DIN 66399 Material Classification F refers to information in miniaturized form, for example microfilms. The Security Levels run from F-1 to F-7 with F-1 being recommended for data carriers with general data which have to made illegible, to F-7 for data carriers with top secret data where the strictest security standards must be maintained.

F1

• Recommended, for example, for data carriers holding general data to be rendered illegible
• Max. material particle size 160 mm²
• Shredded data can be reproduced without special knowledge or equipment, although the process is time-consuming

F2

• Recommended, for example, for data carriers holding general data to be rendered illegible
• material particle size 30 mm²
• Shredded data can be reproduced with equipment, although the process is time-consuming

F3

• Recommended, for example, for data carriers holding sensitive, confidential and personal data
• Max. material particle size 10 mm²
• Shredded data can only be reproduced with maximum effort and special equipment

F4

• Recommended, for example, for data carriers holding particularly sensitive, confidential and personal data
• Max. material particle size 2.5 mm²
• Shredded data can only be reproduced utilizing equipment that is not readily available commercially

F5

• Recommended, for example, for data carriers holding confidential information
• Max. material particle size 1 mm²
• Shredded data is unlikely to be reproduced even with special equipment

F6

• Recommended, for example, for data carriers holding confidential information demanding an exceptionally high level of security
• Max. material particle size 0.5 mm²
• Shredded data cannot be reproduced even with special equipment

F7

• Recommended, for example, for data carriers holding strictly confidential information demanding the highest security precautions (e.g. classified and top secret)
• Max. material particle size 0.2 mm²
• Shredded data cannot be reproduced in any way with the current state of science and art