Per 346.3, at least 5 years after the record is generated for the project for the following:
(a) examination procedures
(b) examination personnel qualifications.
There is no defined time limit in B31.3 for maintaining film and other NDE or Leak Test records. Certain pipe systems are further governed by Jurisdictions, which may require maintaining them for the life of the project.
You should check with your Legal department and Insurer regarding records maintenance.