Within This Page
The Basement Parking space type refers to parking located below grade within an occupied building. As defined for the WBDG, the Level of Service (LOS) (refer to Architectural Graphic Standards, 10th Edition, page 106) of the Inside/Basement Parking is LOS B, indicating use by some unfamiliar users, moderate daily turnover, and medium percentage of small cars and light trucks; and requiring one-way aisles of 11'-0" straight-ways and 13'- 6" turns. See also WBDG Parking Structure.
All parking structures—whether basement, structured, or surface—must provide for the safe and efficient passage of automobiles and visitors to and from their vehicles. Therefore, attention should be given to providing the maximum driver visibility possible at all turning points along the roadway. While Federal Courthouses have Inside/Basement parking for only the judges and Marshals Service, it is typical beneath Office Buildings for building occupants and visitors as well. Typical features of the Parking: Basement space type include the list of applicable design objectives elements as outlined below. For a complete list and definitions of the design objectives within the context of whole building design, click on the titles below.
- Parking Spaces and Entrances: Accessible parking spaces must be provided for each parking structure associated with the building and calculated separately. At least one of every 6 accessible spaces, or fraction of 6, in each parking facility must be sized to accommodate vans. Accessible spaces must be dispersed among accessible entrances and be located on the shortest route to the entrances that they serve. (There are variations to the rules depending on the building type. See the U.S. Access Board for more information.)
- Finishes: Incorporate slip-resistant finishes to meet accessibility requirements.
- Signage: The international symbol of accessibility must be placed in front of the parking spaces mounted at least five feet above the ground, measured to the bottom of the sign. Van accessible spaces include the designation "van accessible".
- Materials and Colors: Parking is as much of a destination as the building. Drivers are trying to locate the parking garage and the best way to enter it. Aesthetics play an important role in how the overall building and the companies/organizations within it are perceived. Care and attention should be given to the colors and materials used in the space to create a feeling of safety and ease of access. Durable materials and finishes should be used to maintain the appearance of the space.
- Graphics: Incorporate visually interesting and informative graphics to relay messages about directions, activities, and events within the building.
- Life Cycle Analysis: Incorporate materials, products, and systems that meet long-term life-cycle performance goals to reduce operations and maintenance costs.
- Maintenance: Care and maintenance of the parking structure should be part of the plan to keep the aesthetic value and prolong its service life.
- Plan for Additional Uses: Design parking for future adaptations into spaces such as offices or apartments, which will generate additional revenues. Consider renting out unused parking spaces to nearby tenants to share costs and also generate additional revenue. Consider developing near mass transit if building a new structure or even renovating an existing structure to save costs and promote alternative forms of transportation.
Functional / Operational
- Additional Structural Requirements: Below grade extension of the building structure to accommodate basement parking is required. This involves additional excavation, structural frame, floor slabs above, sloped vehicle access ramps, and basement perimeter walls and partitions separating parking from other building enclosed areas. Typical structural floor construction is 4000 PSI 6" concrete slab with welded wire fabric designed for a live load of 80 LBS/SF, and with a ramp slope of no more than 5.5%.
- Space Allocation: An average garage requires three to six times more square feet than the actual dimension of a car to accommodate drive aisles, ramps, and standard parking space dimensions. Land costs continue to rise, while the availability of space is becoming scarce. Consider incorporating lift technology or automated parking systems where land and space are at a premium. This can reduce the amount of needed square feet as well as save on construction costs and overall operating costs.
- Signage and Wayfinding: Signage should indicate all major internal pedestrian access points as well as external major roads and buildings. In basement parking, pavement markings are reflective paint and traffic control signage is usually reflective metal with minimum 5" high letters. The Manual on Uniform Traffic Control Devices for Streets and Highways (ANSI D 6.1e) provides guidance on pavement marking and signage.
- Ventilation: The parking area is generally supplied with unconditioned air utilizing multiple speed fans, preferably interlocked with carbon monoxide detectors tied into an alarm system. 1-1/2 CFM per square foot capacity and 100% exhaust air coordinated with the supply air system is recommended.
- Parking Management: Pre-manufactured booths with transaction windows and deal trays can be installed at vehicular entrances/exits to manage entering and exiting vehicles. A cooling system, like a packaged terminal air conditioner (PTAC), is usually incorporated to supply the booth with outside air at a positive pressure relative to surrounding parking areas. Additionally, consider implementing electronic entry and exit machines, making it easier for users to self-park and pay. This is an excellent way to track garage traffic user patterns and manage money more effectively and safely.
Secure / Safe
- Security Protection: Beyond parking management, several security measures are incorporated into typical basement parking spaces to ensure the security of visitors. These generally include: uniform lighting coverage, preferably with energy-efficient light fixtures; closed circuit television (CCTV) cameras; card reader access control for vehicle entrance doors; concrete filled protective bollards to protect vehicle entry keypads; and hydraulic lift wedge type barriers for egress control. Also critical is security control of access from the parking area to other occupied areas of the building either through termination at a security screening in the main lobby or through access control at the elevator or stair entrance. Elevator lobbies are usually tempered safety glass panels with glazed exterior doors containing keyed lever lockset with panic release bar. See also WBDG Secure /Safe—Security for Building Occupants and Assets.
- Fire and Life Safety: Proper notification systems, lighting, and signage are required to facilitate safe and speedy evacuations during an emergency in the basement parking spaces. This is usually accomplished with proper fire alarm wiring, pull stations, strobes, annunciators, and exit signage. In addition, exposed pipe sprinkler system is extended into the basement parking, with a hose bib at every level. See also WBDG Secure / Safe—Fire Protection.
- Drainage and Storm Water Management: Water runoff from vehicles is typically dealt with in basement parking spaces by installing trench drains with cast iron covers at all vehicle entrance/exit points, sand and oil traps at all storm drain discharge points, and floor area drains at every low point.
- Lighting: Incorporate energy efficient lighting and lighting controls into the parking areas, entrances, and exits to improve lighting levels while also reducing energy use.
- Parking Priorities: Plan for and provide priority parking for hybrid cars and electric vehicles (EV). Also provide EV charging stations to contribute to the adoption of EVs. Many cities are requiring buildings with parking to be EV ready, meaning that wiring and conduits are built into the structure, even if charging stations are not.
- Construction Materials: Use durable and sustainable materials with a reduced carbon footprint or that are locally procured and/or recyclable. Consider the material life cycle in the decision-making process in order to reduce the production and consumption of new materials.
- Indoor Environmental Quality: Use natural ventilation, heat recovery, and other sustainable technologies whenever possible. Using exhaust sensors to automatically turn fans on and off can reduce fan runtime, which will reduce energy consumption without reducing air quality.
The following is representative of a plan of a basement garage located in a high-rise office building.
Relevant Codes and Standards
- GSA PBS-P100 Facilities Standards for the Public Buildings Service
- ICC IBC International Building Code
- Lighting Energy Efficiency in Parking (LEEP) certification: Offered by The US Department of Energy, LEEP enables facility owners and managers to take advantage of savings opportunities from high-efficiency lighting solutions in their parking facilities.
- Parksmart: The Green Parking Council's Green Garage Certification is a way for parking lot owners and operators to back-check their parking structure sustainability.
- Sustainable Sites Certification
- UFGS 32 17 24.00 10 Pavement Markings
- US Access Board: ADA Guidelines: Chapter 5, Accessible Parking Requirements
- US Green Building Council LEED Rating System
- Architectural Graphic Standards, 12th Edition by The American Institute of Architects, Dennis J. Hall. New York, NY: John Wiley & Sons, Inc., 2016.
- Guide to FEMP-Designated Parking Structure Lighting by the Federal Energy Management Program. Washington, DC: FEMP, March 2013.
- High-Efficiency Parking Lighting in Federal Facilities Case Study of Camp Pendleton by the U.S. Department of Energy.
- Low Energy Parking Structure Design by the National Renewable Energy Laboratory (NREL). Golden, Colorado: NREL, January 2013.