Excerpted from this web page: Tape Vaulting Storage Glossary
If you can’t retrieve the data on a tape, it is useless for recovering your business. The cost of proper data tape storage is far less than the cost of avoidable data loss or theft.
Proper construction – Walls are supported by foundation, not other walls. Contained within a structure, not a standalone building or portable. No water pipes, natural gas pipes, or sewer pipes within the vault. No water source above the vault.
Temperature / humidity control – Set to remain within acceptable limits with only minor fluctuations.
Fire rating – Walls, floor, ceiling and door are properly fire-rated.
Access – Locked entrance, with limited authorized access.
Geographic separation – From your company, from disaster-prone areas, from the elements.