shown below:
| US, Canada, Mexico, Caribbean |
$7,000 USD |
| All Others |
$10,000 USD |
Cancellation Fees:
Withdrawal of an application in-process will result in a $330 USD ($575 USD beginning January 1, 2025) application withdrawal fee.
Shop review cancellations after having been scheduled by the National Board will result in a $400 USD review cancellation fee, plus any loss of incurred expenses.
Organizations holding a T/O Certificate of Authorization who are having a name change prior to renewal must submit an online revision application through the company's Certificate Administrator account on the National Board Business Center, along with a copy of their revised Quality Manual. There is a fee of $50 USD for a name change to a certificate.
NOTE: If the name change is being done at the time of renewal, an online revision application does not need to be submitted, and the $50 revision fee is not needed. The name change should be noted on the online renewal application.
Organizations holding a T/O Certificate of Authorization who are having a location change or scope change, must submit an online revision application through the company's Certificate Administrator account on the National Board Business Center. A review of your facility may be required prior to issuance of a revised certificate. Cost will be determined upon receipt of the application.
Ownership Change:
If ownership of an organization changes, the new owners may agree to take full responsibility for all work previously performed under the T/O Certificate of Authorization. If the new owners do not want to take responsibility for previous work performed under the organization’s T/O Certificate, the new owners shall submit an NB-550 form to apply for a new T/O Certificate of Authorization, in which a new T/O number will be assigned.
Contact Change:
Organizations needing to update/change their primary contact or contact information (title/phone/email) should log into the National Board Business Center using their company Certificate Administrator credentials, click the Company Certifications tab, and then click the applicable Contact Change link.
NOTE: If the contact update/change is being done at the time of the renewal, the updates/changes should be noted on the renewal application; the contact change link does not need to be used.
If there are questions on the certification program, please contact the Technical Department Pressure Relief Laboratory at prd@nbbi.org.
Payments can be made as follows:
- By check payable in U.S. Dollar, drawn on a U.S. Bank, to The National Board of Boiler and Pressure Vessel Inspectors and remit to the address below, to the attention of the Accounting Department.
- For all other payment types, please contact the Accounting Department as follows:
- ACH (preferable) — send your ACH authorization form to the Accounting Department for banking information by mail or fax.
- Credit Cards (VISA, MasterCard, American Express) — send credit card information by fax or call the Accounting Department.
- Accounting Department contact information:
| Address |
1055 Crupper Avenue
Columbus, OH 43229 |
| Telephone |
614.888.8320 ext. 217 |
| Fax |
614.985.4615 |
| Email |
accountingdept@nbbi.org |
PLEASE NOTE: FOR SECURITY REASONS, WE DO NOT ACCEPT CREDIT CARD INFORMATION VIA EMAIL.