The ideal archive
- The relative temperature and humidity should be maintained within very strict limits. The optimal values are 19°C and 40% RH. Any deviation of the temperature must be reflected in a proportional deviation, in the opposite direction, of the relative humidity (in the proportion + 1°C → - 3% RH).
- The archive must be equipped with an air conditioning plant fitted with filters of 0.3 µm to eliminate most of the atmospheric contaminants.
- All magnetic fields: electrical motors, loudspeakers, etc., must be avoided.
- The presence of any solid foods, liquids or smoke in the vicinity of the audio supports must be avoided.
- Any backup copies must be stored in a safe place, possibly in another building, maintaining the same archiving conditions.
- The security, intrusion and fire plant should be rather sophisticated. As regards fires, the only method that is effective and not harmful for the audio carriers is currently the use of a substitute of Halon gas or a "dry fog" dousing system. It is, of course, important to try to prevent any accidents by dedicating attention to the materials stored in the archive.
- The coefficient of use of the space available in the archive must be as high as possible (close to 1.00). It may be judged satisfactory, however, if it is equal to 0.70.
Meticulousness in the search for the optimal conditions is not limited however to the environmental and logistic conditions, but extends to the materials used (packing, cleaning liquids, etc.) and to the working methods used. The archive of the Swiss National Sound Archives satisfies all these requirements, so it is an archive suitable for the long-term preservation of every type of audio carrier.