Conventional Shelving:

As you may have observed in most libraries, books are kept on open shelves which are usually arranged in  parallel rows  with passages from 75 to 80 cm in  width between the rows. The normal height of the shelves is 190 to 205 cm which permits taking books from the upper most shelf. Single faced shelves are placed along the walls. Within the rooms themselves, between the aisles, the shelves are double-faced. Single faced sections have six or seven  one metre shelves.  While double faced sections have twelve to fourteen one metre shelves. Under these\circumstances, taking into account all aisles and gangways and approaches only about 30 per cent of the floor space is actually used for shelves themselves. The conventional shelving system is high on accessibility, but quite low on economy. Thus the question is that of striking the right balance between the two opposing considerations.  

The degree of usage of different parts of the stacks of a library must become the basis for selecting  the most rational arrangement of shelves.

For collections which are  'n active use or Etc. those that are open to free use by readers, the conventional shelving is considered to be more suitable. For collections that are rarely requested or used,  a more compact arrangement of shelves must be undertaken - with a view to increase considerable to the capacity of the area of the stacks in which they are stored. 

A recent trend is to combine stacking of reading materials with provision for reading space.