5 C.F.R. § 1312.25
All classified material in the possession of OMB will be stored in a GSA-approved container or in vault-type rooms approved for Top Secret storage. Under the direction of the EOP Security Officer, combinations to safes used in the storage of classified material will be changed when the equipment is placed in use, whenever a person knowing the combination no longer requires access to it, whenever the combination has been subjected to possible compromise, whenever the equipment is taken out of service, or at least once a year. Knowledge of combinations will be limited to the minimum number of persons necessary, and records of combinations will be assigned a classification no lower than the highest level of classified information stored in the equipment concerned. An SF-700, Security Container Information, will be used in recording safe combinations. Standard Form-702, Security Container check sheet, will be posted to each safe and will be used to record opening, closing, and checking the container whenever it is used.
5 C.F.R. § 1312.25