Another method of storage equipment is the compact storage system. Compact storage methods have been advocated and explored since the last century. However, these became popular only since the last two decades, due to the availability of many types of equipment for compact shelving.
Compact shelves are a special type of storage equipment which makes possible a substantial increase in the capacity of storage space through various arrangements of units, sections and complete shelving systems, as well as adaptation of the shelf loading surface themselves. The construction, organisation, and the method of employment of this equipment differ from the traditional shelves and traditional storage equipment.
The storage of collections shelved with this equipment is known as `Compact Storage' because of the higher degree of compactness achieved. Compact shelving falls into the following types:
Stationary shelves combined with movable revolving segments.
Stationary shelves with movable drawers, and
Movable sliding shelves.
All revolving compact shelves use a suspended construction with vertically hung hinged sections of various types usually combined with a guide rail arrangement. It could be either double faced or single faced. The essential principle of compact shelving results in firmly packed collections as against more porous or dispersed fashion of shelving. While traditional shelves use up only 30 per cent of the floor space, the different methods of compact shelving are said to increase the capacity of the stacks having the same area from 50 to 65 per cent.
However, compact storage in addition to decreasing the accessibility, it has other disadvantages. They are: `Cost of the shelving equipment' - as the cost of fixtures themselves are reasonable; increase in building costs for most of these equipment requires buildings designed specifically for their use; mechanical functioning and safety features. Librarians have to be judicious in the matter and ensure that compact storage has sufficient advantages to offset its obvious disadvantages.