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Public libraries can be differentiated from academic, school, and special libraries because they function to serve the needs of a diverse service population including small children, students, professionals, and the elderly. In contrast, academic libraries serve college and university faculty and students; school libraries serve elementary, middle, and high school students and faculty; and special libraries (such as Presidential Libraries) serve scholars and experts within narrowly defined fields.
A. Types of Spaces
There are seven broad types of public library space:
- Collection space (including public electronic workstation space)
- User seating space
- Staff work space
- Meeting space
- Special use space
- Non-assignable space (including mechanical space)
Careful analysis of the following will allow designers to determine the space needs for the seven general spaces listed above, which are common to public libraries:
- Identification of the library's population of users
- Estimation of the collections provided by the library and the space needed to accommodate those provisions to meet the future needs of its users
- Estimation of floor space needed to accommodate seating areas
- Estimation of floor space needed by staff
- Estimation of floor space needed for meeting rooms
- Estimation of miscellaneous public- and staff-use space (special use space)
- Estimation of space needed for entry halls, mechanical rooms, bathrooms, etc. (non-assignable space).
B. Determining the Building's Attributes
The following steps can be used to determine the library's general building attributes. The steps below do not assess exterior space needs such as parking and site amenities, which vary widely depending on site selection as determined in the library program.
Step 1: Determine the Service Population
A projection of the needs of the design (service) population for 20 years is the start of the library design process. This design projection will allow the library to serve the future needs of its population of users and allows the designer to determine the space needed for the preceding categories of library spaces.
Population estimates can be gathered from local municipalities, county, or regional planning commissions, or from a state's Office of Policy and Management. Since most public libraries serve residents of outlying communities, it is important to include the effect that non-resident use will have on library space allotments.
Step 2: Determine Needs for Collection Space
Since the needs of the design population are projected over 20 years, the collection size must also respond to the 20-year projection, i.e., collection space must be projected over a 20-year period. In addition, public libraries should have a "weeding policy" whereby outdated material is omitted from collections. This will allow additional space for future expansion.
The number of volumes of books, non-print materials (music CDs, audio books, etc.), and periodicals that are maintained by the library can change from 5 to 25 volumes per square foot depending on shelf height, aisle width, and the kind of material, whether it's magazines or encyclopedias.
Calculate Space Needs for Books—As a general rule of thumb, to estimate the square footage of book storage space (with aisles at least 36 inches wide) divide the total projected number of volumes by 10. The square footage needed for compact book storage is equal to the total projected collection divided by 25. For example, if the total projected collection over 20 years is 50,000 volumes, 50,000 divided by 10 equals 5,000 square feet needed to house the projected collection.
Calculate Space Needs for Non-print Items—To determine the square footage necessary to store non-print material, divide the total number of non-print items projected over 20 years by 10. For example, if the projected non-print items over 20 years equals 20,000, then 20,000 divided by 10 equals 2,000 square feet of space needed for non-print items over a 20–year period.
Calculate Space Needs for Periodicals—Use the following formula to determine space needs for periodicals. Divide the number of current periodicals that will be maintained by the library by 1.5. That number equals the space in square feet needed to house the current periodicals. Multiply the number of back issues of periodicals that will be kept in the library by 0.5. Multiply that number by the average number of years the periodical will be maintained in the library. That result is the space needed to house back issues. For example, if there are 100 current periodicals, then 100 divided by 1.5 is 67 square feet of space needed for current periodicals. If the library will house 40 back issues of each title for 5 years, then 40 divided by 0.5 multiplied by 5 years equals 100 square feet of space need for back issues of periodicals. The square footage needed for current periodicals (67) plus the square footage needed for back issues (100) equals the total square footage needed for periodicals over a 20–year period.
Obviously, the recommended size of a library's collections (including the number of electronic workstations needed—see Step 3), will determine how much floor space is needed for the collections. Some state library agencies or state library associations issue standards that provide guidance in determining the appropriate collection size. Also note the recommendations regarding recommended planning processes for public libraries, issued by the Public Library Association, a division of the American Library Association.
Step 3: Determine Space Needs for Electronic Workstation Space
Work/study desks and tables in the primary library space and in meeting rooms must provide connections for computers and other devices that utilize two-way communication services, such as the Internet.
Calculate Space Needs for Public Access Computer Stations (PACs)—PACs consist of a computer terminal (monitor and hard drive), keyboard, and access to a printer. A PAC station used from a seated position requires at least 40 square feet. A PAC station used from a standing position requires at least 20 square feet. PACs can by placed anywhere in the library. For example, a PAC that can be used by a standing person can be placed near the entry area and can function only to direct users to particular spaces in the library depending on the users' inputted needs.
Calculate Space Needs for Computer Workstations—As an alternative, or in addition to PACs, libraries can provide electronic workstations equipped with two-way communication system hook-ups to accommodate users with their own computer equipment. A space of 75 square feet can be used as a general average for each computer workstation.
Calculate Space Needs for Microfilm or Microfiche Workstations—A general rule of thumb is 35 square feet for each microfilm or microfiche workstation.
Step 4: Determine Space Need for User Seating
In general, public libraries should provide at least 5 seats for every 1,000 users in its service population. As a guide, public libraries that serve no more than 10,000 users should accommodate 7 to 10- seats for every 1,000 users. These guides do not include the seats needed in meeting rooms or staff areas. The number of seats can be adjusted depending on the library. For example, if the library is one that encourages long-term use, i.e., extensive collections of research materials, then the number of seats should be inflated. If the library encourages browsing, i.e., latest magazines or best sellers, the number of seats needed may be less.
Calculate Square Footage Needs for User Seating—The square footage needed for user seating varies depending on the type of seating, i.e., lounge chair, table seating, etc. As a general rule of thumb, for table seating use 25 square feet per seat; for study carrel seating use 30 square feet per seat; and for seating in lounge chairs use 35 square feet per seat. As a general average, designers can use 30 square feet per seat.
To determine total square footage necessary for user seating, subtract the number of PAC and electronic workstation seats and meeting and conference room seats (if these rooms are used only for meetings and conferences) from the projected number of total seats. That number multiplied by 30 is the projected square footage needed for user seating.
Step 5: Determine Space Needs for Staff Work Areas
Staff space should include space for computers for online access to outside resources. Staff workloads and the number of library staff at each area where library services are provided, i.e., reference desk, circulation desk, multimedia stations, are important in determining the space needed for staff. Office space for library administrators and staff-only areas (such as staff lounges or staff eating areas) is an important part of staff space.
- Calculate Space Needs for Staff Work Areas—On average, the space needed for staff work areas is approximately 150 square feet per work area. Some work areas may be larger than others. For example, check-out areas may require more square footage than help-desk areas. As a general rule of thumb, the square footage allotment for staff work areas equals the number of projected staff areas multiplied by 150.
Step 6: Determine the Space Needs for Meeting Rooms
Many public libraries incorporate meeting space for library- and community- sponsored meetings or events. Meeting rooms also serve as staff or library patron training space. Depending on the library's function as determined in the library program, Internet connections and other two-way communication system outlets may be necessary.
- Calculate the Space Needs for Meeting Rooms—There are two types of seating arrangements common in public library meeting rooms: theater seating and conference room seating. For theater, or lecture hall, seating arrangements, the projected square footage needed in the meeting room equals the number of seats multiplied by 10. For conference room seating, the projected square footage needed equals the number of seats multiplied by 25. The square footage needed in meeting rooms targeted for children's activities will require 10 square feet per seat. Meeting room space does not include other square footage necessary for other peripheral spaces including a kitchen area in or nearby the meeting room and storage areas for audiovisual equipment, chairs, tables, etc.
Step 7: Determine Space Needs for Special-Use Areas
The need for special-use spaces (such as a history or genealogy room, a job center, or a community information area) will vary depending on the function of the library as determined in its written program.
- Calculate Space Needs for Special-Use Areas—Some special-use spaces and their required square footage are included in the table below.
|Items In Special-Use Areas*||Square Footage Required per Item|
|*The items listed are for example and are an abbreviated list of items that may be included in the special-use space. Depending on the role of the library as determined in the program, the number of items and the number of special-use areas may vary.|
Step 8: Determine Space Needs for Non-Assignable Areas (such as Mechanical Rooms)
Non-assignable spaces are important for the general operation of the library facility but they are not a direct part of the services offered by the library. These spaces include mechanical rooms, bathrooms, entrance halls, corridors, stairs, security rooms, and elevators. These non-assignable spaces make up 20% to 30% of gross floor area of the library.
Computer technology continues to affect the way libraries function and, as a result, the way they are planned and designed. As a result, the electric and wiring needs of modern-day public libraries must accommodate changing technology. Today, public libraries must be able to support wired and wireless connections to digital communications from networks within and from outside the library. Outside digital communication systems include the Internet, area networks, public telephone networks, and networks accessed through digital service providers (such as cable companies) that utilize copper wire, cable, wireless, or fiber-optic capabilities. See also WBDG Productive—Integrate Technological Tools.
The recommended wiring capability of modern public libraries is Category 5 (CAT 5) wiring optimized for 1,000BASE–T using RJ45 connectors. Exterior-mounted satellite dishes may also be a consideration in some library programs.
Circuits and electrical outlets should be plentiful so that changing technology can be supported. Dedicated circuits for computers and surge protection for electronic workstations and PACs should be incorporated into the design of library spaces.
Another emerging technology—radio frequency identification (RFID)—is coming to the library market in the form of charging and security systems that are easier to configure into patron self-service stations, allowing some libraries to radically reconsider the organization of functions at the entry. Some public libraries that have adopted RFID-based patron self-charge systems have been able to position circulation functions—traditionally in a prominent entry location—to the sides, allowing a newly-prominent information desk to become the centerpiece of the library's entry. This in turn changes the patron's experience of the entry and the character of the space.
Still other libraries-notably the recently—opened Seattle Public Library—are using wireless communications technologies to allow library staff members to roam through the stacks and reader seating, without being bound to a reference desk, the better to provide support to patrons at the point of contact.
Sustainable design should be a part of every library program so that the building can function efficiently without wasting energy during its lifetime. Below is a checklist to ensure that public libraries incorporate sustainable design. See WBDG Sustainable Branch for more guidance on sustainable design.
Is the building designed and constructed in ways that preserve the natural outdoor environment and promote a healthful indoor habitat?
Is the building designed to avoid adversely impacting the natural state of the air, land, and water, by using resources and methods that minimize pollution and waste?
Is the building designed to maximize passive and natural sources of heating, cooling, ventilation, and lighting? See WBDG Passive Solar Heating, High–Performance HVAC, Natural Ventilation, and Daylighting.
Are innovative strategies and technologies employed such as porous paving to conserve water, reduce effluent and run-off, thus recharging the water table?
Is the project planned to reduce the need for individual automobiles, use alternative fuels, and encourage public and alternate modes of transportation?
Is the building constructed and operated using materials, methods, and mechanical and electrical systems that ensure a healthful indoor air quality while avoiding contamination by carcinogens, volatile organic compounds, fungi, molds, bacteria, and other known toxins?
Are the HVAC system's outdoor air intakes located as high as possible above the ground and far enough away from the exhaust ducts to reduce the intake of ground level air pollution?
Are stainless-steel-strip bird guards installed over the horizontal rooftop outdoor air intakes to prevent birds from settling on the grating and polluting the shafts below?
Does the HVAC have an efficiency air filtration system with pre-filters and final filters at 30 % and 85% efficiency respectively?
Are air filters designed to be easy to access and clean and/or replace? See WBDG Sustainable O&M Practices.
Has the exposed fiberglass within the HVAC system been encapsulated to eliminate amplification sites for fungal and bacterial micro-organisms?
Is the rate of ventilation with outdoor air at least 25 cubic feet per minute?
Are copy rooms and similar spaces that emit possibly toxic substances equipped with their own dedicated air exhaust systems?
Is particleboard that emits formaldehyde emissions prohibited in the building? See Evaluating and Selecting Green Products.
Is furniture constructed without particleboard that emits formaldehyde? See WBDG Evaluating and Selecting Green Products.
Are only solvent-free paints specified for the project? See WBDG Evaluating and Selecting Green Products.
Relevant Codes and Standards
Model Building Codes that may apply include the following (check with local building departments for code requirements):
Note: Some states have their own state-written building codes. In addition, some localities have their own local codes. State and local building departments are the best resource for applicable codes.
- Americans with Disabilities Act (ADA)
- American with Disabilities Act Accessibility Guidelines (ADAAG)
- The Design and Evaluation of Public Library Buildings by Nolan Lushington and James M. Kusack. Hamden, CT: Library Professional Publications, 1991.
- Determining Your Public Library's Future Size: A Needs Assessment Planning Model by Lee B. Brawner and Donald K. Beck. Chicago, IL: American Library Association, 1996.
- Library Facility Siting and Location Handbook by Christine M. Koontz. Westport, CT: Greenwood Press, 1997.
- Planning the Small Library Facility, 2nd ed. by Anders C. Dahlgren. Chicago, IL: American Library Association, 1996.
- Public Library Space Needs: A Planning Outline by Anders C. Dahlgren. Wisconsin Department of Public Instruction, Public Library Development, 2009.