Stack maintenance

Maintaining an orderly arrangement of library materials is an important function generally assigned to circulation. A library must have an accurate and efficient shelving operation or good library service is impossible. Backlogs of unshelved materials cause delays in service and require staff time to locate materials. Misshelved materials are as good as lost until they are somehow noticed and reshelved correctly. When closed stacks were the rule and only library staff had access to them, maintaining an accurate arrangement was at least possible. But with the advent of the public library and the gradual elimination of closed stacks in favor of open stacks for patron browsing, maintaining orderly collections of materials has become a constant battle waged by the circulation department.

The most common way in which libraries first sort their collections is by format. Books, periodicals, audiovisual media, government documents, pamphlets, and so forth are grouped together by format. This is done for two reasons. First, different formats are often arranged differently. For example, books are filed by classification number, periodicals are often organized by title, government documents are arranged by special federal or state classification systems, and pamphlets are grouped by subject.

Another reason information formats are housed together is that materials are stored differently based on their shape and size. Books and periodicals are housed on shelving, pamphlets in file cabinets, microfilm is filed in microfilm cabinets, audiovisual materials require special shelving or display racks, and maps are laid flat in map cases. Because books and periodicals are the most common items in libraries, we limit our discussion here of stack maintenance procedure to these formats.

Books are the most traditional item in most collections and are housed on shelves in bookstacks and arranged by classification number. Some books, such as rare or antiquarian books, special collections materials, and oversized volumes, require special handling, but these, too, will have a classification or accession number to allow orderly shelving. Although support staff or librarians will, in all but the smallest libraries, usually do little shelving, they must know enough to train the clerical and student assistants to handle all phases of the shelving operation.

Classification systems
There are two popular classification systems in use in the United States. The older Dewey Decimal system is found primarily in school and public libraries, and the more recent Library of Congress system is used in most academic libraries. Special libraries frequently use their own classification system rather than Dewey or Library of Congress. Often these libraries contain materials on a single topic and a chronological numbering system may be more useful.

The conceptual basis behind both systems is identical: to group books together by subject, and within each subject by author. The Dewey Decimal system uses decimal numbers to classify knowledge, while the Library of Congress system employs a combination of letters and whole numbers. The Dewey Decimal system may present more problems in shelving because of the numbers to the right of the decimal point. It is important to remember that, because these numbers are decimal fractions, a number like .16 is smaller than .9 and will file before the latter. As an example, the Dewey classification numbers below are given in the order in which t hey will appear on the shelves:

581.21 581.21 581.31 581.4 581.498 581.5
D4 E73 A4 A47 R3 J6

Notice that .498 files before .5 because it is the smaller decimal. The second line is a number, also a decimal, used to group items by the same author together. For example:
512 512 512
A37 A4 D26

The Library of Congress classification is arranged first by letters and then by numbers. The third line is the number that, like the second line of the Dewey Decimal Classification, serves to keep material in alphabetical order by author. Notice that the book number in the examples below is treated like a decimal:

L L LA LB LC LC
7 7 96 3063 4701 4701
D47 D5 G5 R71 R19 R2

Circulation staff must train shelvers to understand the classification system used and its relation to shelving materials. Staff who do the shelving must also understand the importance of correct shelving and how it relates to good library service.

Shelving
Materials to be shelved come from several sources:

1. New acquisitions;
2. Circulated materials that have been returned;
3. Materials used in the library and not reshelved by the customers (most libraries, to prevent misshelving, discourage customers from reshelving materials).

The details of shelving operations vary among libraries. Shelvers may bring materials to a central location where they first rough-sort them and then place them in precise order. Larger libraries commonly have sorting areas on each floor. Prior to shelving, books may be sorted on shelves and then filed in exact order on book trucks, or sorted and placed in exact order on the shelves before being loaded onto book trucks. Shelving is a tiring and uninteresting job if performed for too long (one or two hours is about right) and become careless.

Shelf-reading
To maintain the library collection in good order staff must regularly check the order of materials on the shelves. This is called shelf-reading. Shelf-reading is accomplished by scanning the shelves and reading the call numbers on the material to see that each item stands on the shelf in proper order. A collection with material out of order is difficult to use; trying to locate misshelved items wastes a lot of customer and staff time.

As the clerk or student assistant reads the shelves, misshelved items are placed in correct order and items are straightened on the shelves. The shelf reader also sometimes shifts books from one shelf to another to alleviate overcrowding. The employee also looks for damaged materials and loose or defaced labels and removes this material for repair.

The support staff and librarians do little shelf-reading, except to check or revise the work of new personnel. The supervisor will establish schedules to ensure that the collection is shelf-read at regular intervals. Some of the more heavily used parts of the collection require frequent shelf-reading, while other parts of the collection may need to be checked only occasionally. Staff must be familiar with circulation patterns and shelf-reading statistics to identify the more heavily used parts of the collection.

As may be surmised, shelf-reading is tedious work. Shelf readers can maintain the concentration needed for accuracy for only about one or two hours at a time. When scheduling personnel for this work, the supervisor must consider these limitations.

Collection growth and shifting
As the library adds materials to its collection the shelves in some areas become full. When this happens the shifting of materials is necessary to permit further growth. A section of shelving is considered full, for practical purposes, at about 75 percent capacity. At this point, shelvers will frequently have to move books from shelf to shelf to create needed space. When shelves become full, the shelvers should report this to the person responsible for stack maintenance. Also, staff members who are responsible for stack maintenance should check the shelves regularly for crowded areas. Books should never be shelved tightly because damage is sure to result.

A book shift may involve moving only a few shelves of books or it may require the movement of several stack ranges. The less space for growth a library has, the more shifting is necessary to move the existing space where it is needed. Libraries running out of shelf space may need to shift substantial portions of their collection every year, at considerable cost, or resort to remote storage of a portion of their collection.

The library collection is not arranged randomly; it requires considerable planning by the librarian. In formulating such plans, the librarian may consider the following:

1. placing frequently used materials in accessible places;
2. keeping related materials together;
3. placing little-used materials where they do not occupy the most valuable floor space;
4. arranging materials logically on each floor so customers are able to find them with as little trouble as possible.

Shifting, too, requires a great deal of planning. When planning a shift, staff must consider collection growth rates, understand the nuances of shelving patterns, make sure that the workers performing the shift have received adequate training in shifting and handling techniques, and perform accurate measurements on the portion of the collection to be shifted to guarantee that the shift is successful. Although it is the librarian who makes shelving decisions, the paraprofessional often plans and carries them out and must be aware of the rationale behind the decisions. The support staff should be alert for shelving problems, and staff should report these problems to the librarian with recommendations for their solution.

Evans, G. Edward, Amodeo, Anthony J., and Carter, Thomas L. Introduction to library public services. 6th ed. Greenwood Village, CO : Libraries Unlimited, 1999, pp. 236-241.