Precautionary measures must be taken so papers stored in the container will not protrude from the drawers when they are closed, or cannot be fished out through the cleft surrounding the drawers. One method is the insertion of stiff cardboard, such as a file folder, in a horizontal position above papers filed in the drawer. Storage areas for bulky Secret or Confidential material must have access openings secured by GSA-approved combination padlocks or key-operated padlocks with high security cylinders. If these storage requirements cannot be met afloat or aboard aircraft, Secret or Confidential material may be stored in a locked container of substantial metal or wood construction secured by an approved GSA combination padlock. In this case, the area must be locked when not manned and checked at least once every 24 hours. NEW STORAGE CONTAINERS New security containers should not be procured until a physical security survey of existing equipment and a review of classified records on hand has been made. It might be determined that it would not be feasible to use the equipment or to retire, return, or declassify or destroy a sufficient volume of records currently on hand to make the needed security storage space available. Only containers that have been approved by the Federal Government as security filing equipment should be procured. Equipment is selected from the National Supply Schedule of the GSA following the procedures outlined in SECNAVINST 10463.1. Modification of any equipment that is used to store classified material is prohibited. Exceptions to permit acquisition of special-purpose equipment or to modify filing cabinets to bar-padlock types suitable for storing classified material must be requested from the CNO. A security container records form (fig. 11-1) will be maintained for each security container used for the storage of classified material. The container will be inspected each watch. Security containers conforming to Federal specifications bear a test certification label on the locking drawer, attesting to the security capabilities of the container and lock. NONAPPROVED SECURITY CONTAINERS Nonapproved security containers are available in many shapes and sizes; however, containers of this type may not be used to store classified material even though they may be equipped with manipulation- proof or manipulation-resistant locks and have other security and fire protection features. Nonapproved containers used to safeguard classified material should be replaced by an approved GSA security container. COMBINATIONS A security container, vault, or storeroom must be fitted with a lock that resists opening by unauthorized persons. Manipulation-resistant (MR) and manipulation-proof (MP) locks are tested by the Underwriters' Laboratory (UL) and must have the UL label attached to the back of the lock. Federal specifications governing the manufacture of security containers and security vault doors require that the unit be equipped with a top-reading changeable combination lock that controls the locking of the container. The top-reading design replaced the front-reading design to provide increased protection against the combination being ascertained by covert viewing. Combination locks are available with two forms of combination changing: hand or key. Hand-changing requires removing the wheel pack and changing the wheel to the new combination. Key-changing requires the use of a key that is inserted into the lock case, permitting a new combination to be set. The type of combination lock desired should be specified when ordering the container. The following requirements help ensure the effectiveness of combination locks: 1. Combinations must be changed only by individuals having the responsibility and an appropriate security clearance. 2. The combination will be given only to people whose official duties demand access to the container. 3. The combination to a security container is changed at the time the container is received, at the time any person having knowledge of the combination leaves the organization, at any time there is reason to believe that it has been compromised, or as a minimum every 24 months. In selecting combination numbers, multiples of 5, simple ascending or descending arithmetical series, and personal data (such as birthdates and service numbers) should be avoided. The same combination will not be used for more than one container in any one component. 11-8