Description

Historically, precious handwritten books were stored in boxes or chests and carried near the person of the owner. The printing press brought about an accessibility to books and with common book ownership book titles were written on the spine. Shelves were designed to display these spines. Early shelving was made of wood and often built into the walls of the room itself. This perimeter shelving, prevalent throughout many centuries, has become obsolete since the early 20th century, with Asplund’s City Library in Stockholm one of the last prominent examples. With the introduction of cast iron and subsequently steel, shelves, both perimeter and freestanding, were fabricated of materials that could withstand the required physical loads. A special case were multi-tiered cast iron systems that supported not only the weight of the books but also the floor platforms and even the roof structure, thus making shelving part of the load-bearing structure. The introduction of digital technology in the 1990s unleashed conjectures of future bookless libraries. Despite such predictions digital technology has been integrated into the library without the elimination of the book. Today, the physical collection remains a critical part of the library and the accommodation of the collection a crucial part of library design.

Shelving Systems

Shelving system types are cantilever style, case style, high-density and automated-retrieval. Cantilever and case style are commonly used in all libraries and design requirements refer primarily to these types. High-density and automated-retrieval storage have individual requirements specific to their system. In the U.S., shelving systems are standardized and designs of libraries are based on the availability of pre-determined shelving sizes. In Europe, shelving is often custom-designed.

Shelving systems, be they cantilever or case style, are modular and consist of multiples of a single shelf unit. The dimensions of the single unit (SFU, single-faced shelving unit) as stand-alone or placed back to back with another unit (DFS, double-faced shelving unit) form the basis of the shelving system. Heights depend on the numbers of shelves per unit, with units seven shelves high at typical stacks. In reference areas shelving units may be two to three shelves high. The characteristics of these units impact the design of many different aspects of the library; book capacity, structure, layout, lighting, egress.

Stacks and Layout

A row of shelving units, single-faced or double-faced, makes up a range. Stacks consist of ranges of shelves and the aisles that give access to them. Aisle nomenclature specifies their locations within the shelving layout; side aisles run parallel to the stacks while cross aisles run perpendicular to the side aisles, providing breaks in the side aisles. End aisles are at the end of a group of ranges and may serve single-faced sections against a wall. Main aisles, also perpendicular to side aisles, are a part of major access routes.

As means of egress the characteristics of the aisle – width, height and length – affect the occupant’s health, safety and welfare and must comply with building, safety and accessibility regulations. Optimal shelving layouts use ranges of six to seven double-faced shelving units, although practice permits longer ranges. The length of such a range maximizes the linear continuity of shelving while remaining within comfortable lengths of travel.

While book capacity is important, human comfort is of equal importance in shelving layouts. Repetitive shelving ranges are, in fact, densely positioned walls and, depending on the aisle width and shelving height used, they impact the psychological perception of the space. In heavily trafficked urban libraries, for example, a shelving aisle of minimum width could be perceived as less inviting than a wider one. Similarly, shelving ranges of more than six shelves in length (each shelf at 1.2 m) comply with travel distances but may be perceived as oppressive or even threatening in some situations. Shelving heights (or numbers of shelves per unit height) are determined as a compromise of volume capacity and the atmosphere created by such height. Seven-shelf high shelves are most efficient in terms of book storage, but their height renders the top shelves inaccessible for universal reach. Allowing also for the advantage of organizing oversized volumes within the running order of the collection (requiring greater spacing of the shelves), shelving height in publicly accessible libraries is typically limited to six shelves or even five shelves. While maximum shelving capacity is an issue of economics, the design parameters of aisle widths and shelving lengths and heights are determinants of the atmosphere of a stack area.

Classification Systems

Determined by available space, structure, economy and efficiency, shelving layouts have an impact on the physical placement of books. The need for systems of book location originated in the second half of the 19^th century with the introduction of the open-stack library. Since then, all books had to be identified through a library classification system. While the earliest systems were enumerative for book location, today’s systems are distinguished by different types of order; classification through chronology, subject, geography, language as well as minute subdivisions of such classification. The predominant universal systems include Dewey Decimal Classification, Library of Congress Classification, Universal Decimal System. There are also some nation-specific systems such as Britain’s Bliss Classification, Sweden’s SAB Sveriges Allmanna Bibliotekforening, Germany’s Gesamt-Hochschul-Bibliotheks-Systematik (GHBS), the Colon Classification, used primarily in India, Japan’s Nippon Decimal Classification, Korea’s Korean Decimal Classification, China’s Chinese Library Classification (CLC) and the Russian Library-Bibliographical Classification (LBC). In addition, single subject fields have their own classification systems. For example, the MCS stands for Mathematics Subject Classification or PACS is the Physics and Astronomy Classification Scheme.

A widespread classification system is the Dewey Decimal Classification system (DDC), a system created by Mevil Dewey in 1876. It is most prevalent in the Anglo-American realm and in use in 85 % of all U.S. libraries, in particular public libraries and some smaller academic libraries. This system of classification consists of ten classes; 000- computer science, library and information science and general works, 100- philosophy and psychology, 200- religion, 300- social science, etc. Each class is further divided into divisions; for example, a book on European economy would be labeled 330.94 in which the 100^th’s place denotes social sciences, the 10^th’s place is specific to the subject of economics and the decimals reference geographical location, in this case, Europe. Most research and academic libraries in the U.S. use the Library of Congress (LCC) system of classification developed by Herbert Putnam in 1897 for the Library of Congress, or a similar universal system. Subjects are divided into broad categories that are enumerative. The system uses 21 letters of the alphabet to denote different subjects. For example; B is for philosophy, psychology and religion, K is for law, N for fine arts, etc. Each of these subjects is further divided into subcategories. For example, Class B is divided into B for general philosophy, BC for logic, BD for speculative philosophy, BF for psychology, BH for aesthetics, with each class letter followed by a number sequence. Books are stored and arranged in ascending order according to classification. Repetitive bays of double-faced shelving are conducive to sequential book numbering. LCC-classified books are optimally placed within a shelving layout that permits a consecutive order by section. The Book Spiral at the Seattle Central Library (OMA, 2004), where the DDC classifications were incorporated into the signage system on the floor, is an example of a system in which book classifications and sequencing were considered as part of the design and shelving layout. The use of single-faced shelving, typically placed on walls, maximizes the book capacity of a space but complicates the continuous flow of the numbering sequence.

Shelving Applications

In application, these general principles and dimensions can be and, in fact, are adjusted according to the collection and the user type. Multiples of densely placed shelving bays are most applicable for stacks where storage capacity is a priority and user access limited to book retrieval. This economy of repeated bays of rectilinear shelving cannot be overestimated and is confirmed by its use in the majority of libraries. At the Lewis Library at Princeton University (Frank Gehry, 2008) that is uniquely characterized by curving, sculptural forms, where never­theless orthogonal floor plans and stack shelving plans prevail, providing repetitive and efficient rectilinear bays. Similarly, at Sendai Mediatheque in Japan (Toyo Ito, 2001) economical, orthogonal and repetitive shelving layouts are utilized in a library that is otherwise designed without a repetitive structural grid.

Shelving layouts at TU Delft Central Library (Mecanoo, 1998) are based on the Pareto Principle, a theory that the majority of users use only a small percentage of all available books. With a total collection of almost 1 million items, the TU Delft Library shelving design accommodates the majority of the volumes, i.e. the “less used”, in the closed stacks below ground, while the “most used”, in this case 80,000 volumes, are on display in the general reading room on four-story high, suspended steel frame shelving.

The recommended shelving limits adjust to the needs of different collections and users by variations of range lengths and aisle widths. Stacks, with their storage function, may often be designed with longer ranges while other parts of the library such as the reference or new books area may be designed with shorter lengths and wider aisles suited to frequent use. The many uses of shelving at the Seattle Central Library illustrate this planning concept. At the Book Spiral on floors five to eight, the stacks are densely arranged and repetitive ranges of six and seven shelves (7.2–8.4 m) extend the maximum permissible length. The reference room shelving arrangement in comparison is a classic bay of a five-shelf (6 m) range with generous aisle space that is conducive to the frequent use characteristic of the reference collection. In the Living Room on the second floor, repetitive shelving bays are used in a less structured fashion with ranges of different lengths, arranged in a playful pattern. Such a configuration accommodates fewer books but provides a different atmosphere.

High-density shelving (compact shelving) layouts

2

The alternate option of off-site storage is discussed in: Danuta A. Nitecki, Curtis L. Kendrick, Library Off-Site Shelving: Guide for High-Density Facilities, Englewood, CO: Libraries Unlimited, 2001.

differ from cantilevered or case style shelving primarily in aisle requirements. Based on the concept of moveable ranges, high-density shelving slides on a system of tracks. With this mobility, shelving ranges are placed immediately next to one another without individual aisles. Groups of ranges share a track system that includes the accommodation for a single aisle. When access is required at a particular range, the ranges move apart, manually or electronically, creating an egress aisle where needed. With this system, the space requirements are half that of regular shelving.

1

“Description of Shelving Options”, University of Chicago Library Shelving Additions, University of Chicago Board of Trustees, May 11, 2005, p. 3.

Due to the density of the shelves, however, the floor loads are doubled and require additional structural support. The limits of the range lengths are the same as with cantilevered shelving. At Viana do Castelo Public Library in Portugal (Alvaro Siza, 2007) different lengths of ranges correspond to the different uses of the shelves from conservation to storage of periodicals.

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Originally published in: Nolan Lushington, Wolfgang Rudorf, Liliane Wong, Libraries: A Design Manual, Birkhäuser, 2016.