Generally, fireproof vaults hold 500-1000 1000ft reels. Efforts should be made to isolate films in the smallest possible units. Commercial film vaults can use shelves of non-combustible insulating material and archival vaults should be divided into individual or paired compartments with no less than 3/8inch thick non-combustible insulating material between such as gypsum or sheetrock. The dimensions of vaults are based off the amount of film in them and whether the purpose is commercial or archival. Commercial storage is limited to 750 cubic feet, while archival storage is limited to 1000 cubic feet of space. The size of the vented area is also based on the quantity of film, for example no less than 2,670 square inches per 1000 pounds of archival film. Specifications are also made for the required number and spacing of sprinklers.

 

It is absolutely necessary to provide good ventilation because the air in the film cans must be constantly replaced. Nitrate film must never be stored in airtight cans because the gases it emits as it decomposes will combine with the natural moistures of the gelatin to form nitric acids that bleach the images and accelerate disintegration. Therefore, every enclosure storing nitrate film should have an outlet to the outer air that will open automatically as temperature rises.

 

The opening of the air exhausts correlate with temperature because the chemical reactions slow as temperatures fall. Ideally permanent archives are stored at the lowest possible temperature because it decelerates the release of gases affecting the rate of decay. Cold temperatures also reduce the risk of spontaneous combustion. The most favorable temperature is close to freezing, but most archives store films at 15-21 degrees Celsius to save on the cost of air conditioning. Likewise, consistent humidity levels should be maintained along with temperature. Increased moisture also accelerates disintegration caused by nitrate gases so it is important to find a balance of moisture levels that are not too dry or too humid. The most ideal relative humidity is 40-60%.